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3 1176 00159 9936
. NASA Technical Memorandum 82771
NASA-TM-82771 19820005273
··1 . NASA Research in
Aircraft Propulsion'
Milton A. Beheim
Lewis Research Center
. Cleveland, Ohio
• . r-
lIBRARY COpy
. JAN 2 '11982
LANGLEY RESEARCH CENTER LIBRARY. NASA HAMPTON. VIRGINIA
Prepared for the .'
Twenty-seventh Annual International Gas Turbine Conference'
sponsored by the American Society. of Mechariical Engineers
London, England, ~pril 18-:-22, 1982
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NASA RESEARCH IN AIRCRAFT PROPULSION Milton A. Beheim National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohio 44135 on the propulsion R&T program being performed at the INTRODUCTION Lewis Research Center. The first portion will address the propulsion needs of specific vehicles, and the The activities of NASA in the field of aero- second portion the generic research in propulsion nautics are indicated in figure 1 to be oriented systems and components.
around three broad objectives: to promote an improved civil air transportation system encompassing both the SPECIFIC VEHICLE ACTIVITIES large transport and the smaller general aviation air- 'craft, to enhance the competitive position of the U.S.
The propulsion requirements of specific types industry in the international marketplace, and to of aircraft are established in NASA by focusing ac- contribute to the aviation capabilities of the U.S.
tivities toward the needs of those aircraft in the military services. The accomplishment of these ob- manner illustrated in figure 4. The NASA centers jectives is achieved through the research and tech- work jointly with the aircraft industry in establish- nology (R&T) programs of its field centers. The ing the technological advances required for major principal roles of these centers are summarized in improvements in future aircraft of the types that are figure 2. The Langley Research Center focuses its listed. These advances are prioritized and, to the effort on the needs of conventional takeoff and land- extent that resources permit, are further pursued ing (CTOL) aircraft for transport, combat, and general with inhouse, contract, and university grant research aviation purposes. The Ames Research Center performs programs. Each of the seven activities shown on the a similar function for special purpose aircraft such figure will be explained in a little more detail in 'as rotorcraft and vertical or short takeoff and land- subsequent figures.
ing (V/STOL) systems. An extensive flight research The largest contract projects in NASA's aero- program is conducted in conjunction with the nearby nautics program are directed to subsonic transport Dryden Flight Research Center. The Lewis Research technology. The current emphasis is to improve their Center specializes in the R&T programs required for energy efficiency to lessen the economic impact of the propulsion systems of all these types of aircraft.
high fuel prices. The propulsion portions of that Figure 3 indicates that the objectives of the propul- program are illustrated in figure 5. In the near sion program are to advance the state of the art in term, component improvements were achieved for modest propulsion systems and components and also to address gains in efficiency for new models of transport en- the propulsion needs of specific vehicles. These ad- gines currently in production: the JT8D, JT9D, and vances will provide new opportunities for improved the CF6. A longer term effort is directed to all new aircraft performance and complements the efforts of d~signs of high bypass turbofan engines with signif- the other centers in identifying innovative and icant savings in fuel. Most of the gains are achIeved creative concepts that yield new capabilities in by using very high pressures and temperatures in the aircraft design.
core to enhance thermal efficiency. Modest gains in ", The emphasis of this particular report will be propulsive efficiency are provided by a mixer for the fan and core flows. Much larger gains in propulsive efficiency can be achieved with a propeller rather than a fan. The uncertainty, however, is whether or not that gain can be maintained at the high cruise speeds of interest for transport aircraft. NASA 1s pursuing a program to resolve that uncertainty in a longer term effort. If successful, then the large fuel savings indicated in figure 5 .for the advanced For all types of rotorcraft, NASA-Lewis is conducting research on advanced transmissions for power transfer.
turboprop could become a reality.
