ALBERT

Description: The new genus Lianus of subfamily Doryctinae (Hymenoptera: Braconidae) is described and illustrated. The differences from other genera of Doryctinae are discussed. Both included species originate from the Atlantic forest at Campos do Jordão, São Paulo State, Brazil.

Description: A new species of the genus Artocella van Achterberg is described from Spain. On the basis of its substantial sexual dimorphisim, the differences between the two previously known species of this Turanian-Mediterranean genus, which had each been described from specimens of only one (and differing) sex, are reassessed.

Description: Dasypoda intermedia spec. nov. from Iran is described. Its description fills a gap of our knowledge of the East Mediterranean fauna of the genus Dasypoda. The West Mediterranean Dasypoda species are well known but the eastern species lack convincing records. Moreover, D. intermedia spec. nov. is a very interesting species from a phylogenetic point of view. It shares some characters common to subgenera Dasypoda s. str. and Megadasypoda Michez, 2004, which provide further evidence for the close relationship of both subgenera.

Description: The Pterophoridae (Ochyroticinae, Deuterocopinae, Pterophorinae (Tribus: Platyptiliini, Exelastini, Oxyptilini)) species of the Neotropical fauna are reviewed. The species are redescribed. Moths are illustrated in colour for the first time, their genitalia are illustrated in line drawings. The examination of type specimens revealed the presence of four new synonyms: Platyptilia juanvinas Gielis, 1999, is a junior synonym of Platyptilia gravior Meyrick, 1932; Platyptilia jonesi Gielis, 1996, is a junior synonym of Platyptilia semnopis Meyrick, 1931; Oxyptilus maleficus Meyrick, 1926, is a junior synonym of Leptodeuterocopus neales (Walsingham, 1915); Lioptilus parvus Walsingham, 1880, is a junior synonym of Lioptilodes albistriolatus (Zeller, 1871). During the study of much new material 40 new species were discovered: Leptodeuterocopus tungurahue, L. angulatus, L. panamaensis, L. duchicela, Sochchora mulinus, Melanoptilia nigra, Platyptilia spicula, Stenoptilodes maculatus, S. agricultura, S. heppneri, S. medius, S. altiaustralis, Postplatyptilia nebuloarbustum, P. antillae, P. caribica, P. uruguayensis, P. pluvia, P. seitetazas, P. transversus, P. carchi, P. boletus, P, ugartei, P. drechseli, P. corticis, P. zongoensis, P. vorbecki, Amblyptilia landryi, A. kosteri, Lioptilodes altivolans, L. arequipa, L. yungas, L. salarius, L. cocodrilo, Michaelophorus margaritae, M. bahiaensis, Geina integumentum, Capperia browni, Buckleria brasilia, Megalorhipida paraiso, M. dubiosa. In the larger genera the species are arranged in groups. For a distinct group of species a new genus: Melanoptilia is proposed. A comprehensive checklist of the species has been made. To facilitate identification a key is presented to the genus level.

Description: A bibliography of the family Braconidae/Hymenoptera: Ichneumonidae is given for the period 1964-2003. It is an addition to Shenefelt's bibliography (1965), which covers the period 1785-1963. In total 10,436 references are listed.

Description: The European species of the genus Helorus Latreille, 1802, are keyed and illustrated, with special reference to their distribution in The Netherlands. Three of the four European species are newly reported for The Netherlands. The description of a new species from Sulawesi (Indonesia) is added: H. celebensis spec. nov.

Description: Two new genera of Entedoninae are described from Afrotropical region. The genus Janicharis gen. nov. (type species: J. africana spec. nov.) is described from Cameroon, Nigeria and Madagascar. The genus Hakuna gen. nov. (type species: H. matata spec. nov.) is described from Uganda. Both genera have a rather characteristic habitus and a peculiar propodeum bearing large anterolateral strips. A new, but yet unnamed, species of the genus Trisecodes Delvare & LaSalle, 2000, is recorded from Cameroon. This is the fi rst Afrotropical record of this genus, originally described from the Neotropical region.

Description: Thirty-one species of the family Platystictidae of the Philippines are revised, i.e. all species recognised, excluding the species of the Drepanosticta halterata-group. The following new taxa are described: 16 species in Drepanosticta Laidlaw: D. acuta spec. nov., D. aurita spec. nov., D. centrosaurus spec. nov., D. clados spec. nov., D. flavomaculata spec. nov., D. furcata spec. nov., D. hermes spec. nov., D. krios spec. nov., D. luzonica spec. nov., D. malleus spec. nov., D. myzouris spec. nov., D. paruatia spec. nov., D. pistor spec. nov., D. quadricornu spec. nov., D. rhamphis spec. nov., D. trachelocele spec. nov., two in Protosticta Selys, viz. P. lepteca spec. nov. and P. plicata spec. nov., and three in Sulcosticta gen. nov., viz. S. striata spec. nov., S. pallida spec. nov. and S. viticula spec. nov. The status of eleven previously described nominal taxa is established. One, D. septima Needham & Gyger, is doubtfully considered a synonym of D. mylitta Cowley. Based on a preliminary phylogenetic analysis, the species of Drepanosticta are divided into informal species groups. Most species of the Philippines have affinities to species of Sulawesi, the Moluccas and New Guinea. Several species confined to Palawan have sister-group relationships with species from Borneo. The affinities of various other species confined to the Sulu archipelago, are unsettled as yet. The species of Platystictidae here assigned to Protosticta Selys are presumably not closely related to the type species, P. simplicinervis Selys from Sulawesi. However, a better placement has to await a more detailed phylogenetic study of the family. For three species the new genus Sulcosticta gen. nov. is erected. These species are closely allied based on the structure of the appendages, but should have been assigned to different genera if based on the present generic definitions. Many species here described have small distributional ranges, a common phenomenon in Platystictidae. Since most forests in the Philippines are heavily under threat or have already disappeared in the last fifty years, several taxa described in this paper should be considered under threat of immediate extinction.

