ALBERT

Description: Tweestaarten Diplura behoren met de springstaarten Collembola en beentasters Protura tot de Entognatha. Dat zijn kleine ongevleugelde bodemdieren met zes poten, die zich onderscheiden van de insecten door hun verzonken monddelen. Tot nu toe waren twee soorten voor Nederland gemeld, maar voor België 13. Tijdens een onderzoek naar in mierennesten levende organismen werden twee soorten gevonden die nog niet uit Nederland bekend waren. Verder onderzoek zal zeker nog meer nieuwe tweestaarten kunnen opleveren.

Description: Larven van kriebelmuggen komen uitsluitend voor in stromend water, waar ze met hun waaiervormige monddelen deeltjes filteren uit het voorbij stromende water. Het zijn goede indicatoren voor zuurstofrijk water. Tot nu toe was niet duidelijk welke soorten precies voorkomen in Nederland en België en de determinatie van kriebelmuggen wordt vaak als lastig beschouwd. Om dit te verhelpen, presenteren we hier determinatietabellen voor alle in Nederland en België voorkomende soorten, zowel voor larven van het laatste stadium als voor poppen.

Description: De catalogus van de Nederlandse kevers uit 2010 geeft het meest recente overzicht van de Nederlandse kevers. Er staan 372 soorten loopkevers op deze lijst. Per soort wordt een overzicht gegeven van de provincies waaruit waarnemingen bekend zijn. Voor elk zogenaamd provincierecord is een collectie-exemplaar aangeduid als bewijsexemplaar. Sinds 2010 is er veel nieuwe informatie over loopkevers bekend geworden. In dit artikel worden de wijzigingen in de lijst toegelicht.

Description: Hoe een leek op het gebied van wespen en bijen toch een leuke vondst kan doen. Op zonnige dagen gaat de auteur regelmatig op ‘tuinsafari’. Een tuin waarin rekening wordt gehouden met vogels en insecten, door keuze van beplanting en het ophangen van insectenhotels. De inspanningen leverden op 23 juli 2014 een opvallende wesp op. In een bijna automatische reactie werden snel foto’s gemaakt, in de hoop ze later te kunnen determineren. De wesp vloog daarna weg en werd niet meer gezien. Na determinatie blijkt het reuzenertswesp Leucospis dorsigera te zijn, een nieuwe soort bronswesp voor Nederland.

Description: De gewone citroenzweefvlieg Xanthogramma pedissequum is een eenvoudig te herkennen zweefvlieg. Tenminste, dat dachten we tot voor kort. Nu blijkt dat de bijna identieke X. dives en X. stackelbergi ook in Nederland rondvliegen. Gelukkig zijn er enkele kenmerken waarmee deze drie soorten citroenzweefvlieg in het veld redelijk herkenbaar blijken. In dit artikel bespreken we deze kenmerken en geven we informatie over verspreiding en vliegtijden van de drie soorten.

Description: Wespblaaskoppen Leopoldius worden ondanks hun opvallende uiterlijk maar weinig waargenomen. De soorten zijn lastig van elkaar te onderscheiden en bovendien werden tot voor kort variabele kenmerken gebruikt, wat tot veel verwarring heeft geleid. Nu blijkt dat alleen vrouwtjes met zekerheid te herkennen zijn aan de vorm van het klampje. Dit is een lepelvormig uitsteeksel onder het vijfde achterlijfsegment. Het wordt gebruikt bij het afzetten van eieren op een gastheer. Waarschijnlijk zijn limonadewespen de belangrijkste gastheer van Leopoldius. In dit artikel wordt een nieuwe soort voor België en een nieuwe soort voor Luxemburg gemeld. Daarnaast wordt een overzicht geboden van waarnemingen in Nederland, België en Luxemburg en een sleutel tot de Noordwest-Europese soorten.

Description: Ondanks de fors toegenomen aandacht voor watermacrofauna sinds begin jaren 1980 is de schietmot Molanna albicans maar sporadisch aangetroffen. In dit artikel wordt de eerste larvenvondst van M. albicans buiten Drenthe beschreven. Samen met de vindplaatsen in Drenthe is de soort nu van vijf vennen in Nederland bekend. Aanvullend worden de determinatiekenmerken aan de hand van foto’s geïllustreerd.

Description: Caddisflies are a species rich insect order. The adults are moth-like, but their wings bear hairs instead of scales. The larvae are aquatic and live in self-constructed cases, made of plant material, sand or debris. The species are used as indicators of water quality, but much is still not known about their biology and ecology. In this paper the preferred substrates and phenology of the larvae of 13 species are described, using the data of a survey of two lowland streams in the east of the Netherlands.

Description: Slakkendodende vliegen danken hun naam aan hun roofzuchtige, parasitaire larven, die het op slakken gemunt hebben. Uit België en Nederland zijn circa 60 soorten uit deze familie bekend, maar er zijn er zeker meer te ontdekken. Dit artikel meldt een nieuwe soort voor de Nederlandse fauna uit het genus Psacadina, dat in beide landen drie soorten telt. De herkenning en het voorkomen van de drie soorten wordt uitgebreid besproken.

Description: Zwarte vliegen behoren tot de muggen, maar door hun korte antennen doen ze oppervlakkig aan vliegen denken. De mannetjes zien er met hun grote kop en grote ogen heel anders uit dan de vrouwtjes, die een kleine kop met kleine ogen hebben. In het voorjaar vormen sommige soorten opvallend grote zwermen op windluwe plekken. Aan de 17 soorten die reeds uit Nederland bekend waren, kan er nu één worden toegevoegd: Bibio venosus.

Description: Astrobunus laevipes is een hooiwagen die via het Rijnbekken recentelijk ons land is binnengekomen. Er waren al vondsten langs de Waal en Nederrijn in Gelderland en het meest oostelijke puntje van de provincie Utrecht. Door gerichte inventarisaties kunnen wij de hooiwagen nu nieuw voor de provincies Zuid-Holland en Noord-Brabant melden. Daarnaast is er van A. laevipes nu ook een waarneming langs de IJssel en enkele westelijker in de provincie Utrecht. Allerlei rivierbegeleidende biotopen langs (uitlopers van) de Nederrijn en Waal worden al door deze opmerkelijke hooiwagen bevolkt, maar de noordelijke uitbreiding via de IJsselvallei lijkt veel trager te verlopen. De Maas lijkt nog niet bereikt.

Description: De familie der sluipvliegen is één der soortenrijkste vliegenfamilies in ons land. De larven ontwikkelen zich inwendig in ongewervelden, veelal vlinderrupsen. De familie is in ons land relatief goed bestudeerd. In dit artikel wordt wederom een soort voor het eerst uit ons land vermeld. Hiermee komt het totaal aantal soorten dat in Nederland ooit vastgesteld is op 334.

Description: Mariene borstelwormen vormen een ecologisch belangrijke, soortenrijke groep. Van diverse families is niet veel bekend over het voorkomen in Nederland en de bamboewormen (familie Maldanidae) behoren tot de slechtst bekende groepen. Bamboewormen danken hun naam aan de lange en aan het uiteinde verdikte segmenten. In dit artikel wordt een nieuwe bamboeworm voor Nederland besproken en een opsomming gegeven van de nu bekende inheemse soorten.

Description: Slakkendodende vliegen zijn nog relatief slecht onderzocht in ons land, zeker de kleine soorten. De vertegenwoordigers van het genus Anticheta zijn kleine vliegjes, waarvan slechts twee soorten uit ons land bekend waren. Uitgebreider onderzoek, zowel in collecties als in het veld, heeft twee nieuwe soorten voor de fauna aan het licht gebracht: Anticheta nigra en A. obliviosa. Van de eerste soort waren wereldwijd slechts acht exemplaren bekend.

Description: Zelfs in een goed onderzochte insectengroep als de zweefvliegen zijn nog altijd nieuwe soorten voor de Nederlandse fauna te ontdekken. Ook in 2014 was het weer raak, dit keer in het fraaie natuurgebied rond de Drentsche Aa. Het lijkt niet toevallig dat deze aanvulling op de Nederlandse fauna juist hier werd gevonden. Deze vindplaats vult ecologische informatie uit het buitenland aan, waardoor langzamerhand een beeld begint te ontstaan van de levenswijze van deze zeldzame zweefvlieg, waarover tot voor kort weinig bekend was.

Description: De doornkaakzandbij ziet er in het voorjaar een beetje anders uit dan in de zomer. Daarom worden de voorjaarsdieren door sommigen tot een andere soort beschouwd dan de zomerdieren. Uit Nederland zijn slechts drie exemplaren bekend: twee uit het voorjaar en één uit de zomer. Toevallig komen alle exemplaren uit hetzelfde gebied. Of is dit geen toeval?

Description: Elfjes behoren tot de vroegste zweefvliegen die in het voorjaar uit de pop kruipen. Rond bloeiende wilgen wemelt het vaak van wilgenelfjes Melangyna lasiophthalma, waardoor het zoeken naar de zeldzamere soorten soms lastig is. Toch zijn de meeste soorten relatief makkelijk van elkaar te onderscheiden. Met de vondst van het Sachalinelfje M. pavlovskyi wordt het echter weer iets lastiger.

Description: Steltmuggen lijken op langpootmuggen en zijn daar nauw aan verwant. Veel soorten zijn groot en karakteristiek gekleurd, maar toch zijn ze in Nederland nog weinig bestudeerd. Dit artikel bewijst dat er nog veel te ontdekken valt: in één jaar tijd zijn drie soorten gevonden die nog niet uit ons land bekend waren: Atypophthalmus inustus, Molophilus niger en Arctoconopa melampodia. Hiermee komt het totaal aantal soorten voor Nederland op 149. De nieuwe meldingen sluiten goed aan op het bekende verspreidingsgebied.

