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  • 1
    facet.materialart.
    Unbekannt
    In:  Herausgeberexemplar
    Publikationsdatum: 2024-03-06
    Beschreibung: Die Pflanzengesellschaften verschiedener feuerländischer Hochmoore wurden nach der Methode von BRAUN-BLANQUET untersucht. Die untersuchten Moore liegen im argentinischen Teil von Feuerland in der Nähe von Ushuaia. Das vorhandene Untersuchungsmaterial läßt zwei neue Hochmoor-Pflanzengesellschaften erkennen: Carici magellanici- phagnetum fimbriati [und] Pernettyo-Sphagnetum. Das Carici magellanici-Sphagnetum fimbriati entspricht dem europäischen Caricetum limosae. Das Pernettyo-Sphagnetum gehört (nur dieses kann bislang gesagt werden) zur Oxycocco-Sphagnetea. Über eine endgültige Zuordnung kann erst entschieden werden, wenn weiteres Untersuchungsmaterial aus den Hochmooren der Südhemisphäre vorliegt. Die chemischen Kennwerte ähneln denjenigen der norddeutschen Hochmoore. Die höheren pH-‚ K-, Ca-‚ Mg- und Na-Werte zeigen die Meeresnähe der feuerländischen Hochmoore an.
    Beschreibung: The plant communities of various raised bogs of the Tierra del Fuego were investigated according to the method BRAUN-BLANQUET. The investigated bogs are in the Argentine part of Tierra del Fuego in the vicinity of Ushuaia. The available examination material shows two new bog plant communities: Carici magellanici-Sphagnetum fimbriati [and] Pernettyo-Sphagnetum. The Carici magellanici-Sphagnetum fimbriati corresponds to the European Caricetum limosae. The Pernettyo-Sphagnetum belongs to the Oxycocco-Sphagnetea. Further classification can be decided only after more material from the bogs of the southern hemisphere available for examination. The characteristic chemical values are similar to those of the North-German raised bogs. The higher pH-, K-, Ca-, Mg- and Na-values indicate that the bogs of Tierra del Fuego are close to the ocean.
    Beschreibung: Las comunidades vegetales de diferentes turberas sfagnosas de la Tierra del Fuego fueron estudiadas y analizadas de acuerdo con el método BRAUN-BLANQUET. Las zonas pantanosas se encuentran en la parte Argentina de la Tierra del Fuego, cerca de Ushuaia. En virtud del resultado explorativo del material disponible se pueden reconcer dos comunidadas vegetales nuevas en las turberas sfagnosas: e Carici magellanici-Sphagnetum fimbriati [e] Pernettyo–Sphagnetum. El Carici magellanici-Sphagnetum fimbriati corresponde al Caricetum limosae de Europa. El Pernettyo-Sphagnetum pertenece a Oxycocco-Sphagnetea. No se puede decidir sobre una clasificacion mäs detallada hasta que haya mas material exploacion de las turberas sfagnosas del hemisferio sur. Los valores caracteristicos quimicos se parecen a aquellos de las turberas sfagnosas del norte de Alemania. Los contenidos mäs elevados de pH, K, Ca, Mg y Ca demuestran que las turberas sfagnosas de la Tierra del Fuego se encuentran el mar.
    Beschreibung: research
    Beschreibung: DFG, SUB Göttingen, DGMT
    Schlagwort(e): ddc:553.21 ; ddc:581.7 ; Moor ; Torf ; Vegetation ; peatland ; peat
    Sprache: Deutsch
    Materialart: doc-type:article
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  • 2
    facet.materialart.
    Unbekannt
    In:  Other Sources
    Publikationsdatum: 2011-08-16
    Beschreibung: The papers in this volume deal essentially with the question whether the amplification of noise is due to the jet noise phenomenon or perhaps an interaction of airframe and core engine noise. In the area of jet noise suppression, various promising suppressor concepts are examined. The swirling flow jet noise suppressor is shown to provide significant noise reduction with minimal thrust losses. Progress in the aircraft engine core noise problem is reflected by seven research-type papers. Two possible mechanisms are seen to be responsible for core noise. One is the direct noise radiated from the turbulent combustion in the primary combuster and transmitted through the turbine, passing out the nozzle into the far field. The other mechanism is the noise that is emitted from hot spots being convected through the turbine. Which of these mechanisms (or perhaps both mechanisms) is responsible for core noise, and what are the coupling mechanisms of core engine noise and jet noise are the questions confronting researchers.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
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  • 3
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2017-10-02
    Beschreibung: The effects of afterburner light-off and shut-down transients on the compressor stability are investigated. The reported experimental results are based on detailed high response pressure and temperature measurements on the TF30-P-3 turbofan engine. The tests were performed in an altitude test chamber simulating high altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: AGARD Unsteady Phenomena in Turbomachinery; 12 p
    Format: text
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  • 4
    Publikationsdatum: 2017-10-02
    Beschreibung: Propulsion systems are evaluated in terms of relative aircraft range for a fixed payload and takeoff gross weight with a design cruise Mach number of 2.7. In order to put the performance of these engines in perspective, a comparison of these engines and the former U.S. SST engine is made with an idealized variable cycle engine whose performance at all operating points matches that of an optimized point design cycle within specified limits. Range comparisons are made with and without noise level constraints to determine the influence of noise upon cycle selection. The critical areas requiring new or improved technology for each cycle are delineated.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: AGARD Variable Geometry and Multicycle Eng.; 19 p
    Format: text
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  • 5
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The status of the Federal Aviation Administration's High Altitude Pollution Program is described which was instituted to develop the detailed quantitative information needed to judge whether or not regulatory action to limit such exhaust emissions would be necessary. The complexities of this question and the nature and magnitude of uncertainties still present in our scientific understanding of the potential interactions between aircraft exhaust emissions and stratospheric ozone and climate are reviewed. The direction and scope of future Federal and international activities are described.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Langley Res. Center Proc. of the SCAR Conf., Pt. 2,; 10 p
    Format: application/pdf
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  • 6
    Publikationsdatum: 2016-06-07
    Beschreibung: Various experiments are sponsored and conducted by NASA to explore the potential of advanced combustion techniques for controlling aircraft engine emissions into the upper atmosphere. Of particular concern are the oxide of nitrogen (NOx) emissions into the stratosphere. The experiments utilize a wide variety of approaches varying from advanced combustor concepts to fundamental flame tube experiments. Results are presented which indicate that substantial reductions in cruise NOx emissions should be achievable in future aircraft engines. A major NASA program is described which focuses the many fundamental experiments into a planned evolution and demonstration of the prevaporized-premixed combustion technique in a full-scale engine.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Proc. of the SCAR Conf., Pt. 2,; 22 p
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  • 7
    Publikationsdatum: 2016-06-07
    Beschreibung: Two engine components, fan blades and exhaust systems, were selected for composite materials development efforts in support of the supersonic cruise aircraft research (SCAR) engine program. The materials selected were boron/aluminum for fan blades and silicon carbide/superalloy sheet for the exhaust system. The current status of the research into applying these two composite materials to SCAR engines is reviewed.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Proc. of the SCAR Conf., Part 1; p 457-468
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  • 8
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The objectives and status of the propulsion program, along with the results acquired in the various technology areas, are discussed. The instrumentation requirements for and experience with flight testing the propulsion systems at high supersonic cruise are reported. Propulsion system performance differences between wind tunnel and flight are given. The effects of high frequency flow fluctuations (transients) on the stability of the propulsion system are described, and shock position control is evaluated.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Proc. of the SCAR Conf., Part 1; p 417-456
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  • 9
    Publikationsdatum: 2016-06-07
    Beschreibung: The propulsion control requirements of supersonic aircraft are presented. Integration of inlet, engine, and airframe controls is discussed. The application of recent control theory developments to propulsion control design is described. Control component designs for achieving reliable, responsive propulsion control are also discussed.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Proc. of the SCAR Conf., Part 1; p 399-415
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  • 10
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The performance of candidate supersonic cruise inlets is reviewed and the aerodynamic installation penalties for each type are defined. The main characteristics that affect the airflow schedules of variable cycle engines are defined. These schedules are compared with the airflow schedules of the candidate inlets, and appropriate inlets are matched to the variable-cycle engine characteristics. Auxiliary inlets are also considered.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Proc. of the SCAR Conf., Part 1; p 387-397
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  • 11
    Publikationsdatum: 2016-06-07
    Beschreibung: The Variable Stream Control Engine is studied for advanced supersonic cruise aircraft. Significant environmental and performance improvements relative to first generation supersonic turbojet engines are cited. Two separate flow streams, each with independent burner and nozzle systems are incorporated within the engine. By unique control of the exhaust temperatures and velocities in two coannular streams, significant reduction in jet noise is obtained.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Langley Res. Center Proc. of the SCAR Conf., Part 1; p 341-352
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  • 12
    Publikationsdatum: 2016-06-07
    Beschreibung: Sustained supersonic cruise propulsion systems for military applications are studied. The J79-5 in the Mach 2 B-58; YJ93 in the Mach 3.0 B-70 and the current F101 in the B-1, are all examples of military propulsion systems and airplanes operated at sustained supersonic cruise speeds. The Mach 2.7 B2707 transport powered by GE4 turbojet engines was the only non-military, sustained supersonic cruise vehicle intended for commercial passenger service.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA Proc. of the SCAR Conf., Part 1; p 353-370
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  • 13
    Publikationsdatum: 2016-06-07
    Beschreibung: Variable cycle engine (VCE) concepts for a supersonic cruise aircraft were studied. These VCE concepts incorporate unique critical components and flow path arrangements that provide good performance at both supersonic and subsonic cruise and appear to be economically and environmentally viable. Certain technologies were identified as critical to the successful development of these engine concepts and require considerable development and testing. The feasibility and readiness of the most critical VCE technologies, was assessed, a VCE component test program was initiated. The variable stream control engine (VSCE) component test program, tested and evaluated an efficient low emission duct burner and a quiet coannular ejector nozzle at the rear of a rematched F100 engine.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Proc. of the SCAR Conf., Part 1; p 371-385
