NACA TM 83741 Energy Efficient Engine Program Contribution to Aircraft Fuel Conservation

8/3/2019 NACA TM 83741 Energy Efficient Engine Program Contribution to Aircraft Fuel Conservation

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NASA Technical Memorandum 83741

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Energy Efficient Engine ProgramContributions to AircraftFuel Conservation

Peter G. BattertonLewis Research CenterCleveland, Ohio

Prepared for theAviation Fuel Conservation Symposiumsponsored by the Federal Aviation AdministrationWashington, D .C . , September 10-1 1 , 1984


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ENERGY EFFICIENT ENGINE PROGRAM CONTRIBUTIONSTO AIRCRAFT FUEL CONSERVATIONby Peter G. Batterton

National Aeronautics and Space AdministrationLewis Research CenterCleveland, Ohio 44135

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BACKGROUNDBecause o f t he 1973 OPEC o i l em bargo, t h e p r i c e o f j e t

f u e l n e a r l y t r i p l e d a nd t h e Energy Cr i s i s s t a r t e d . Dur ing t h en e x t c o u p l e o f years , NASA performed s e v e r a l s t u d i e s t oe s t a b l i s h e n e r g y / t r a n s p o r t a t l o n research programs t os u b s t a n t i a l l y r ed u ce f u e l c on su mp tio n by t r a n s p o r t a i r c r a f t .One su ch progr am was t h e JT8D-Refan Pro gra n. In Ja nu ar y 1975,however, N A S A was s p e c i f i c a l l y r e q u e s t e d by t h e S e n a t eCommittee on Aer ona ut i ca l and Space Sc i enc es t o e s t t b l i s h ar e sea r ch p rogram t h a t would have t h e r e d u c t - on o f f u t u r ea i r c r a f t f u e l co nsu mp tio n as I t s pr ime o b j e c t i v e . N A S Aa s s e m b le d a t a s k f o r c e c o n s i s t i n g of N A S A , Department ofT r a n s p o r t a t i o n , F e d e r a l A v i a ti o n A d m i n i s t ra t i o n , a nd t h eDepartment of Defense w i t h a s s i s t a n c e fro m e n g in e a nd a i r f ramem a n u fa c t ur e r s, a i r l i n e s and severa l a d v i s o r y b o a r d s . The t a s kf o r c e p r o d u c e d a r e p o r t o u t l i n i n g t h i s p l an wh i ch was c a l l e dt h e A ir c r a f t Energy Ef f i c i ency ( A C E E ) progrsm ( s ee Refe rence 1f o r a n ov er vi ew o f t h e e n t i r e ACEE Program) .

The s i x b a s i c elements of t h e p l a n a r e shown i n F i g u r e1. O f t h e s e s i x , t h r e e are a i r f rame r e l a t e d and t h r e e a rep r o p u l s i o n r e l a t e d . The t h r e e ai rf rame e l emen t s werec om po si te s t r u c t u r e s f o r l i g h t e r w e i gh t, t h e E n e r g y E f f i c i e n tT r a n s p o r t w i t h advanced aerodynamics and a c t i v e c o n t r o l s f o rb o t h w e i g ht a n d d r a g r e d u c t i o n , a nd l a m i n a r f lo w c o n t r o l f o r


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drag r e d u c t i o n . The t h r e e p r o p u l s i o n e l e m e n t s were EngineComponent Improvement, a n e a r term program t o improvee f f i c i e n c y and i d e n t i f y s o u r c es of d e t e r i o r a t i o n i n t h e np r o d u c t i o n e n g i n e s ; t h e E n e r g y E f f i c i e n t E n g i n e , a l a t e 1 9 8 0 r sadvanced t echno l ogy t u rbo fan and sub j ec t of t h i s p r e s e n t a t i o n ;and t h e Advanced Turboprop, w i t h t h e g rea t e s t f u e l s a v i n g sp o t e n t i a l b u t a much h i g h e r r i s k e f f o r t . The t o t a l p r o g r a mg o a l was t o e s t a b l i s h t ec hn ol og y f o r a 5 0 % f u e l r e du c t i o n f o rt r a n sp o r t a i r c r a f t by 1985. The p l a n was approved by t h eS e n a t e i n November of 1975.