The next aircraft type to be considered is the Traction drive concepts are of particular interest in supersonic cruise vehicle. For the past decade, NASA this effort. Additional effort is directed to enhance has maintained a modest level of effort to advance the efficiency of small gas turbine engine components.
technology required for efficient aircraft of that A relatively new effort at Lewis is a research program type with particular emphasis on transport concepts. directed to the icing problems of rotorcraft in order Because of recent budgetary constraints, the scope of that an all weather capability can be achieved.
that effort has been diminished and other applications A V/STOL airplane currently offers the most of that technology are being explored. Current plans challenging opportunities to the propulsion community.
for supersonic cruise research are indicated in figure The aircraft capabilities are highly sensitive to the 6. System studies are being used to evaluate a va- level of sophistication in propulsion component de- riety of engine cycle concepts and core temperature sign, and many imaginative propulsion system concepts requirements. Effort is continuing on advanced jet appear competitive for both subsonic and supersonic noise suppressors in a search for effective devices applications. The tilt nacelle airplane model shown with low performance losses. Programs in inlet tech- in fugure 10 is one such concept and has recently been nology are establishing acou&tic suppression char- tested at the Ames Research Center. At Lewis, a acteristics of supersonic design concepts and are series of one-third scale inlet models were used to exploring stability and control techniques for mixed explore methods of achieving high angles of attack compression configurations. Design studies are also without flow separation. Additional studies were made underway to assess the feasibility of a supersonic of thrust modulation techniques such as with variable through flow fan. Because of the reduction in inlet inlet guide vanes (VIGV's). A different propulsion weight, significant increases in range can potentially concept illustrated on the right of the figure is the be achieved. tandem fan. It uses a single core to drive two Another type of transport aircraft with its separate fans with independent inlet and exhaust sys- unique set of technical requirements is in the com- tems. A unique exhaust concept for this propulsion muter class. Although NASA does not presently system is the front nozzle which is closely coupled to support a focused program for this aircraft type, it the fan. Flow visualization is achieved with multi- has completed studies of advanced concepts and is color paints in the study that is depicted in the providing some generic research in its disciplinary figure.
programs which are described in a later portion of.
An even greater diversity of propulsion re- quirements is evident in the class of combat aircraft.
this report. These studies of Small Transport Air- craft Technology (STAT) yielded the propulsion related Figure 11 illustrates some related activities in NASA.
results shown in figure 7. Turboprop concepts were' The F-15 aircraft shown here is being used at the the only ones of interest and significant benefits Dryden Flight Research Center for research into in- were projected with improvements in the illustrated tegrated digital controls for the propulsion system.
components. For small gas turbines of this type, Precursor tests were performed in an altitude test radial flow compressor and turbine stages are of cell at Lewis to evaluate the electronic control for increased interest because passage heights become too the engine of that aircraft. Another flight program small for good efficiency in conventional axial at Dryden uses a remotely piloted vehicle to explore designs. the integration of diverse technologies to achieve Closely related to the commuter transport tech- extreme maneuverability at transonic speeds and hence nology requirements is that associated with general is called the HiMAT (Highly Maneuverable Aircraft aviation. This category is represented by the small Technology). One phase of that effort was an inlet business aircraft with single or twin propeller test at Lewis to insure compatibility of the inlet powered propulsion systems with around 500 shaft flow characteristics to prevent compressor stall 'dur- horsepower. Propulsion concept studies recently ing afterburner augmentation of the thrust. An en- tirely different type of propulsion system which is 'supported by NASA are illustrated in figure 8. Ad- also illustrated is a solid fuel ramjet under test in vances in propeller technology were highlighted that one of the Lewis wind tunnels. Multiple inlets are enhance aero acoustic performance and utilize com- used to supply a single combustion chamber containing posite structural designs for improved safety. Four different advanced engine types proved to be com- solid propellant. Matching of the inlets and their stability was the principal area of study in this petitive in this power range. A general preference was indicated by the study results for rotary com- program.
bustion (Wankel), diesel piston, spark ignition piston, and turbine engines in that order of pri- DISCIPLINE ACTIVITIES oritization. The rotary combustion engine appeared to offer the best combinati9n of fuel efficiency, low The work described in the previous section weight, simplicity, and low initial cost. Key tech- illustrates that the needs of specific vehicles impose nologies to make it an effective aircraft engine are requirements on the propulsion system that result in improved seals, cooling, and air flow capacity and a innovative and creative solutions that produce a multifuel capability. A modest research program of better aircraft. A companion effort equally impvrtant this type has been initiated. is the generic advances in component technology that The next aircraft type for discussion is the produce opportunities for enhanced capabilities of rotocraft. Figure 9 illustrates one of the advanced aircraft of all types. Figure 12 summarizes eleven concepts presently being considered in the U.S.--the disciplinary activities underway at the Lewis Research X wing. Such an aircraft requires a convertible Center. As in the previous section, a figure will be engine: turboshaft power for the rotor during hover; used to depict typical activities of each type here and turbofan power for thrust during level flight. indicated.