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  • 14
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The exhaust emission test was designed to measure hydrocarbons, carbon monoxide, and oxides of nitrogen concentrations and determine mass emissions through calculations during a simulated aircraft landing-takeoff cycle. The calculations required to convert exhaust emission concentrations (raw emission measurements) into mass emissions were emphasized.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 357-378
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  • 15
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Good instrumentation was required to obtain reliable and repeatable baseline data. Problems that were encountered in developing such a total system were: (1) accurate airflow measurement, (2) precise fuel flow measurement, and (3) the instrumentation used for pollutant measurement was susceptible to frequent malfunctions. Span gas quality had a significant effect on emissions test results. The Spindt method was used in the piston aircraft emissions program. The Spindt method provided a comparative computational procedure for fuel/air ratio based on measured emissions concentrations.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 337-356
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  • 16
    Publikationsdatum: 2016-06-07
    Beschreibung: The General Aviation Manufacturers recommended that the EPA rescind the aircraft piston engine emissions regulations currently on the books. The reason was the very small emission reduction potential and the very poor benefit-cost ratio involved in this form of emission reduction. The limited resources of this industry can far better be devoted to items of much greater benefit to the citizens of this country - reducing noise, improving fuel efficiency (which will incidently reduce exhaust emissions), and improving the safety, operational, and economic aspects of aircraft, all far greater contributions to our total national transportation system.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 329-336
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  • 17
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The most promising alternative engine (or engines) for application to general aircraft in the post-1985 time period was defined, and the level of technology was cited to the point where confident development of a new engine can begin early in the 1980's. Low emissions, multifuel capability, and fuel economy were emphasized. Six alternative propulsion concepts were considered to be viable candidates for future general-aircraft application: the advanced spark-ignition piston, rotary combustion, two- and four-stroke diesel, Stirling, and gas turbine engines.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aircraft Piston Eng. Exhaust Emissions Symp.; p 315-328
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  • 18
    Publikationsdatum: 2016-06-07
    Beschreibung: A long-range technology plan in support of general aviation engines was formulated and is being implemented at the Lewis Research Center. The overall program was described, and that part of the program that represents the in-house effort at Lewis was presented in detail. Three areas of government and industry effort involving conventional general-aviation piston engines were part of a coordinated overall plan: (1) FAA/NASA joint program, (2) NASA contract exhaust emissions pollution reduction program, and (3) NASA in-house emissions reduction and new technology program.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aircraft Piston Eng. Exhaust Emissions Symp.; p 295-314
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  • 19
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The emission problem or source points were defined and new materials, hardware, or operational procedures were developed to exercise the trends defined by the data collected. The programs to reduce the emission output of aircraft powerplants were listed. Continued establishment of baseline emissions for various engine models, continued characterization of effect of production tolerances on emissions, carbureted engine development and flight tests, and cylinder cooling/fin design programs were several of the programs investigated.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 283-294
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  • 20
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The standards promulgated by the Environmental Protection Agency (EPA) for carbon monoxide (CO), unburned hydrocarbon (HC), and oxides-of-nitrogen (NOx) emissions were the basis in a study of ways to reduce emissions from aircraft piston engines. A variable valve timing system, ultrasonic fuel atomization, and ignition system changes were postulated.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 255-274
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  • 21
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The NASA Lewis Research Center issued requests for proposal to Avco Lycoming and Teledyne Continental Motors for a contractual effort to establish and demonstrate engine modifications to reduce exhaust emissions safely with minimum adverse effects on cost, weight, and fuel economy. The secondary objective was reducing fuel consumption.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aircraft Piston Eng. Exhaust Emissions Symp.; p 225-226
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  • 22
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: A company program was planned which has a main drive to develop those emission reduction concepts that have the promise of earliest success. These programs were proposed in an attempt to enhance existing engine systems, exploiting their potential for emission reduction as far as is compatible with retaining the well established features in them that are well understood and in current production. The intended programs identified in the area of new concepts were: (1) upgrading the TCM fuel system, (2) evaluation of accelerator pump, (3) reduced cooling requirement, and (4) variable spark timing.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 275-282
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  • 23
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Two different aircraft designs, each with two modified fuel control systems, were evaluated. Each aircraft was evaluated in a given series of defined ground and flight conditions while quantitative and qualitative observations were made. During this program, some ten flights were completed, and a total of about 13 hours of engine run time was accumulated by the two airplanes. The results of these evaluations with emphasis on the operational and safety aspects were analyzed. Ground tests of the engine alone were not able to predict acceptable limiting lean mixture settings for the flight envelopes of the Cessna Models 150 and T337.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 209-224
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  • 24
    Publikationsdatum: 2016-06-07
    Beschreibung: Five different engine models were tested covering combinations of all engine categories in current production in the range from 100 to 435 brake horsepower. Engines were divided into five major types: carbureted, fuel injected, direct drive, geared, and turbocharged. Emissions data were categorized by three separate fuel system schedules: baseline, case 1, and case 2. Baseline was defined as the average fuel flow rate established by the fuel system's production tolerance band when operated with the mixture control at the full-rich position. Case 1 was defined as the minimum allowable fuel flow rate established by the engine certification. Case 2 was defined as the fuel rate corresponding to the leanest fuel-air ratio obtainable before a safety limit occurred with the engine operating on a propeller test stand. Safety limits that developed during testing were cylinder-head overheating or inadequate acceleration from a given mode of operation.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 179-208
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  • 25
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The Avco Lycoming flight test program for reduced emissions was conducted to determine and document the lean fuel schedule limits for current production aircraft based on flight safety. Based on analysis of the emissions profile, Avco Lycoming proposed to evaluate the effect of leaner schedules in the idle/taxi, climb, and approach modes. These modes were selected as areas where it was felt that possible improvements could be made with the greatest improvement in cyclic emissions reduction. The fuel systems to produce these leaner stepped fuel schedules were tailored specifically for the flight test.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 141-178
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  • 26
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Exhaust gas pollutant emissions data under test stand conditions were obtained for the following: (1) full-rich baseline test (7-mode cycle), (2) lean-out tests for each power mode, and (3) different spark settings. The test data were also used to create a theoretical 5-mode cycle baseline. The emissions data in the framework of the theoretical 5-mode cycle were emphasized. There is no significant difference in the test results produced by data exhibited on the 7-mode cycle or 5-mode cycle. The 5-mode cycle was slightly more conservative for the carbon monoxide pollutant than the 7-mode cycle. The data were evaluated to determine which mode(s) had the greatest influence on improving general aviation piston engine emissions. Improvements that were achieved as a result of making lean-out adjustments to the fuel metering device were: (1) taxi mode only, (2) taxi and approach modes combined, and (3) leaning-out of the climb mode to best power.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 121-140
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  • 27
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The computational procedures that are involved in exhaust emissions data reduction and the use of these computational procedures for determining the quality of the data that is obtained from exhaust measurements were considered. Four problem areas were calculated: (1) the various methods for performing the carbon balance, (2) the method for calculating water correction factors, (3) the method for calculating the exhaust molecular weight, and (4) assessing the quality of the data.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 73-84
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  • 28
    Publikationsdatum: 2016-06-07
    Beschreibung: The importance of measuring accurate air and fuel flows as well as the importance of obtaining accurate exhaust pollutant measurements were emphasized. Some of the problems and the corrective actions taken to incorporate fixes and/or modifications were identified.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 45-72
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  • 29
    Publikationsdatum: 2016-06-07
    Beschreibung: Five different engine models were tested to experimentally characterize emissions and to determine the effects of variation in fuel-air ratio and spark timing on emissions levels and other operating characteristics such as cooling, misfiring, roughness, power acceleration, etc. The results are given of two NASA reports covering the Avco Lycoming 0-320-D engine testing and the recently obtained results on the Teledyne Continental TSIO-360-C engine.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aircraft Piston Eng. Exhaust Emissions Symp.; p 85-120
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  • 30
    Publikationsdatum: 2016-06-07
    Beschreibung: The possibility was evaluated for achieving the EPA Standards for HC and CO emissions through the use of air-fuel ratio enleanment at selected power modes combined with improved air-fuel mixture preparation, and in some cases improved cooling. Air injection was also an effective approach for the reduction of HC and CO, particularly when combined with exhaust heat conservation techniques such as exhaust port liners.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 23-44
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  • 31
    facet.materialart.