Description: In this part the remaining 78 species of the genus Pepsis, belonging to ten species-groups, are described and figured, and their phylogenetics and biogeography are discussed. 14 of the species are described as new: P. achterbergi spec. nov., P. adonta spec. nov., P. boharti spec. nov., P. caliente spec. nov., P. dayi spec. nov., P. esmeralda spec. nov., P. ianthoides spec. nov., P. jamaicensis spec. nov., P. krombeini spec. nov., P. martini spec. nov., P. multichroma spec. nov., P. nanoides spec. nov., P. wahisi spec. nov., and P. willinki spec. nov. Three species-names, P. infuscata Spinola, 1841, P. lampas Lucas, 1895, and P. thoreyi Dahlbom, 1845, are recalled from synonymy. The following 293 names are newly synonymized (the valid names are listed first): P. atalanta Mocsáry, 1885 = P. nitens Mocsáry, 1894, P. mocsaryi Lucas, 1895; P. inclyta Lepeletier, 1845 = P. mutabilis Lepeletier, 1845, P. vagabunda Lepeletier, 1845, P. cupripennis Taschenberg, 1869, P. violaceipennis Mocsáry, 1885, P. clotho Mocsáry, 1888, P. spengeli Mocsáry, 1888, P. sickmanni Mocsáry, 1888, P. nireus Mocsáry, 1894, P. atrovirens Lucas, 1895, P. cerastes Lucas, 1895, P. pygidialis Brèthes, 1908, P. guaranitica Brèthes, 1908, P. parca Lucas, 1919, P. atahualpa Banks, 1946, opimicornis, Haupt, 1952, atropos, Haupt, 1952, azurea Haupt, 1952; crassicornis Mocsáry, 1885 = P. sappho Brèthes, 1908, P. nitocris Brèthes, 1908, P. vivida Brèthes, 1908, P. arechavaletai Brèthes, 1908, P. lynchii Brèthes, 1908, P. operosa Brèthes, 1908, P. ataraqua Banks, 1946, P. splendida Haupt, 1952; P. sommeri Dahlbom, 1845 = P. azteca Cameron, 1893; P. xanthocera Dahlbom, 1843 = P. nigrescens Smith, 1855, P. fulgidipennis Mocsáry, 1885, P. juno Brèthes, 1908, P. ismare Banks, 1946, P. nigroprasina Haupt, 1952; P. seifferti Lucas, 1895 = P. cornuta Lucas, 1895, P. moebiusi Lucas, 1895, P. stygia Lucas, 1895; P. luteicornis Fabricius, 1804 = P. strenua Erichson, 1848, P. tinctipennis Smith, 1873, P. citreicornis Mocsáry, 1894, P. venosa Banks, 1945, P. alector Banks, 1946; P. asteria Mocsáry, 1894 = P. luridicornis Brèthes, 1926; P. convexa Lucas, 1895 = P. humeralis Brèthes, 1914; P. helvolicornis Lucas, 1895 = P. bahiae Brèthes, 1914; P. vitripennis Smith, 1855 = P. obscura Lepeletier, 1845, P. amabilis Mocsáry, 1885, P. centralis Cameron, 1893, P. margarete Lucas, 1895, P. venezuelae Kaye, 1913, P. aeneipennis Banks, 1946, P. helenae Haupt, 1952, P. coeruleoviridis Haupt, 1952; P. fumipennis Smith, 1855 = P. pallidicornis Mocsáry, 1885; P. amyntas Mocsáry, 1885 = P. vicina Lucas, 1895, P. clarinervis Brèthes, 1908, P. amyntoides Lucas, 1919, P. eurydice Lucas, 1919; P. dimidiata Fabricius, 1804 = P. vittigera Lucas, 1897, P. argentina Brèthes, 1908, P. sanctaeannae Brèthes, 1908, P. virgo Brèthes, 1908, P. externa Brèthes, 1908, P. transversa Brèthes, 1908, P. cordubensis Brèthes, 1908, P. banghaasi Lucas, 1919; P. menechma Lepeletier, 1845 = P. elegans Lepeletier, 1845, P. dubitata Cresson, 1867, P. prismatica Smith, 1855, P. advena Mocsáry, 1885, cinctipennis Mocsáry, 1885, P. guatemalensis Cameron, 1893, P. nestor Mocsáry, 1894, P. nigricornis Mocsáry, 1894, P. auranticornis Lucas, 1895, P. fruhstorferi Lucas, 1895, P. concolor Lucas, 1895, P. cerberus Lucas, 1895, P. euchroma Lucas, 1895, P. nigrocincta Lucas, 1895, P. mordax Lucas, 1895, P. inermis Fox, 1898, P. roberti Brèthes, 1908, P. janira Brèthes, 1908, P. cultrata Brèthes, 1908, P. novitia Banks, 1921; P. decipiens Lucas, 1895 = P. similis Lucas, 1895; P. minarum Brèthes, 1914 = P. pulchra Brèthes, 1914; P. basifusca Lucas, 1895 = P. angustimarginata Viereck, 1908; P. chrysoptera Burmeister, 1872 = P. exigua Lucas, 1895, P. smaragdinula Lucas, 1895, P. nebulosa Lucas, 1895, P. karschi Lucas, 1895, P. anisitsii Brèthes, 1908, P. indistincta Brèthes, 1908, P. dimidiatipennis Brèthes, 1908, P. chloroptera Brèthes, 1908, P. culta Brèthes, 1908, P. recta Brèthes, 1908, P. tornowii Brèthes, 1908, P. schrottkyi Brèthes, 1908, P. itinerata Brèthes, 1908, P. miniata Brèthes, 1908, P. spegazzinii Brèthes, 1908, P. paulistana Brèthes, 1914, P. chloe Brèthes, 1914, P. coronaria Brèthes, 1914, P. semilucana Haupt, 1952, P. bruneipes Haupt, 1952, P. brachynotus Haupt, 1952, P. diagonalis Haupt, 1952, P. discrepans Haupt, 1952; P. elongata Lepeletier, 1845 = P. purpurascens Smith, 1855, P. fuscipennis Smith, 1873, P. longula Banks, 1946; P. australis Saussure, 1867 = P. centaurus Lucas, 1897; P. cyanescens Lepeletier, 1845 = P. micans Mocsáry, 1885, P. jucunda Mocsáry, 1885, P. balloui Banks, 1946, P. diversa Haupt, 1952; P. lampas Lucas, 1895 = P. venturii Schrottky, 1902; P. nitida Lepeletier, 1845 = P. lucidula Smith, 1855, P. vaualba Smith, 1855, P. pruinosa Mocsáry, 1894, P. cylindrica Lucas, 1895, P. andina Brèthes, 1908, P. dilatata Brèthes, 1908, P. holmbergi Brèthes, 1908, P. concava Brèthes, 1908, P. ephebus Brèthes, 1908, P. vaga Brèthes, 1908, P. fuscobasalis Brèthes, 1908, P. cordata Brèthes, 1914, P. impatiens Brèthes, 1914, P. tricolor Brèthes, 1914, P. joergenseni Brèthes, 1914, P. cleone Brèthes, 1914, P. dorsata Brèthes, 1914, P. aretheas Brèthes, 1914, P. lassonis Lucas, 1819, P. consors Banks, 1946, P. interrupta Banks, 1946, P. analis Haupt, 1952; P. seladonica Dahlbom, 1843 = P. deuteroleuca Smith, 1855, P. kohli Lucas, 1895, P. venezolana Brèthes, 1908, P. burmeisteri Brèthes, 1908; P. cybele Banks, 1945 = P. weberi Banks, 1946; P. thoreyi Dahlbom, 1845 = P. lurida Lucas, 1895, P. euterpe Brèthes, 1908; P. flavescens Lucas, 1895 = P. periphetes Lucas, 1895, P. limbatella Brèthes, 1908, P. discoidalis Brèthes, 1914, P. limbatica Brèthes, 1914, P. militaris Brèthes, 1914, P. cavillatrix Haupt, 1952, P. arcuata Haupt, 1952, P. recterugosa Haupt, 1952, P. adversatrix Haupt, 1952; P. nigricans Lucas, 1895 = P. troglodytes Brèthes, 1908; P. montezuma Smith, 1855 = P. quitonensis Packard, 1869, P. sibylla Mocsáry, 1885, P. circe Mocsáry, 1885, P. occidentalis Cameron, 1893, P. peruanus Lucas, 1895, P. fulva Lucas, 1895, P. nessus Lucas, 1895, P. fusca Lucas, 1895, P. andicola Cameron, 1903, P. chilloensis Cameron, 1903, P. patagonica Brèthes, 1908, P. fasciculata Brèthes, 1908, P. pisoensis Strand, 1911, P. pacifica Brèthes, 1914, P. huascar Banks, 1946; P. completa Smith, 1855 = P. quichua Brèthes, 1908, P. comes Banks, 1946; P. smaragdina Dahlbom, 1843 = P. thunbergi Dahlbom, 1843, P. lara Mocsáry, 1888, P. satrapes Lucas, 1895, P. nupta Lucas, 1895, P. erynnis Lucas, 1895, P. fraterna Lucas, 1895, P. diabolus Lucas, 1895, P. mystica Lucas, 1895, P. thalia Brèthes, 1908, P. brasiliensis Brèthes, 1908, P. pallida Brèthes, 1908, P. iheringi Brèthes, 1908, P. dromeda Brèthes, 1908, P. sepultrix Lucas, 1919, P. strickeri Lucas, 1919; P. discolor Taschenberg, 1869 = P. sinnis Lucas, 1895, P. jujuyensis Brèthes, 1908, P. modesta Brèthes, 1908, P. comparata Brèthes, 1908, P. neutra Brèthes, 1908, P. terebrans Brèthes, 1908, P. procera Haupt, 1952, P. plaumanni Haupt, 1952, P. ogloblini Haupt, 1952, P. deletrix Haupt, 1952; P. limbata Guérin, 1831 = P. richteri Brèthes, 1908, P. polita Brèthes, 1908, P. limbella Haupt, 1952, P. artemis Haupt, 1952; P. basalis Mocsáry, 1885 = P. erdmanni Lucas, 1895, P. basinigra Haupt, 1952; P. infuscata Spinola, 1841 = P. niobe Mocsáry, 1885, P. sagana Mocsáry, 1894, P. incerta Banks, 1946; P. hyalinipennis Mocsáry, 1885 = P. subruficornis Haupt, 1952; P. festiva Fabricius, 1804 = P. pulchella Lepeletier, 1845, P. solitaria Smith, 1879, P. gallardoi Brèthes, 1908, P. hora Brèthes, 1914, P. amok Lucas, 1919, P. riojaneirensis Lucas, 1919; P. gracilis Lepeletier, 1845 = P. diana Mocsáry, 1885, P. hecate Mocsáry, 1885, P. spathulifera Lucas, 1895, P. sphinx Lucas, 1895, P. ierensis Banks, 1945, P. alceste Banks, 1946, P. scalaris Haupt, 1952; P. mildei Stål, 1857 = P. charon Mocsáry, 1885, P. cyanoptera Lucas, 1895, P. dryas Lucas, 1919; P. filiola Brèthes, 1914 = P. denserugosa Haupt, 1952; P. ruficornis Fabricius, 1804 = P. saphirus Palisot de Beauvois, 1805, P. violacea Mocsáry, 1885, P. hexamita Lucas, 1895, P. omniviolacea Haupt, 1952; P. brunneicornis Lucas, 1895 = P. glabripennis Lucas, 1895; P. purpurea Smith, 1873 = P. pan Mocsáry, 1885, P. parthenope Mocsáry, 1885, P. sagax Lucas, 1895, P. clypeata Brèthes, 1914, P. consimilis Banks, 1946, P. laconia Banks, 1946; P. viridisetosa Spinola, 1841 = P. eximia Smith, 1873; P. viridis Lepeletier, 1845 = P. errans Lepeletier, 1845, P. chlorotica Mocsáry, 1885, P. excelsa Lucas, 1895, P. selene Lucas, 1895, P. fimbriata Lucas, 1895, P. calypso Brèthes, 1908, P. fluminensis Brèthes, 1908, P. argentinicus Strand, 1910, P. mimetica Brèthes, 1914, P. garbei Brèthes, 1914, P. erecta Brèthes, 1914, P. tandilensis Brèthes, 1914, P. meridionalis Brèthes, 1914, P. minor Lucas, 1919, P. basifulgens Lucas, 1919, P. nebulosipennis Lucas, 1919, P. purpurea Lucas, 1919, P. koerberi Lucas, 1919, P. inimicissima Lucas, 1919, P. debilitans Lucas, 1919, P. itapaca Banks, 1946; P. aciculata Taschenberg, 1869 = P. nero Lucas, 1895; P. atripennis Fabricius, 1804 = P. flavilis Brèthes, 1908; P. ianthina Erichson, 1848 = P. fulvicornis Mocsáry, 1885, P. sirene Lucas, 1895, P. balboae Lucas, 1919, P. herodes Lucas, 1919, P. curti Lucas, 1919; P. nana Mocsáry, 1885 = P. mapiriensis Lucas, 1919, P. vinciens Lucas, 1919, P. ilione Banks, 1946, P. moesta Banks, 1946, P. orestes Banks, 1946, P. amautas Banks, 1946, P. inaequalis Haupt, 1952; P. hirtiventris Banks, 1946 = P. viridaurea Haupt, 1952, P. aequalis Haupt, 1952; P. auriguttata Burmeister, 1872 = P. aurimacula Mocsáry, 1885, P. flavicornis Mocsáry, 1894, P. guttata Lucas, 1895, P. incendiaria Lucas, 1895, P. pubiventris Lucas, 1895, P. planifrons Lucas, 1895, P. lestes Lucas, 1895, P. villosa Brèthes, 1908; P. sabina Mocsáry, 1885 = P. astioles Banks, 1946; and P. purpureipes Packard, 1869 = P. chlorana Mocsáry, 1885, P. antennalis Cameron, 1893, P. sulcifrons Cameron, 1903, P. carinata Brèthes, 1914, P. equatoriana Brèthes, 1914, P. angusta Banks, 1946. Keys to all forms are given. The mimicry-groups of P. atripennis Fabricius, 1804, and P. completa Smith, 1855, are defined and described and a comparative account of mimicry based on all four mimicrygroups in Pepsis is given. Lists of excluded species (with their current taxonomic placement and depository where ascertained), unplaced names, and a nomen nudum are given.