Description: Jalla dumosa is een in Nederland zeer zeldzame pentatomide, die in 1969 voor het laatst was waargenomen op Terschelling. Na 45 jaren zonder waarnemingen werd ze in 2014 weer in klein aantal waargenomen in de Kooiduinen op Ameland. Rupsen van onder andere de duinparelmoervlinder en de sint-jansvlinder stonden daar op het menu. In deze bijdrage wordt informatie samengevat over de vondsten in Nederland, de biologie en de verspreiding van de soort.

Description: In August 2014 the exotic jellyfish Blackfordia virginica was captured in the harbour of Amsterdam. This is the first confirmed record of this species in the Netherlands, although in October 2013 a possible specimen was filmed and released. This indicates that the species might be established in the Amsterdam area, although repeated introduction with ballast water cannot be ruled out. In September 2014 hydrozoan polyp colonies closely resembling those of B. virginica were collected near IJmuiden in the Noordzeekanaal, a canal connecting Amsterdam with the North Sea at IJmuiden.

Description: Wie een steen of boomstronk omkeert en voor het eerst een Trogulus opmerkt, zal dit bizarre beest niet direct associëren met een hooiwagen. Met de korte, stevige poten, het afgeplatte achterlijf dat overdekt is met strooisel en zand, en een trage manier van voortbewegen is het een ongewone verschijning. De soorten van dit geslacht zijn bodembewoners die zich voornamelijk voeden met kleine huisjesslakken. Uit ons land waren tot nu toe twee soorten bekend. De identiteit van een van die twee was lang onzeker, maar door nieuwe inzichten is nu duidelijk om welke soort het werkelijk gaat. In Nederland blijkt bovendien nog een derde soort voor te komen, die hier voor het eerst gemeld wordt.

Description: Roofvliegen zijn met 40 Nederlandse soorten een vrij kleine groep, die behoorlijk goed is onderzocht. Het gebeurt dan ook niet vaak dat er een nieuwe soort voor de Nederlandse fauna kan worden opgetekend. De meeste roofvliegen zijn grijze vliegen, zo niet de stamjagers van het genus Choerades. Dit zijn juist vrij opvallend gekleurde vliegen. Zo heeft de rode dennenstamjager Choerades gilvus een rood gekleurd achterlijf. Opmerkelijk genoeg blijkt dat in Nederland juist onder deze opvallende verschijning twee soorten schuilgaan.

Description: Onlangs werd op een braakliggend terrein in Roermond de zaadkever Bruchus brachialis verzameld. Dit is de eerste Nederlandse vondst van deze zuidelijke soort. Een reeks recente waarnemingen uit de ons omringende landen laat zien dat deze soort al enige jaren in een noordwaartse areaaluitbreiding verwikkeld is. Met deze ontdekking komt het aantal Nederlandse Bruchus-soorten op zeven.

Description: Nieuw gevormd landschap, zoals jonge duinvalleien, opgespoten polders en bedrijventerreinen in ontwikkeling vormen de habitat van gespecialiseerde soorten. Je moet tegen een stootje kunnen om in een dergelijke zandige, schaars begroeide omgeving te overleven. Vooral langdurig warme, droge perioden vormen een probleem voor vochtminnende bodemdieren. De springstaartsoorten die hier overleven zijn warmteminnend en droogteresistent, een bijzondere combinatie voor bodemdieren. Dit geldt ook voor Entomobrya unostrigata, een nieuwe aanwinst voor de fauna van Noordwest-Europa. Er is een aantal populaties van deze soort op de Tweede Maasvlakte gevonden. De dieren zaten hier onder stenen en hout op opgespoten zand.

Description: De Polychaeta vormen een groep van vrijwel uitsluitend mariene wormen, gekenmerkt door een geleed lichaam met aan de meeste leden een tamelijk groot aantal borstels. Het is een soortenrijke groep; ze spelen een belangrijke rol in de ecologie en diversiteit van vooral zachte, maar ook harde zeebodems. In vergelijking met de kreeftachtigen en weekdieren, eveneens soortenrijke groepen in dezelfde biotoop, zijn borstelwormen minder goed onderzocht. In dit artikel wordt de zeerups Fimbriosthenelais minor nieuw voor ons land gemeld. Met name op stenige en schelprijke bodems zijn nog meer nieuwe borstelwormen voor ons land te verwachten.

Description: Het kalkdoorntje is een zeldzame sprinkhanensoort, die vooral bekend is uit Zuid-Limburg en van enkele locaties in het rivierengebied. Over het voorkomen van dit kleine sprinkhaantje binnen de Gelderse Poort was lange tijd weinig bekend. Pas vanaf 2007 worden regelmatig waarnemingen gedaan. Toevallige waarnemingen op, voor de auteur, onverwachte locaties vormden de aanleiding voor een grondige inventarisatie in de jaren 2011-2013. Hieruit komt naar voren dat het kalkdoorntje een ruime verspreiding heeft binnen de Gelderse Poort en een meer diverse biotoopkeuze heeft dan voorheen bekend was.

Description: One of the greatest challenges when developing propulsion systems is predicting the interacting effects between the fluid loads, thermal loads, and structural deflection. The interactions between technical disciplines often are not fully analyzed, and the analysis in one discipline often uses a simplified representation of other disciplines as an input or boundary condition. For example, the fluid forces in an engine generate static and dynamic rotor deflection, but the forces themselves are dependent on the rotor position and its orbit. It is important to consider the interaction between the physical phenomena where the outcome of each analysis is heavily dependent on the inputs (e.g., changes in flow due to deflection, changes in deflection due to fluid forces). A rigid design process also lacks the flexibility to employ multiple levels of fidelity in the analysis of each of the components. This project developed and validated an innovative design environment that has the flexibility to simultaneously analyze multiple disciplines and multiple components with multiple levels of model fidelity. Using NASA's open-source multidisciplinary design analysis and optimization (OpenMDAO) framework, this multifaceted system will provide substantially superior capabilities to current design tools.

Description: Computational and experimental analyses of a PICS-Pilot-In-Can-Swirler technology injector, developed by United Technologies Research Center (UTRC) are presented. NASA has defined technology targets for near term (called "N+1", circa 2015), midterm ("N+2", circa 2020) and far term ("N+3", circa 2030) that specify realistic emissions and fuel efficiency goals for commercial aircraft. This injector has potential for application in an engine to meet the Pratt & Whitney N+3 supersonic cycle goals, or the subsonic N+2 engine cycle goals. Experimental methods were employed to investigate supersonic cruise points as well as select points of the subsonic cycle engine; cruise, approach, and idle with a slightly elevated inlet pressure. Experiments at NASA employed gas analysis and a suite of laser-based measurement techniques to characterize the combustor flow downstream from the PICS dump plane. Optical diagnostics employed for this work included Planar Laser-Induced Fluorescence of fuel for injector spray pattern and Spontaneous Raman Spectroscopy for relative species concentration of fuel and CO2. The work reported here used unheated (liquid) Jet-A fuel for all fuel circuits and cycle conditions. The initial tests performed by UTRC used vaporized Jet-A to simulate the expected supersonic cruise condition, which anticipated using fuel as a heat sink. Using the National Combustion Code a PICS-based combustor was modeled with liquid fuel at the supersonic cruise condition. All CFD models used a cubic non-linear k-epsilon turbulence wall functions model, and a semi-detailed Jet-A kinetic mechanism based on a surrogate fuel mixture. Two initial spray droplet size distribution and spray cone conditions were used: 1) an initial condition (Lefebvre) with an assumed Rosin-Rammler distribution, and 7 degree Solid Spray Cone; and 2) the Boundary Layer Stripping (BLS) primary atomization model giving the spray size distribution and directional properties. Contour and line plots are shown in comparison with experimental data (where this data is available) for flow velocities, fuel, and temperature distribution. The CFD results are consistent with experimental observations for fuel distribution and vaporization. Analysis of gas sample results, using a previously-developed NASA NOx correlation, indicates that for sea-level takeoff, the PICS configuration is predicted to deliver an EINOx value of about 3 for the targeted supersonic aircraft. Emissions results at supersonic cruise conditions show potential for meeting the NASA goals with liquid fuel.

Description: This paper summarizes the procedures of inserting a thin-layer mesh to existing inviscid polyhedral mesh either with or without hanging-node elements as well as presents sample results from its applications to the numerical solution of a single-element LDI combustor using a releasable edition of the National Combustion Code (NCC).

Description: This lecture will provide an overview of the aircraft turbine engine control research at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC). A brief introduction to the engine control problem is first provided with a description of the current state-of-the-art control law structure. A historical aspect of engine control development since the 1940s is then provided with a special emphasis on the contributions of GRC. The traditional engine control problem has been to provide a means to safely transition the engine from one steady-state operating point to another based on the pilot throttle inputs. With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at GRC is leading and participating in various projects in partnership with other organizations within GRC and across NASA, other government agencies, the U.S. aerospace industry, and academia to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA programs under the Aeronautics Research Mission. The second part of the lecture provides an overview of the various CDB technology development activities in aircraft engine control and diagnostics, both current and some accomplished in the recent past. The motivation for each of the research efforts, the research approach, technical challenges and the key progress to date are summarized. The technologies to be discussed include system level engine control concepts, gas path diagnostics, active component control, and distributed engine control architecture. The lecture will end with a futuristic perspective of how the various current technology developments will lead to an Intelligent and Autonomous Propulsion System requiring none to very minimum pilot interface, interfacing directly with the flight management system to determine its mode of operation, and providing personalized engine control to optimize its performance given the current condition and mission objectives.