The Energy Ef f i c i en t Eng i ne ( E E E ) used f u e l e f f i c i e n c y asa p r i m e o b j e c t i v e b u t a l s o f a c t o r e d i n d i r e c t o p e r a t i n g c o s ta nd e n v ir o n me n t al a c c e p t a b i l i t y . The EEE would be a !'cleansh ee t of pape r r r d e s i g n w i t h 1985 be ing t h e t a r g e t d a t e f o ri n t r o d u c t i o n . The main ob j ec t i ve s o f t h e E E E program were:

- A t l e a s t 1 2 p e r c e n t r e d u c t i o n i n s p e c i f i c f u e lconsumption w i t h a t l e a s t a 5 0 p e r c e n t r e d u c t i o n i np e r f o r m a n c e d e t e r i o r a t i o n r a t e

- Im prove d i r e c t o p e r a t i n g c o s t s by a t l e a s t 5 p e r c e n t- Meet f u t u r e e n v i r o n m e n t a l r e g u l a t i o n s s u c h as t h e

FAA 1978 FAR-36 n o i s e and EPA 1 9 8 1 e r i s s i o n s s t an d a rd sENERGY EFFICIENT ENGINE PROGRAM OVE3VIEW

F i g u r e 2 shows t h e program schedu l e as i t i s u l t i m a t e l ybeing comple ted , b u t I t can be u s e d t o g e n e r a l l y o u t l i n e t h epro gra m. The program i s p r i m a r i l y a $200+M c o n tr a c t e d e f f o r tw l t h b o t h G e n e r a l E l e c t r i c a n d P r a t t & W h i t n e y o r i g i n a l l yh a v i n g e s s e n t i a l l y p a r a l l e l c o n t r a c t s .

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Th e prog ram cons i s t ed o f th ree main a c t i v i t i e s . Thesewere P r o p u l s i o n S y s t e m D e f i n i t i on , Componen t Techno log ies , andS ys te ms I n t e g r a t i o n . P r o p u l s i on Sys t em D e f i n i t i o n i mp l e me n t e dt h e o r i g i n a l " c le a n shee t " d e s i g n of a p a p e r e n g i n e ,references 2 and 3 . The a c t i v i t y d e f in e d th e o v e r a l l e n g i n ec y c l e a n d t h e t e c h n o l o gi e s r e q u i r e d t o a c h i e v e i t . Thesep a p e r e n g i n e s , c a l l e d F l i g h t Propu l s ion Sys tems (FPS) were t or e p r e s e n t t h e f u l l y d ev el op ed , p r o d u c t i on v e r s i o n s of t h eEEE. As component te ch no lo gi es and t e s t r e s u l t s becamea v a i l a b l e f r o m t h e res t of t h e e f f o r t , t he se FPS p r o p u l s i o ns y s t e ms were upda ted and new per fo rmance and f u e l b en e f i t sc a l c u l a t e d .

The m os t a g g r e s s i v e t e c h n o l o g i e s i d e n t f e d i n t h eI n i t i a l FPS d e s i g n were deve loped du r ing t h e ComponentT e c h n o l o g y e f f o r t . The t e c h n o l o g i e s were e v a l u a t e d t h r o u g hs u b - s c a l e and f u l l - s c a l e r i g t e s t s f o r v e r i f i c a t i o n .

The System I n t e g r a t i o n i n v ol v e d b ot h c o r e and i n t e g r a t e dc o r e / l o w s p o o l t u r b o f a n e n g in e t e s t i n g . By h a v i n g t h i se l e m e n t , it was p o s s i b le t o e v a l u a t e th e i n t e r a c t i o n s and t h eo p e r a b i l i t y o f t h e advanced tec hnolo gy components i n ac o mp l e t e s y s t e m .

Completion of a l l component and sys t em a c t i v i t i e s coup ledw i t h t h e f i n a l u p da t e of t h e FPS computer models would definet h e a c t u a l l e v e l of f u e l s a v i n g s a ch ie ve m en t of t h e EEE.T e c h n o l o g y r e a d i n e s s was provided by t h e t e s t i n g a n d i t wast h e n up t o i n d u s t r y t o i n c o r p o r a t e t h i s t e c h n o l o g y i n t op r o d u c t i o n e n g i n e s .