Description: In total 32 new species of Tenthredinidae are described from Vietnam and 18 new species from Indonesia: Nesoselandria albotonkinensis spec. nov., N. albeotegularissima spec. nov., N. devriesiana spec. nov., Anapeptamena achterbergiana spec. nov., Neostromboceros nigrogiganteus spec. nov., N. gracilioides spec. nov., N. alboclypeatus spec. nov., N. daoensis spec. nov., N. phuongensis spec. nov., Abusarbidea bicoloristigmata spec. nov., Eusunoxa alboapicalis spec. nov., Neopoppia tonkinometallica spec. nov., Abeleses vietnamensis spec. nov., A. metallotonkinensis spec. nov., Heptamelus tonkinensis spec. nov., Athlophorus devriesi spec. nov., Rhopographus vietnamensis spec. nov., Xenapatidea hematothoracica spec. nov., X. devriesi spec. nov., Allantidea achterbergiana spec. nov., Neothrinax nigrotonkinensis spec. nov., Indotaxonus flavissimus spec. nov., Darjilingia vietnamensis spec. nov., D. tonkinensis spec. nov., D. hoangliensis spec. nov., Ferna achterbergi spec. nov., Monophadnus bicoloritonkinensis spec. nov., Eutomostethus phongdiensis spec. nov., Eutomostethus albotegularissimus spec. nov., Tenthredo octomaculatus spec. nov., T. tricoloritonkinensis spec. nov. and T. danangiensis spec. nov. from Vietnam. Neostromboceros pleuronotatus spec. nov., N. albopedissimus spec. nov., N. flavopedis spec. nov., N. rubroguinealis spec. nov., N. rubromalayensis spec. nov., Eusunoxa malaya spec. nov., Emphytus danumiensis spec. nov., Hemibeleses sulawesiensis spec. nov., Neopoppia irregulata spec. nov., Tenthredo nigrosabahensis spec. nov., T. djampangensis spec. nov., Neothrinax kaindiensis spec. nov., N. excavata spec. nov., N. gedehensis spec. nov., Abeleses metallojavanus spec. nov., Caliroa nigrojavana spec. nov., Nesoselandria sulawesiensis spec. nov. and Athlophorus achterbergianus spec. nov. from Indonesia. Monophadnus glaucus Enderlein, 1919; Monophadnus sumatranus Enderlein, 1919; Amonophadnus nigripennis Benson, 1935; Amonophadnus nigrojavanus Haris, 2002; Corporaalinus azureus Forsius, 1925; Corporaalinus cyanescens Forsius, 1925; and Corporaalinus jacobsoni Forsius, 1929, are proposed as new synonyms of Monophadnus rivalis Konow, 1906. An identification key is added for the known Tenthredinidae of Borneo, Sumatra, Java, Sulawesi and New Guinea.

Description: Two new host records for Exasticolus fuscicornis (Cameron, 1887)(Hymenoptera: Braconidae: Homolobinae)are presented with detailed larvae morphology and other biological information.

Description: Thirty species belonging to 16 genera of the family Braconidae (Hymenoptera) are reported from Greenland. Seven are new species described and illustrated below: Dacnusa groenlandica spec. nov.; Aphidius tarsalis spec. nov.; Praon brevistigma spec. nov.; Blacus (B.) groenlandicus spec. nov.; Cotesia crassifemorata spec. nov.; C. fascifemorata spec. nov. and Microplitis lugubroides spec. nov.

Description: The little-known monotypic genus Paracyphocrania Redtenbacher, 1908 (Phasmatinae: Phasmatini) is reviewed and now comprises two species: P. lativentris Redtenbacher, 1908, and P. tecticollis (Redtenbacher, 1908) comb. nov., which are redescribed and illustrated. A neotype is designated for P. lativentris which is newly recorded from Sulawesi.

Description: Vestalaria vinnula spec.nov. (holotype male, southern Vietnam, Lam Dong province, Blao, 1962) is described in both sexes and compared with other species of Vestalaria May, 1935 (= the Vestalis smaragdina - group), which is ranked as valid genus.

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Description: An drei Orten im nordwestdeutschen Flachlande konnten zwei Interstadiale der Weichseleiszeit festgestellt werden. Vermutlich gehören die Torfe oberhalb des Interglazials von Eversen bei Rotenburg/Hann. ebenfalls einem dieser Interstadiale an (Wolff & Schröder 1940). Die stratigraphischen Verhältnisse lassen eine eindeutige Eingliederung in die Weichselvereisung zu. In allen Fällen liegen die beiden Torfbänke oberhalb des letzten Interglazials und sind in Sanden der letzten Eiszeit eingeschlossen. Von einer Parallelisierung mit den Stadien der Weichselvereisung soll vorläufig Abstand genommen werden. Durch die Pollenanalyse ergab sich eine Unterteilung in eine Birken- und in eine Kiefernphase. Das Klima war subarktisch-ozeanisch. Die Wiedervereisung nach dem letzten Interglazial und den beiden Interstadialen wurde durch ein feucht-kühles, niederschlagsreiches (vermutlich schneereiches) Klima eingeleitet. Beide Interstadiale haben mit der Alleröd-Oszillation gemeinsame Züge, lassen sich jedoch klar von ihr trennen. Ob eine Unterscheidung der beiden Interstadiale mit Hilfe der Pollenanalyse vorgenommen werden kann, ließen die bisherigen Untersuchungen nicht erkennen und muß daher den weiteren Arbeiten vorbehalten bleiben.

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Description: Im Aufschluss Nußloch südlich von Heidelberg ist ein neu aufgeschlossener Lößrücken paläopedologisch aufgenommen und ein Standardprofil mit verschiedenen Methoden untersucht worden. Im Einzelnen wurden Sedimentanalysen (Korngrößen, Kohlenstoff, Kalkgehalt) und die magnetische Suszeptibilität bestimmt, biomorphologische und malakologische Untersuchungen durchgeführt sowie 27 Proben mit der IRSL-Methode datiert. Stratigraphisch umfasst der untersuchte Abschnitt das Jungpleistozän mit einem mehrgliedrigen Eem-Boden und einem ungewöhnlich mächtigen Würmlöß (ca. 18 m). Bodentypologisch wurden ein Bt-Horizont, eine Humuszone und zahlreiche Nassböden von unterschiedlicher Intensität mit und ohne Verbraunungszone nachgewiesen. Von den fünf ausgewiesenen Verbraunungszonen (WB2 - WB6) sind WB2, WB4 und WB5 aufgrund der Molluskenführung als interstadiale Bildungen anzusehen. Hinzu kommt noch eine der drei interstadialen Mosbacher Humuszonen (WB1) im stark reduzierten Altwürmabschnitt mit einem Alter von ca. 75 ka BP. Als kräftigster Interstadialboden ist der Bv-Horizont einer arktischen Braunerde erkannt worden (WB4), welcher aufgrund verschiedener Kriterien mit dem Lohner Boden bei ca. 30 ka BP parallelisiert wurde. Der im Hangenden des Lohner Bodens überlieferte Jungwürmlöß ist mit 12 m für Mitteleuropa sehr mächtig und von zahlreichen Nassböden (mindestens 10) untergliedert. Besonders aufgespaltet ist der Bereich des E2-Nassbodens, in dem auch die Böden WB5 und WB6 mit schwachen Verbraunungszonen liegen. Auch der jüngste Jungwürmlöß über dem Leithorizont des Eltviller Tuffs ist mit 4,5 m relativ mächtig und mehrgliedrig überliefert, so dass von einem E4/E5-Komplex gesprochen wird. Die paläopedologischen Befunde stimmen hervorragend mit den Veränderungen in der Molluskenfauna und der Suszeptibilitätskurve überein, so dass detaillierte stratigraphische und paläoklimatische Rekonstruktionen möglich sind. Die absoluten Altersdatierungen bestätigen dabei weitgehend die vorgenommenen Alterseinstufungen. Abschließend wird das neu bearbeitete Profil in Nußloch mit Ergebnissen von ANTOINE et al. (2001) verglichen, welche im gleichen Aufschluss an anderer Stelle erzielt worden sind.

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Description: research

Description: research

Description: In der Nachbarschaft von Flüssen und größeren Bächen nimmt der Löß sehr häufig eine sandige Beschaffenheit an, in vielen Gebieten ist sogar die Sandkomponente in Form von verschieden starken Schichten (Sandbänder) eingeschaltet. Die vorliegende Arbeit beschäftigt sich in der Hauptsache mit der Lagerung der Sandbänder im vertikalen Profil und mit den Veränderungen in horizontaler Richtung. Auf Grund der allgemeinen Ausbildung und der Körnungsunterschiede des Lößes konnten westlich Königgrätz 4 Faziesbereiche unterschieden werden und zwar die Flugsand-, Bänder-, Übergangs- und Normalfazies. Die 4 Fazieszonen folgen von O nach W aufeinander. Die speziellen Untersuchungen an den Sandbändern führten zu folgenden Ergebnissen: 1. Die Abnahme des prozentualen Anteils der Gesamtmächtigkeit der Sandbänder am Löß erfolgt linear mit dem Logarithmus der Entfernung vom Auswehungsgebiet. 2. Die durchschnittliche Anzahl der Sandbänder je Meter Löß ändert sich mit der Zunahme der Entfernung vom Ursprungsgebiet, wie im einzelnen aus Abb. 10 hervorgeht. 3. Neben der Gesamtmächtigkeit und der Anzahl der Sandbänder wurde auch die Häufigkeit der verschiedenen Mächtigkeitsstufen ermittelt und graphisch aufgetragen (Abb. 11). Dabei ergab sich, daß in unmittelbarer Nähe des Auswehungsgebietes neben wenigen 9 und 10 cm mächtigen Bändern die 2 und 2,5 cm starken überwiegen. In einer Entfernung von etwa 300 m vom Flußufer dominieren die 1 und 1,5 cm starken. Weiter nach W nehmen aber nach und nach die dickeren Lagen wieder zu, so daß am Ende der Sandbänderfazies die 2 und 2,5 cm starken die häufigsten sind. Aus den mitgeteilten Ergebnissen und aus zahlreichen Körnungsanalysen wird geschlossen, daß sowohl die eingelagerten Sandschichten als auch der gößte Teil des Lößes äolischen Ursprungs sind. Sandlagen und Löß wurden durch östliche Winde aus dem breiten Tal der Elbe ausgeweht und auf die benachbarten Höhen transportiert. Dabei gelangte der in Form von Bändern abgelagerte Sand bis zu einer Entfernung von ca. 700 m. Die Kornfeinheit des Lößes nimmt nach W hin immer mehr zu. Weitere Beobachtungen an dem Bystrice- und Cidlina-Tal im W des Untersuchungsgebietes bestätigen die Annahme von der Auswehung des Lößes und der Sandschichten aus den Tälern durch Winde aus östlicher Richtung. Daß die allgemeine Lößverbreitung auch von der Breite der Täler abhängig ist, zeigt ein Blick auf die Karte (Abb. 1).

Description: research

Description: research

Description: research

Description: research

Description: Dieser Artikel diskutiert den Charakter von Pollentypen. Wir argumentieren, dass Pollentypen und Pflanzentaxa komplett unterschiedliche Entitäten (morphologische bzw. taxonomische) sind, und deswegen unterschiedlich behandelt und dargestellt werden sollten. Allgemeine Probleme der konventionellen Nomenklatur von Pollentypen werden anhand von Beispielen aus der europäischen palynologischen Praxis illustriert. Wir plädieren für Deutlichkeit in der Nomenklatur von Pollentypen und für die wissenschaftliche Freiheit, ‘unkonventionelle‘ Methoden zu benutzen, um Verwirrung zu vermeiden.