NASA and the Defense Advanced Research Projects Agency A very rapidly advancing technology is that (PARPA) are sponsoring an exploratory effort of this associated with computational methods as depicted in type using a TF34 engine illustrated in the figure. figure 13. Very impressive achievements have resulted from the utilization of the large digital computers A large area of research is dedicated to the for structures, fluid mechanics, geometry definition, mechanical components of engines such as those and even to a limited extent the additional com":'>,'- depicted in figure 22. This work encompasses shaft plexities of combustion phenomena. dynamics, seals of many types, gears, bearings, and The success of the digital computer has also lubrication. The results of this work are applicable made it a new and powerful factor in control system to turbofan engines in the manner illustrated and also to turboshaft engines and to transmissions such as technology. Figure 14 indicates the large increase in controlled variables that are required in advanced those for rotorcraft.
In the area of high temperature materials, very engines. The hydromechanical control is rapidly giving way to the electronic digital control which advanced concepts are evolving as illustrated in figure 23 for disks and blades. Particular emphasis provides greater reliability and flexibility for op- timal performance characteristics of complex engines.
is currently being placed on the technology for con- There is particular interest in applying optical sen- servation of critical materials that are in limited sors to enhance control system reliability.
supply, such as chromium, cobalt, columbium, and Figure 15 illustrates some current activities tantalum. Additional effort is being initiated for related to combustion research. The emphasis is on improved prediction methods of life and durability of the impact of alternate sources of hydrocarbon fuels hot components. Figure 24 illustrates additional and on improved analytical techniques and their areas of ,structures research with special emphasis on verification for combustion modeling. Applications the application of composite materials and analysis are oriented to aircraft needs, but generic results techniques.
also relate to ground power needs.
Figure 16 indicates the scope of interest for CONCLUDING REMARKS inlet and exhaust nozzle research currently pursued at Lewis. Areas of emphasis include supersonic inlet This report presents a broad overview of the performance and control, off design perf'ormance of scope of research presently being supported by NASA supersonic ejectors, efficiency of turbofan mixer in aircraft propulsion. Aircraft systems work is nozzles, exhaust nozzle cooling, angle of attack performed to identify the requirements for the pro- characteristics of subsonic inlets, and thrust de- pulsion system that enhance the mission capabiiities flection characteristics of exhaust systems. of the aircraft. It is an important source of in- In the area of aircraft safety, the emphasis at novation and creativity that drives the direction of Lewis is on aircraft icing research. As indicated in propulsion research. In a companion effort, com- figure 17, the emphasis is on accretion character- ~onent research of a generic nature is performed to istics of airfoils and inlets. Advanced ice protec- provide a better basis for design and provides an tion techniques such as icephobics, electroimpulse, evolutionary process for technological growth that electrothermal, and pneumatic devices are being increases the capabilities of all types of aircraft.
explored. Additional effort is being expended for They are both important.
modern instrumentation concepts for icing measurements and for improved methods of simulating natural icing conditions in ground test facilities and flight tankers.
Additional instrumentation research is in progress for propulsion systems, as illustrated in figure 18. Principal objectives are related to flow, clearance, emission, and stress measurements in engines. Significant progress has especially been achieved in the application of optical methods, as in laser velocimetry.
Research is continuing in turbomachinery and jet noise. Figure 19 illustrates fan and propeller noise research at Lewis using an anechoic chamber and both low and high speed wind tunnels. Outdoor facilities are used for engine and jet noise. The jet noise work places current emphasis on dual stream effects as encountered with coannular nozzles.