Description: Future civil transport designs may incorporate engine inlets integrated into the body of the aircraft to take advantage of efficiency increases due to weight and drag reduction. Additional increases in engine efficiency are predicted if the inlet ingests the lower momentum boundary layer flow. Previous studies have shown, however, that efficiency benefits of Boundary Layer Ingesting (BLI) ingestion are very sensitive to the magnitude of fan and duct losses, and blade structural response to the non-uniform flow field that results from a BLI inlet has not been studied in-depth. This paper presents an effort to extend the modeling capabilities of an existing rotating turbomachinery unsteady analysis code to include the ability to solve the external and internal flow fields of a BLI inlet. The TURBO code has been a successful tool in evaluating fan response to flow distortions for traditional engine/inlet integrations, such as the development of rotating stall and inlet distortion through compressor stages. This paper describes the first phase of an effort to extend the TURBO model to calculate the external and inlet flowfield upstream of fan so that accurate pressure distortions that result from BLI configurations can be computed and used to analyze fan aerodynamics and structural response. To validate the TURBO program modifications for the BLI flowfield, experimental test data obtained by NASA for a flushmounted S-duct with large amounts of boundary layer ingestion was modeled. Results for the flow upstream and in the inlet are presented and compared to experimental data for several high Reynolds number flows to validate the modifications to the solver. Quantitative data is presented that indicates good predictive capability of the model in the upstream flow. A representative fan is attached to the inlet and results are presented for the coupled inlet/fan model. The impact on the total pressure distortion at the AIP after the fan is attached is examined.

Description: This paper presents a model-based architecture for performance trend monitoring and gas path fault diagnostics designed for analyzing streaming transient aircraft engine measurement data. The technique analyzes residuals between sensed engine outputs and model predicted outputs for fault detection and isolation purposes. Diagnostic results from the application of the approach to test data acquired from an aircraft turbofan engine are presented. The approach is found to avoid false alarms when presented nominal fault-free data. Additionally, the approach is found to successfully detect and isolate gas path seeded-faults under steady-state operating scenarios although some fault misclassifications are noted during engine transients. Recommendations for follow-on maturation and evaluation of the technique are also presented.

Description: Boundary layer ingesting propulsion systems have the potential to significantly reduce fuel burn for future generations of commercial aircraft, but these systems must be designed to overcome the challenge of high dynamic stresses in fan blades due to forced response. High dynamic stresses can lead to high cycle fatigue failures. High-fidelity computational analysis of the fan aeromechanics is integral to an ongoing effort to design a boundary layer ingesting inlet and fan for a wind-tunnel test. An unsteady flow solution from a Reynoldsaveraged Navier Stokes analysis of a coupled inlet-fan system is used to calculate blade unsteady loading and assess forced response of the fan to distorted inflow. Conducted prior to the mechanical design of a fan, the initial forced response analyses performed in this study provide an early look at the levels of dynamic stresses that are likely to be encountered. For the boundary layer ingesting inlet, the distortion contains strong engine order excitations that act simultaneously. The combined effect of these harmonics was considered in the calculation of the forced response stresses. Together, static and dynamic stresses can provide the information necessary to evaluate whether the blades are likely to fail due to high cycle fatigue. Based on the analyses done, the overspeed condition is likely to result in the smallest stress margin in terms of the mean and alternating stresses. Additional work is ongoing to expand the analyses to off-design conditions, on-resonance conditions, and to include more detailed modeling of the blade structure.

Description: This presentation contains Wind-US results presented at the 2nd Propulsion Aerodynamics Workshop. The workshop was organized by the American Institute of Aeronautics and Astronautics, Air Breathing Propulsion Systems Integration Technical Committee with the purpose of assessing the accuracy of computational fluid dynamics for air breathing propulsion applications. Attendees included representatives from government, industry, academia, and commercial software companies. Participants were encouraged to explore and discuss all aspects of the simulation process including the effects of mesh type and refinement, solver numerical schemes, and turbulence modeling. The first set of challenge cases involved computing the thrust and discharge coefficients for a 25deg conical nozzle for a range of nozzle pressure ratios between 1.4 and 7.0. Participants were also asked to simulate two cases in which the 25deg conical nozzle was bifurcated by a solid plate, resulting in vortex shedding (NPR=1.6) and shifted plume shock (NPR=4.0). A second set of nozzle cases involved computing the discharge and thrust coefficients for a convergent dual stream nozzle for a range of subsonic nozzle pressure ratios. The workshop committee also compared the plume mixing of these cases across various codes and models. The final test case was a serpentine inlet diffuser with an outlet to inlet area ratio of 1.52 and an offset of 1.34 times the inlet diameter. Boundary layer profiles, wall static pressure, and total pressure at downstream rake locations were examined.

Description: This paper presents a model-based architecture for performance trend monitoring and gas path fault diagnostics designed for analyzing streaming transient aircraft engine measurement data. The technique analyzes residuals between sensed engine outputs and model predicted outputs for fault detection and isolation purposes. Diagnostic results from the application of the approach to test data acquired from an aircraft turbofan engine are presented. The approach is found to avoid false alarms when presented nominal fault-free data. Additionally, the approach is found to successfully detect and isolate gas path seeded-faults under steady-state operating scenarios although some fault misclassifications are noted during engine transients. Recommendations for follow-on maturation and evaluation of the technique are also presented.

Description: Recent calculations of pulse-combustors operating at high-pressure conditions produced pressure gains significantly lower than those observed experimentally and computationally at atmospheric conditions. The factors limiting the pressure-gain at high-pressure conditions are identified, and the effects of fuel injection and air mixing characteristics on performance are investigated. New pulse-combustor configurations were developed, and the results show that by suitable changes to the combustor geometry, fuel injection scheme and valve dynamics the performance of the pulse-combustor operating at high-pressure conditions can be increased to levels comparable to those observed at atmospheric conditions. In addition, the new configurations can significantly reduce the levels of NOx emissions. One particular configuration resulted in extremely low levels of NO, producing an emission index much less than one, although at a lower pressure-gain. Calculations at representative cruise conditions demonstrated that pulse-combustors can achieve a high level of performance at such conditions.

Description: A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the lowboom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.

Description: Distributed Engine Control (DEC) is an enabling technology that has the potential to advance the state-of-the-art in gas turbine engine control. To analyze the capabilities that DEC offers, a Hardware-In-the-Loop (HIL) test bed is being developed at NASA Glenn Research Center. This test bed will support a systems-level analysis of control capabilities in closed-loop engine simulations. The structure of the HIL emulates a virtual test cell by implementing the operator functions, control system, and engine on three separate computers. This implementation increases the flexibility and extensibility of the HIL. Here, a method is discussed for implementing these interfaces by connecting the three platforms over a dedicated Local Area Network (LAN). This approach is verified using the Commercial Modular Aero-Propulsion System Simulation 40k (C-MAPSS40k), which is typically implemented on one computer. There are marginal differences between the results from simulation of the typical and the three-computer implementation. Additional analysis of the LAN network, including characterization of network load, packet drop, and latency, is presented. The three-computer setup supports the incorporation of complex control models and proprietary engine models into the HIL framework.

Description: This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

Description: NASA's Rotary Wing Project is investigating technologies that will enable the development of revolutionary civil tilt rotor aircraft. Previous studies have shown that for large tilt rotor aircraft to be viable, the rotor speeds need to be slowed significantly during the cruise portion of the flight. This requirement to slow the rotors during cruise presents an interesting challenge to the propulsion system designer as efficient engine performance must be achieved at two drastically different operating conditions. One potential solution to this challenge is to use a transmission with multiple gear ratios and shift to the appropriate ratio during flight. This solution will require a large transmission that is likely to be maintenance intensive and will require a complex shifting procedure to maintain power to the rotors at all times. An alternative solution is to use a fixed gear ratio transmission and require the power turbine to operate efficiently over the entire speed range. This concept is referred to as a variable-speed power-turbine (VSPT) and is the focus of the current study. This paper explores the design of a variable speed power turbine for civil tilt rotor applications using design optimization techniques applied to NASA's new meanline tool, the Object-Oriented Turbomachinery Analysis Code (OTAC).

Description: The Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS) is a tool that has been developed to allow a user to build custom models of systems governed by thermodynamic principles using a template to model each basic process. Validation of this tool in an engine model application was performed through reconstruction of the Commercial Modular Aero-Propulsion System Simulation (C-MAPSS) (v2) using the building blocks from the T-MATS (v1) library. In order to match the two engine models, it was necessary to address differences in several assumptions made in the two modeling approaches. After these modifications were made, validation of the engine model continued by integrating both a steady-state and dynamic iterative solver with the engine plant and comparing results from steady-state and transient simulation of the T-MATS and C-MAPSS models. The results show that the T-MATS engine model was accurate within 3 of the C-MAPSS model, with inaccuracy attributed to the increased dimension of the iterative solver solution space required by the engine model constructed using the T-MATS library. This demonstrates that, given an understanding of the modeling assumptions made in T-MATS and a baseline model, the T-MATS tool provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

Description: A two-dimensional, computational fluid dynamic (CFD) simulation of a semi-idealized rotating detonation engine (RDE) is described. The simulation operates in the detonation frame of reference and utilizes a relatively coarse grid such that only the essential primary flow field structure is captured. This construction yields rapidly converging, steady solutions. Results from the simulation are compared to those from a more complex and refined code, and found to be in reasonable agreement. The performance impacts of several RDE design parameters are then examined. Finally, for a particular RDE configuration, it is found that direct performance comparison can be made with a straight-tube pulse detonation engine (PDE). Results show that they are essentially equivalent.