Description: research

Description: System studies have shown the benefits of reducing blade tip clearances in modern turbine engines. Minimizing blade tip clearances throughout the engine will contribute materially to meeting NASA s Ultra-Efficient Engine Technology (UEET) turbine engine project goals. NASA GRC is examining two candidate approaches including rub-avoidance and regeneration which are explained in subsequent slides.

Description: Fretting is a structural damage mechanism observed when two nominally clamped surfaces are subjected to an oscillatory loading. A critical location for fretting induced damage has been identified at the blade/disk and blade/damper interfaces of gas turbine engine turbomachinery and space propulsion components. The high-temperature, high-frequency loading environment seen by these components lead to severe stress gradients at the edge-of-contact. These contact stresses drive crack nucleation and propagation in fretting and are very sensitive to the geometry of the contacting bodies, the contact loads, materials, temperature, and contact surface tribology (friction). To diagnose the threat that small and relatively undetectable fretting cracks pose to damage tolerance and structural integrity of in-service components, the objective of this work is to develop a well-characterized experimental fretting rig capable of investigating fretting behavior of advanced aerospace alloys subjected to load and temperature conditions representative of such turbomachinery components.

Description: This viewgraph presentation describes a turbine seal rig concept to meet next generation engine speed and temperatures requirements. The contents include: 1) Turbomachinery Seal Development Objectives; 2) High Temperature Turbomachinery Seal Test Rig; 3) Test Parameters; 4) Highlights of Engineering Calculations; 5) Seal Rig Global Thermal Analysis; 6) Test Rig Status; 7) Seal Rig Schematic; 8) Test Chamber Enlarged View; and 9) Rig Features Unique Measurement Systems.

Description: A commercially available code is utilized to analyze a plain and grooved liquid annular seal. These type seals are commonly used in modern turbopumps and have a pronounced effect on the rotordynamic behavior of these systems. Accurate prediction of both leakage and dynamic reaction forces is vital to ensure good performance and sound mechanical operation. The code SCISEAL developed by CFDRC is a generic 3-D, finite volume based CFD code solving the 3-D Reynolds averaged Navier Stokes equations. The code allows body-fitted, multi-blocked structured grids, turbulence modeling, rotating coordinate frames, as well as integration of dynamic pressure and shear forces on the rotating journal. The code may be used with the commercially available pre-and post-processing codes from CFDRC as well.

Description: The two dimensinal bifurcated inlet, down selected for the HSR program, and the engine bay cowling consist of many sealing interfaces. The variable geometry characteristics of this inlet and the size of the propulsion system impose new sealing requirements for commercial transport aircraft. Major inlet systems requiring seal development and testing include the ramp system, the bypass/take-off system, and the inlet/engine interface. Engine bay cowling seal interfaces include the inlet/cowling interface, the keel split line, the hinge beam/engine bay cowling, and the nozzle/cowling interface. These seals have to withstand supersonic flight operating temperatures and pressures with typical commercial aircraft reliability and lives. The operating conditions and expected seal lives will be identified for the various interfaces. Boeing's SST seal development program will also be discussed.

Description: The High Speed Civil Transport (HSCT) engine concept is a large mixed flow turbofan similar in construction to current military fighter engines. The mission, however, is quite different. The engine will operate for long periods of time at very high Mach numbers and high altitudes. The engine is required to have very low emissions and noise levels to be acceptable in commercial service. Current thrust levels are in the 55000 lb range. At the current supercruise speed requirement of Mach 2.4, the engine inlet temperature will be at least 380 F. This is the lowest cycle temperature expected anywhere in the propulsion system.Seals will be exposed to operate at this temperature and higher for thousands of hours without failure. Durability, cost, and weight will all be very important in determining the type of seals selected for a successful HSCT engine.

Description: New engines experience durability problems after entering service. The most prevalent and costly is the hot section, particularly the high-pressure turbine. The origin of durability problems can be traced back to: 1) the basic aero-mechanical design systems, assumptions, and design margins used by the engine designers, 2) the available materials systems, and 3) to a large extent, aggressive marketing in a highly competitive environment that pushes engine components beyond the demonstrated capability of the basic technology available for the hardware designs. Unfortunately the user must operate the engine in the service environment in order to learn the actual thrust loading and the time at max effort take-off conditions used in service are needed to determine the hot section life. Several hundred thousand hours of operational service will be required before the demonstrated reliability of a fleet of engines or the design deficiencies of the engine hot section parts can be determined. Also, it may take three to four engine shop visits for heavy maintenance on the gas path hardware to establish cost effective build standards. Spare parts drive the oerator's engine maintenance costs but spare parts also makes lots of money for the engine manufacturer during the service life of an engine. Unless competition prevails for follow-on engine buys, there is really no motivation for an OEM to spend internal money to improve parts durability and reduce earnings derived from a lucrative spare parts business. If the hot section life is below design goals or promised values, the OEM migh argue that the engine is being operated beyond its basic design intent. On the other hand, the airframer and the operator will continue to remind the OEM that his engine was selected based on a lot of promises to deliver spec thrust with little impact on engine service life if higher thrust is used intermittently. In the end, a standoff prevails and nothing gets fixed. This briefing will propose ways to hold competing engine manufacturers more accountable for engine hot section design margins during the entire Engine Development process as well as provide tools to assess the design temperature margins in the hot section parts of Service Engines.

Description: AlliedSignal aerospace company is committed to significantly improving the reliabilities of air/oil seals in their gas turbine engines. One motivation for this is that aircraft cabin air quality can be affected by the performance of mainshaft air/oil seals. In the recent past, coking related failure modes have been the focus of air/oil seal R&D at AlliedSignal. Many significant advances have been made to combat coke related failures, with some more work continuing in this area. This years R&D begins to address other commin failure modes. Among them, carbon seal "blistering" has been a chronic problem facing the sealing industry for many decades. AlliedSignal has launched an aggressive effort this year to solve this problem for our aerospace rated carbon seals in a short (one to two year) timeframe. Work also continues in developing more user-friendly tools and data for seal analysis & design. Innovations in seal cooling continue. Nominally non-contacting hydropad sealing concept is being developed for aerospace applications. Finally, proprietary work is in planning stages for development of a seal with the aggressive aim of zero oil leakage.

Description: The author will present results obtained to date of a secondary flow study currently being conducted. The purpose of the study is to investigate and report all the ramifications of introducing advanced sealing technology into gas turbine engine secondary flow systems. In addition to detailed cost/benefit results we will also derive seal operational requirements which can be fed into a subsequent advanced seal development program. Using the current Allison AE3007 engine as a model/baseline we have examined 6 different advanced seal variations. We have settled on a design with 2 advanced seals which results n a savings of 2% in chargeable cooling. The introduction of these advanced seals has resulted in substantial changes to surrounding engine components which will be reported.

Description: This paper presents an overview of the design methodology used in the development of the aerodynamic configuration of the nacelle core compartment vent for a typical Boeing commercial airplane together with design challenges for future design efforts. Core compartment vents exhaust engine subsystem flows from the space contained between the engine case and the nacelle of an airplane propulsion system. These subsystem flows typically consist of precooler, oil cooler, turbine case cooling, compartment cooling and nacelle leakage air. The design of core compartment vents is challenging due to stringent design requirements, mass flow sensitivity of the system to small changes in vent exit pressure ratio, and the need to maximize overall exhaust system performance at cruise conditions.

Description: Airlines are extremely sensitive to the amount of dollars spent on maintaining the external engine hardware in the field. Analysis reveals that many problems revolve around a central issue, reliability. Fuel and oil leakage due to seal failure and electrical fault messages due to wire harness failures play a major role in aircraft delays and cancellations (D&C's) and scheduled maintenance. Correcting these items on the line requires a large investment of engineering resources and manpower after the fact. The smartest and most cost effective philosophy is to build the best hardware the first time. The only way to do that is to completely understand and model the operating environment, study the field experience of similar designs and to perform extensive testing.

Description: The proven technology of brush seals has been extended to the mitigation of problems arising from friction and wear at the bristle-rotor interface at high surface speeds. In prototype testing, the brush is mounted on, and free to rotate with the shaft, thus providing a complaint primary seal. A face seal positioned between the backing plate of the brush seal and the housing provides a secondary seal. The purpose of this paper is to demonstrate the interaction between the brush bristles and the shaft at high surface speeds as well as introduce a numerical model to simulate the bristle behavior. A test facility was constructed to study the effects of centrifugal forces on bristle deflection in a single rotating brush seal. The bristle-rotor interface was observed through a video camera, which utilized a high magnification borescope and a high frequency strobe light source. Rotational speeds of the rotor and the brush seal were measured by a magnetic and optical speed sensor, respectively. Preliminary results with speeds up to 11,000 rpm show no speed differential between the brush seal and rotor, or any instability problems associated with the brush seal. Bristle liftoff from the rotor is successfully captured on video.

Description: The U-Plex(Registered TradeMark) was designed to allow greater elastic deflection capability in a given gland volume than the now conventional E-seal(Regitered TradeMark). Greater deflection capability with the associated lower bending stresses provides several benefits. For pneumatic duct joints, the axial free height is increased to allow sealing of flanges with weld distortions significantly in excess of what could be tolerated with E-seals(Registered TradeMark), This performance is achieved while maintaining the reusability and ease of assembly typical of E-seal(Registered TradeMark) rigid duct joints.

Description: The nature of the RS-68 turbopumps requires that the hydrogen seals separating the pump from the turbine must have extremely low levels of leakage and be contained in small packages. Conventional seal technologies are not able to reasonably satisfy such design requirements. A review of experimental measurements and analysis publications suggests that brush seals are well suited for the design requirements. Brush seals are shown to have less leakage than conventional labyrinth and damper seals and have no adverse effects on the rotordynamics of the machine. The bulk-flow analysis presented by Hendricks et al. is used as a guideline to create a spreadsheet that provides mass flow through the seal and heat generated by the rubbing contact of the bristles on the shaft. The analysis is anchored to published data for LN2 and LH2 leakage tests. Finally, the analysis is used to design seals for both applications. It is observed that the most important analysis parameter is the thickness of the bristle pack and its relationship to seal clearance, lay angle and pressure drop.

Description: The configuration of the propulsion system engine externals must meet many airplane requirements such as cost, thrust, weight, range and systems power extraction. On the 737-700 several program requirements also played a major role in the development of the engine externals. These program goals were increased range, same cost as a 1994 737-300, 15% reduction in maintenance costs from the 737-300, and a propulsion package that appeared as if it was designed by one company. This presentation will show how these requirements shaped the design of the engine externals for the 737-700/CFM56-7B.