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Piston engine light aircraft are significant sources of carbon monoxide in the vicinity of high activity general aviation airports. Substantial reductions in carbon monoxide were achieved by fuel mixture leaning using improved fuel management systems. The air quality impact of the hydrocarbon and oxides of nitrogen emissions from piston engine light aircraft were insufficient to justify the design constraints being confronted in present control system developments.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 1-22
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  • 32
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Combustion research related to hypersonic scramjet (supersonic combustion ramjet) propulsion is discussed from the analytical point of view. Because the fuel is gaseous hydrogen, mixing is single phase and the chemical kinetics are well known; therefore, the potential for analysis is good relative to hydro-carbon fueled engines. Recent progress in applying two and three dimensional analytical techniques to mixing and reacting flows indicates cause for optimism, and identifies several areas for continuing effort.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Advan. in Eng. Sci., Vol. 4; p 1629-1639
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  • 33
    Publikationsdatum: 2016-06-07
    Beschreibung: A digitally implemented integrated inlet/engine control system was developed and tested on a mixed compression, Mach 2.5, supersonic inlet and augmented turbofan engine. The control matched engine airflow to available inlet airflow so that in steady state, the shock would be at the desired location, and the overboard bypass doors would be closed. During engine induced transients, such as augmentor lights and cutoffs, the inlet operating point was momentarily changed to a more supercritical point to minimize unstarts. The digital control also provided automatic inlet restart.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Advanced Control Technol. and its Potential for Future Transport Aircraft; p 503-524
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  • 34
    Publikationsdatum: 2017-10-02
    Beschreibung: Single stage fans designed for two levels of pressure ratio or blade loading were subjected to screen induced circumferential distortions of 90 degree extent. Both fan rotors were designed for a blade tip speed of 425 m/sec, blade solidity of 1.3 and a hub-to-tip radius ratio of 0.5. Circumferential measurements of total pressure, temperature, static pressure, and flow angle were obtained at the hub, mean and tip radii at five axial stations. Rotor loading level did not appear to have a significant influence on rotor response to distorted flow. Losses in overall pressure ratio due to distortion were most severe in the stator hub region of the more highly loaded stage. At the near stall operating condition tip and hub regions of (either) rotor demonstrated different response characteristics to the distorted flow. No effect of loading was apparent on interactions between rotor and upstream distorted flow fields.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: AGARD Unsteady Phenomena in Turbomachinery; 26 p
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  • 35
    Publikationsdatum: 2019-06-27
    Beschreibung: A variable pitch fan actuation system was designed which incorporates a remote nacelle-mounted blade angle regulator. The regulator drives a rotating fan-mounted mechanical actuator through a flexible shaft and differential gear train. The actuator incorporates a high ratio harmonic drive attached to a multitrack spherical cam which changes blade pitch through individual cam follower arms attached to each blade trunnion. Detail design parameters of the actuation system are presented. These include the following: design philosophies, operating limits, mechanical, hydraulic and thermal characteristics, mechanical efficiencies, materials, weights, lubrication, stress analyses, reliability and failure analyses.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134852 , HSER-7001
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  • 36
    Publikationsdatum: 2019-06-27
    Beschreibung: The mechanical design of the boiler plate nacelle and core exhaust nozzle for the QCSEE under the wing engine is presented. The nacelle, which features interchangeable hard-wall and acoustic panels, is to be utilized in the initial engine testing to establish acoustic requirements for the subsequent composite nacelle as well as in the QCSEE over the wing engine configuration.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135008 , R76AEG222
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  • 37
    Publikationsdatum: 2019-06-27
    Beschreibung: The preliminary design and installation of high bypass, geared turbofan engine with a composite nacelle forming the propulsion system for a short haul passenger aircraft are described. The technology required for externally blown flap aircraft with under the wing (UTW) propulsion system installations for introduction into passenger service in the mid 1980's is included. The design, fabrication, and testing of this UTW experimental engine containing the required technology items for low noise, fuel economy, with composite structure for reduced weight and digital engine control are provided.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134868 , R75AEG349
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  • 38
    Publikationsdatum: 2019-06-27
    Beschreibung: The aerodynamic and mechanical design of a fixed-pitch 1.36 pressure ratio fan for the over-the-wing (OTW) engine is presented. The fan has 28 blades. Aerodynamically, the fan blades were designed for a composite blade, but titanium blades were used in the experimental fan as a cost savings measure.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134915
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  • 39
    Publikationsdatum: 2019-06-27
    Beschreibung: Declining U.S. oil reserves and escalating energy costs underline the need for reducing fuel consumption in aircraft engines. The most promising unconventional aircraft engines based on their potential for fuel savings and improved economics are identified. The engines installed in both a long-range and medium-range aircraft were evaluated. Projected technology advances are identified and evaluated for their state-of-readiness for application to a commercial transport. Programs are recommended for developing the necessary technology.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135065 , PWA-5434
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  • 40
    Publikationsdatum: 2019-06-27
    Beschreibung: The acoustic tests and data analysis for a 0.508-scale fan vehicle of a 111,300 newton (25,000 pound) thrust, full-size engine, which would have application on an advanced transport aircraft, is described. The single-stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec (1,650 ft/sec) to achieve the desired pressure ratio in a single-stage fan with low radius ratio (0.38), and to maintain adequate stall margin. The fan has 44 tip-shrouded rotor blades and 90 outlet guide vanes. The two basic approaches taken in the acoustic design were: (1) minimization of noise at the source, and (2) suppression of the generated noise in the inlet and bypass exhaust duct. Suppression of the generated noise was accomplished in the inlet through use of the hybrid concept (wall acoustic treatment plus airflow acceleration suppression) and in the exhaust duct with extensive acoustic treatment including a splitter. The goal of the design was attainment of twenty effective perceived noise decibels (20 EPNdB) below current Federal Air Regulation noise standards for a full-scale fan at the takeoff, cutback, and approach conditions. The suppression goal of FAR 36-20 was not reached, but improvements in the technology of both front and aft fan-noise suppression were realized. The suppressed fan noise was shown to be consistent with the proposed federal regulation on aircraft noise.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134894
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  • 41
    Publikationsdatum: 2019-06-27
    Beschreibung: Computer program performance results of a Mach 6 hypersonic research engine during supersonic and subsonic combustion modes were presented. The combustion mode transition was successfully performed, exit surveys made, and effects of altitude, angle of attack, and inlet spike position were determined during these tests.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-72822
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  • 42
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: A brief summary of previous work carried out on end wall flow phenomena is presented with major emphasis on annulus wall boundary layer.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-148310
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  • 43
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: The major tasks undertaken were (1) analytical and laboratory experiments on the propagation of sound from sources near a flat surface of finite acoustic impedance; (2) laboratory experiments dealing with the reflection of sound from finite sized plane patches; and (3) the diffraction of sound by wedge-and trapezoidal-shape barriers. In addition, a series of measurements were made of the background noise levels for various jet flow conditions in the Anechoic Noise Facility of the Langley Research Center's Acoustic and Noise Reduction Laboratory.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-148321 , FTR-2
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  • 44
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: Improved instrumentation suitable for measuring aircraft noise and sonic booms is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable and amplified by a zero drive amplifier. The converter consists of a local oscillator, a dual-gate field-effect transistor mixer, and a voltage regulator/impedance translator. The improvements include automatic tuning compensation against changes in static microphone capacitance and means for providing a remote electrical calibration capability.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
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  • 45
    Publikationsdatum: 2019-06-27