Engine systems research of the type illustrated in figure 20 is currently in progress. The emphasis with large turbine engines is on system dynamics due to large perturbations (such, as stall) and the appropriate control procedures for recovery. A new effort has been initiated for small turbine engines to enhance contingency power by using water injection to augment cooling of the turbine. Research with piston engines is oriented to emissions and multifuel capabilities, and with rotary combustion engines efforts are being made to improve air flow handling capacity as with turbocharging.
The next subject is related to advanced turbo- machinery aerodynamics. Figure 21 illustrates the scope of this effort for compressors, fans, turbines, and propellers. Of particular interest is the work being performed to determine the aerodynamic effects of film cooling on turbine performance.
• SAFER , MORE ECONOMICAL , EFFICIENT and ENVIRONMENTALLY ACCEPTABLE AIR TRANSPORTATION SYSTEM • FAVORABLE COMPETITIVE POSITION for the U .S. in the INTERNATIONAL AVIATION MARKETPLACE • MAINTENANCE of SUPERIORITY of U.S .
MILITARY AIRCRAFT C-80-276 Figure 1. - NASA Aeronautics - Mis si on Objec tive s.
AMES
LEWIS
• ROTORCRAFT • PROPULSION • FLIGHT • SUBSONIC and SUPERSONIC CTOL • HIGH PERFORMANCE AIRCRAFT • GENERAL AVIATION "*, ..
........
Figure 2. - Roles of NASA Aeronautics - Field centers.
o ADVANCE STATE-OF-THE-ART
IN PROPULSION SYSTEMS and COMPONENTS
o ADDRESS PROPULSION NEEDS
OF SPECIFIC VEHICLES Figure 3. - Aeronautical Propulsion Research Objectives.
Figure 4. - Research programs for specific vehicles.
ADVANCED TURBOPROP ENGINE COMPONENT IMPROVEMENT ,,*," YEAR Figure 5. - Energy efficie nt p rop ulsion te ch nology .
ADVANCED JET NOISE ENGINE CYCLE EVALUATION SUPPRESSORS .
• AIRCRAFT I ENGINE SYSTEMS STUDIES - TBE, V SC E,DBE,LBE,IFE • HIGH TEMPERATURE CORE BENEFITS INLET TECHNOLOGY • OUTER STREAM SUP PRESSOR • THERMAL ACOUSTIC SHIELD • AERODYNAMIC PERFORMANCE SUPERSONIC FAN
~
• PRELIMINARY ENGINE STUDIES • AERO & CONTROLS ANALYSIS • FAN AERODYNAMIC DESIGN • AERO / ACOUSTIC .AERO/MECHANICAL DESIGN PERFORMANCE MODELS Figure 6. - Supersonic cr u ise research.
CONTROL AND ACCESSORIES IMPROVEMENTS BENEFITS ~ EFFEIENCY 12·20'1. RIEL 20-30% 4-5 YEARS TO DOC 10-20% TECHHOl06Y REAOIIESS WEIGHT 15-25% MAIITEIWICE 25-55% RELlAIII.ITY / DEPElIOABLlTY CD-12548-Q 2 NOISE 10dB LOWER NOISE Figure 7. - Research in small transport aircraft technology .
Figure 8. - Propulsion R&T for general aviation.
----, Figure 9. - Advanced rotorcraft propulsion technology.
Figure 10 . - V/STOL Propulsion Research.
Figure 11. - Research programs for combat vehicles.
MECHANICAL ENGINE COMPONENTS CONTROLS PROPELLERS , COMBUSTION, COMPRESSORS, EMISSIONS, and FUELS FANS & TURBINES TURBINE and INLETS and PISTON ENGINE SYSTEMS NOZZLES NOISE SAFETY Figure 12. - Disciplinary research for aeronautical propulsion.
- , I STRUCTURAL ANALYSIS SUPERCRITICA l COMPRESSOR STA TOR ANALYS IS COMBU ST OR MODELING Figure 13. - Computational and ana l yti c al research.
NUMBER OF CONTROLLED VARIABLES Figure 14. - Engine controls evol ution .
• ADVANCED COMBUSTOR CONCEPTS • COMBUSTOR TECHNOLOGY FOR ALTERNATIVE FUELS Figure 15. - Combustion R& T.
