NASA / TM--1998-208405 AIAA-98-2505

Engine Technology Challenges for the

High-Speed Civil Transport Plane

Robert M. Plencner, Ajay Misra, Edwin J. Graber, Jr.,

Robert J. Shaw, and Gary T. Seng

Lewis Research Center, Cleveland, Ohio

Prepared for the

20th Advanced Measurement and Ground Testing Technology Conference

sponsored by the American Institute of Aeronautics and Astronautics

Albuquerque, New Mexico, June 15-18, 1998

National Aeronautics and

Space Administration

Lewis Research Center

December 1998

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Engine Technology Challenges

for the

High-Speed Civil Transport Plane

Robert M. Plencner

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135

Ajay Misra

Edwin J. Graber, Jr.

Robert J. Shaw

Gary T. Seng

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135

Introduction

Ongoing NASA-funded (ref. 1,2) and

privately funded studies continue to indicate that an

opportunity exists fl)r a second generation supersonic

commercial airliner, or High-Speed Civil Transport

(HSCT), to become a key part of the 21st century

international air transportation system. Long distance

air travel is projected to be the fastest growing segment

of the air transportation market by the turn of the

century with increases at about 5 percent per annum

over the next two decades (rcf. 3-5). This projection

suggests that by the year 2015, more than 600,000

passengers per day will be traveling long distances,

predominantly over water. These routes would provide

the greatest potential for an HSCT to become a

significant part of the international air transportation

system.

The potential market tor an HSCT is currently

project to be anywhere from 500-1500 aircraft over the

2005-2030 time period. Such an aircraft fleet size

would represent a considerable share of the potential

long-range aircraft market. However, this projected

HSCT fleet can become a reality only if technologies

are developed which will allow an HSCT design that is

( I ) environmentally compatible and (2) economically

viable.

Simply stated, the HSCT will be a technology

driven airplane. Without significant advances in

airframe and propulsion technologies over the levels

currently available, there will be no second generation

supersonic airliner!

This paper will briefly describe the propulsion

technology challenges which must be met prior to any

product launch decision being made by industry and

the progress toward meeting these challenges through

NASA's High-Speed Research (HSR) Program, a

partnership between NASA and Boeing, General

Electric and Pratt & Whitney.

Environmental Challenges

The two environmental challenges that must

be met before an HSCT product launch could be

considered are atmospheric ozone depletion and airport

noise. Meeting these challenges requires advances in

propulsion technologies, specifically combustor

technology to meet the ozone depletion challenge and

low noise propulsion system technology to address the

airport noise challenge.

Ozone Depletion

Potential depletion of the Earth's protective

ozone layer is attributed to HSCT engine exhaust

products, specifically the nitric oxide (NO x) levels.

Thus combustor designs must evolve that produce

ultra-low levels of NO x such that no harm is done to the

ozone layer whilc at the samc time having high levels

of combustion efficiency and operability across the

mission profile.

Airport Noise

Tbe other HSCT environmental barrier challenge

that must be met is aircraft noise during

NASA/TM-- 1998-208405 I
takeoff and landing portions of the mission. Unlike

the current subsonic aircraft fleet, the prime contributor

to an HSCT noise signature at takeoff is the jet

exhaust, and thus an approach to quieting the jet

exhaust without seriously impacting propulsion system

performance or weight must be developed. However,

during landing, noise emanating from the fan also

becomes an important contributor along with the .jet

exhaust.

Any HSCT propulsion noise reduction

approach pursued must take into consideration that a

noise rule stricter than the current FAA FAR 36 Stage

3 may be in place by the time an HSCT would enter the

fleet. Thus candidate approaches must be evaluated

for potential to have even greater noise reduction than

those currently required lbr certification of subsonic

aircraft.