Description: Advances in electric machine efficiency and energy storage capability are enabling a new alternative to traditional propulsion systems for aircraft. This has already begun with several small concept and demonstration vehicles, and NASA projects this technology will be essential to meet energy and emissions goals for commercial aviation in the next 30 years. In order to raise the Technology Readiness Level of electric propulsion systems, practical integration and performance challenges will need to be identified and studied in the near-term so that larger, more advanced electric propulsion system testbeds can be designed and built. Researchers at NASA Armstrong Flight Research Center are building up a suite of test articles for the development, integration, and validation of these systems in a real world environment.

Description: The objective of this paper is to describe an accurate and efficient reduced order modeling method for aeroelastic (AE) analysis and for determining the flutter boundary. Without losing accuracy, we develop a reduced order model based on the Volterra series to achieve significant savings in computational cost. The aerodynamic force is provided by a high-fidelity solution from the Reynolds-averaged Navier-Stokes (RANS) equations; the structural mode shapes are determined from the finite element analysis. The fluid-structure coupling is then modeled by the state-space formulation with the structural displacement as input and the aerodynamic force as output, which in turn acts as an external force to the aeroelastic displacement equation for providing the structural deformation. NASA's rotor 67 blade is used to study its aeroelastic characteristics under the designated operating condition. First, the CFD results are validated against measured data available for the steady state condition. Then, the accuracy of the developed reduced order model is compared with the full-order solutions. Finally the aeroelastic solutions of the blade are computed and a flutter boundary is identified, suggesting that the rotor, with the material property chosen for the study, is structurally stable at the operating condition, free of encountering flutter.

Description: No abstract available

Description: The ability to monitor the structural health of the rotating components, especially in the hot sections of turbine engines, is of major interest to aero community in improving engine safety and reliability. The use of instrumentation for these applications remains very challenging. It requires sensors and techniques that are highly accurate, are able to operate in a high temperature environment, and can detect minute changes and hidden flaws before catastrophic events occur. The National Aeronautics and Space Administration (NASA) has taken a lead role in the investigation of new sensor technologies and techniques for the in situ structural health monitoring of gas turbine engines. As part of this effort, microwave sensor technology has been investigated as a means of making high temperature non-contact blade tip clearance, blade tip timing, and blade vibration measurements for use in gas turbine engines. This paper presents a summary of key results and findings obtained from the evaluation of two different types of microwave sensors that have been investigated for use possible in structural health monitoring applications. The first is a microwave blade tip clearance sensor that has been evaluated on a large scale Axial Vane Fan, a subscale Turbofan, and more recently on sub-scale turbine engine like disks. The second is a novel microwave based blade vibration sensor that was also used in parallel with the microwave blade tip clearance sensors on the experiments with the sub-scale turbine engine disks.

Description: This report presents results of the work completed in Phase 2 of the Engine Validation of Noise Reduction Concepts (EVNRC) contract. The purpose of the program is to validate, through engine testing, advanced noise reduction concepts aimed at reducing engine noise up to 6 EPNdB and improving nacelle suppression by 50 percent relative to 1992 technology. Phase 1 of the program is completed and is summarized in NASA/CR-2014-218088.

Description: Health monitoring of rotorcraft components, currently being performed by Health and Usage Monitoring Systems through analyses of vibration signatures of dynamic mechanical components, is very important for their safe and economic operation. HUMS analyze vibration signatures associated with faults and quantify them as condition indicators to predict component behavior. Vibration transfer paths are characterized by frequency response functions derived from the input/output relationship between applied force and dynamic response through a structure as a function of frequency. With an objective to investigate the differences in transfer paths, transfer path measurements were recorded under similar conditions in the left and right nose gearboxes of an AH-64 helicopter and in an isolated left nose gearbox in a test fixture at NASA Glenn Research Center. The test fixture enabled the application of measured torques-common during an actual operation. An impact hammer as well as commercial and lab piezo shakers, were used in conjunction with two types of commercially available accelerometers to collect the vibration response under various test conditions. The frequency response functions measured under comparable conditions of both systems were found to be consistent. Measurements made on the fixture indicated certain real-world installation and maintenance issues, such as sensor alignments, accelerometer locations and installation torques, had minimal effect. However, gear vibration transfer path dynamics appeared to be somewhat dependent on the presence of oil, and the transfer path dynamics were notably different if the force input was on the internal ring gear rather than on the external gearbox case.

Description: A low-NOx emission combustor concept has been developed for NASA's Environmentally Responsible Aircraft (ERA) program to meet N+2 emissions goals for a 70,000 lb thrust engine application. These goals include 75 percent reduction of LTO NOx from CAEP6 standards without increasing CO, UHC, or smoke from that of current state of the art. An additional key factor in this work is to improve lean combustion stability over that of previous work performed on similar technology in the early 2000s. The purpose of this paper is to present the final report for the NASA contract. This work included the design, analysis, and test of a multi-point combustion system. All design work was based on the results of Computational Fluid Dynamics modeling with the end results tested on a medium pressure combustion rig at the UC and a medium pressure combustion rig at GRC. The theories behind the designs, results of analysis, and experimental test data will be discussed in this report. The combustion system consists of five radially staged rows of injectors, where ten small scale injectors are used in place of a single traditional nozzle. Major accomplishments of the current work include the design of a Multipoint Lean Direct Injection (MLDI) array and associated air blast and pilot fuel injectors, which is expected to meet or exceed the goal of a 75 percent reduction in LTO NOx from CAEP6 standards. This design incorporates a reduced number of injectors over previous multipoint designs, simplified and lightweight components, and a very compact combustor section. Additional outcomes of the program are validation that the design of these combustion systems can be aided by the use of Computational Fluid Dynamics to predict and reduce emissions. Furthermore, the staging of fuel through the individually controlled radially staged injector rows successfully demonstrated improved low power operability as well as improvements in emissions over previous multipoint designs. Additional comparison between Jet- A fuel and a hydrotreated biofuel is made to determine viability of the technology for use with alternative fuels. Finally, the operability of the array and associated nozzles proved to be very stable without requiring additional active or passive control systems. A number of publications have been publish

Description: An extensive wind tunnel test campaign was undertaken to quantify the performance and acoustics of a counter-rotating open rotor system. The present document summarizes the portion of this test performed with the so-called "Historical Baseline" rotor blades, designated F31/A31. It includes performance and acoustic data acquired at Mach numbers from take-off to cruise. It also includes the effect of propulsor angle of attack as well as an upstream pylon. This report is accompanied by an electronic data set including relevant acoustic and performance measurements for all of the F31/A31 data.

Description: The Non-Metallic Gas Turbine Engine project, funded by NASA Aeronautics Research Institute (NARI), represents the first comprehensive evaluation of emerging materials and manufacturing technologies that will enable fully nonmetallic gas turbine engines. This will be achieved by assessing the feasibility of using additive manufacturing technologies for fabricating polymer matrix composite (PMC) and ceramic matrix composite (CMC) gas turbine engine components. The benefits of the proposed effort include: 50 weight reduction compared to metallic parts, reduced manufacturing costs due to less machining and no tooling requirements, reduced part count due to net shape single component fabrication, and rapid design change and production iterations. Two high payoff metallic components have been identified for replacement with PMCs and will be fabricated using fused deposition modeling (FDM) with high temperature capable polymer filaments. The first component is an acoustic panel treatment with a honeycomb structure with an integrated back sheet and perforated front sheet. The second component is a compressor inlet guide vane. The CMC effort, which is starting at a lower technology readiness level, will use a binder jet process to fabricate silicon carbide test coupons and demonstration articles. The polymer and ceramic additive manufacturing efforts will advance from monolithic materials toward silicon carbide and carbon fiber reinforced composites for improved properties. Microstructural analysis and mechanical testing will be conducted on the PMC and CMC materials. System studies will assess the benefits of fully nonmetallic gas turbine engine in terms of fuel burn, emissions, reduction of part count, and cost. The proposed effort will be focused on a small 7000 lbf gas turbine engine. However, the concepts are equally applicable to large gas turbine engines. The proposed effort includes a multidisciplinary, multiorganization NASA - industry team that includes experts in ceramic materials and CMCs, polymers and PMCs, structural engineering, additive manufacturing, engine design and analysis, and system analysis.

Description: The aircraft exhaust engine nozzle system includes a fan nozzle to receive a fan flow from a fan disposed adjacent to an engine disposed above an airframe surface of the aircraft, a core nozzle disposed within the fan nozzle and receiving an engine core flow, and a pylon structure connected to the core nozzle and structurally attached with the airframe surface to secure the engine to the aircraft.

Description: A jet engine exhaust nozzle flow effector is a chevron formed with a radius of curvature with surfaces of the flow effector being defined and opposing one another. At least one shape memory alloy (SMA) member is embedded in the chevron closer to one of the chevron's opposing surfaces and substantially spanning from at least a portion of the chevron's root to the chevron's tip.