    Beschreibung: An aerodynamic engine inlet analysis was performed on the experimental results obtained at nominal Mach numbers of 5, 6, and 7 from the NASA Hypersonic Research Engine (HRE) Aerothermodynamic Integration Model (AIM). Incorporation on the AIM of the mixed-compression inlet design represented the final phase of an inlet development program of the HRE Project. The purpose of this analysis was to compare the AIM inlet experimental results with theoretical results. Experimental performance was based on measured surface pressures used in a one-dimensional force-momentum theorem. Results of the analysis indicate that surface static-pressure measurements agree reasonably well with theoretical predictions except in the regions where the theory predicts large pressure discontinuities. Experimental and theoretical results both based on the one-dimensional force-momentum theorem yielded inlet performance parameters as functions of Mach number that exhibited reasonable agreement. Previous predictions of inlet unstart that resulted from pressure disturbances created by fuel injection and combustion appeared to be pessimistic.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3365 , L-10400
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  • 46
    Publikationsdatum: 2019-06-27
    Beschreibung: A JT8D-17 turbofan engine was tested in the NASA-Ames 40- by 80-foot wind tunnel to determine flight effects on jet and fan noise. Baseline, quiet nacelle with 20-lobe ejector/suppressor, and internal mixer configurations were tested over a range of engine power settings and tunnel velocities. Flight effects derived from the 40- by 80-foot wind tunnel test are compared with 727/JT8D flight test data and with model data obtained in a smaller wind tunnel. Procedures are defined for measuring noise data in a wind tunnel relatively near the sources and analyzing the results to obtain far-field flight effects. Wind tunnel and 727 flight test noise results compare favorably for both the baseline and quiet nacelle configurations. Two reports are provided, including a comprehensive version with extensive test results and analysis and the subject summary version that emphasizes data analysis and program finding.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-2576 , D6-42813-1
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  • 47
    Publikationsdatum: 2019-06-27
    Beschreibung: An analytical study was performed on a novel disk design to replace the existing high-pressure turbine, stage 1 disk on the CF6-50 turbofan engine. Preliminary studies were conducted on seven candidate disk design concepts. An integral multidisk design with bore entry of the turbine blade cooling air was selected as the improved disk design. This disk has the unique feature of being redundant such that if one portion of the disk would fail, the remaining portion would prevent the release of large disk fragments from the turbine system. Low cycle fatigue lives, initial defect propagation lives, burst speed, and the kinetic energies of probable disk fragment configurations were calculated, and comparisons were made with the existing disk, both in its current material, IN 718, and with the substitution of an advanced alloy, Rene 95. The design for redundancy approach which necessitated the addition of approximately 44.5 kg (98 lb) to the design disk substantially improved the life of the disk. The life to crack initiation was increased from 30,000 cycles to more than 100,000 cycles. The cycles to failure from initial defect propagation were increased from 380 cycles to 1564 cycles. Burst speed was increased from 126 percent overspeed to 149 percent overspeed. Additionally, the maximum fragment energies associated with a failure were decreased by an order of magnitude.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135033 , R76AEG324
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  • 48
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: The unsteady response of an axial flow fan rotor to steady, circumferential inflow velocity and stagnation pressure distortions is assessed by two different methods. These are: (1) investigation of the unsteady normal force and pitching moment on a chordwise element of a rotor blade; and (2) investigation of the variation of the stagnation pressure distortion between the inlet and exit of the rotor. Experimental measurements of these unsteady characteristics are presented as a function of the geometry of the rotor -- stagger angle, solidity and steady angle of incidence -- for sinusoidally varying circumferential distortions with different numbers of distortion cycles. These measurements are compared with several theoretical analyses. While these comparisons indicate some of the deficiencies which exist in the theories, the existence of an unsteady cascade effect and the ability of the theories to adequately predict the trend of the unsteady response due to variations in reduced frequency, rotor stagger angle, solidity and mean incidence angle is clearly demonstrated.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: AGARD Unsteady Phenomena in Turbomachinery; 13 p
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  • 49
    Publikationsdatum: 2019-06-27
    Beschreibung: A small experimental axial-flow turbojet engine in the 2,669-Newton (600-lbf) thrust class was designed, fabricated, and tested to demonstrate the feasibility of several low-cost concepts. Design simplicity was stressed in order to reduce the number of components and machining operations. Four engines were built and tested for a total of 157 hours. Engine testing was conducted at both sea-level static and simulated flight conditions for engine speeds as high as 38,000 rpm and turbine-inlet temperatures as high as 1,255 K (1,800 F).
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3392 , E-8590
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  • 50
    Publikationsdatum: 2019-06-27
    Beschreibung: The aerodynamic design for a half-scale fan vehicle, which would have application on an advanced transport aircraft, is described. The single stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec 11,650 ft/sec). The fan and booster components are designed in a scale model flow size convenient for testing with existing facility and vehicle hardware. The design corrected flow per unit annulus area at the fan face is 215 kg/sec sq m (44.0 lb m/sec sq ft) with a hub-tip ratio of 0.38 at the leading edge of the fan rotor. This results in an inlet corrected airflow of 117.9 kg/sec (259.9 lb m/sec) for the selected rotor tip diameter if 90.37 cm (35.58 in.). The variable geometry inlet is designed utilizing a combination of high throat Mach number and acoustic treatment in the inlet diffuser for noise suppression (hybrid inlet). A variable fan exhaust nozzle was assumed in conjunction with the variable inlet throat area to limit the required area change of the inlet throat at approach and hence limit the overall diffusion and inlet length. The fan exit duct design was primarily influenced by acoustic requirements, including length of suppressor wall treatment; length, thickness and position on a duct splitter for additional suppressor treatment; and duct surface Mach numbers.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134801 , R76AEG257-VOL-1
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  • 51
    Publikationsdatum: 2019-06-27
    Beschreibung: Two single-stage, 0.77 hub/tip ratio axial-flow compressors were tested to evaluate the effectiveness of low aspect ratio blading as a means of obtaining higher stage loadings. One compressor, designated Stage F, was comprised of circular arc blading with an aspect ratio of 0.9 for both the rotor and stator. This compressor was tested with uniform inlet flow, hub radial, tip radial, and 180 deg arc circumferential inlet distortion. The second compressor, designated Stage G, was comprised of multiple circular arc blading with an aspect ratio of 1.0 for both the rotor and stator. This compressor was tested with uniform inlet flow only. Design rotor tip speeds for Rotor F and Rotor G were 285 m/sec (934 ft/sec) and 327 m/sec (1,074 ft/sec) respectively. Both stages operated at high loading levels with adequate efficiency and operating range. The peak efficiencies and corresponding average stage diffusion factors for Stages F and G at design rotor speed were 86.4% and 84.1% and 0.59 and 0.55 respectively. The surge margin at peak efficiency for Stage F was 12.6% and the corresponding value for Stage G was 16.5%. Both stages experienced a loss in efficiency with increasing rotor speed; however, the multiple circular arc rotor delayed the characteristic loss in efficiency within increasing Mach number to higher Mach number.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134993 , PWA-FR-7033-PT-9-VOL-1
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  • 52
    Publikationsdatum: 2019-06-27
    Beschreibung: Radiometric data were obtained over a range of parametric test conditions at three positions along the length of an experimental combustor segment corresponding to the primary, intermediate, and dilution zones. The concentration of soot entrained in the combustion gases was calculated by a technique using spectral radiance measurements. Tests were conducted primarily with Jet A fuel, although limited data were taken with two fuels having higher aromatic content, diesel oil number 2 and a blend of 40 percent tetralin in Jet A fuel. Radiometric observation of the combustion gases indicated that the maximum total radiance peaked at the intermediate zone, which was located immediately upstream of the dilution holes. Soot concentrations calculated from optical measurements in the dilution zone compared favorably with those obtained by in situ gas sampling at the exhaust. The total radiance increased with the higher aromatic content fuels.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3394 , E-8630
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  • 53
    Publikationsdatum: 2019-06-27
    Beschreibung: The results are presented of a one-dimensional dynamic digital blade row compressor model study of a J85-13 engine operating with uniform and with circumferentially distorted inlet flow. Details of the geometry and the derived blade row characteristics used to simulate the clean inlet performance are given. A stability criterion based upon the self developing unsteady internal flows near surge provided an accurate determination of the clean inlet surge line. The basic model was modified to include an arbitrary extent multi-sector parallel compressor configuration for investigating 180 deg 1/rev total pressure, total temperature, and combined total pressure and total temperature distortions. The combined distortions included opposed, coincident, and 90 deg overlapped patterns. The predicted losses in surge pressure ratio matched the measured data trends at all speeds and gave accurate predictions at high corrected speeds where the slope of the speed lines approached the vertical.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134978 , R75AEG406
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  • 54