Economic Challenges

Solutions to the environmental challenges

discussed above as well as the demanding performance

requirements of supersonic cruise will require the use

of many advanced technologies. However, the HSCT

has the same constraints as any commercial aircraft

design; the technologies employed in the design must

improve the product but not at the expense of

significantly increased costs (acquisition, operation,

and maintenance). Clearly, tor the HSCT to become a

reality, it must be a profitable venture, both for the

aircraft and engine manufactures, as well as for the

airlines. The already mentioned market studies being

conducted have in some cases involved surveys with

the flying public. These surveys suggest that lor the

long haul. primarily over water routes across the Atlantic

and Pacific Oceans. travelers would be willing to pay

as much as 20 to 30 percent more for tickets with the

prospect of halving the travel time. The motivation to

pay more for reduced travel time. not too surprisingly,

increases as the travel time exceeds 4-5 hours. This

inlbrmation gives one some insight into what economic

viability means for an HSCT in the view of the traveling

public, who are the ultimate customers and will in part

help determine what technologies will be included on

the HSCT.

System Requirements and Technology Drivers

Figure 1compares the Concorde, the world' s

only operational commercial supersonic aircraft, with

the current perspectives on the HSCT. While the

Concor:le remains an engineering marvel almost 30

years rfter its maiden flight, it achieved neither

environmental compatibility nor economic viability.

Hence only 16 Concorde aircraft were ever built and 13

are currently in operation, serving selected trans Atlantic

routes with fares several times higher than widebody

subsonic aircraft. For the HSCT to become a reality, it

is envisioned that the aircraft design must have at least

the features depicted on the right halt" of this figure.

Translating thesc system level HSCT

requirements shown on figure I into those for the

HSCT propulsion system suggests that the engine

manufacturers must design, build and certify an HSCT

propulsion system that meets the following

requirements. First, in order to achieve supersonic

cruise capability the propulsion system must have

performance levels comparable to a supersonic military

fighter engine. Second, to be acceptable to the general

public, the HSCT propulsion system must contribute

to meeting the environmental challenges of NO x and

community noise. The requirement to produce low

NO x re_';tssolely with the development of new types of

combu.'tor designs. These stringent requirements

compared to what is possible using current combustor

technology are shown in figure 2. However, this figure

also shows that the sol ution to the H SCT noise challenge

cannot I,e meet simply by improving a single component

but wi:l require a systems engineering approach.

Contributions to the vehicle noise reduction will come

from several sources including, advanced exhaust

nozzles, engine cycle characteristics, advanced fans,

advanced high-lift concepts and possibly advanced

aircraft operational procedures such as programmed

lapse rz,tc.

Third an HSCT propulsion system must

contrihte to meeting the HSCT economic viability

require:nents. The propulsion system must be light

weight and demonstrate good efficiency in order to

achieve a vehicle with sufficient range and payload to

be an economic success. At the same time it must

demonstrate durability and long life characteristics

that at. _ comparable with subsonic commercial

propuls on systems. As shown in figure 2, the maximum

cycle t._mperatures are comparable with those of

existin_ engines today. However, these temperatures

must bt maintained throughout the cruise portion of

NASA/TM-- 1998-208405 2
themissionratherthanonlyatshortsegmentsofthe

flight such as takeoff. This results in a requirement

tor the engine to operate at the combined conditions of

high temperature and high stress for 30 times longer

than either subsonic transports or military fighters do

today.

In addition, the HSCT propulsion system

will be big. as figure 3 depicts. The overall length will

be about 50 feet with a maximum diameter of about 50

inches. This overall propulsion system size will provide

a significant design challenge for all components. As

an example, figure 4 shows that the high pressure

turbine disk for the HSCT is estimated to be about

twice the size of the disks found in current subsonic

transports.

Technology Development Accomplishments

As discussed above, the technology challenges

related to environmental compatibility and economic

viability for the HSCT propulsion system and indeed

for the whole vehicle are tremendous. Clearly the

HSCT engine designers will not be able to meet these

challenges with currently available propulsion

technologies. As is shown in figure 5, NASA began the

HSR Program in FY 1990 in order to address these

technology shortfalls both for the airframe and the

propulsion system. Since its inception, the HSR

Program has had as a vision the development and

transfer of the high risk, high payoff technologies to

industry, which in turn would be able to make a lower

risk product launch decision at the time when all the

factors contributing to a commercial aircraft launch arc

considered. The HSR Program was constructed so as

to first address the environmental challenges (Phase I)

and only if there were viable solutions developed for

NOx and noise reduction would the Phase II program

be initiated. The Phase II Program would have as its

emphasis the development of the highest payoff

technologies associated with economic viability.