Description: Center Director Free is providing the Keynote at the Disruptive Propulsion Conference, sponsored by Cranfield University, Cranfield, Bedfordshire, England in November. Director Free will be presenting a PowerPoint presentation titled, NASA Green Propulsion Technologies Pushing Aviation to New Heights at both the conference and a meeting at the Royal Aeronautical Society.

Description: The tool for turbine engine closed-loop transient analysis (TTECTrA) is a semi-automated control design tool for subsonic aircraft engine simulations. At a specific flight condition, TTECTrA produces a basic controller designed to meet user-defined goals and containing only the fundamental limiters that affect the transient performance of the engine. The purpose of this tool is to provide the user a preliminary estimate of the transient performance of an engine model without the need to design a full nonlinear controller.

Description: A study has been conducted for NASA Glenn Research Center under contract NNC10BA05B, Task NNC11TA80T to identify beneficial arrangements of the turboshaft engine, transmissions and related systems within the propulsion pod nacelle of NASA's Large Civil Tilt-Rotor 2nd iteration (LCTR2) vehicle. Propulsion pod layouts were used to investigate potential advantages, disadvantages, as well as constraints of various arrangements assuming front or aft shafted engines. Results from previous NASA LCTR2 propulsion system studies and tasks performed by Boeing under NASA contracts are used as the basis for this study. This configuration consists of two Fixed Geometry Variable Speed Power Turbine Engines and related drive and rotor systems (per nacelle) arranged in tilting nacelles near the wing tip. Entry-into-service (EIS) 2035 technology is assumed for both the engine and drive systems. The variable speed rotor system changes from 100 percent speed for hover to 54 percent speed for cruise by the means of a two speed gearbox concept developed under previous NASA contracts. Propulsion and drive system configurations that resulted in minimum vehicle gross weight were identified in previous work and used here. Results reported in this study illustrate that a forward shafted engine has a slight weight benefit over an aft shafted engine for the LCTR2 vehicle. Although the aft shafted engines provide a more controlled and centered CG (between hover and cruise), the length of the long rotor shaft and complicated engine exhaust arrangement outweighed the potential benefits. A Multi-Disciplinary Analysis and Optimization (MDAO) approach for transmission sizing was also explored for this study. This tool offers quick analysis of gear loads, bearing lives, efficiencies, etc., through use of commercially available RomaxDESIGNER software. The goal was to create quick methods to explore various concept models. The output results from RomaxDESIGNER have been successfully linked to Boeing spreadsheets that generate gear tooth geometry in Catia 3D environment. Another initial goal was to link information from RomaxDESIGNER (such as hp, rpm, gear ratio) to populate Boeing's parametric weight spreadsheet and create an automated method to estimate drive system weight. This was only partially achieved due to the variety of weight models, number of manual inputs, and qualitative assessments required. A simplified weight spreadsheet was used with data inputs from RomaxDESIGNER along with manual inputs to perform rough weight calculations.

Description: The work presented in this paper is to promote research leading to a closed-loop control system to actively suppress thermo-acoustic instabilities. To serve as a model for such a closed-loop control system, a one-dimensional combustor simulation composed using MATLAB software tools has been written. This MATLAB based process is similar to a precursor one-dimensional combustor simulation that was formatted as FORTRAN 77 source code. The previous simulation process requires modification to the FORTRAN 77 source code, compiling, and linking when creating a new combustor simulation executable file. The MATLAB based simulation does not require making changes to the source code, recompiling, or linking. Furthermore, the MATLAB based simulation can be run from script files within the MATLAB environment or with a compiled copy of the executable file running in the Command Prompt window without requiring a licensed copy of MATLAB. This report presents a general simulation overview. Details regarding how to setup and initiate a simulation are also presented. Finally, the post-processing section describes the two types of files created while running the simulation and it also includes simulation results for a default simulation included with the source code.

Description: Gas turbine engine technology is constantly challenged to operate at higher combustor outlet temperatures. In a modern gas turbine engine, these temperatures can exceed the blade and disk material limits by 600 F or more, necessitating both internal and film cooling schemes in addition to the use of thermal barrier coatings. Internal convective cooling is inadequate in many blade locations, and both internal and film cooling approaches can lead to significant performance penalties in the engine. Micro Cooling Concepts, Inc., has developed a turbine blade cooling concept that provides enhanced internal impingement cooling effectiveness via the use of microstructured impingement surfaces. These surfaces significantly increase the cooling capability of the impinging flow, as compared to a conventional untextured surface. This approach can be combined with microchannel cooling and external film cooling to tailor the cooling capability per the external heating profile. The cooling system then can be optimized to minimize impact on engine performance.

Description: The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were measured at design flow rate and speed. The measured efficiency and stall margin were lower than pre-test CFD predictions by 2.4 percentage points (pt) and 4.5 pt, respectively. Initial impressions from the experimental data indicated that the loss in the efficiency and stall margin can be attributed to a design shortfall in the impeller. However, detailed investigation of experimental data and post-test CFD simulations of higher fidelity than pre-test CFD, and in particular the unsteady CFD simulations and the assessment with a wider range of turbulence models, have indicated that the loss in efficiency is most likely due to the impact of unfavorable unsteady impeller/diffuser interactions induced by diffuser vanes, an impeller/diffuser corrected flow-rate mismatch (and associated incidence levels), and, potentially, flow separation in the radial-to-axial bend. An experimental program with a vaneless diffuser is recommended to evaluate this observation. A subsequent redesign of the diffuser (and the radial-to-axial bend) is also recommended. The diffuser needs to be redesigned to eliminate the mismatching of the impeller and the diffuser, targeting a slightly higher flow capacity. Furthermore, diffuser vanes need to be adjusted to align the incidence angles, to optimize the splitter vane location (both radially and circumferentially), and to minimize the unsteady interactions with the impeller. The radial-to-axial bend needs to be redesigned to eliminate, or at least minimize, the flow separation at the inner wall, and its impact on the flow in the diffuser upstream. Lessons were also learned in terms of CFD methodology and the importance of unsteady CFD simulations for centrifugal compressors was highlighted. Inconsistencies in the implementation of a widely used two-equation turbulence model were identified and corrections are recommended. It was also observed that unsteady simulations for centrifugal compressors require significantly longer integration times than what is current practice in industry.

Description: The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were measured at design flow rate and speed. The measured efficiency and stall margin were lower than pre-test CFD predictions by 2.4 percentage points (pt) and 4.5 pt, respectively. Initial impressions from the experimental data indicated that the loss in the efficiency and stall margin can be attributed to a design shortfall in the impeller. However, detailed investigation of experimental data and post-test CFD simulations of higher fidelity than pre-test CFD, and in particular the unsteady CFD simulations and the assessment with a wider range of turbulence models, have indicated that the loss in efficiency is most likely due to the impact of unfavorable unsteady impeller/diffuser interactions induced by diffuser vanes, an impeller/diffuser corrected flow-rate mismatch (and associated incidence levels), and, potentially, flow separation in the radial-to-axial bend. An experimental program with a vaneless diffuser is recommended to evaluate this observation. A subsequent redesign of the diffuser (and the radial-to-axial bend) is also recommended. The diffuser needs to be redesigned to eliminate the mismatching of the impeller and the diffuser, targeting a slightly higher flow capacity. Furthermore, diffuser vanes need to be adjusted to align the incidence angles, to optimize the splitter vane location (both radially and circumferentially), and to minimize the unsteady interactions with the impeller. The radial-to-axial bend needs to be redesigned to eliminate, or at least minimize, the flow separation at the inner wall, and its impact on the flow in the diffuser upstream. Lessons were also learned in terms of CFD methodology and the importance of unsteady CFD simulations for centrifugal compressors was highlighted. Inconsistencies in the implementation of a widely used two-equation turbulence model were identified and corrections are recommended. It was also observed that unsteady simulations for centrifugal compressors require significantly longer integration times than what is current practice in industry.

Description: Turbine engine control technology is poised to make the first revolutionary leap forward since the advent of full authority digital engine control in the mid-1980s. This change aims squarely at overcoming the physical constraints that have historically limited control system hardware on aero-engines to a federated architecture. Distributed control architecture allows complex analog interfaces existing between system elements and the control unit to be replaced by standardized digital interfaces. Embedded processing, enabled by high temperature electronics, provides for digitization of signals at the source and network communications resulting in a modular system at the hardware level. While this scheme simplifies the physical integration of the system, its complexity appears in other ways. In fact, integration now becomes a shared responsibility among suppliers and system integrators. While these are the most obvious changes, there are additional concerns about performance, reliability, and failure modes due to distributed architecture that warrant detailed study. This paper describes the development of a new facility intended to address the many challenges of the underlying technologies of distributed control. The facility is capable of performing both simulation and hardware studies ranging from component to system level complexity. Its modular and hierarchical structure allows the user to focus their interaction on specific areas of interest.

Description: Significant reduction in carbon dioxide emission for future air transportation system will require adoption of electric propulsion system and more electric architectures. Various options for aircraft electric propulsion include hybrid electric, turboelectric, and full electric system. Realization of electric propulsion system for commercial aircraft applications will require significant increases in power density of electric motors and energy density of energy storage system, such as the batteries and fuel cells. In addition, transmission of MW of power in the aircraft will require high voltage power transmission system to reduce the weight of the power transmission system. Finally, there will be significant thermal management challenges. Significant advances in material technologies will be required to meet these challenges. Technologies of interest include materials with higher electrical conductivity than Cu, high thermal conductivity materials, and lightweight electrically insulating materials with high breakdown voltage, high temperature magnets, advanced battery and fuel cell materials, and multifunctional materials. The presentation will include various challenges for commercial electric aircraft and provide an overview of material improvements that will be required to meet these challenges.