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: The near-term technology improvements which can reduce the fuel consumed in the JT9D, JT8D, and JT3D turbofans in commercial fleet operation through the 1980's are identified. Projected technology advances are identified and evaluated for new turbofans to be developed after 1985. Programs are recommended for developing the necessary technology.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135002 , PWA-5318
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  • 55
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: The YF-12 research program was initiated to establish a technology base for the design of an efficient propulsion system for supersonic cruise aircraft. The major technology areas under investigation in this program are inlet design analysis, propulsion system steady-state performance, propulsion system dynamic performance, inlet and engine control systems, and airframe/propulsion system interactions. The objectives, technical approach, and status of the YF-12 propulsion program are discussed. Also discussed are the results obtained to date by the NASA Ames, Lewis, and Dryden research centers. The expected technical results and proposed future programs are also given. Propulsion system configurations are shown.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-56039 , H-935
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  • 56
    Publikationsdatum: 2019-06-27
    Beschreibung: The aerodynamic performance of two trailing edge ejection cooling configurations of a core-engine stator vane were experimentally determined in an ambient inlet-air full-annular cascade where three-dimensional effects could be obtained. The tests were conducted at the design mean-radius ideal aftermixed critical velocity ratio of 0.778. Overall vane aftermixed thermodynamic and primary efficiencies were obtained over a range of coolant flows to about 10 percent of the primary flow at a primary to coolant total temperature ratio of 1.0. The radial variation in efficiency and the circumferential and radial variations in vane-exit total pressure were determined. Comparisons are made with the solid (uncooled) vane.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3369 , E-8566
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  • 57
    Publikationsdatum: 2019-06-27
    Beschreibung: Circumferential inlet distortion testing of a TF30-P-3 afterburning turbofan engine was conducted at NASA-Lewis Research Center. Pratt and Whitney Aircraft analyzed the data using its multiple segment parallel compressor model and classical compressor theory. Distortion attenuation analysis resulted in a detailed flow field calculation with good agreement between multiple segment model predictions and the test data. Sensitivity of the engine stall line to circumferential inlet distortion was calculated on the basis of parallel compressor theory to be more severe than indicated by the data. However, the calculated stall site location was in agreement with high response instrumentation measurements.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134996 , PWA-5302
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  • 58
    Publikationsdatum: 2019-06-27
    Beschreibung: The fuel consumption of a modern compound engine with that of an advanced high pressure ratio turbofan was compared. The compound engine was derived from a turbofan engine by replacing the combustor with a rotary combustion (RC) engine. A number of boost pressure ratios and compression ratios were examined. Cooling of the RC engine was accomplished by heat exchanging to the fan duct. Performance was estimated with an Otto-cycle for two levels of energy lost to cooling. The effects of added complexity on cost and maintainability were not examined and the comparison was solely in terms of cruise performance and weight. Assuming a 25 percent Otto-cycle cooling loss (representative of current experience), the best compound engine gave a 1.2 percent improvement in cruise. Engine weight increased by 23 percent. For a 10 percent Otto-cycle cooling loss (representing advanced insulation/high temperature materials technology), a compound engine with a boost PR of 10 and a compression ratio of 10 gave an 8.1 percent lower cruise than the reference turbofan.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-71906 , E-8695
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  • 59
    Publikationsdatum: 2019-06-27
    Beschreibung: A family of fans designed with low noise features was acoustically evaluated, and noise results are documented for a 1.6-pressure-ratio, 472-m/sec (155-ft/sec) tip speed fan. The fan is described and some aerodynamic operating data are given. Far field noise around the fan was measured over a range of operating conditions for a variety of configurations having different arrangements of sound absorbing material in the flow ducts. Complete results of 1.3 octave band analysis of the data are presented in tabular form. Included also are acoustic power spectra and sideline perceived noise levels. Representative 1/3 octave band data are presented graphically, and sample graphs of continuous narrow band spectra are also provided.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3360 , E-8530
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  • 60
    Publikationsdatum: 2019-06-27
    Beschreibung: Low speed wind tunnel tests were conducted to establish a procedure for determining inlet-lip flow separation and to make preliminary examination of the incidence angle bounds for lip flow separation on inlets intended for the nacelles of STOL (short takeoff and landing) aircraft. Three inlets were tested. Two of the inlets had short centerbodies with lower lip area contraction ratios of 1.30 and 1.44. The third inlet had a cylindrical centerbody extended forward into the inlet throat with a lower lip area contraction ratio of 1.44. The inlets were sized to fit a 13.97 centimeter-diameter fan. For inlet throat Mach numbers less than about 0.43, the lip flow separation angle was increased by either increasing the ratio of throat velocity to freestream velocity (Vt/Vo) or by increasing the lower lip area contraction ratio. For throat Mach numbers greater than a certain value (ranging from 0.43 to 0.52), increasing throat Mach number in some cases resulted in a decrease in the lip flow separation angle. Extending a cylindrical centerbody into the inlet throat increased the flow separation angle for nearly all values of Vt/Vo.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3351 , E-8523
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  • 61
    Publikationsdatum: 2019-06-27
    Beschreibung: Plug nozzle film cooling data were obtained downstream of a slot located at 42 percent of the total plug length on a J-85 engine. Film cooling reduced the aft end wall temperature as much as 150 K, reduced total pressure loss in the upstream convection cooling passages by 50 percent, and reduced estimated compressor bleed flow requirement by 14 percent compared to an all convectively cooled nozzle. Shock waves along the plug surface strongly influenced temperature distributions on both convection and film cooled portions. The effect was most severe at nozzle pressure ratios below 10 where adverse pressure gradients were most severe.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3362 , E-8553
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  • 62
    Publikationsdatum: 2019-06-27
    Beschreibung: It is important to know whether the relatively high takeoff speeds of supersonic transport aircraft will change the exhaust noise levels of nozzles from those measured at static conditions. To gain some insight into this question, a modified F-106B aircraft was used to conduct flyover and static tests on a wedge nozzle. Flight velocity had an adverse effect on exhaust noise when compared with static results at the same relative jet velocity but a beneficial effect when compared with static results at the same absolute jet velocity. The wedge nozzle, which has a two-dimensional wedge surface rather than an axisymmetric plug surface, had a higher peak flyover noise level than the plug nozzle.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3361 , E-8548
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  • 63
    Publikationsdatum: 2019-06-27
    Beschreibung: Sideline noise and takeoff field length were varied for two types of Mach 2.32 cruise airplane to determine their effect on engine cycle selection. One of these airplanes was the NASA/Langley-LTV arrow wing while the other was a Boeing modified delta-plus-tail derived from the earlier 2707-300 concept. Advanced variable cycle engines were considered. A more conventional advanced low bypass turbofan engine was used as a baseline for comparison. Appropriate exhaust nozzle modifications were assumed, where needed, to allow all engines to receive either an inherent co-annular or annular jet noise suppression benefit. All the VCE's out-performed the baseline engine by substantial margins in a design range comparison, regardless of airplane choice or takeoff restrictions. The choice among the three VCE's considered, however, depends on the field length, noise level, and airplane selected.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-71865 , E-8631
    Format: application/pdf
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  • 64
    Publikationsdatum: 2019-06-27
    Beschreibung: Exhaust pollutant emissions were measured from a 501-D22A turboprop engine combustor and three low emission combustor types -- reverse flow, prechamber, and staged fuel, operating over a fuel-air ratio range of .0096 to .020. The EPAP LTO cycle data were obtained for a total of nineteen configurations. Hydrocarbon emissions were reduced from 15.0 to .3 lb/1000 Hp-Hr/cycle, CO from 31.5 to 4.6 lb/1000 Hp-Hr/cycle with an increase in NOx of 17 percent, which is still 25% below the program goal. The smoke number was reduced from 59 to 17. Emissions given here are for the reverse flow Mod. IV combustor which is the best candidate for further development into eventual use with the 501-D22A turboprop engine. Even lower emissions were obtained with the advanced technology combustors.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135040 , EDR-8708
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  • 65
    Publikationsdatum: 2019-06-27
    Beschreibung: The structural design for a half-scale fan vehicle, which would have application on an advanced transport aircraft, is described. The single stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec (1,650 ft/sec). This mechanical design report describes the fan rotor design and the design of various structures of the vehicle; eg, stators, casings, splitters, seals, adapters, etc.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134802 , R76AEG258-VOL-2
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  • 66
    Publikationsdatum: 2019-06-27