To date, the propulsion element of the HSR

Program has enjoyed considerable technical success.

In Phase 1, viable laboratory solutions for the

environmental challenges were developed and

demonstrated. In Phase II, which is currently being

executed the propulsion technologies for the critical

components, including advanced high temperature

engine materials are being successfully transitioned

from the laboratory to the larger scale component

designs. These components will be tested and evaluated

in severe realistic engine environments. Figure 6overviews

the propulsion element content of the Phase I and II efforts

of the HSR Program.

Progress has also been significant in the

airframe element of the HSR Program. Specifically,

advanced high lift approaches have been developed

and demonstrated in model scale along with improved

supersonic performance planfi)rm configurations and

advanced composite materials for the airframe structure

which are capable of withstanding up to the 350 °F

temperatures that the HSCT will encounter during

supersonic cruise. In addition, concepts for advanced

flight deck designs have been evolved utilizing synthetic

vision which offer possibilities for increased levels of

aircraft safety beyond those available today.

The remainder of this paper will overview

some of the technology advancements being made by

the propulsion element of the HSR Program.

Technology Concept Propulsion System

Since the HSR Program is a focused technology

program driven by vehicle requirements (including the

propulsion system), it is necessary to have a technology

concept aircraft to focus the technology development

efforts so as to make informed decisions about which

technologies to pursue and which can be discarded,

either being too risky to pursue or having too little payoff

to merit investment of critical resources. In 1996, a

technology concept aircraft was developed by the NASA/

industry team along with a technology concept propulsion

system as depicted in figure 7. This "paper propulsion

system" was configured after incorporating the results

of over 12,0(X) hours of scale combustor, nozzle, and

inlet tests, over 50,000 hours of engine materials testing,

and over 250 work years of propulsion and airframe

systems studies. The technology concept propulsion

system will continue to serve a critical role in the

remaining years of the HSR Program as it will enable

NASA and industry personnel to evaluate individual

component and subcomponent technologies against the

overall system requirements.

Figure 8 lists some of the maior technology

advances made for the various components of the HSCT

propulsion system. These will be briefly reviewed in the

following paragraphs.

NASA/TM-- 1998-208405 3
Inlet

A seriesof subscale(approximately25%

HSCTscale)supersonicwindtunneltestshavebeen

conductedof candidateaxi-symmctricandtwo

dimensional mixedcompression configurations. All

testswereconductedintheNASALewisResearch

Center(LeRC)10xl0SupersonicWindTunnelto

evaluatesupersonicperformanceand isolated

component operability.Thesetestresultsalongwith

asystemsevaluationandarelativeriskassessment of

thecandidateinletswereusedtomakeanHSRProgram

down-selectto a two dimensionalbifurcated

configuration. Figure9showsatwodimensional inlet

testconfigurationinthe10xlOSWT.Todatealltests

havebeencoldpipetests,thatistheydidnotinvolve

enginetesting.Futuretestswill involveusingaGE

J85turbojetenginetoexamineinlet-engineoperability

requirements.

In addition,a large-scale, simulatedinletengineoperabilitytestwasconductedinRussiaaspart

oftheUS/RussiaTU-144program. Figures10and I I

show the overall setup and a close-up of the simulated

supersonic inlet flowpath, The engine used for these

experiments was an RD36-51A which was used on the

original TU 144 aircraft. These test results are giving

the NASA and industry personnel added insight into

some of the important design features for the subsonic

diffuser of the HSCT inlet and in particular how close

coupled the inlet and fan can be without adversely

affecting performance and operability. Reference 6

gives added information on these highly successful

international test efforts.