Description: Computational and experimental analyses of a PICS-Pilot-In-Can-Swirler technology injector, developed by United Technologies Research Center (UTRC) are presented. NASA has defined technology targets for near term (called "N+1", circa 2015), midterm ("N+2", circa 2020) and far term ("N+3", circa 2030) that specify realistic emissions and fuel efficiency goals for commercial aircraft. This injector has potential for application in an engine to meet the Pratt & Whitney N+3 supersonic cycle goals, or the subsonic N+2 engine cycle goals. Experimental methods were employed to investigate supersonic cruise points as well as select points of the subsonic cycle engine; cruise, approach, and idle with a slightly elevated inlet pressure. Experiments at NASA employed gas analysis and a suite of laser-based measurement techniques to characterize the combustor flow downstream from the PICS dump plane. Optical diagnostics employed for this work included Planar Laser-Induced Fluorescence of fuel for injector spray pattern and Spontaneous Raman Spectroscopy for relative species concentration of fuel and CO2. The work reported here used unheated (liquid) Jet-A fuel for all fuel circuits and cycle conditions. The initial tests performed by UTRC used vaporized Jet-A to simulate the expected supersonic cruise condition, which anticipated using fuel as a heat sink. Using the National Combustion Code a PICS-based combustor was modeled with liquid fuel at the supersonic cruise condition. All CFD models used a cubic non-linear k-epsilon turbulence wall functions model, and a semi-detailed Jet-A kinetic mechanism based on a surrogate fuel mixture. Two initial spray droplet size distribution and spray cone conditions were used: (1) an initial condition (Lefebvre) with an assumed Rosin-Rammler distribution, and 7 degree Solid Spray Cone; and (2) the Boundary Layer Stripping (BLS) primary atomization model giving the spray size distribution and directional properties. Contour and line plots are shown in comparison with experimental data (where this data is available) for flow velocities, fuel, and temperature distribution. The CFD results are consistent with experimental observations for fuel distribution and vaporization. Analysis of gas sample results, using a previously-developed NASA NOx correlation, indicates that for sea-level takeoff, the PICS configuration is predicted to deliver an EINOx value of about three for the targeted supersonic aircraft. Emissions results at supersonic cruise conditions show potential for meeting the NASA goals with liquid fuel.

Description: An Ultrasonic Configurable Fan Artificial Noise Source (UCFANS) was designed, built, and tested in support of the NASA Langley Research Center's 14x22 wind tunnel test of the Hybrid Wing Body (HWB) full 3-D 5.8% scale model. The UCFANS is a 5.8% rapid prototype scale model of a high-bypass turbofan engine that can generate the tonal signature of proposed engines using artificial sources (no flow). The purpose of the program was to provide an estimate of the acoustic shielding benefits possible from mounting an engine on the upper surface of a wing; a flat plate model was used as the shielding surface. Simple analytical simulations were used to preview the radiation patterns - Fresnel knife-edge diffraction was coupled with a dense phased array of point sources to compute shielded and unshielded sound pressure distributions for potential test geometries and excitation modes. Contour plots of sound pressure levels, and integrated power levels, from nacelle alone and shielded configurations for both the experimental measurements and the analytical predictions are presented in this paper.

Description: This lecture will provide an overview of the aircraft turbine engine control research at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC). A brief introduction to the engine control problem is first provided with a description of the current state-of-the-art control law structure. A historical aspect of engine control development since the 1940s is then provided with a special emphasis on the contributions of GRC. The traditional engine control problem has been to provide a means to safely transition the engine from one steady-state operating point to another based on the pilot throttle inputs. With the increased emphasis on aircraft safety, enhanced performance and affordability, and the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at GRC is leading and participating in various projects in partnership with other organizations within GRC and across NASA, other government agencies, the U.S. aerospace industry, and academia to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA programs under the Aeronautics Research Mission. The second part of the lecture provides an overview of the various CDB technology development activities in aircraft engine control and diagnostics, both current and some accomplished in the recent past. The motivation for each of the research efforts, the research approach, technical challenges and the key progress to date are summarized. The technologies to be discussed include system level engine control concepts, gas path diagnostics, active component control, and distributed engine control architecture. The lecture will end with a futuristic perspective of how the various current technology developments will lead to an Intelligent and Autonomous Propulsion System requiring none to very minimum pilot interface, interfacing directly with the flight management system to determine its mode of operation, and providing personalized engine control to optimize its performance given the current condition and mission objectives.

Description: A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.propulsion system dynamics, the structural dynamics, and aerodynamics.

Description: The Intelligent Control and Autonomy Branch (ICA) at NASA (National Aeronautics and Space Administration) Glenn Research Center (GRC) in Cleveland, Ohio, is leading and participating in various projects in partnership with other organizations within GRC and across NASA, the U.S. aerospace industry, and academia to develop advanced controls and health management technologies that will help meet the goals of the NASA Aeronautics Research Mission Directorate (ARMD) Programs. These efforts are primarily under the various projects under the Fundamental Aeronautics Program (FAP) and the Aviation Safety Program (ASP). The ICA Branch is focused on advancing the state-of-the-art of aero-engine control and diagnostics technologies to help improve aviation safety, increase efficiency, and enable operation with reduced emissions. This paper describes the various ICA research efforts under the NASA Aeronautics Research Mission Programs with a summary of motivation, background, technical approach, and recent accomplishments for each of the research tasks.

Description: Variable-Speed Power Turbines (VSPT) for rotorcraft applications operate at low Reynolds number and over a wide range in incidence associated with shaft speed change. A comprehensive linear cascade data set obtained includes the effects of Reynolds number, free-stream turbulence and incidence is available and this paper concerns itself with the presentation and numerical simulation of conditions resulting in a selected set of those data. As such, post-dictions of blade pressure loading, total-pressure loss and exit flow angles under conditions of high and low turbulence intensity for a single Reynolds number are presented. Analyses are performed with the three-equation turbulence models of Walters-Leylek and Walters and Cokljat. Transition, loading, total-pressure loss and exit angle variations are presented and comparisons are made with experimental data as available. It is concluded that at the low freestream turbulence conditions the Walters-Cokljat model is better suited to predictions while for high freestream conditions the two models generate similar predications that are generally satisfactory.

Description: The NASA Glenn Research Center (GRC) Radioisotope Power System Program Office (RPSPO) sponsored two studies lead by their mission analysis team. The studies were performed by NASA GRCs Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team. Typically a complete toplevel design reference mission (DRM) is performed assessing conceptual spacecraft design, launch mass, trajectory, science strategy and sub-system design such as, power, propulsion, structure and thermal.

Description: Variable-Speed Power Turbines (VSPT) for rotorcraft applications operate in conditions of low Reynolds number and a wide range in incidence resulting from rotational speed variation. A comprehensive data set obtained in a linear cascade which includes the effects of Reynolds number, free-stream turbulence and incidence is now available and this paper concerns itself with the post-diction of boundary layer transitionseparation, blade pressure loading and total pressure loss pertaining to the conditions set for measurements in that data set. The distinction between the state of the measured data presented here and the earlier publications is the addition of high free-stream turbulence intensity. We will, for the purposes of the numerical post-diction, present some of the higher free stream turbulence data in this paper but defer a comprehensive presentation and treatment of the measured data will be done elsewhere.

Description: NASA is taking a leadership role with regard to developing new options for low-carbon propulsion. Work related to the characterization of alternative fuels is coordinated with our partners in government and industry, and NASA is close to concluding a TC in this area. Research on alternate propulsion concepts continues to grow and is an important aspect of the ARMD portfolio. Strong partnerships have been a key enabling factor for research on this strategic thrust.

Description: The relative sensitivities of 309 common invertebrate species in Dutch marine waters are presented for environmental and anthropogenic pressures like organic enrichment, sedimentation and fisheries. The species were furthermore appointed to trophic groups like suspension and deposit feeders. The Dutch Ministry of Infrastructure and the Environment uses these data when calculating the Benthic Ecosystem Quality Index 2 and the Infaunal Trophic Index. These metrics aid in the mandatory monitoring of ecological quality for example for the European Water Framework Directive. The common Dutch species were selected based on their abundance according to, 1. the mwtl dataset including results of on-going monitoring programs issued by the Ministry, 2. the monitoring by volunteer scuba-divers for the anemoon Foundation and 3. the monitoring of fouling plates for the project setl.

Description: Onze fauna verandert en de mariene fauna is daarop geen uitzondering. Zuidelijke soorten koloniseren onze kustwateren en exotische soorten worden door de mens aangevoerd. Voor sommige soorten is niet duidelijk waarom ze hier opduiken. De sterk veranderende kustbiotopen spelen ongetwijfeld eveneens een rol. Een niet-aflatende stroom onverwachte soorten, soms zelfs behorend tot nieuwe genera en zelfs families maken faunistisch onderzoek in de kustwateren verrassend en boeiend. In het kader van een inventarisatie van kreeftachtigen in het Deltagebied werden in de Oosterschelde bij Zierikzee verscheidene kleine monsters genomen van diverse substraten. De monsters van roodwieren bevatten een aantal opmerkelijke soorten. Dit artikel behandelt Uromunna spec., een zeepissebeddensoort van een familie die in ons land nog niet was aangetroffen.