    Beschreibung: Accurate spillage drag and pressure data are presented for a realistic supersonic inlet configuration. Results are compared with predictions from a finite-differencing, inviscid analysis computer procedure. The analytical technique shows good promise for the evaluation of inlet drag, but necessary refinements were identified. A detailed description of the analytical procedure is contained in the Appendix.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-2680
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  • 67
    Publikationsdatum: 2019-06-27
    Beschreibung: Test variables were inlet Reynolds number index (0.2 to 0.5), flight Mach number (0.2 to 0.8), and flow distortion (tip radial and combined circumferential - tip radial patterns). Results are limited to fan bypass and overall engine performance. There were no discernible effects of Reynolds number on fan performance. Increasing flight Mach number shifted the fan operating line such that pressure ratio decreased and airflow increased. Inlet flow distortion lowered stall margin. For a Reynolds number index of 0.2 and flight Mach number of 0.54, the sound suppressing nacelle lowered fan efficiency three points and increased specific fuel consumption about 10 percent.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3385 , E-8592
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  • 68
    Publikationsdatum: 2019-06-27
    Beschreibung: Emissions of nitrogen oxides, carbon monoxide, and unburned hydrocarbons were measured in a burner where liquid Jet A fuel was sprayed into the heated air stream and vaporized upstream of a perforated plate flameholder. The burner was tested at inlet air temperatures at 640, 800, and 833 K, an inlet pressure of 5.6 X 100,000 N/m squared, a reference velocity of 25 m/sec, and equivalence ratios from lean blowout to 0.7. Nitrogen oxide levels of below 1.0 g NO2/kg fuel were obtained at combustion efficiencies greater than 99 percent. The measured emission levels for the liquid fuel agreed well with previously reported premixed gaseous propane data and agreed with well stirred reactor predictions. Autoignition of the premixed fuel air mixture was a problem at inlet temperatures above 650 K with 104 msec premixing time.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3383 , E-8589
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  • 69
    Publikationsdatum: 2019-06-27
    Beschreibung: Tabulated computer program results of wind tunnel tests for Mach 5 components are presented.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-72824
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  • 70
    Publikationsdatum: 2019-06-27
    Beschreibung: The aerodynamic design of a highly loaded multistage fan drive turbine is discussed. Turbine flowpath and airfoil sections are presented along with respective pressure and velocity distributions. Vibrational modes are identified in the expected turbine operating range.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-2659 , PWA-5101
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  • 71
    Publikationsdatum: 2019-06-27
    Beschreibung: A test program was conducted to evaluate the effects of four flame stabilizer designs on the performance and gaseous pollutant levels of an experimental full-annular swirl-can combustor. Combustor operating parameters, including inlet-air temperature, reference velocity, and fuel-air ratio, were set to simulate conditions in a 30:1 pressure ratio engine. Combustor inlet total pressure was held constant at 6 atm due to the facility limit. Combustor performance and gaseous pollutant levels were strongly affected by the geometry and resulting total pressure loss of the four flame stabilizer designs investigated. The addition of shrouds to two designs produced an 18 to 22% decrease in the combustion chamber pressure loss and thus resulted in doubling the exit temperature pattern factor and up to 42% higher levels of oxides of nitrogen. A previously developed oxides of nitrogen correlating parameter agreed with each model within an emission index of plus or minus 1 but was not capable of correlating all models together.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3373 , E-8564
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  • 72
    Publikationsdatum: 2019-06-27
    Beschreibung: The structural and thermal design of a hydrogen fueled regeneratively cooled three dimensional fixed geometry scramjet was examined. An exploratory study was conducted at Mach 5.3 in the 7-inch Mach 7 pilot tunnel to investigate the unstart phenomena and to provide the experimental data base required to predict the design pressure loads. The test results indicate that the peak pressures occurred during the transient unstart and not during steady state started or unstarted flow conditions. The local peak pressures can be conservatively predicted by normal shock wave theory as the peak approaches the pressure that would exist behind a stationary normal shock with an upstream Mach number equal to the area weighted local Mach number for the normal started condition.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TN-D-8156 , L-10643
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  • 73
    Publikationsdatum: 2019-06-27
    Beschreibung: Tests were conducted in a low speed wind tunnel to determine the aerodynamic performance of several flared fan nozzles. Each of the flared nozzles was a downstream-facing inlet to a model fan that was used to simulate a variable pitch fan during reverse thrust operation. The total pressure recovery of each of the flared nozzles as well as that of an unflared nozzle and a serrated flare nozzle was obtained for comparison. The aerodynamic performance of a selected flared nozzle was considered in further detail. The nozzle surface pressures for a flared nozzle were also determined. Results indicated that the differences in aerodynamic performance among the nozzles were most apparent at the wind-tunnel-off condition. A nonzero free stream velocity significantly reduced the perforamnce of all the nozzles, and crosswind flow (free stream flow perpendicular to the model axis) further reduced the performance of the nozzles. The unflared nozzle and the serrated flare nozzle had reduced aerodynamic performance compared to a solid surface flared nozzle.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3367 , E-8539
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  • 74
    Publikationsdatum: 2019-06-27
    Beschreibung: Experiments were conducted to determine the effectiveness of several premixing prevaporizing gas turbine combustor designs in reducing formation of oxides of nitrogen at the supersonic cruise condition. An atomized spray from a single injector mounted on the axis of the mixer tube produced a high initial concentration of fuel near the axis and only moderate premixed conditions entering the combustor. A fuel spray produced by 12 flush-mounted normal injection orifices in the mixer tube wall produced a good initial despersion of fuel and resulted in nearly complete premixing. Oxides of nitrogen emission levels of the order of 0.2 g NO2/kg fuel were obtained at 99 percent combustion efficiency at an equivalence ratio of 0.4. Overall total pressure drop was less than 3 percent through the 1-meter combustor module.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-2657 , TR-793
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  • 75
    Publikationsdatum: 2019-06-27
    Beschreibung: A J85-13 engine was equipped with a compressor case that allowed changes to the case wall over the rotor tips of six of its eight stages. The engine was tested with four inlet configurations: uniform inlet flow, 180 degree circumferential distortion, hub radial distortion, and tip radial distortion. Slotted inserts were installed in the first three stages, and the compressor was mapped under similar conditions. Overall compressor performance obtained with tip treatment was inferior to the performance for the compressor's normal operating range. Pumping capacity with the slotted inserts was reduced. Overall compressor efficiency was reduced 1 to 2 percent with the slotted rings installed for 90 and 100 percent corrected engine speeds.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3350 , E-8485
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  • 76
    Publikationsdatum: 2019-06-27
    Beschreibung: A series of tests was conducted to determine the aerodynamic and acoustic performance of several sonic inlet takeoff and approach geometries. The effects of inlet lip shape and diffuser length were also investigated. The tests were conducted in a low-speed wind tunnel at free-stream velocities of 0 and 45 meters per second. Inlet incidence angle was varied from 0 deg to 50 deg. The inlets were sized to fit a 13.97-centimeter-diameter fan. In terms of the highest level of inlet total pressure recovery for a given amount of noise suppression, a cylindrical centerbody takeoff geometry and a bulb-shaped centerbody approach geometry provided the best results over all conditions of free-stream velocity and incidence angle. Increasing inlet lip contraction ratio extended the maximum incidence angle for attached lip flow, while increasing inlet diffuser length resulted in a higher total pressure recovery for a given amount of noise suppression.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3332 , E-8445
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  • 77
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: Additional preliminary design studies were performed for a turbotip lift/cruise fan propulsion system for a Navy multimission aircraft. The LCF459/J97 propulsion system was previously designed for this application. These studies extended the analysis in areas of (1) scroll commonality, (2) increased engine-out contingency ratings, (3) mounting systems, (4) manufacturing cost reductions, and (5) vulnerability.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134928 , R76AEG152
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  • 78
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: A computer program written in FORTRAN that may be used for the design analysis of radial-inflow turbines was documented. The following information is included: loss model (estimation of losses), the analysis equations, a description of the input and output data, the FORTRAN program listing and list of variables, and sample cases. The input design requirements include the power, mass flow rate, inlet temperature and pressure, and rotational speed. The program output data includes various diameters, efficiencies, temperatures, pressures, velocities, and flow angles for the appropriate calculation stations. The design variables include the stator-exit angle, rotor radius ratios, and rotor-exit tangential velocity distribution. The losses are determined by an internal loss model.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TN-D-8164 , E-8394
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  • 79