Com bustor

A large number of flame tube (figure 12) and

subscale sector (figure i3 t tests of candidate ultra-low

NOx combustor configurations have been tested in

NASA and industry facilities since the HSR Program

began in 1990. Tests have been conducted of both

Lean Premixed-Prevaporized (LPP) and Rich Burn/

Quick Quench/Lean Burn (RQL) configurations. Both

flame tube and sector test results have been promising,

with NOx results being measured in the E1 range of 2-

7 gm NOx/kg fuel being measured. A combustor

down-select will occur in 1998 and the most promising

configuration will then be evaluated in both full size

sector and full annular rig testing in the remaining

years of the HSR Phase II Program.

The HSCT combustor cannot rely on

conventional wall film cooling techniques if ultralow levels of NOx are to be achieved. The HSR

Program has been developing a Ceramic Matrix

Composite (CMC) material from which a combustor

liner could be designed that would require only

backside cooling. Initially a number of candidate

fibers, matrices and processing techniques were

evaluated, but in 1996 an SiC based CMC was selected

which incorporates a melt infiltration processing

technique. As figure 14 shows, the HSR Program has

been very successful in taking this material from the

laboratory to fabricating complex three dimensional

shapes r_lore representative of a combustor liner.

Durability tests are currently underway to evaluate

material performance in the oxidizing and reducing

environments of an HSCT combustor. Recognizing

the risks associated with a CMC liner material, the

program:is evaluating a metallic liner with thick

thermal barrier coating as a backup approach. A liner

material down-selection will occur in 1999 and the

selected nateriai will be evaluated in a full annular

combustor rig test.

Nozzle

Like the combustor, a large number of small

scale (approximately I/7 to 1/10 HCST scale) nozzle

configurations have been designed and tested to evaluate

the most promising approaches for significant reductions

in noise a_sociated with the exhaust jet at both takeoff

and landing conditions, while at the same time

maintaini lg high levels of aerodynamic performance

(i.e., thrua coefficient) at low speed conditions. The

HSCT m,zzle design must be a balanced one that

addresses both aerodynamic and acoustic requirements

simultaneously. Many of the tests have been dedicated

to acquiring fundamental data so that the underlying

physics o'the nozzle internal flowfield and especially

the mixin gregion are will understood.

l:igure 15 is an example o1" an early

configuration tested in the Boeing Low Speed

Aeroacoustics Facility (LSAF). The small scale test

results have been most encouraging as sideline noise

levels at _akeoff conditions below 100 EPNDB have

been mea: ured, which compares to a 120 EPNDB level

measured tor the Concorde. Based upon not only the

many thousands of hours of test data, but also the

supportin ; airframe and propulsion system studies, the

NASA/in. tustry team selected the mixer-ejector nozzle

as the app oath that offered the greatest potential for the

NASA/TM-- 1998-208405 4
HSCTapplication. Successive generationsofsmall scae

testsarecontinuingtopursuemixer-ejector cnfigurations

thatpromiseadditional noisereductionandimproved

aerodynamic performance.

In additionto theisolatednozzletests,the

impactof theairframeonthemixer-ejectornozzle

performance(aerodynamicandacoustic)hasbeen

evaluatedthroughtestsconductedintheNASAAmes

NationalFullScaleAerodynamic Complex(NFAC)as

showninfigure16.This13.5percent halfplanemodel

testresultshavegiventheUSteamconfidencethatthe

integrationeffectscanbeminimized.Recently, thefirst

ofaseriesoflargescalemodeltestswascompleted.

Advancedmaterialssystemsarecriticaltoall

aspectsofthedesignofavariableHSCTnozzlesystem.

Specificallythenozzlemustdemonstrateacceptable

aero/acoustic performance, weightanddurability.A

numberof candidatematerialsystemshavebeen

evaluatedthroughavarietyofdesign, fabricationtestand

analysisactivities. Basedonthiscomprehensive database

andtheairframeandpropulsionsystemstudies, materials

down-selects wererecentlycompleted, asdepictedin

figure17.EmphasisintheHSRProgramisnowturning

torefiningthefabricationadscale-upapproaches selected

foreachof thenozzlesub-components andevaluating

thesetechnologiesinbenchmarkteststobeconductedat

NASALeRC.