Description: Two numerical approaches are used to model the interaction between the turbine main gas flow and the wheelspace cavity seal flow. The 3-D, unsteady Reynolds-averaged Navier-Stokes equations are solved with a CFD code based on a structured grid to study the interaction between the turbine main gas flow and the wheelspace cavity seal flow. A CFD code based on an unstructured grid is used to solve detailed flow feature in the cavity seal which has a complex geometry. The numerical results confirm various observations from earlier experimental studies under similar flow conditions. When the flow rate through the rim cavity seal is increased, the ingestion of the main turbine flow into the rim seal area decreases drastically. However, a small amount of main gas flow is ingested to the rim seal area even with very high level of seal flow rate. This is due to the complex nature of 3-D, unsteady flow interaction near the hub of the turbine stage.

Description: The overview for HSR seals includes defining objectives, summarizing sealing and material requirements, presenting relevant seal cross-sections, and identifying technology needs. Overview presentations are given for the inlet, turbomachinery, combustor and nozzle. The HSCT and HSR seal issues center on durability and efficiency of rotating equipment seals, structural seals and high speed bearing and sump seals. Tighter clearances, propulsion system size and thermal requirements challenge component designers.

Description: During an aerospace engineer's undergraduate studies, he or she will attend classes in aerodynamics, thermodynamics, structures, stability and control, dynamics, design, propulsion, and computer science, along with the related courses in mathematics, physics, statistics, and chemistry required to understand the material. Upon graduation, the new engineer will have acquired a basic knowledge of how to build an aerospace vehicle. What only comes through experience, however, is the understanding of the inevitable imperfect process through which an aerospace vehicle is built. This is the adventure of turning a basic concept into functional hardware. Engineers working on a project must often deal with ambiguous situations. They are routinely asked by management to provide risk assessments of a project, yet even after careful analysis uncertainties remain. The project must be accomplished within finite limits of time and money. The question an engineer answers is whether the solution to potential problem is worth the cost and schedule delay, or if the solution might actually be worse than the problem it is meant to solve. Review protocols are established to ensure that an unknown has not been overlooked. But these cannot protect against an unknown unknown. Examples of these situations can be found in the history of the X-43A Hyper-X (Hypersonic Experiment) program. In this NASA project, a supersonic combustion ramjet (scramjet) engine was flight tested on a subscale vehicle. The X-43A Hyper-X Research Vehicle (HXRV) was launched from a B-52B mothership, then boosted to the test speed by a modified Pegasus rocket first stage, called the Hyper-X Launch Vehicle (HXLV). Once at the proper speed and altitude, the X-43A separated from the booster, stabilized itself, and then the engine test began. Although wind-tunnel scramjet engine tests had begun in the late 1950s, before the Hyper-X program there had never been an actual in-flight test of such an engine integrated with an appropriate airframe. Thus, while the scramjet had successfully operated in the artificial airflow of wind tunnels, the concept had yet to be proven in real air. These conditions meant changes in density and temperature, as well as changes in angle of attack and sideslip of a free-flying vehicle. A wind tunnel is limited in its ability to simulate these subtle factures, which have a major impact on almost any vehicle, but especially that of a scramjet's performance. The Hyper-X project was to provide a real-world benchmark of the ground test data. The full scale X-43A engine would be operated in the wind tunnel, and then flown, and the data from its operation would then be compared with projections. If these matched, the wind tunnel data would be considered a reliable design tool for future scramjet. If there were significant differences, the reasons for these would have to be identified. Until such information was available, scramjets would lack the technological maturity to be considered for future space launch or high-speed atmospheric flight vehicles.

Description: The objective is to develop and demonstrate a fast-acting active clearance control system to improve turbine engine performance, reduce emissions, and increase service life. System studies have shown the benefits of reducing blade tip clearances in modern turbine engines. Minimizing blade tip clearances throughout the engine will contribute materially to meeting NASA's Ultra-Efficient Engine Technology (UEET) turbine engine project goals. NASA GRC is examining two candidate approaches including rub-avoidance and regeneration which are explained in subsequent slides.

Description: To achieve jet noise reduction goals for the High Speed Civil Transport aircraft, researchers have been investigating the mixer-ejector nozzle concept. For this concept, a primary nozzle with multiple chutes is surrounded by an ejector. The ejector mixes low-momentum ambient air with the hot engine exhaust to reduce the jet velocity and, hence, the jet noise. It is desirable to mix the two streams as fast as possible in order to minimize the length and weight of the ejector. An earlier model of the mixer-ejector nozzle was tested extensively in the Aerodynamic Research Laboratory (ARL) of GE Aircraft Engines at Cincinnati, Ohio. While testing was continuing with later generations of the nozzle, the earlier model was brought to the NASA Lewis Research Center for relatively fundamental measurements. Goals of the Lewis study were to obtain details of the flow field to aid computational fluid dynamics (CFD) efforts and obtain a better understanding of the flow mechanisms, as well as to experiment with mixing enhancement devices, such as tabs. The measurements were made in an open jet facility for cold (unheated) flow without a surrounding coflowing stream.

Description: In a continuing research program, jets from nozzles of different geometries are being investigated with the aim of increasing mixing and spreading in those flows. Flow fields from nozzles with elliptic, rectangular, and other more complex cross-sectional shapes are being studied in comparison to circular nozzles over a wide Mach number range. As noted by previous researchers, noncircular jets usually spread faster than circular jets. Another technique being investigated to increase jet spreading even further for a given nozzle is the use of "tabs" to generate vortices. A typical tab is a triangular-shaped protrusion placed at the nozzle exit, with the base of the triangle touching the nozzle wall and the apex leaning downstream at 45 to the stream direction. This geometry was determined by a parametric study to produce the optimum effect for a given area blockage. The tabs can increase jet spreading significantly. The underlying mechanism traces to a pair of counter-rotating streamwise vortices originating from each tab. These vortex pairs persist in the flow; and with the appropriate number and strength, they can increase spreading.

Description: Because of its high efficiency, fuel cell technology may be used to launch a new generation of more-electric aeropropulsion and power systems for future aircraft. Electric-motor-driven airplanes using fuel-cell powerplants would be beneficial to the environment because of fuel savings, low noise, and zero carbon-dioxide emissions. In spite of the fuel cell s efficiency benefit, to produce the same shaft drive power, a fuel cell- powered electric-drive system must be definitely heavier than a turbine-drive system. However, the fuel-cell system s overall efficiency from fuel-to-shaft power is higher than for a turbine-drive system. This means that the fuel consumption rate could be lower than for a conventional system. For heavier, fuel-laden planes for longer flights, we might achieve substantial fuel savings. In the airplane industry, in fact, an efficiency gain of even a few percentage points can make a major economic difference in operating costs.

Description: With growing concerns about global warming, there is a need to develop pollution-free aircraft. One approach is to use hydrogen-fueled aircraft that use fuel cells or turbogenerators to produce electric power to drive the electric motors that turn the aircraft s propulsive fans. Hydrogen fuel would be carried as a liquid, stored at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are too heavy for aircraft propulsion. We need to develop high-power, lightweight electric motors (highpower- density motors). One approach is to increase the conductivity of the wires by cooling them with liquid hydrogen (LH2). This would allow superconducting rotors with an ironless core. In addition, the motor could use very pure aluminum or copper, substances that have low resistances at cryogenic temperatures. A preliminary design of a 450-hp LH2-cooled electric motor was completed and is being manufactured by a contractor. This motor will be tested at the NASA Glenn Research Center and will be used to test different superconducting materials such as magnesium diboride (MgB2). The motor will be able to operate at speeds of up to 6000 rpm.

Description: The theory of discrete event supervisory (DES) control was applied to the optimal control of a twin-engine aircraft propulsion system and demonstrated in a simulation. The supervisory control, which is implemented as a finite-state automaton, oversees the behavior of a system and manages it in such a way that it maximizes a performance criterion, similar to a traditional optimal control problem. DES controllers can be nested such that a high-level controller supervises multiple lower level controllers. This structure can be expanded to control huge, complex systems, providing optimal performance and increasing autonomy with each additional level. The DES control strategy for propulsion systems was validated using a distributed testbed consisting of multiple computers--each representing a module of the overall propulsion system--to simulate real-time hardware-in-the-loop testing. In the first experiment, DES control was applied to the operation of a nonlinear simulation of a turbofan engine (running in closed loop using its own feedback controller) to minimize engine structural damage caused by a combination of thermal and structural loads. This enables increased on-wing time for the engine through better management of the engine-component life usage. Thus, the engine-level DES acts as a life-extending controller through its interaction with and manipulation of the engine s operation.

Description: Current aircraft engine controllers are designed and operated to provide desired performance and stability margins. Except for the hard limits for extreme conditions, engine controllers do not usually take engine component life into consideration during the controller design and operation. The end result is that aircraft pilots regularly operate engines under unnecessarily harsh conditions to strive for optimum performance. The NASA Glenn Research Center and its industrial and academic partners have been working together toward an intelligent control concept that will include engine life as part of the controller design criteria. This research includes the study of the relationship between control action and engine component life as well as the design of an intelligent control algorithm to provide proper tradeoffs between performance and engine life. This approach is expected to maintain operating safety while minimizing overall operating costs. In this study, the thermomechanical fatigue (TMF) of a critical component was selected to demonstrate how an intelligent engine control algorithm can significantly extend engine life with only a very small sacrifice in performance. An intelligent engine control scheme based on modifying the high-pressure spool speed (NH) was proposed to reduce TMF damage from ground idle to takeoff. The NH acceleration schedule was optimized to minimize the TMF damage for a given rise-time constraint, which represents the performance requirement. The intelligent engine control scheme was used to simulate a commercial short-haul aircraft engine.

Description: The future of aviation propulsion systems is increasingly focused on the application of control technologies to significantly enhance the performance of a new generation of air vehicles. Active flow control refers to a set of technologies that manipulate the flow of air and combustion gases deep within the confines of an engine to dynamically alter its performance during flight. By employing active flow control, designers can create engines that are significantly lighter, are more fuel efficient, and produce lower emissions. In addition, the operating range of an engine can be extended, yielding safer transportation systems. The realization of these future propulsion systems requires the collaborative development of many base technologies to achieve intelligent, embedded control at the engine locations where it will be most effective. NASA Glenn Research Center s Controls and Dynamics Technology Branch has developed a state-of-the-art low-speed Active Flow Control Laboratory in which emerging technologies can be integrated and explored in a flexible, low-cost environment. The facility allows the most promising developments to be prescreened and optimized before being tested on higher fidelity platforms, thereby reducing the cost of experimentation and improving research effectiveness.

Description: The transformation of engine control systems from centralized to distributed architecture is both necessary and enabling for future aeropropulsion applications. The continued growth of adaptive control applications and the trend to smaller, light weight cores is a counter influence on the weight and volume of control system hardware. A distributed engine control system using high temperature electronics and open systems communications will reverse the growing trend of control system weight ratio to total engine weight and also be a major factor in decreasing overall cost of ownership for aeropropulsion systems. The implementation of distributed engine control is not without significant challenges. There are the needs for high temperature electronics, development of simple, robust communications, and power supply for the on-board electronics.