Figure 16. - Research for inlets and nozzles .
FACILITY CAPABILITY
COOLING - 20°F AIR SPEED 0-300 MPH TEST SECTION 6 FT. x 9 FT. x 20 FT.
•
WING DEICING HELICOPTER INLET ICING ... NO Figure 17 . - Icing Research.
AUTOMATED EXHAUST GAS ANALYSIS THIN FILM TEMPERATURE DYNAMIC PRESIURE, FLOW, AND STRAIN SENSORS AND CLEARANCE PROBES
co -81-12636
Figure 18. - Advanced instrumentation for propulsion research.
•
9 x 15 ANECHOIC WINO TUNNEL FORWARD VELOCITY EFFECTS ON FAN NOISE Figure 19. - Propulsion sy stems noise reductions.
HIGH BYPASS ENGINE PISTON RESEARCH ENGINE SUPERSONIC PROPULSION SYSTEM -- Figure 20. - Turbine and piston engine systems .
HIGH PRESSURE RESEARCH TURBINE HIGH PRESSURE COMPRESSOR HIGH SPEED ENERGY FULL COVERAGE FILM EFFICIENT PROPELLER COOLED TURBINE BLADE Figure 21. - Research programs for rotating components.
GEARS LU BRICATION TECHNOLOGY BEARINGS GAS PA TH SE ALS SHAFT BALANCING SHAFT SEALS
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--
Fig u re 22. - Po wer transfer components.
r-
ODS+ y' SUPERALLOY SINGLE CRYSTAL TURBINE BLADE TURBINE BLADE CONSERVATION OF CRITICAL MATERIALS (LAI!GE GRAtiS) SlJ>ER1OR CREEP SUPERIOR LOW-CYQ.E RESISTANCE FATIGUE RESISTANCE LONG LIFE POWDER METALLURGY DISK DUAL ALLOY POWDER METALLURGY DISK CD-8H2521- 26 Figure 23 . - Advanced high temperature s uperalloys.
STRUCTURAL STRUCTURAL FATIGUE/CREEPI FRACTURE COMPOSITE _ ....
ANALYSIS DYNAMICS LIFE PREDICTION MECHANICS STRUCTURES ""' ..
Figure 24. - Engine structures research.
2. Government A<:c('Ssion No.
1. Report No. 3. Recipient's Catalog No.
NASA TM-82771 4. Title and Subtitle 5. Report Date I NASA RESEARCH IN AIRCRAFT PROPULSION I 6. Performing Organization Code I I 505-32-12 I 7. Autho~l,sl 8. Performing Organization Report No.
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Milton A. Beheim E-1096 I !
10. Work Unit No.
!
9. Performing Organization Name and Address National Aeronautics and Space Administration 11. Contract or Grant No.
Lewis Research Center 44135 Cleveland, Ohio 13. Type of Report and Period Covered 12. Sponsoring Agency Name and Address Technical Memorandum National Aeronautics and Space Administration 14. Sponsoring Agency Code Washington, D. C. 20546 15. Supplementary Notes I Prepared for the Twenty-seventh Annual International Gas Turbine Conference sponsored by the I American Society of Mechanical Engineers, London, England, April 18-22, 1982.
. I 16. Abstract I This rep::>rt presents .a broad overview of the scope of research presently being supported by NASA in aircraft propulsion. Aircraft systems work is performed to identify the requirements' for the propulsion system that enhance the mission caJabllities of the aircraft. It is an impor- tant source of innovation and creativity that drives the :direction of prop:Jlsion research. In a companion effort, component research of a generic nature is performed to provide a better . I basis for design and provides an evolutionary process for technological growth that increases They are both impJrtant.
the capabilities of all types of aircraft.
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17. Key Words (Suggested by Author(sll 18. Distribution Statement Uncl'assified - unlimited Aircraft propulsion research I STAR Category 07
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I I , 19. Security Classif. (of this reportl 22. Price' 20. Security Classif. (of this pagel 'I 21. No. of Pages Unclassified I Unclassified • For sale by the National Technical Information Servl1ce. Springfield. VirgilltJ 22161 , I
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