Description: This paper describes the discovery of a settled juvenile specimen of the stomatopod Platysquilla eusebia on the Dutch part of the Dogger Bank in the central North Sea. This is the northernmost record in Europe. The species is native to the Mediterranean and to the Atlantic coast from Portugal up to France. Further investigations have to show if the species already forms populations this far north. As the planktonic stages of P. eusebia have already been recorded in prior years, the establishment of the species should not be a problem, providing the circumstances are favourable.

Description: Met enige regelmaat duiken nieuwe springstaartsoorten op in ons land. Het vinden van een nieuwe soort is soms op toeval gebaseerd. Op een foto van een sprinkhaan was naast de linker voorpoot een klein, donker vlekje te zien. Uitvergroot bleek het om een klein springstaartje te gaan. Het zwart-wit gestreepte patroon liet geen ruimte voor twijfel over de determinatie: Fasciosminthurus quinquefasciatus, een nieuwe springstaart voor de Nederlandse fauna. In dit artikel wordt het genus en de soort voorgesteld, beschrijven we de habitat en geven we informatie over de verspreiding in de rest van Europa.

Description: De roodbruine heiderouwzwever Exoprosopa capucina is een fraaie en karakteristieke koffiebruine verschijning op de Nederlandse heideterreinen. Zoals veel wolzwevers is deze te herkennen aan de vleugeltekening en de kleur van de lichaamsbeharing. Echter naarmate de dieren ouder worden verliezen ze deze beharing en wordt de determinatie lastiger. Vermoedelijk heeft het verfomfaaide uiterlijk van een vrouwtje Exoprosopa cleomene er voor gezorgd dat deze ruim 50 jaar onopgemerkt tussen de exemplaren van E. capucina heeft gestaan.

Description: In de afgelopen jaren werd op verschillende plekken in Nederland een houtzwamkever gevonden die tot nu toe niet officieel gemeld werd: Sulcacis bidentulus. Deze soort valt binnen de zeer eenvormige familie Ciidae op door de kleur van de dekschilden, die duidelijk iets lichter bruin zijn dan de rest van het lichaam. De soort zou zich ontwikkelen in de bleke borstelkurkzwam, die voornamelijk op populieren groeit. Oudere vondsten ontbreken en de ontdekking van deze soort op meerdere locaties duidt op een recente vestiging in ons land. Dit sluit aan bij de geconstateerde uitbreiding in Midden-Europa.

Description: De boomkrekel is een slanke geelbruine krekel, die vooral opvalt door zijn melodieuze zang. Vroeger moest je naar Frankrijk om dit geluid te horen, maar tegenwoordig heerst ook in het rivierengebied bij Nijmegen een mediterrane sfeer. De boomkrekel is in 2004 voor het eerst langs de Waal gevonden en heeft zich daarna uitgebreid. In 2010 en 2011 heeft de Flora- en faunawerkgroep Gelderse Poort met vele vrijwilligers onderzoek gedaan naar de precieze verspreiding. In totaal werd de boomkrekel in 57 kilometerhokken gevonden en de verwachting is dat de soort zich de komende jaren verder zal uitbreiden.

Description: Hongerwespen behoren tot de grote groep van de sluipwespen. Het zijn slanke wespjes die typisch met hangende pootjes vliegen, waarbij de verbrede achterschenen opvallen. Ze parasiteren bijen en mogelijk ook bepaalde angeldragende wespen en worden daarom vaak bij bijenhotels waargenomen. In het kader van dit artikel zijn de meldingen van Nederlandse hongerwespen kritisch beschouwd. In totaal zijn nu negen soorten uit ons land bekend, waarvan er hier maar liefst zes voor het eerst worden gemeld.

Description: As most of the sea bottom in the Dutch part of the North Sea consists of sand, marine fauna that live in association with hard substrates are rarely monitored. We report here on the results of a species inventory in June 2011 done by scuba-diving while focusing on a wreck on the Dogger Bank and on rocky bottoms on the Cleaver Bank. This resulted in various new records of species for the Dutch part of the North Sea. This result appeared for a large part linked to the added value of monitoring with scuba-divers. It is therefore concluded that scuba-divers should be used in addition to the more traditional monitoring methods in which dredges and grabs are used, if one aims at getting an accurate view of the biodiversity present in marine regions like the North Sea.

Description: Five years after the commissioning of the offshore wind farm Egmond aan Zee, the monopiles and the rocks of the scour protection layers were covered by a wide variety of marine organisms. This paper describes the results of qualitative and quantitative assessments carried out in 2008 and 2011. The assessments were based on video footage, pictures and samples collected by divers at three different wind turbines. The ecological relevance of identified taxa is also discussed.

Description: De gouden kegelbij Coelioxys aurolimbata is uit ons land recent alleen bekend uit de zuidelijke helft van Limburg. Vóór 1960 kwam deze parasiet van de lathyrusbij Chalicodoma ericetorum ook in het rivierengebied voor. In juli van dit jaar werd de gouden kegelbij gevangen in Duiven. Mogelijk is dit de voorbode van een herovering van het rivierengebied door deze bedreigde soort.

Description: During an expedition with scuba-divers to the Dutch part of the Brown Ridge in the central North Sea in June 2013, two colonies of the jewel anemone Corynactis viridis were found on the wreck Anna Graebe. With the jewel anemone both a new species and a new animal order, the Corallimorpharia, are added to the autochthonous fauna of the Netherlands. This species typically occurs in the Mediterranean and along the Atlantic coast from Portugal and the west British Isles up to Shetland. As other records of settled colonies of C. viridis in the North Sea were recently reported from Belgian, German and English waters, it is concluded that the jewel anemone, which used to be known as an occasional visitor, should now be considered autochthonous in the North Sea.

Description: In de bodem van de Noordzee leeft een bijzondere groep van kreeften. Zij brengen hun leven door in een ondergronds gangenstelsel: de molkreeften. Het zijn algemene bewoners van het Friese Front, de Oestergronden en de Klaverbank. In, op en bij deze kreeften leven verschillende andere diersoorten: parasitaire pissebedden, een mosdiertje en twee soorten tweekleppigen. Deze bijdrage gaat in op de ecologie van de molkreeften en hun symbionten.

Description: Bryozoa or moss animals constitute a conspicuous and species-rich component of hardsubstrate benthic communities in marine and estuarine habitats. To gain insight into the biodiversity of these habitats, knowledge of bryozoan species is indispensable. Since the last comprehensive publication on Dutch species in 2004 much new information has become available. Particularly from the Dutch part of the Continental Flat of the North Sea, the largest natural area of the Netherlands, many new records have been collected. Other reasons to present an updated review are changes in nomenclature, the arrival of some exotic species and identification issues.

Description: Heleomyzidae zijn kleine tot middelgrote vliegen. Ze krijgen niet veel aandacht, omdat de meeste soorten een nogal verborgen leven leiden en bovendien niet opvallend gekleurd of getekend zijn. De Nederlandse familienaam, afvalvliegen, is voor de meeste soorten niet echt passend, maar veel soorten van de subfamilie Heteromyzinae, waartoe Tephrochlaena oraria behoort, worden dan wel weer vaker rond afval aangetroffen. Tephrochlaena oraria is echter in meerdere opzichten een buitenbeentje. Met deze soort komt de lijst van Nederlandse Heleomyzidae op 49.

Description: Cucujus cinnaberinus is een recent voor Nederland ontdekte soort. De kever staat op de Habitatrichtlijn, wat onder meer betekent dat hij beschermd is en dat de populatie gemonitord dient te worden. Inventarisatie en monitoring gebeurt in het algemeen door het weghalen van schors van recent gestorven bomen. Hierdoor wordt het leefgebied van de kever echter flink aangetast. Wij voerden een klein onderzoek uit naar de mogelijkheden om C. cinnaberinus te vangen in azijnzuurvallen, zodat de habitat intact gelaten kan worden en de soort toch geïnventariseerd kan worden. Tijdens het voorjaar van 2013 werden vier vallen opgehangen op een locatie waar zich een populatie van deze soort bevindt. Er werden slechts twee individuen verzameld; de vangmethode lijkt dus niet bijzonder geschikt.

Description: The tanaid Zeuxo holdichi, described in 1990 from Arcachon Bay in southwest France, has since then been recorded from west Portugal to northern Brittany and southwest England. The species is recorded here from the Netherlands, a further northward expansion of the range. It is hypothesised that Z. holdichi may be non-native to Europe.

Description: This paper reports on observations made during wreck dive expeditions in 2010-2012, in order to investigate the ecological relevance of shipwrecks on the Dutch Continental Shelf (dcs). Shipwrecks are biodiversity hotspots. The number of species recorded on shipwrecks is similar to the number of species found in soft bottoms of the entire dcs. The soft substrates, however, represent a vastly larger habitat on the dcs than the shipwrecks. Amongst many other taxa, juvenile and large Atlantic cod, linear skeleton shrimp, goldsinny wrasses and leopard spotted gobies were found in the shipwreck habitats. The presence of these important species and their absence from many other habitats, illustrate that shipwrecks function as key habitats, nurseries, and refugia that are rare or absent anywhere else in the Netherlands.

Description: Wolzwevers zijn vliegen waarvan de larven parasitair leven bij andere insecten. Wolzwevers van het genus Villa veroorzaken vaak determinatieproblemen. Deze problemen lijken verleden tijd met recent gepubliceerde taxonomische inzichten. Eindelijk konden nu ook de Nederlandse exemplaren van dit genus op naam gebracht worden. Deze bleken te behoren tot vier soorten, waarvan er twee vermoedelijk reeds zijn verdwenen.