    Publikationsdatum: 2019-06-27
    Beschreibung: An analysis was made to determine the potential benefits of using a ceramic thermal insulation coating of calcia-stabilized zirconia on cooled engine parts. The analysis was applied to turbine vanes of a high temperature and high pressure core engine and a moderate temperature and low pressure research engine. Measurements made during engine operation showed that the coating substantially reduced vane metal wall temperatures. Evaluation of the durability of the coating on turbine vanes and blades in a furnace and engine were encouraging.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3352 , E-8557
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  • 80
    Publikationsdatum: 2019-06-27
    Beschreibung: Flyover noise measurements were made (using Federal Aviation Regulations, part 36 procedures) of two DC-9 aircraft, one equipped with refanned JT8D-109 engines and the other equipped with hardwalled JT8D-9 engines. NASA analyses show a refan centerline noise reduction of about 9.1 EPNdB and 10.0 EPNdB for takeoff with cutback and 50 deg. flap landing approach, respectively. A comparison of refan and hardwall PNLTM spectra shows that the refan noise reduction may be attributed to lower jet noise levels on takeoff and reduced high-frequency tonal content on landing approach. A general description of the test procedures and results are included along with detailed descriptions of the measurement and analysis systems.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-72804
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  • 81
    Publikationsdatum: 2019-06-27
    Beschreibung: Experiments were conducted to determine the performance of a premixing prevaporizing gas turbine primary zone combustor design over a range of combustor inlet temperatures from 700 to 1000 K and a range of inlet pressures from 40 to 240 N/sq cm. The 1 meter long combustor could be operated at pressures up to and including 120 N/sq cm without autoignition in the premixing duct or flashback from the stabilized combustion zone. Autoignition occurred in the mixer tube at the 240 N/sq cm pressure level with an entrance temperature of 830 K and a mixer residence time of 4 msec. Measured NOx level, combustion inefficiency, and hydrocarbon emission index correlated well with adiabatic flame temperature. The NOx levels varied from approximately 0.2 to 2.0 g NO2/kg fuel at combustion inefficiencies from 4 to 0.04 percent, depending upon adiabatic flame temperature and pressure. Measured NOx levels were sensitive to pressure. Tests were made at equivalence ratios ranging from 0.35 to 0.65. The overall total pressure drop for the configuration varied slightly with reference velocity and equivalence ratio, but never exceeded 3 percent.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-2740 , GASL-TR-227
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  • 82
    Publikationsdatum: 2019-06-27
    Beschreibung: A set of long chord stator vanes was designed to replace the vanes in an existing fan stage. The long chord stator vanes consisted of a turning section and axial extension pieces, all of which incorporated acoustic damping material. The long chord stator vanes were tested in two lengths, with the long version giving more noise reduction than the short, primarily because of the additional lining material. The noise reduction achieved with the acoustically treated long chord stator vanes was compared with the reduction achieved by an acoustically treated exhaust splitter. The long chord stator was at least as good as the splitter as a method for incorporating acoustic lining material. In addition, comparing an acoustic three ring inlet and an acoustic wall-only inlet discloses that the wall-only inlet could be used in an engine where the noise reduction requirements are not too stringent.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TN-D-8250 , E-8736
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  • 83
    Publikationsdatum: 2019-06-27
    Beschreibung: Thermal barrier ceramic coatings of stabilized zirconia over a bond coat of Ni Cr Al Y were tested for durability on air cooled turbine rotor blades in a research turbojet engine. Zirconia stabilized with either yttria, magnesia, or calcia was investigated. On the basis of durability and processing cost, the yttria stabilized zirconia was considered the best of the three coatings investigated.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3410 , E-8700
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  • 84
    Publikationsdatum: 2019-06-27
    Beschreibung: An optimum, axial flow, high pressure ratio compressor for a turbofan engine was defined for commercial subsonic transport service starting in the late 1980's. Projected 1985 technologies were used and applied to compressors with an 18:1 pressure ratio having 6 to 12 stages. A matrix of 49 compressors was developed by statistical techniques. The compressors were evaluated by means of computer programs in terms of various airline economic figures of merit such as return on investment and direct-operating cost. The optimum configuration was determined to be a high speed, 8-stage compressor with an average blading aspect ratio of 1.15.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135091 , PWA-5386
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  • 85
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: The primary objectives of this three-phase program are to develop technology for the design of advanced combustors with significantly lower pollutant emission levels than those of current combustors, and to demonstrate these pollutant emission reductions in CF6-50C engine tests. The purpose of the Phase 2 Program was to further develop the two most promising concepts identified in the Phase 1 Program, the double annular combustor and the radial/axial staged combustor, and to design a combustor and breadboard fuel splitter control for CF6-50 engine demonstration testing in the Phase 3 Program. Noise measurement and alternate fuels addendums to the basic program were conducted to obtain additional experimental data. Twenty-one full annular and fifty-two sector combustor configurations were evaluated. Both combustor types demonstrated the capability for significantly reducing pollutant emission levels. The most promising results were obtained with the double annular combustor. Rig test results corrected to CF-50C engine conditions produced EPA emission parameters for CO, HC, and NOX of 3.4, 0.4, and 4.5 respectively. These levels represent CO, HC, and NOX reductions of 69, 90, and 42 percent respectively from current combustor emission levels. The combustor also met smoke emission level requirements and development engine performance and installation requirements.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134971 , R76AEG422
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  • 86
    Publikationsdatum: 2019-06-27
    Beschreibung: Combustor noise measurements were performed using wave guide probes. Test results from two full scale annular combustor configurations in a combustor test rig are presented. A CF6-50 combustor represented a current design, and a double annular combustor represented the advanced clean combustor configuration. The overall acoustic power levels were found to correlate with the steady state heat release rate and inlet temperature. A theoretical analysis for the attenuation of combustor noise propagating through a turbine was extended from a subsonic relative flow condition to include the case of supersonic flow at the discharge side. The predicted attenuation from this analysis was compared to both engine data and extrapolated component combustor data. The attenuation of combustor noise through the CF6-50 turbine was found to be greater than 14 dB by both the analysis and the data.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135045 , R75AEG147-13-ADD
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  • 87
    Publikationsdatum: 2019-06-27
    Beschreibung: Results for three velocity decayer nozzle configurations are compared with those obtained with a separate flow coannular nozzle tested on the same quieted turbofan engine. Peak sideline noise, which occurred 110 degrees from the inlet, was 2 to 4 db louder than with the coannular nozzle at the same ideal effective exhaust velocity and 8 to 11 db louder at the same thrust level. The decayer nozzles produced an increase in loss equivalent to about 4 percent of the engine thrust and also increased the effective exhaust velocity of the engine. The exhaust decayed to 0.35 of its peak velocity, compared with no decay for the coannular nozzle, within 3 equivalent nozzle diameters of the exit. The peak exhaust gas temperature was 400 K lower for the decayer configuration at the same location. The increase in perceived noise level for the decayer nozzles as compared with the coannular nozzle was attributed to the increase in exhaust velocity and the shift in peak spectrum frequency produced by these nozzles.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3413 , E-8676
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  • 88
    Publikationsdatum: 2019-06-27
    Beschreibung: A Pollution Reduction Technology Program to develop and demonstrate the combustor technology necessary to reduce exhaust emissions for aircraft engines using can-annular combustors is described. The program consisted of design, fabrication, experimental rig testing and assessment of results and was conducted in three program elements. The combustor configurations of each program element represented increasing potential for meeting the 1979 Environmental Protection Agency (EPA) emission standards, while also representing increasing complexity and difficulty of development and adaptation to an operational engine. Experimental test rig results indicate that significant reductions were made to the emission levels of the baseline JT8D-17 combustor by concepts in all three program elements. One of the Element I single-stage combustors reduced carbon monoxide to a level near, and total unburned hydrocarbons (THC) and smoke to levels below the 1979 EPA standards with little or no improvement in oxides of nitrogen. The Element II two-stage advanced Vorbix (vortex burning and mixing) concept met the standard for THC and achieved significant reductions in CO and NOx relative to the baseline. Although the Element III prevaporized-premixed concept reduced high power NOx below the Element II results, there was no improvement to the integrated EPA parameter relative to the Vorbix combustor.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135027 , PWA-5394
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  • 89
    Publikationsdatum: 2019-06-27