Description: Advanced model-based control architecture overcomes the limitations state-of-the-art engine control and provides the potential of virtual sensors, for example for thrust and stall margin. "Tracking filters" are used to adapt the control parameters to actual conditions and to individual engines. For health monitoring standalone monitoring units will be used for on-board analysis to determine the general engine health and detect and isolate sudden faults. Adaptive models open up the possibility of adapting the control logic to maintain desired performance in the presence of engine degradation or to accommodate any faults. Improved and new sensors are required to allow sensing at stations within the engine gas path that are currently not instrumented due in part to the harsh conditions including high operating temperatures and to allow additional monitoring of vibration, mass flows and energy properties, exhaust gas composition, and gas path debris. The environmental and performance requirements for these sensors are summarized.

Description: Active Control can help to meet future engine requirements by an active improvement of the component characteristics. The concept is based on an intelligent control logic, which senses actual operating conditions and reacts with adequate actuator action. This approach can directly improve engine characteristics as performance, operability, durability and emissions on the one hand. On the other hand active control addresses the design constrains imposed by unsteady phenomena like inlet distortion, compressor surge, combustion instability, flow separations, vibration and noise, which only occur during exceptional operating conditions. The feasibility and effectiveness of active control technologies have been demonstrated in lab-scale tests. This chapter describes a broad range of promising applications for each engine component. Significant efforts in research and development remain to implement these technologies in engine rig and finally production engines and to demonstrate today s engine generation airworthiness, safety, reliability, and durability requirements. Active control applications are in particular limited by the gap between available and advanced sensors and actuators, which allow an operation in the harsh environment in an aero engine. The operating and performance requirements for actuators and sensors are outlined for each of the gas turbine sections from inlet to nozzle.

Description: New challenges concerning system health-monitoring and life-extending robust controls for the Ultra-Efficient Engine Technology Project, as well as other advanced engine and power system concepts at NASA and elsewhere, have renewed the control community s interest in smart, model-based methods. In particular, these challenges have further motivated efforts at the NASA Glenn Research Center to exploit the versatility and superiority of the dynamic features extraction of multiscale analysis for controls--such as with "wavelets" and "wavelet filter-banks.' The accomplishments reported herein pertain to the active suppression of combustion instabilities in liquid-fuel combustors via fuel modulation. The fundamentals and initial success of this innovation were reported for a unique demonstration of active combustion control (a research collaboration of NASA Glenn with Pratt & Whitney and the United Technologies Research Center, UTRC). This demonstration, conducted in 2002 at UTRC on the NASA single nozzle rig (SNR) combustor, was the first known suppression of high-frequency instability with a liquid-fueled combustor. The SNR is based on a high-powered military engine combustor that exhibited well-known instabilities.

Description: The operational envelope of gas turbine engines is constrained by the stability limit of the compression system. The dangers of exceeding this limit are severe, with the potential for engine failure and loss of the aircraft. To avoid such failures, compressor designers provide an adequate stability (stall) margin in the compressor design to account for inlet distortions, degradation due to wear, throttle transients, and other factors that reduce compressor stability from the original design intent. In some cases, the required stall margin results in the compressor operating line being below the maximum efficiency potential of the compression system. Current approaches to increasing stability tend to decrease the efficiency of the compressor. The focus of this work is to increase the stall margin of compressors without decreasing their efficiency.

Description: Future advanced aircraft fueled by hydrogen are being developed to use electric drive systems instead of gas turbine engines for propulsion. Current conventional electric motor power densities cannot match those of today s gas turbine aircraft engines. However, if significant technological advances could be made in high-power-density motor development, the benefits of an electric propulsion system, such as the reduction of harmful emissions, could be realized.

Description: A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made using a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and outer-race bearing operating temperatures are compared for the laboratory test rig and the turbojet engine. Inner- and outer-race cooling-correlation curves were obtained for the turbojet-engine turbine-roller bearing with the same inner- and outer-race correlation parameters and exponents as those determined for the laboratory test-rig bearing. The inner- and outer-race turbine roller-bearing temperatures may be predicted from a single curve, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter or any combination of these parameters. The turbojet-engine turbine-roller-bearing inner-race temperatures were 30 to 60 F greater than the outer-race-maximum temperatures, the exact values depending on the operating condition and oil viscosity; these results are in contrast to the laboratory test-rig results where the inner-race temperatures were less than the outer-race-maximum temperatures. The turbojet-engine turbine-roller bearing, maximum outer-race circumferential temperature variation was approximately 30 F for each of the oils used. The effect of oil viscosity on inner- and outer-race turbojet-engine turbine-roller-bearing temperatures was found to be significant. With the lower viscosity oil (6x10(exp -7) reyns (4.9 centistokes) at 100 F; viscosity index, 83), the inner-race temperature was approximately 30 to 35 F less than with the higher viscosity oil (53x10(exp -7) reyns (42.8 centistokes) at 100 F; viscosity index, 150); whereas the outer-race-maximum temperatures were 12 to 28 F lower with the lower viscosity oil over the DN range investigated.

Description: A literature survey was conducted to determine the relation between aircraft ignition sources and inflammables. Available literature applicable to the problem of aircraft fire hazards is analyzed and, discussed herein. Data pertaining to the effect of many variables on ignition temperatures, minimum ignition pressures, and minimum spark-ignition energies of inflammables, quenching distances of electrode configurations, and size of openings incapable of flame propagation are presented and discussed. The ignition temperatures and the limits of inflammability of gasoline in air in different test environments, and the minimum ignition pressure and the minimum size of openings for flame propagation of gasoline - air mixtures are included. Inerting of gasoline - air mixtures is discussed.

Description: Tests of two propellers having two blades and differing only in the inboard pitch distribution were made in the Langley 8-foot highspeed tunnel to determine the effect of inboard pitch distribution on propeller performance. propeller was designed for operation in the reduced velocity region ahead of an NACA cowling; the inboard pitch distribution of the modified propeller was increased for operation at or near free-stream velocities, such as would be obtained in a pusher installation. conditions covering climb, cruise, and high-speed operation. Wake surveys were taken behind the propellers in order to determine the distribution of thrust along the blades and to aid in the analysis of the results. Test results showed that the modified propeller was about 2.5 percent less efficient for a typical climb condition at all altitudes, 2 percent more efficient for one cruise condition, and 5 percent more efficient for high-speed operation. speed condition, the modified propeller showed a 6-percent loss in efficiency due to compressibility; whereas the original propeller showed an 11-percent efficiency loss due to compressiblity. The lower compressibility loss for the modified propeller resulted from the fact that the inboard sections of this propeller could operate at increased thrust loading after compressibility losses had occurred at the outboard sections.

Description: Turbine vane heat transfer predictions are given for smooth and rough vanes where the experimental data show transition moving forward on the vane as the surface roughness physical height increases. Consistent with smooth vane heat transfer, the transition moves forward for a fixed roughness height as the Reynolds number increases. Comparisons are presented with published experimental data. Some of the data are for a regular roughness geometry with a range of roughness heights, Reynolds numbers, and inlet turbulence intensities. The approach taken in this analysis is to treat the roughness in a statistical sense, consistent with what would be obtained from blades measured after exposure to actual engine environments. An approach is given to determine the equivalent sand grain roughness from the statistics of the regular geometry. This approach is guided by the experimental data. A roughness transition criterion is developed, and comparisons are made with experimental data over the entire range of experimental test conditions. Additional comparisons are made with experimental heat transfer data, where the roughness geometries are both regular and statistical. Using the developed analysis, heat transfer calculations are presented for the second stage vane of a high pressure turbine at hypothetical engine conditions.

Description: Computational fluid dynamics (CFD) was used to evaluate the flow field and thrust performance of a promising concept for reducing the noise at take-off of dual-stream turbofan nozzles. The concept, offset stream technology, reduces the jet noise observed on the ground by diverting (offsetting) a portion of the fan flow below the core flow, thickening and lengthening this layer between the high-velocity core flow and the ground observers. In this study a wedge placed in the internal fan stream is used as the diverter. Wind, a Reynolds averaged Navier-Stokes (RANS) code, was used to analyze the flow field of the exhaust plume and to calculate nozzle performance. Results showed that the wedge diverts all of the fan flow to the lower side of the nozzle, and the turbulent kinetic energy on the observer side of the nozzle is reduced. This reduction in turbulent kinetic energy should correspond to a reduction in noise. However, because all of the fan flow is diverted, the upper portion of the core flow is exposed to the freestream, and the turbulent kinetic energy on the upper side of the nozzle is increased, creating an unintended noise source. The blockage due to the wedge reduces the fan mass flow proportional to its blockage, and the overall thrust is consequently reduced. The CFD predictions are in very good agreement with experimental flow field data, demonstrating that RANS CFD can accurately predict the velocity and turbulent kinetic energy fields. While this initial design of a large scale wedge nozzle did not meet noise reduction or thrust goals, this study identified areas for improvement and demonstrated that RANS CFD can be used to improve the concept.

Description: As the aviation industry moves toward higher efficiency electrical power generation, all electric aircraft, or zero emissions and more quiet aircraft, fuel cells are sought as the technology that can deliver on these high expectations. The hybrid solid oxide fuel cell system combines the fuel cell with a micro-turbine to obtain up to 70% cycle efficiency, and then distributes the electrical power to the loads via a power distribution system. The challenge is to understand the dynamics of this complex multidiscipline system and the design distributed controls that take the system through its operating conditions in a stable and safe manner while maintaining the system performance. This particular system is a power generation and a distribution system, and the fuel cell and micro-turbine model fidelity should be compatible with the dynamics of the power distribution system in order to allow proper stability and distributed controls design. The novelty in this paper is that, first, the case is made why a high fidelity fuel cell mode is needed for systems control and stability designs. Second, a novel modeling approach is proposed for the fuel cell that will allow the fuel cell and the power system to be integrated and designed for stability, distributed controls, and other interface specifications. This investigation shows that for the fuel cell, the voltage characteristic should be modeled but in addition, conservation equation dynamics, ion diffusion, charge transfer kinetics, and the electron flow inherent impedance should also be included.

Description: An integrated team of NASA personnel, Government contractors, industry partners, and university staff have developed an innovative new technology for commercial fan cases that will substantially influence the safety and efficiency of future turbine engines. This effective team, under the direction of the NASA Glenn Research Center and with the support of the Federal Aviation Administration, has matured a new class of carbon/polymer composites and demonstrated a 30- to 50-percent improvement in specific containment capacity (blade fragment kinetic energy/containment system weight). As the heaviest engine component, the engine case/containment system greatly affects both the safety and efficiency of aircraft engines. The ballistic impact research team has developed unique test facilities and methods for screening numerous candidate material systems to replace the traditional heavy, metallic engine cases. This research has culminated in the selection of a polymer matrix composite reinforced with triaxially braided carbon fibers and technology demonstration through the fabrication of prototype engine cases for three major commercial engine manufacturing companies.