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A s ment ioned , these were o r i g i n a l l y e s s e n t i a l l y p a r a l l e lc o n t r a c t s . I n 1982, f u n d in g f o r EEE was reduced and t h eprogram had t o be descoped by ab ou t $lgM. Ge ne ra l E l e c t r i c ,however, was w e l l a l o n g a n d t h e v a s t m a j o r i t y o f t h e i r s y s t e ms .i n t e g r a t i o n c o s t s had a l r e a d y be en a c c ru e d . I t was t h e r e f o r edec i ded t o c om pl et e t h e G e n e r a l E l e c t r i c p r o g r a m a n d t e r m i n a t et h e System I n t e g r a t i o n e f f o r t i n t h e P r a t t 8 Whitney program.Later i n 1982 and 1983 some of t h e f u n d i n g was r e s t o r e d t o b eused as tvseedt lmoney f o r a f ol lo w- on t o t h e EEE. A s a r e s u l t ,t h e component t e c h n o l o g y a c t i v i t i e s h a v e b ee n e xp an de d f o rb o t h c o n t r a c t o r s . These e f f o r t s p r i m a r i l y i n c lu d e s h r ou d le s s,h ol lo w f a n t e c hn ol og y an d a d d i t i o n a l t e s t i n g o f t h e EEEcompressors . A t t h i s t ime, n o fu n d i ng f o r a fo l low-ont u rb o fa n p ro g ra m a p p e a r s a v a i l a b l e a n d t h e t ec hn ol og y e f f o r t sw i l l be end ing in 1985 .

F igures 3 and 4 a re cut-away t yp e drawinge of t h e two E EEFPS eng ine s . Fi gur e 3 i s t h e G e n e r a l E l e c t r i c EEE whichc o n s i s t s of a s i n g l e s t a g e f a n a nd q u a r t e r s t a g e o p e n b o o s t e rd r i v e n b y a f i v e - s t a g e low p r e s s u r e t u r b i n e ; a c o r e c o n s i s t i n gof a 1 0- st ag e 2 3 : l p r e s s u r e r a t i o h i g h p r e s s u r e c om p re s so r ,d u a l a n n u l a r c ombu st or f o r low e mi s s i o n s , a n d t wo - s t ag e h i g hp r e s s u r e t u r b i n e ; d a i s y - t y p e m ix er ; an d l o n g d u c t n a c e l l e . I na d d i t i o n , a n e l e c t r o n i c e n g i ne mounted f u e l c o n t r o l , K e vl a rfa n con ta inment , and b u l k a c o u s t i c t r e a t m e n t a r e a l l u s e d .The f a n uses w i d e r o t o r a nd s t a t o r s p a c i n g f c r r e d u c e d n o i s e .

F i g u r e 4 i s t h e P r a t t & Whitney EEE FPS which cons is ts ofa s i n g l e - s t a g e f a n a nd f o u r - s t a g e low p r e s s u r e c o mp re ss or

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d r i v e n by a f i v e - s t a g e low p r e s s u r e t u r b i n e ; a c o r e c o n s i s t i n go f a 10-s tage 1 4 : l p r e s s u r e r a t i o h i g h p r e s s u r e c o mp r es s or ,two zone low emiss ion combus to r , and s i ng le - s t a ge h i g hp r e s s u r e t u r b i n e ; a d a i s y - t y p e m i xe r ; a nd l o n g d u c t n a c e l l e .Although t h e c o n f i g u r a t i o n s o f t h e two eng ines a red i f f e r e n t , t h e c y c l e s a r e q u i t e s i m i l a r w i t h ~ 3 8 : i v e r a l lp r e s s u r e r a t i o , r u 1 3 5 0 C (2450 OF) t u r b i n e r o t o r i n l e tt e mp e r a t u r e , a n d r u 6 . 8 : 1 bypass r a t i o .

These two r rpaper r r ng ines r e a l l y r e p r e s e n t t h e o u t p u t o ft h e EEE program w i t h t h e i r component performance andtechnology assumpt ions proven by t h e EEE t e s t i n g .MAJOR TECHNOLOGY DEVEL9PMENTS F O R FUEL E F F I C I E N C Y

Because t h e s u b j e c t i s p r i m a r i l y f u e l e f f i c i e n c y , o nl yt h o s e t e c h n o l o g i e s which c o n t r i b u t e d s i g n i f i c a n t l y t o r e du ce df u e l c on su mp ti on h av e be en s e l e c t e d f o r t h i s r e vi ew . F u l ld e s c r i p t i o n o f t h e EEE w i l l b e a v a i l a b l e when t h e f i n a lr e p o r t s f o r t h e c o n t r a c t s are completed .

FanH i g h l i g h t e d i n f i g u r e 5 i s t h e G e ne ra l E l e c t r i c EEE f a n-

( r e f . 4 ) . T h i s s i n gl e - s ta g e f a n c o n s i s t s of 32 low as p ec tr a t i o b l a d e s f o l l o w by a q u a r t e r -s t a ge b o os t e r f o r . t h e c o r e.The d e s i g n b y p a s s r a t i o i s 6.8 a t a 1 . 6 5 p res s u re r a t i o a nd400 m/s ec ( 13 15 f t / s e c ) t i p speed . F u e l e f f i c i e n c yt e c h n o l o g i e s i n c l u d e t h e r educed number of b l a d e s w i t h .55span , af t -mounted dampers t o r e d u c e l o s s e s . The q u a r t e r s t a g eb o o s t e r a c h i e v e d a 1 .67 p r es s ur e r a t i o f o r t h e c o re w i t h

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modera te hub load ing . The r e s u l t was a f a n w i t h 89 .2 percen tbypass and 89.5 p e r c en t c o r e e f f i c i e n c i e s .