    Beschreibung: The NASA Hypersonic Research Engine (HRE) Project was initiated for the purpose of advancing the technology of airbreathing propulsion for hypersonic flight. A large component (inlet, combustor, and nozzle) and structures development program was encompassed by the project. The tests of a full-scale (18 in. diameter cowl and 87 in. long) HRE concept, designated the Aerothermodynamic Integration Model (AIM), at Mach numbers of 5, 6, and 7. Computer program results for Mach 6 component integration tests are presented.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-72821
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  • 90
    Publikationsdatum: 2019-06-27
    Beschreibung: For abstract, see N76-23261.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134994 , PWA-FR-7033-PT-9-VOL-2
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  • 91
    Publikationsdatum: 2019-06-27
    Beschreibung: The NASA Hypersonic Research Engine Project was undertaken to design, develop, and construct a hypersonic research ramjet engine for high performance and to flight test the developed concept on the X-15-2A airplane over the speed range from Mach 3 to 8. Computer program results are presented here for the Mach 7 component integration and performance tests.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-72823
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  • 92
    Publikationsdatum: 2019-06-27
    Beschreibung: A 1.25-pressure-ratio 1.83-meter (6-ft) tip diameter experimental fan stage with characteristics suitable for engine application on STOL aircraft was tested for acoustic and aerodynamic performance. The design incorporated proven features for low noise, including absence of inlet guide vanes, low rotor blade tip speed, low aerodynamic blade loading, and long axial spacing between the rotor and stator blade rows. The fan was operated with five exhaust nozzle areas. The stage noise levels generally increased with a decrease in nozzle area. Separation of the acoustic one-third octave results into broadband and pure-tone components showed the broadband noise to be greater than the corresponding pure-tone components. The sideline perceived noise was highest in the rear quadrants. The acoustic results of QF-8 were compared with those of two similar STOL application fans in the test series. The QF-8 had somewhat higher relative noise levels than those of the other two fans. The aerodynamic results of QF-8 and the other two fans were compared with corresponding results from 50.8-cm (20-in.) diam scale models of these fans and design values. Although the results for the full-scale and scale models of the other two fans were in reasonable agreement for each design, the full-scale fan QF-8 results showed poor performance compared with corresponding model results and design expectations. Facility effects of the full-scale fan QF-8 installation were considered in analyzing this discrepancy.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TN-D-8130 , E-8431
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  • 93
    Publikationsdatum: 2019-06-27
    Beschreibung: Emissions of total oxides of nitrogen, nitric oxide, unburned hydrocarbons, carbon monoxide, and carbon dioxide from two J-58 afterburning turbojet engines at simulated high-altitude flight conditions are reported. Test conditions included flight speeds from Mach 2 to 3 at altitudes from 16.0 to 23.5 km. For each flight condition exhaust measurements were made for four or five power levels, from maximum power without afterburning through maximum afterburning. The data show that exhaust emissions vary with flight speed, altitude, power level, and radial position across the exhaust. Oxides of nitrogen emissions decreased with increasing altitude and increased with increasing flight speed. Oxides of nitrogen emission indices with afterburning were less than half the value without afterburning. Carbon monoxide and hydrocarbon emissions increased with increasing altitude and decreased with increasing flight speed. Emissions of these species were substantially higher with afterburning than without.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TN-D-8173 , E-8490
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  • 94
    Publikationsdatum: 2019-06-27
    Beschreibung: A transonic fan stage having a design pressure ratio of 1.57 was tested with a 90 degree circumferential distortion imposed on the inlet flow. The rotor diameter was approximately 50.8 cm, and the design pressure ratio was 1.60 at a tip speed of 425 m/sec. Overall performance at 70 and 100 percent of design speed showed a loss of stall pressure ratio and flow range at design speed and no significant loss in stall pressure ratio at 70 percent of design speed. Detailed flow measurements are presented to show the rotor-upstream flow interactions and the attenuation and amplification properties through the stage.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TN-D-8163 , E-8218
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  • 95
    Publikationsdatum: 2019-06-27
    Beschreibung: Subsonic transport turbofan engine design and technology features which have promise of improving aircraft energy consumption are described. Task I addressed the selection and evaluation of features for the CF6 family of engines in current aircraft, and growth models of these aircraft. Task II involved cycle studies and the evaluation of technology features for advanced technology turbofans, consistent with initial service in 1985. Task III pursued the refined analysis of a specific design of an advanced technology turbofan engine selected as the result of Task II studies. In all of the above, the impact upon aircraft economics, as well as energy consumption, was evaluated. Task IV summarized recommendations for technology developments which would be necessary to achieve the improvements in energy consumption identified.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135053 , R76AEG432
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  • 96
    Publikationsdatum: 2019-06-27
    Beschreibung: A series of two-dimensional plug nozzles was tested with and without ejector shrouds at free stream Mach numbers from 0 to 0.45 and over a range of nozzle pressure ratios from 2 to 4. These nozzles were also tested with and without chute noise suppressors. A two-dimensional plug nozzle has an efficiency of 96.1 percent at an assumed takeoff pressure ratio of 3.0 and Mach 0.36. A 12-chute suppressed nozzle with sidewalls has an efficiency of 81.0 percent (15.1 percent below the unsuppressed nozzle).
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3384 , E-8556
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Publikationsdatum: 2019-06-27
    Beschreibung: The acoustic design for a half-scale fan vehicle, which would have application on an advanced transport aircraft, is described. The single stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec (1,650 ft/sec). The two basic approaches taken in the acoustic design were: (1) minimization of noise at the source, and (2) suppression of the generated noise in the inlet and bypass exhaust duct. Suppression of the generated noise is accomplished in the inlet through use of the hybrid concept (wall acoustic treatment plus airflow acceleration suppression) and in the exhaust duct with extensive acoustic treatment including a splitter. The goal of the design was attainment of twenty effective perceived noise decibels (20 EPNdB) below current Federal Air Regulation noise standards for a full-scale fan at the takeoff, cutback, and approach conditions. Predicted unsuppressed and suppressed fore and aft maximum perceived noise levels indicate that the cutback condition is the most critical with respect to the goal, which is probably unattainable for that condition. This is also true for aft radiated noise in the approach condition.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-134803 , R76AEG259-VOL-3
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Publikationsdatum: 2019-06-27
    Beschreibung: Flame-tube experiments using premixed hydrogen and air were conducted to determine the emissions of oxides of nitrogen (NOx) resulting from ultralean combustion. Measurements of NOx emissions and combustion efficiency were made for inlet mixture temperatures of 600 and 700 K, pressures of 3.8 x 10 to the 5th power and 5.2 x 10 to the 5th power N/m squared, reference velocities of 15 to 18 m/sec, and equivalence ratios of 0.2 to 0.4. At the 700 K inlet mixture temperature, NOx emissions were 0.06 ppmv, and combustion efficiency was 98 percent at an equivalence ratio of 0.24. The use of a high-blockage (92-percent blockage) flameholder made it possible to conduct tests without upstream burning in the premixing duct for mixtures with equivalence ratios less than 0.4. For richer mixtures upstream burning did occur and prevented further testing.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3393 , E-8664
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    facet.materialart.
    Unbekannt
    In:  CASI
    Publikationsdatum: 2019-06-27
    Beschreibung: An opposed reacting jet combustor (ORJ) was tested at a pressure of 1 atmosphere. A premixed propane/air stream was stabilized by a counterflowing jet of the same reactants. The resulting intensely mixed zone of partially reacted combustion products produced stable combustion at equivalence ratios as low as 0.45. Measurements are presented for main stream velocities of 7.74 and 13.6 m/sec with an opposed jet velocity of 96 m/sec, inlet air temperatures from 300 to 600 K, and equivalence ratios from 0.45 to 0.625. Fuel lean premixed combustion was an effective method of achieving low NOx emissions and high combustion efficiencies simultaneously. Under conditions promoting lower flame temperature, NO2 constituted up to 100 percent of the total NOx. At higher temperatures this percentage decreased to a minimum of 50 percent.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-2785 , UCB-ME-76-5
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Publikationsdatum: 2019-06-27
    Beschreibung: A small experimental axial-flow turbojet engine was tested at sea level static conditions and over a range of simulated flight conditions to evaluate its performance as well as to demonstrate the feasibility of low-cost concepts utilized in its design. Testing was conducted at engine speeds as high as 37,000 rpm and at turbine inlet temperatures as high as 1,272 K. For maximum speed the engine produced a net thrust of 3,118 newtons at sea level static operation and 2,318 newtons at its cruise condition of M0 = 0.8 and 6,096 meters. Data obtained over a range of inlet Reynolds number indexes for nominal M0 of 0.38 revealed similar effects or trends on compressor characteristics of those previously established for much larger engines.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-TM-X-3463 , E-8775
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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