Aseriesoflargescalenozzlemodeltestsof

themostpromisingconfigurationshaverecentlybegun.

Thesetestswillevaluatebothaercxtynamicandacoustic

performanceat low speedconditionsfor the

approximately 60%scalemodels.Figure18shows

thefirstLargeScaleNozzletestconfigurationan

outdoorteststandatPratt& Whitney.A Pratt&

WhitneyF-100enginewasusedtoproviderealistic

flowconditionsintothenozzle.Thecomprehensive

largescaledatabaseobtainedfromthesetestswill

provideinsightoftheeffectsonbothaerodynamic and

acousticperformance ofscale,aswellastherealistic

engineenvironment.In addition,majorsubcomponentsuingthedown-selected materialsand

fabricationtechniques arebeingincludedinthesetests

toevaluatetheirpertk)rmance inthehostileengine

environment. Forexample, ceramicmatrixcomposite

(CMC)acoustictilesandceramicbulkabsorberswere

successfullytestedintherecentlycompletedlarge

scalenozzletests.

Turbomachinery

Only selected technology areas of the

engine turbomachinery that are critical to the future

success of an HSCT propulsion system are being

tested under the HSR Phase II Program. These

technology areas are the fan, disk materials and

turbine airfoil systems.

The multi-stage fan design required lbr

the HSCT propulsion system is vastly different

from what is currently used in the subsonic fleet.

As a result, very little is known about the acoustic

signature of this type of fan. Therefore, work is

underway to design, fabricate and test a subscalc

fan and inlet combination in the NASA LeRC 9x 15

Wind Tunnel. This test will provide valuable

acoustic data to substantiate models of the fan

source noise as well as the noise attenuation in the

inlet. This insight into the fan acoustic

characteristics will be used in conjunction with the

nozzle acoustics to mitigate the risk of meeting the

landing and takeoff noise challenges faced by the

HSCT.

The extended time at temperature

requirements of the HSCT requires that the disks

for both the compressor and turbine have a critical

balance of tensile, fatigue and creep strength as well

as fatigue crack growth resistance. These

requirements exceed the capabilities of any of

the available Nickel based superalloys. The HSR

Program has evaluated a large number of

experimented alloys (figure 19) and identified

promising candidates which have met the HSR

Program goals, as the figure suggests. Emphasis is

now turning to taking these most promising alloys

and evaluating the scale-up approaches tk_rIorging

and heat treatment that maintain the critical

performance characteristics. Appropriate subcomponent tests will be conducted as the final

technology validation efforts tor the HSR Program.

The materials system for the turbine airloil

system really consists of three components-a single

crystal Nickel based airfoil superalloy, a bond coat,

and a thermal barrier coating. Significant progress

has been made in the HSR Program to date on

developing experimental alloys that are significantly

better than those currently available tor production

NASAFFM-- 1998-208405 5
applications(figure20).Anewthermal barriercoating

systemisbeingdevelopedto meetHSCTlifegoals.

Progressto date includes identification of new bond coat

and ceramic compositions. Emphasis in the remaining

years of the HSR Program will be to combine the three

components into a turbine airfoil design and demonstrate

technology readiness through appropriate rig tests.

In addition to the technology development in

the fan, disk and turbine airfoil, Conceptual Mechanical

Design Studies of the entire engine have been ongoing in

the HSR Program. These studies ensue that the

technologies that are being developed in the key areas

discussed above can be brought together into a viable

propulsion system that will meet the environmental and

economic challenges faced by the HSCT.

Future Plans

The current HSR Phase II effort is primarily

aimed at developing critical technologies at the component

level and demonstrating these technologies through scale

component tests. To provide additional risk reduction

beyond this Phase I1 effort, the HSR Program is planning

a.Full-Scalc Engine and Nozzle Technology Demonstrator

project. This follow-on project would validate, through

full-scale engine/nozzle tests, the technologies that

contribute to overall HSCT environmental compatibility

as well as the overall system goals tbr pertormance and

operability.