Description: Pollution-free flight is one of NASA s goals for the 21st century. One method of approaching that goal is to use hydrogen-fueled aircraft that use fuel cells or turbogenerators to produce electric power to drive electric motors that turn the aircraft s propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at hydrogen s boiling point of 20.5 K (-422.5 F). The liquid hydrogen could provide essentially free refrigeration to cool electric motor windings before being used as fuel. Either superconductivity or the low resistance of pure copper or aluminum in liquid hydrogen could be applied to greatly increase electric current density and motor power density.

Description: Ongoing research in NASA Glenn Research Center s Structural Mechanics and Dynamics Branch to develop smart materials technologies for adaptive aeropropulsion components has resulted in the design of a prototype variable-area exhaust nozzle (see the preceding photograph). The novel design exploits the potential of smart materials to improve the performance of existing fixed-area exhaust nozzles by introducing new capabilities for adaptive shape control, vibration damping, and flow manipulation. The design utilizes two different smart materials: shape memory alloy wires as actuators and magnetorheological fluids as damper locks.

Description: Large axial loads are induced on the rolling element bearings of a gas turbine. To extend bearing life, designers use pneumatic balance pistons to reduce the axial load on the bearings. A magnetic thrust bearing could replace the balance pistons to further reduce the axial load. To investigate this option, the U.S. Army Research Laboratory, the NASA Glenn Research Center, and Texas A&M University designed and fabricated a 7-in.- diameter magnetic thrust bearing to operate at 1000 F and 30,000 rpm, with a 1000-lb load capacity. This research was funded through a NASA Space Technology Transfer Act with Allison Advance Development Company under the Ultra-Efficient Engine Technology (UEET) Intelligent Propulsion Systems Foundation Technology project.

Description: With growing concerns about global warming, there is a need to develop pollution-free aircraft. One approach is to use hydrogen-fueled airc raft that use fuel cells or turbogenerators to produce electric power to drive the electric motors that turn the aircraft#s propulsive fan s. Hydrogen fuel would be carried as a liquid, stored at its boiling point of 20.5 K (-422.5 ?F). Conventional electric motors, however, are too heavy to use on an aircraft. We need to develop high-power, lig htweight electric motors (high-powerdensity motors).

Description: A subelement-level ultimate strength test was completed successfully at the NASA Glenn Research Center (http://www.nasa.gov/glenn/) on a large gamma titanium aluminide (TiAl) inlet flap demonstration piece. The test subjected the part to prototypical stress conditions by using unique fixtures that allowed both loading and support points to be located remote to the part itself (see the photograph). The resulting configuration produced shear, moment, and the consequent stress topology proportional to the design point. The test was conducted at room temperature, a harsh condition for the material because of reduced available ductility. Still, the peak experimental load-carrying capability exceeded original predictions.

Description: The NASA Glenn Research Center and academic partners are developing advanced multiagent robotic control algorithms that will enable the autonomous inspection and repair of future propulsion systems. In this application, on-wing engine inspections will be performed autonomously by large groups of cooperative miniature robots that will traverse the surfaces of engine components to search for damage. The eventual goal is to replace manual engine inspections that require expensive and time-consuming full engine teardowns and allow the early detection of problems that would otherwise result in catastrophic component failures. As a preliminary step toward the long-term realization of a practical working system, researchers are developing the technology to implement a proof-of-concept testbed demonstration. In a multiagent system, the individual agents are generally programmed with relatively simple controllers that define a limited set of behaviors. However, these behaviors are designed in such a way that, through the localized interaction among individual agents and between the agents and the environment, they result in self-organized, emergent group behavior that can solve a given complex problem, such as cooperative inspection. One advantage to the multiagent approach is that it allows for robustness and fault tolerance through redundancy in task handling. In addition, the relatively simple agent controllers demand minimal computational capability, which in turn allows for greater miniaturization of the robotic agents.

Description: Electric propulsion systems are quickly emerging as attractive options for primary propulsion in low Earth orbit, in geosynchronous orbit, and on interplanetary spacecraft. The driving force behind the acceptance of these systems is the substantial reduction in the propellant mass that can be realized. Unfortunately, system designers are often forced to utilize components designed for chemical propellants in their electric systems. Although functionally acceptable, these relatively large, heavy components are designed for the higher pressures and mass flow rates required by chemical systems. To fully realize the benefits of electric propulsion, researchers must develop components that are optimized for the low flow rates, critical leakage needs, low pressures, and limited budgets of these emerging systems.

Description: The gas turbine industry used a variety of sealing mechanisms to contain and direct secondary flows into and around components for cooling, and to limit leakage into and from bearing and disk cavities. The function of these seals is very important to the component efficiencies and attendant engine performance. Most of these seals are labyrinth seals, which are high-leakage seals that are costly to manufacture. In recent years, brush seals have been introduced which have demonstrated significantly reduced leakage, although they are still expensive and have exhibited wear and hysteresis difficulties. A new innovative concept called finger seal, patented by AlliedSignal, has demonstrated leakage similar to brush seals and is cheaper. The finger seal is comprised of a stack of precision photo-etched sheet metal elements, which allows intricate features to be made at very low cost and with the potential to resist wear and provide the compliance necessary to accomodate rotor excursions. Initial testing in the high-speed/high-temperature seal test facility, at the NASA Lewis Research Center, has corroborated the finger seal performance. The testing also revealed hysteresis problems with the current design. A NASA funded research project is in progress to correct the functional deficiencies of the finger seal and to refine its features to provide sufficient seal life for commercial transport engines and other long-life applications. This research will benefit the aeronautical gas turbine industry as a whole in terms of fuel consumption, operational characteristics, and cost. The first phase of this research to reduce finger seal hysteresis has been in progress for the last one year. This paper presents the results of this research to date. In future the research program will address seal performance, manufacturing, cost and life issues. The research program is expected to be completed by December 1998.

Description: A 36" diameter aspirating face seal for aircraft engine application has undergone extensive testing and analysis. Previous testing indicated that the seal tended to seek equilibrium at axial rotor clearances that were larger than expected. Parameter studies were conducted on several seal design parameters to evaluate effect on seal performance. Mixing of air flows from the air dam and air bearing regions of the seal was shown to have a significant impact on the seal's performance. Two methods of minimizing this flow interaction were studied both analytically and experimentally. The first method is to reduce the labyrinth tooth clearance, thereby limiting flow to the air dam itself. The second method involves utilizing a flow deflector between the air dam and air bearing regions of the seal in order to prevent radial flow from the air dam from disrupting the formation of a hydrostatic film at the air bearing. Both methods were shown to be effective design enhancements, allowing seal closure to be achieved. In both cases, the seal seeks an equilibrium position 0.0015" from the rotor surface, with corresponding low leakage rates.

Description: Experiments are being conducted to gain an understanding of the physics of rim scale cavity ingestion in a turbine stage with the high-work, single-stage characteristics envisioned for Advanced Subsonic Transport (AST) aircraft gas turbine engines fo the early 21st century. Initial experimental measurements to be presented include time-averaged turbine rim cavity and main gas path static pressure measurements for rim seal coolant to main gas path mass flow ratios between 0 and 0.02. The ultimate objective of this work is develop improved rim seal design concepts for use in modern high-work, single sage turbines n order to minimize the use of secondary coolant flow. Toward this objective the time averaged and unsteady data to be obtained in these experiments will be used to 1) Quantify the impact of the rim cavity cooling air on the ingestion process. 2) Quantify the film cooling benefits of the rim cavity purge flow in the main gas path. 3) Quantify the impact of the cooling air on turbine efficiency. 4) Develop/evaluate both 3D CFD and analytical models of the ingestion/cooling process.

Description: Engine external components include all the fluid carrying, electron carrying, and support devices that are needed to operate the propulsion system. These components are varied and include: pumps, valves, actuators, solenoids, sensors, switches, heat exchangers, electrical generators, electrical harnesses, tubes, ducts, clamps and brackets. The failure of any component to perform its intended function will result in a maintenance action, a dispatch delay, or an engine in flight shutdown. The life of each component, in addition to its basic functional design, is closely tied to its thermal and dynamic environment .Therefore, to reach a mature design life, the component's thermal and dynamic environment must be understood and controlled, which can only be accomplished by attention to design analysis and testing. The purpose of this paper is to review analysis and test techniques toward achieving good component health.

Description: Numerical computation predicts that an elastic support can substantially improve the stability of the wave bearing if the dynamic stiffness and damping of this support are in a specific range of values. To experimentally validate this prediction, the housing of a gas bearing was mounted on elastic O-rings and the threshold of sub-synchronous whirl motion was experimentally observed when the bearing runs unloaded with a rotating speed up to 30,000 RPM. The O-ring system was also dynamically characterized by measuring its stiffness and damping at various frequencies up to 500 Hz. Good correlation exists between the experimental data and numerical prediction.

Description: The combuster section of the High Speed Civil Transport (HSCT) requires high temperature seals to minimize leakage between CMC components. The temperature requirements range from 1500 F to 2100 F and the compression requirements range from 10% to 50%. Three distinctly different Nextel braided seals have been developed to seal areas such as the bulkhead heatshields and lean zone outer liner. The seals range from 0.10" dia. rope to triangular braid with 1" sides.