The q u a r t e r - s t a g e o pe n b o o s t e r a l s o pr o v i de d a secondf u e l s a v i n g s t e c hn o l og y wh ic h i s a c e n t r i f u g a l c l e a n i n g a c t i o non t h e c o r e flow. With t h i s d e s i g n , m os t d u s t an d d i r t a ret hr ow n ou tw a rd a nd n o t i n g e s t e d by t h e c o r e . T h i s g r e a t l yr e du c es f o r e i g n o b J e c t i n g e s t i o n an d t h u s e r a s i o n e f f e c t s ont h e compressor b l a d e l e a d i n g e d ge s .

F i n a l l y , a n i n t e g r a l va ne -f ra me w i t h w i de s p a c i n g betweent h e r o t o r and s t a t o r v an es was u s e d f o r r e d u s e d weight andr e du c ed n o i s e g e n e r a t i o n .

b e t t e r a c t i v e and p a s s iv e t i p c l e a r an c e c o n t r o l . S i g n i f i c a n tg a i n s were made on t i p c l e a r a n c e c o n t r o l by u s i n g a s h o r ts t i f f c o r e d e s i g n . The s h o r t e r c o m p r e s s o r s were o b t a i n e d byp r o vi d i ng h i g he r p r e s s u r e r a t i o p e r s t a g e t h e r e b y r e d u c i n g t h et o t a l number o f s t a g e s . The Genera l E l e c t r i c app roach ,r e f e r e n c e 4 , shown on t h e l e f t s i d e o f f i g u r e 6 , i s a 1 0 - s t a g e23 : l p r e s su r e r a t i o d es ig n. T h i s h i g h p r e s su r e r a t i o wasa c h i e v e d th rough h i g h s p e e d r a t h e r t h a n h i g h l o a d i n g . E n d w a l lcon tou r ing was u sed t o minimize w a l l l o s s e s . To a v o i dp ro bl ems of c ompa ri ng e f f i c i e n c i e s f o r c o mp re s s o r s w i t hd i f f e r e n t pr e ss u re r a t i o s , p o l y t r o p i c e f f i c i e n c y i s q u o t e d .For t h i s compressor , a 9 0 . 5 p e r c en t p o l y t r o p i c e f f i c i e n c y waso b t a i n e d . For improved d u r a b i l i t y , t h e f r o n t s t a g e s us e a

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CompressorsShown i n f i g u r e 6 a re b o t h h i g h p r e s s u r e compresso r s .

One of th e f u e l s a v i ng t e c h no l o gi e s f o r t h e E E E i s t o p r ov i de


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low aspect ratio blade design improving foreign objectingestion tolerance.

On the right in figure 6, is the Pratt & Whitney 10-stage14:l pressure ratlo compressor, reference 5. This highlyloaded compressor uses advanced aerodynamics and controlleddiffusion airfoils for a very high 91.5 percent polytropicefficiency. It uses only half the number of blades of theexisting JTgD engines. Eliptic leading edges were used forimproved erosion resistance. This compressor is lower inpressure ratio so that it could be driven by a single-stageturbine.

Both compressors use active clearance control on the lastseveral stages. The active clearance control was used tominimize clearances during cruise, maximizing efficiency, butwould allow maximum clearance during take-off to reducechances for tip wear, reference 6. This helps maintain theirhigh efficiency over the life of an engine.Tur ine

The EEE represented Pratt & Whitney's first opportunityto use a single-stage high pressure turbine, reference 5. Themain features of this turbine are shown in figure 7. Thisturbine used advanced transonic aerodynamics to yield a highefficiency design for a single stage of 88.5 percent. Thishigh efficiency coupled with the reduced weight and partscount had a significant lmpact on reducing direct operatingcost for the Pratt & Whitney EEE. To permit highertemperatures with reduced cooling, single crystal airfoils and


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c e ra mi c c o a t e d o u t e r a i r s e a l s were u s e d. A c t i v e c l e a r a n c ec o n t r o l was a l s o us ed t o ma i nt a in t i g h t c l e ar a n ce s f o r t h ec r u i s e p o r t i o n of o p e r a t i o n .