In addition, this proiect will demonstrate

appropriate HSCT Accelerated Mission (AM) test

techniques to assess full-scale engine/nozzle component

durability tor the HSCT duty cycle and will include the

cvaluation and understanding of the long-term durability

of structural materials with respect to metallurgical

changes resulting from HSCT long-hot-time design

requirements, and the use of economically feasible,

large-scale manufacturing techniques.

Concluding Remarks

NASA's High-Speed Research Program has

been formulated to provide the US industry with the

critical technologies needed to support an informed

decision by industry as to whether to launch an HSCT

early in the next century. The financial risk to launching

an HSCT without adequately mature and proven

technologies in hand is enormous. Industry estimates

indicate that it will cost at least $13-15 billion to design,

build and certify an HSCT once the decision to launch is

made. While such amounts seem incredibly large, the

financial returns estimated for a fleet of 500-1500

aircraft _Jlso must be considered. Industry estimates for

such a fleet (including the initial aircraft as well as spare

parts and maintenance) project that $200 billion in sales

may be realized. Thus it appears that the product launch

of an HSCT will be a major decision for the commercial

aerospace industry to make which will have financial

implicatmns that will be far reaching.

To date the HSR Program has provided industry

with the high risk, high payoff airframe and propulsion

technologies that support the vision of an HSCT

becomir--g part of the 21_' century international air

transportation system. However, the maturity of these

technologies, sometimes called the Technology

Readiness Level (TRL) by NASA is still much too low

for industry to consider the risk of a product launch

decision as being acceptable. It is therefore critical that

the HSR Program continue to successfully mature these

technolegies and transfer them to industry to contribute

to reducing the risk of a product launch decision to

acceptable levels.

I.

.

.

4.

5.

References

"Higln.-Speed Civil Transport Study," NASA CR

4233, 1989.

"Study of High-Speed Civil Transports," NASA

CR 4235, 1989

"Con" mercial High Speed Aircraft Opportunities

and issues," Congressional Research Service

Report 101 14, March 1989

Current market Outlook-1994: World Market

Dem and and Airplane Supply Requirements.

Boei_lg, Seattle, WA 1994.

"Higt -Speed Transport Aircraft," Final Report of

the NASA Aeronautics Advisory Committee by

the ttigh-Speed Transport Aircraft, ad hoc

Rewew Team, Dec. 1989.

6. Acos_a, W. A.; Balser, J. S.: McCartney, T. P.;

Richter, C. A.; and Woike, M. R.: Joint US/Russia

TU- 144 Engine Ground Tests, NASA TM 107516,

1977.

N ASA/TM-- 1998-208405 6
Concorde

3000

128

400,000

Exempt

Premium

20

Range (nmi)

Payload (passengers)

Weight (Ib)

Community Noise Standard

Fare Levels

Emissions Index

........ _ :i -

HSCT

5000 to 6500

250 to 300

750,0O0

FAR 36 Stage III - XdB

Standard + < 20% premium

5

Figure 1.--Comparison of Concorde to High Speed Civil Transport.

EMISSIONS

A Mach 2.4 HSCT will cruise at

altitudes coincident with the highest

concentration of atmospheric ozone.

Unconventional combustors are

required to reduce NOx emissions

to levels which have no significant

impact on the Earth's ozone layer.

50_

Nox

E.I,

- Current

Combustors _'H

///_,'-

_.'////

.......... HSR Goal ...........

_HSR

Nox Severity Parameter

This challenge recluires novel

combustors and adv. materials.

NOISE

High specific thrust engines optimized

for supersonic cruise have high jet

velocities and are inherently noisy.

Unconventional engines/nozzles are

required to achieve compliance with

FAR 36 Stage 3 noise regulations

while providing acceptable subsonic

and supersonic cruise performance.

TOGW

\_ HSR "

1990 Technology

\\

""e ".

".\

-., %%

I I I

-X Stage 3 420 dB

Noise Constraint

This challenge controls inlet

engine nozzle selection.