Description: Sluipwespen van de groep van de Polysphinctini hebben een bijzondere levenswijze. Het vrouwtje van wesp legt een eitje op het achterlijf van een spin. Wanneer het eitje is uitgekomen brengt de larve haar hele leven op het achterlijf van de spin door. Ze maakt kleine wondjes in de huid en voedt zich met lichaamsvloeistof van de spin. Na verloop van tijd ontwikkelt de larve bulten op de rug, een teken dat ze bijna volgroeid is. Ze zuigt dan de spin leeg, de ‘grote slurp’ genaamd, en verpopt zich in het web. In dit artikel wordt de levenswijze van één van deze soorten, Acrodactyla quadrisculpta, voor het eerst beschreven en geïllustreerd.

Description: De bladwespgenera Phyllocolpa, Tubpontania, Pontania en Euura hebben gemeenschappelijk dat ze gallen vormen op wilg. Recentelijk is er veel vernieuwend taxonomisch werk verricht aan deze groepen. In dit artikel wordt de Nederlandse situatie samengevat. Uit oudere literatuur waren 18 soorten bekend en in het recent gepubliceerde gallenboek worden nog eens 11 soorten voor het eerst voor ons land vermeld. In dit artikel worden nog acht soorten aan de lijst toegevoegd en twee soorten worden van de lijst afgevoerd. In totaal zijn nu 35 soorten galvormende bladwespen van wilg uit Nederland bekend.

Description: Snuitvliegen zijn rare snuiters onder de zweefvliegen. Ze hebben een verlengd gezicht en een lange tong. Hiermee kunnen ze foerageren op bloemen met diepliggende nectar, in tegenstelling tot de meeste andere zweefvliegen. Als genus zijn de vliegen makkelijk herkenbaar, maar de zeer zeldzame soorten tussen de zeer algemene gewone snuitvlieg uithalen was niet altijd even makkelijk. In dit artikel wordt de herontdekking van de rode snuitvlieg beschreven en een tabel gegeven voor de drie Noordwest-Europese soorten.

Description: De larven van Trichoptera heten kokerjuffers en leven in het water. Veel soorten bouwen een kokertje van zand, takjes of ander materiaal, vandaar de Nederlandse naam. De volwassen dieren lijken wel wat op nachtvlinders en worden schietmotten genoemd. De laatste jaren heeft het onderzoek naar deze dieren een grote vlucht genomen. Enerzijds spelen ze een rol als indicator voor de waterkwaliteit. De larven worden dan ook veel verzameld tijdens macrofaunabemonsteringen door waterschappen. Anderzijds is er een groeiende groep entomologen die schietmotten bestudeert. In dit artikel wordt Ecclisopteryx dalecarlica voorgesteld, een nieuwe soort voor Nederland.

Description: These presentations cover some of the ongoing work in dynamic modeling and dynamic systems analysis. The first presentation discusses dynamic systems analysis and how to integrate dynamic performance information into the systems analysis. The ability to evaluate the dynamic performance of an engine design may allow tradeoffs between the dynamic performance and operability of a design resulting in a more efficient engine design. The second presentation discusses the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a Simulation system with a library containing the basic building blocks that can be used to create dynamic Thermodynamic Systems. Some of the key features include Turbo machinery components, such as turbines, compressors, etc., and basic control system blocks. T-MAT is written in the Matlab-Simulink environment and is open source software. The third presentation focuses on getting additional performance from the engine by allowing the limit regulators only to be active when a limit is danger of being violated. Typical aircraft engine control architecture is based on MINMAX scheme, which is designed to keep engine operating within prescribed mechanical/operational safety limits. Using a conditionally active min-max limit regulator scheme, additional performance can be gained by disabling non-relevant limit regulators

Description: Centrifugal compressors are compatible with the low exit corrected flows found in the high pressure compressor of turboshaft engines and may play an increasing role in turbofan engines as engine overall pressure ratios increase. Centrifugal compressor stages are difficult to model accurately with RANS CFD solvers. A computational study of the CC3 centrifugal impeller in its vaneless diffuser configuration was undertaken as part of an effort to understand potential causes of RANS CFD mis-prediction in these types of geometries. Three steady, periodic cases of the impeller and diffuser were modeled using the TURBO Parallel Version 4 code: (1) a k- turbulence model computation on a 6.8 million point grid using wall functions, (2) a k- turbulence model computation on a 14 million point grid integrating to the wall, and (3) a k- turbulence model computation on the 14 million point grid integrating to the wall. It was found that all three cases compared favorably to data from inlet to impeller trailing edge, but the k- and k- computations had disparate results beyond the trailing edge and into the vaneless diffuser. A large region of reversed flow was observed in the k- computations which extended from 70 to 100 percent span at the exit rating plane, whereas the k- computation had reversed flow from 95 to 100 percent span. Compared to experimental data at near-peak-efficiency, the reversed flow region in the k- case resulted in an underprediction in adiabatic efficiency of 8.3 points, whereas the k- case was 1.2 points lower in efficiency.

Description: Centrifugal compressors are compatible with the low exit corrected flows found in the high pressure compressor of turboshaft engines and may play an increasing role in turbofan engines as engine overall pressure ratios increase. Centrifugal compressor stages are difficult to model accurately with RANS CFD solvers. A computational study of the CC3 centrifugal impeller in its vaneless diffuser configuration was undertaken as part of an effort to understand potential causes of RANS CFD mis-prediction in these types of geometries. Three steady, periodic cases of the impeller and diffuser were modeled using the TURBO Parallel Version 4 code: 1) a k-epsilon turbulence model computation on a 6.8 million point grid using wall functions, 2) a k-epsilon turbulence model computation on a 14 million point grid integrating to the wall, and 3) a k-omega turbulence model computation on the 14 million point grid integrating to the wall. It was found that all three cases compared favorably to data from inlet to impeller trailing edge, but the k-epsilon and k-omega computations had disparate results beyond the trailing edge and into the vaneless diffuser. A large region of reversed flow was observed in the k-epsilon computations which extended from 70% to 100% span at the exit rating plane, whereas the k-omega computation had reversed flow from 95% to 100% span. Compared to experimental data at near-peak-efficiency, the reversed flow region in the k-epsilon case resulted in an under-prediction in adiabatic efficiency of 8.3 points, whereas the k-omega case was 1.2 points lower in efficiency.

Description: This paper presents an overview of the propulsion research and technology portfolio of NASA Fundamental Aeronautics Program Fixed Wing Project. The research is aimed at significantly reducing the thrust specific fuel/energy consumption of notional advanced fixed wing aircraft (by 60 % relative to a baseline Boeing 737-800 aircraft with CFM56-7B engines) in the 2030-2035 time frame. The research investments described herein are aimed at improving propulsive efficiency through higher bypass ratio fans, improving thermal efficiency through compact high overall pressure ratio gas generators, and exploring the potential benefits of boundary layer ingestion propulsion and hybrid gas-electric propulsion concepts.

Description: In response to growing aviation demands and concerns about the environment and energy usage, a team at NASA proposed and examined a revolutionary aeropropulsion concept, a turboelectric distributed propulsion system, which employs multiple electric motor-driven propulsors that are distributed on a large transport vehicle. The power to drive these electric propulsors is generated by separately located gas-turbine-driven electric generators on the airframe. This arrangement enables the use of many small-distributed propulsors, allowing a very high effective bypass ratio, while retaining the superior efficiency of large core engines, which are physically separated but connected to the propulsors through electric power lines. Because of the physical separation of propulsors from power generating devices, a new class of vehicles with unprecedented performance employing such revolutionary propulsion system is possible in vehicle design. One such vehicle currently being investigated by NASA is called the "N3-X" that uses a hybrid-wing-body for an airframe and superconducting generators, motors, and transmission lines for its propulsion system. On the N3-X these new degrees of design freedom are used (1) to place two large turboshaft engines driving generators in freestream conditions to minimize total pressure losses and (2) to embed a broad continuous array of 14 motor-driven fans on the upper surface of the aircraft near the trailing edge of the hybrid-wing-body airframe to maximize propulsive efficiency by ingesting thick airframe boundary layer flow. Through a system analysis in engine cycle and weight estimation, it was determined that the N3-X would be able to achieve a reduction of 70% or 72% (depending on the cooling system) in energy usage relative to the reference aircraft, a Boeing 777-200LR. Since the high-power electric system is used in its propulsion system, a study of the electric power distribution system was performed to identify critical dynamic and safety issues. This paper presents some of the features and issues associated with the turboelectric distributed propulsion system and summarizes the recent study results, including the high electric power distribution, in the analysis of the N3-X vehicle.

Description: Turbine engines are highly complex mechanical systems that are becoming increasingly dependent on control technologies to achieve system performance and safety metrics. However, the contribution of controls to these measurable system objectives is difficult to quantify due to a lack of tools capable of informing the decision makers. This shortcoming hinders technology insertion in the engine design process. NASA Glenn Research Center is developing a Hardware-inthe- Loop (HIL) platform and analysis tool set that will serve as a focal point for new control technologies, especially those related to the hardware development and integration of distributed engine control. The HIL platform is intended to enable rapid and detailed evaluation of new engine control applications, from conceptual design through hardware development, in order to quantify their impact on engine systems. This paper discusses the complex interactions of the control system, within the context of the larger engine system, and how new control technologies are changing that paradigm. The conceptual design of the new HIL platform is then described as a primary tool to address those interactions and how it will help feed the insertion of new technologies into future engine systems.