Description: The leading Aeronautics program within NASA is the High Speed Research Program (HSR). The HSR program's highest priorities are high pay-off technologies for airframe and propulsion systems required for a high speed civil transport (HSCT). These priorities have been developed collaboratively with NASA, FAA and the US Industry (Boeing-McDonnell Douglas, Pratt & Whitney and General Electric). Phase one of the HSR program started on 1990, and concentrated on the environmental challenges of minimizing NOx and noise. The first program goal is to reduce the NOx emission index to less than 5 (Concord NOx index is 20 and is unacceptable), in order to have little impact on the earth's ozone layer. The second goal is to reduce noise levels to FAR Stage 3 (or better), comparable to those of subsonic aircraft (far below the Concorde noise levels that require exemptions form less stringent standards). This requirement greatly impacts the nozzle design increasing its length and complexity and poses unique sealing challenges. Phase two started in 1993 and initiated work on the technologies required for an economical HSCT. Materials technologies under development include a ceramic-matrix-composite combustion liner, lightweight materials for the nozzle, as well long-life turbomachinery disk and blade alloys. Other required materials are being developed under the DOD-IHPTET program, where there is close cooperation. Economic goals translate into the development of technologies for tri-class service, 5000 nautical mile range aircraft with a ticket price no more than 20% over the subsonic ticket price. The potential market could be as large as 1500 aircraft, according to a Boeing study. Technology alone will not enable this airplane, yet without enabling technologies "on the shelf", it will not occur. The HSCT engine will be the largest engine ever built and operate at maximum conditions for long periods of time posing a number of challenges. The HSR engine mission requires that rotating equipment stay at take-off condition temperatures for hours not minutes per flight. Hence rotating equipment and seals must operate for many thousands of hours at extreme temperatures. It is anticipated that the nozzle will be 12 feet long and roughly 4 ft. by 5 ft. in cross-section with a nominal airflow of 800 lbs/sec. The complex function of the nozzle (including an ejector for noise attenuation) combined with long life place new demands on nozzle seal design. Three inlet configurations are under consideration with attendant sealing challenges, as will be illustrated herein. Four of these engines are required to propel a 5000 nautical mile class vehicle which demand that component reliability be at the highest possible level. In response, an HSR seals session was implemented as a part of the 1997-Seals and Secondary Flow Workshop. Overview presentations were given for each of the following areas: inlet, turbomachinery, combustor and nozzle. The HSCT seal issues center on durability and efficiency of rotating equipment seals (including brush seals), structural seals (including rope seals and other advanced concepts), and high-speed bearing and sump seals. Tighter clearances, propulsion system size and thermal requirements represent extremes that challenge the component designers. This document provides an initial step toward defining HSR seal needs. The overview for HSR seal designs includes, defining seal objectives, summarizing sealing and materials requirements, presenting relevant seal cross-sections, and identifying technology needs for the HSR office.

Description: Results of a numerical analysis evaluating the feasibility of high-temperature shape memory alloys (HTSMA) for active clearance control actuation in the high-pressure turbine section of a modern turbofan engine has been conducted. The prototype actuator concept considered here consists of parallel HTSMA wires attached to the shroud that is located on the exterior of the turbine case. A transient model of an HTSMA actuator was used to evaluate active clearance control at various operating points in a test bed aircraft engine simulation. For the engine under consideration, each actuator must be designed to counteract loads from 380 to 2000 lbf and displace at least 0.033 in. Design results show that an actuator comprised of 10 wires 2 in. in length is adequate for control at critical engine operating points and still exhibit acceptable failsafe operability and cycle life. A proportional-integral-derivative (PID) controller with integrator windup protection was implemented to control clearance amidst engine transients during a normal mission. Simulation results show that the control system exhibits minimal variability in clearance control performance across the operating envelope. The final actuator design is sufficiently small to fit within the limited space outside the high-pressure turbine case and is shown to consume only small amounts of bleed air to adequately regulate temperature.

Description: The usage and integrated vehicle health management of the NASA C-17. Propulsion health management flight objectives for the aircraft include mapping of the High Pressure Compressor in order to calibrate a Pratt and Whitney engine model and the fusion of data collected from existing sensors and signals to develop models, analysis methods and information fusion algorithms. An additional health manage flight objective is to demonstrate that the Commercial Modular Aero-Propulsion Systems Simulation engine model can successfully execute in real time onboard the C-17 T-1 aircraft using engine and aircraft flight data as inputs. Future work will address aircraft durability and aging, airframe health management, and propulsion health management research in the areas of gas path and engine vibration.

Description: The goal of doubling thrust-to-weight ratio for gas turbine engines has placed significant demands on engine component materials. Operating temperatures for static seals in the transition duct and turbine sections for instance, may well reach 2000 F within the next ten years. At these temperatures conventional age-hardenable superalloys lose their high strength via overaging and eventual dissolution of the gamma precipitate, and are well above their oxidation stability limit. Conventional solid-solution-strengthened alloys offer metallurgical stability, but suffer from rapid oxidation and little useful load bearing strength. Ceramic materials can theoretically be used at these temperatures, but manufacturing processes are in the developmental stages.

Description: This viewgraph presentation describes the effects of compression, staging and braid angle on braided rope seals. The contents include: 1) Test Fixture Schematics; 2) Comparison of Hybrid Seal Braid Architecture; 3) Residual Interference After Compression Cycling; 4) Effect of Compression, Braid, and Staging on Seal Flow; 5) Effect of Staging on Seal Pressure Drop; 6) Three Stag Seal Durability; 7) P&W Turbine Vane Seal Requirements; and 8) Next Generation Fighter F-22 P&W F119 Engines.

Description: It is common practice to use Pre-Swirl Nozzles to facilitate getting the turbine blade cooling air onboard the rotating disk with minimum pressure loss and reduced temperature. Higher engine OPR's and expanded aircraft operating envelopes have pushed cooling air temperatures to the limits of current disk materials and are stressing the capability to cool the blade with practical levels of cooling air flow. Providing 'Cooled' Cooling Air is one approach being considered to overcome these limitations. This presentation looks at how the introduction of 'Cooled' Cooling Air impacts the design of the Pre-Swirl Nozzles, specifically in relation to the radial location of the nozzles.

Description: The LM2500+ industrial aeroderivative gas turbine, a 25% enhanced power derivative of the LM2500 gas turbine, recently completed its development test program during the period 5/96 - 10/96. Early in the engine program a Quality Function Deployment (QFD) process was used to determine customer needs for this project.The feedback obtained from the QFD process showed without doubt that gas turbine customers now emphasize product reliability and availability at the top of their needs. One area of development on the LM2500+ was to investigate the use of a brush seal as a means to reduce undesirable turbine cooling leakages within the turbine mid frame in order to enhance part life. This presentation presents a case study on the factors that went into evaluating a brush seal during engine test, test results, and the ultimate decision not to implement the brush seal for cost and other reasons.

Description: Detailed information of the flow-fields in the secondary flowpaths and their interaction with the primary flows in gas turbine engines is necessary for successful designs with optimized secondary flow streams. Present work is focused on the development of a simulation methodology for coupled time-accurate solutions of the two flowpaths. The secondary flowstream is treated using SCISEAL, an unstructured adaptive Cartesian grid code developed for secondary flows and seals, while the mainpath flow is solved using TURBO, a density based code with capability of resolving rotor-stator interaction in multi-stage machines. An interface is being tested that links the two codes at the rim seal to allow data exchange between the two codes for parallel, coupled execution. A description of the coupling methodology and the current status of the interface development is presented. Representative steady-state solutions of the secondary flow in the UTRC HP Rig disc cavity are also presented.

Description: Efforts are in progress to develop advanced sealing for large utility industrial gas turbine engines (combustion turbines). Such seals have been under developed for some time for aero gas turbines. It is desired to transition this technology to combustion turbines. Brush seals, film riding face and circumferential seals, and other dynamic and static sealing approaches are being incorporated into gas turbines for aero applications by several engine manufacturers. These seals replace labyrinth or other seals with significantly reduced leakage rates. For utility industrial gas turbines, leakage reduction with advanced sealing can be even greater with the enormous size of the components. Challenges to transitioning technology include: extremely long operating times between overhauls; infrequent but large radial and axial excursions; difficulty in coating larger components; and maintenance, installation, and durability requirements. Advanced sealing is part of the Advanced Turbine Systems (ATS) engine development being done under a cooperative agreement between Westinghouse and the US Department of Energy, Office of Fossil Energy. Seal development focuses on various types of seals in the 501ATS engine both at dynamic and static locations. Each development includes rig testing of candidate designs and subsequent engine validation testing of prototype seals. This presentation gives an update of the ongoing ATS sealing efforts with special emphasis on brush seals.

Description: Market forces are driving industry to reproduce product cycle time (the time required to conceive, design, build, test, validate and deliver a product). Application of existing tools in new areas can reduce the time required to design a new product and increase the confidence of acceptable test results later in the expensive testing and validation phase. Finite element methods, computational fluid dynamics codes and sharing of CAD datasets when applied to the design of engine externals can provide methods for product improvement and expedited delivery to the customer.

Description: As part of a general investigation of propellers at high forward speeds, tests of two 2-blade propellers having the NACA 4-(3)(8)-03 and NACA 4-(3)(8)-45 blade designs have been made in the Langley 8-foot high-speed tunnel through a range of blade angle from 20 degrees to 60 degrees for forward Mach numbers from 0.165 to 0.725 to establish in detail the changes in propeller characteristics due to compressibility effects. These propellers differed primarily only in blade solidity, one propeller having 50 percent and more solidity than the other. Serious losses in propeller efficiency were found as the propeller tip Mach number exceeded 0.91, irrespective of forward speed or blade angle. The magnitude of the efficiency losses varied from 9 percent to 22 percent per 0.1 increase in tip Mach number above the critical value. The range of advance ratio for peak efficiency decreased markedly with increase of forward speed. The general form of the changes in thrust and power coefficients was found to be similar to the changes in airfoil lift coefficient with changes in Mach number. Efficiency losses due to compressibility effects decreased with increase of blade width. The results indicated that the high level of propeller efficiency obtained at low speeds could be maintained to forward sea-level speeds exceeding 500 miles per hour.

Description: An investigation has been made to explore the possibilities of axial-flow compressors operating with supersonic velocities into the blade rows. Preliminary calculations showed that very high pressure ratios across a stage, together with somewhat increased mass flows, were apparently possible with compressors which decelerated air through the speed of sound in their blading. The first phase of the investigation was the development of efficient supersonic diffusers to decelerate air through the speed of sound. The present report is largely a general discussion of some of the essential aerodynamics of single-stage supersonic axial-flow compressors. As an approach to the study of supersonic compressors, three possible velocity diagrams are discussed briefly. Because of the encouraging results of this study, an experimental single-stage supersonic compressor has been constructed and tested in Freon-12. In this compressor, air decelerates through the speed of sound in the rotor blading and enters the stators at subsonic speeds. A pressure ratio of about 1.8 at an efficiency of about 80 percent has been obtained.

Description: An analysis of combined heat and mass transfer from a flat plate has been made in terms of Prandtl t s simplified physical concept of the turbulent boundary layer. The results of the analysis show that for conditions of reasonably small heat and mass transfer, the ratio of the mass-and heat-transfer coefficients is dependent on the Reynolds number of the boundary layer, the Prandtl number of the medium of diffusion, and the Schmidt number of the diffusing fluid in the medium of diffusion. For the particular case of water evaporating into air, the ratio of mass-transfer coefficient to heat-transfer coefficient is found to be slightly greater than unity.

Description: The trajectories of droplets in the air flowing past an NACA 65AO04 airfoil at an angle of attack of 8 deg were determined.. The amount of water in droplet form impinging on the airfoil, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface were calculated from the trajectories and presented to cover a large range of flight and atmospheric conditions. These impingement characteristics are compared briefly with those previously reported for the same airfoil at an angle of attack of 4 deg.