DURABILITY

Over their entire life, current tactical

fighter and subsonic commercial

transport engines accumulate 250-

300 hours at max cycle temperatures

and stress levels. HSCT propulsion

systems must operate at these

conditions for 9,000 hours. Thus,

the HSCT duty cycle is 30X that of

current engines.

...... Subsonic Transport

........ HSCT

su eT:icI

Subsonic

Cruise _.

Flight Time

This challenge demands

advanced high-temp materials

and cooling schemes.

Figure 2.--HSCT propulsion system technical challenges.

NASA/TM-- 1998-208405 7
HSCT propulsion systems are big engines

Figure 3.--Artist's concept of the full-scale HSCT propulsion system.

_.2. .. JL

4.5" 3.4"

HSCT Subsonic Transport

Figure 4.--Comparison of High Pressure Turbine disk sizes for HSCT and Subsonic Transport

propulsion systems.

NASA/TM-- 1998-208405 8
Tasks FY

Market

, Feasibility

° Requirements

° Atmospheric Emissions

0Noise

, SonicBoom

° Laminar FI0wC0ntr04

0 Propulsion Materials

0Propulsion Cmponents

° Airframe Materials &Structures

Aerodynamic Performance

Flight DeckSystems

Systems integration

s71s8189190 91 92 93 94 95

Studies!

PK isel .........................

Environmental Concerns

96 97 98 99 00 01 02

.......................................... i...... T-T--

Figure 5.wNAS/Vlndustw High-Speed Research Program.

Phase I

Environmental Compatibility

• Laboratow/small scale evaluations of

promising concepts for meeting

emissions and noise goals

• Evaluations of candidate advanced

materials systems

• Propulsion system evaluations of

candidate cycles

Phase II

Economic Viability

• Sub/full scale component design and

evaluations (inlet, fan, combustor, nozzle)

• Design, fabrication, and testing of

subcomponents using advanced

materials (eg. combustor liners)

• Refinement of downselected cycle to

meet mission requirements j

Figure 6.wHigh-Speed Research Program (Propulsion Element).

NASA/TM-- 1998-208405 9
0

©

U

D

0

D

I HSR Technology Concept Propulsion System /

- Two-dimensional inlet l

- Mixed-flow turbofan cycle I

- Two-dimensional mixer-ejector nozzle

Figure 7.DHSR Technology Concept Propulsion System.

• Completed initial subscale flame tube and sector tests for a

variety of Lean Pre-mixed, Pre-Vaporized (LPP) and Rich Burn,

Quick Quench, Lean Burn (RQL) concepts and demonstrated

ultralow NO x potential of both approaches.

• Developed a CMC material which shows great promise

for use as HSCT combustor liner which meets environmental

and economic requirements.

• Completed subscale tests

of candiate axisymmetric

and two-dimensional

concepts.

• Completed large-scale

inletJengine operability

tests as part of U.S/Russia

TU 144 program.

I Developed experimental alloys

for turbomachinery disk and

turbine airfoil applications

which show promise of meeting

HSCT design requirements.

• Completed initial small-scale

nozzle tests of configurations

which meet aerodynamic and

acoustic performance goals. Have

identified approaches for further

performance improvements.

• Completed evaluation of

candidate materials systems for

nozzle and demonstrated

fabrication scale-up capabilities.

Figure 8.DHSR (propulsion) major technology advancements.

NASA/TM-- 1998-208405 I0
Figure 9.--Two-dimensional inlet test in NASA Lewis 10- by 10-Foot Supersonic Wind Tunnel.

Figure 10.--U.SJRussia TU 144 engine ground test setup,

NASA/TM-- 1998-208405 I I
Figure 11.mCloseup view of simulated supersonic inlet fiowpath.

Figure 12.ECombustion flame tul:e test setup.

N ASA/TM-- 1998-208405 12
Figure 13.RCombustor sector test setup.

Figure 14.RFabrication of complex shape from SiC-based ceramic matrix composite.

NASA/TM-- 1998-208405 13
Figure 15.--Nozzle subscale tests setup.

Figure 16.--Propulsion airframe integration test model.

NASA/TM--1998-208405 14
Cast Superalloy Mixer

Stiffened Facesheet

Cast Superalioy Convergent Flap CMC Acoustic Tile

Figure 17.--Exhaust nozzle subelements fabricated for testing.

Figure 18.--Large-scale model nozzle test.

NASA/TM-- 1998-208405 !5
HSCT disk airfoil alloy developed

k.

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li

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t_

q)

c_

Production Current (_

...... _11o_ ...... -- --

-i B--

Hours to 0.2 percent creep

Figure 19.--Status of development of advanced turbomachinery disk alloy.

HSCT airfoil alloy developed

L_

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d

.n

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 oun '2

",Test Results ,"

Goal

Range

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. Test Results:

Production Experience -"--

Oxidation Life, hr

Figure 20.--Status of development of advanced turbine airfoil alloy.

NASA/TM-- 1998-208405 16
REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188

Public reporting burden for this collection ol information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources,

gathering and maintaining the data needed, and completing and reviewing the collection of inlormation. Send comments regarding this burden estimate or any other aspect of this

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1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

December 1998 Technical Memorandum

4. TITLE AND SUBTITLE

Engine Technology Challenges for the High-Speed Civil Transport Plane

6. AUTHOR(S)

Robert M. Plencner, Ajay Misra, Edwin J. Grabcr, Jr., Robert J. Shaw,

and Gary T. Seng

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135-3191

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

5. FUNDING NUMBERS

WU-537-05-23-(X)

8. PERFORMING ORGANIZATION

REPORT NUMBER

E-11238

10. SPONSORIN_MONITORING

AGENCY REPORT NUMBER

NASA TM--1998-208405

AIAA-98-2505

11. SUPPLEMENTARY NOTES

Prepared for the 22th Advanced Measurement and Ground Testing Technology Conference sponsored by the

American Institute of Aeronautics and Astronautics, Albuquerque, New Mexico, June 15-18, 1998. Responsible

person, Robert M. Plencner, organization code 2300, (216) 977-7010.

12a. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified - Unlimited

Subject Categories: 01 and 07 Distribution: Nonstandard

This publication is available from the NASA Center for AeroSpace Information, (301) 621-0390

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

Ongoing NASA-funded and privately funded studies continue to indicate that an opportunity exists for a second generation supersonic

commercial airliner, or High-Speed Civil Transport (HSCT), to become a key part of the 21st century international air transportation

system. Long distance air travel is projected to be the fastest growing segment of the air transportation market by the turn of the century

with increases at about 5 percent per annum over the next two decades. This pr(_iection suggests that by the year 2015, more than

600,000 passengers per day will be traveling long distances, predominantly over water. These routes would provide the greatest

potential for an HSCT to become a significant part of the international air transportation system. The potential market for an HSCT is

currently projected to be anywhere from 500-150t,) aircraft over the 2(X)5-2030 time period. Such an aircraft fleet size would represent a

considerable share of the potential long-range aircraft market. However. this projected HSCT fleet can become a reality only if

technologies are developed which will allow an HSCT design that is ( 1 ) environmentally compatible and (2) economically viable.

Simply stated, the HSCT will be a technology driven airplane. Without significant advances in airframe and propulsion technologies

over the levels currently available, there will be no second generation supersonic airliner! This paper will briefly describe the propulsion

technology challenges which nmst be met prior to any product launch decision being made by industry and the progress toward meeting

these challenges through NASA's High-Speed Research (HSR) Program, a partnership between NASA and Boeing. General Electric and

Pratt & Whitney.

14. SUBJECT TERMS

High speed civil transport: Supersonic propulsion: Environmental compatability:

Economic viability: Components tests

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION

OF REPORT OF THIS PAGE

Unclassified Unclassified

NSN 7540-01-280-5500

19. SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

15. NUMBER OF PAGES

22

16. PRICE CODE

A03

20. LIMITATION OF ABSTRACT

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39-18

298-102