Not shown i s t h e G e ne r al E l e c t r i c t wo -s ta ge h i g h pressuret u rb i n e which a c h i e v e d a 9 2.5 p e r c e n t e f f i c i e n c y . Ceramic t i ps e a l s , a c t i v e c l e a r a n c e c o n t ro l a n d a d v a n c e d a e ro d y n a mi c s wereu se d t o a c h i e v e t h i s h i g h e f f i c i e n c y .

Both low pre ss ur e tu r bi ne s used advanced aerodynamics anda c t i v e c l ea r an c e c o n t r o l t o a c h ie v e h i g h e f f i c i e n c i e s .

I n summary, f o r a l l t h e t u r b i n e s , a t l e a s t one po in ti mp ro vemen t i n e f f i c i e n c y was o b t a i n e d o v e r mid 1 9 7 0 ' st e c h n o l o g y .Mixers

Both EEE eng ines used m i x e r s and l o n g d u c t n a c e l l e s ,r e f e r e n c e s 5 a nd 7. In b o t h c a s e s t h e m i x e r s c o n t r i b u t e da b o u t 1 / 5 o f t h e t o t a l f u e l s a v i n g s b e n e f i t s f o r t h e E E E .Both E E E ' s l lda l sy - type l l exhaus t gas mixers are shown in a s i d eview in t h e upper l e f t o f f i g u r e 8 , G e n e r a l E l e c t r i c ' sr e f e r e n c e 8, i s t h e upper and P r a t t & W h i t n e y ' s I s t h e lower .The u pp er r i g h t of f i g u r e 8 shows t h e p r o g r e s s i o n o f m i x e re x p e r i e n c e f ro m t h e a :l bypass eng ine th rough a s e r i e s oft h r e e model t e s t s . I n t h e end, both m i x e r des:gns provideda b o u t t h e same b e n e f i t . F o r - 7: l b y pa s s r a t i o t u r b o f a ne n g i n e s , these m i x e r s p ro v i d e a b o u t 3 p e r c e n t f u e l s a v i n g sbenef i t .

The bottom l e f t s e c t i o n of f i g u r e 8 g i v e s t h e o v e r a l ld e s ig n c h a r a c t e r i s t i c s f o r b ot h m i x e r d e s i g n s . B o t h a r e

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s c a l l o p e d 1 8 l o b e d e s i g n s . The m a i n d i f f e r e n c e i s t h ep e n e t r a t i o n o f t h e l o be s i n t o t h e f a n s t r e a n . Higherp e n e t r a t i o n y i e l d s b e t t e r mi x i n g b u t a l s o h i g h e r p r e s s u r el o s s e s .

Exhaus t gas m i x e r s r e q u i r e t h e use o f long du c tn a c e l l e s . Nacelle l o c a t i o n s were e v a l u a t e d i n model t e s t swhere i n s t a l l a t i o n s w i t h a n e t b e n e f i t were found t h e r e b ya v o i d i n g t h e p e n a l t y n o r m a l l y a s s o c i a t e d w i t h s u c h n a c e l l e s .INTEGRATED SYSTEM EVALUATION

A s s t a t e d e a r l i e r t h e G e n e r a l E l e c t r i c c o n t r a c t was notte r mi na t ed when fun d ing was c u t b a c k . T h e re fo re , G e n e ra lE l e c t r i c ' s EEE went through th e s y s t ems i n t e g r a t i o n e v a lu a t io nw hi ch i n c l u d e d b o t h c o re e n g i n e t e s t s and f u l l y I n t e g r a t e dco re and low sp oo l ( I C L S ) t u r b o f a n t e s t s . These e n g i n ec o n f i g u r a t i o n s had f u l l ae rodynamic equ iva lency w i t h t h e i rc o r r e s p o n d i n g p a r t s of t h e EEE FPS. The hardware was a l s of l i g h t wei gh t i n t h e gas p a t h b u t o t h e r hardware such ase n g i n e c a s e s , g ea r bo x , e t c . , was b o i l e r p l a t e . A lso , f o r t h et u r b o f a n c o n f i g u r a t io n , a b e l l -mo u t h i n l e t was u s e d f o r t h eground t e s t a n d t h e n a c e l l e had o n l y i n t e r i o r a e r o d y n a m i cs u r f a c e s .

F i g u r e 9 i s a photograph of t h e t u r b o f a n e n g i n e I n t h et e s t s t a n d a t G e n er a l E l e c t r i c ' s P e e b l es , Ohio, t e s t s i t e .A l l t h e f u e l sa vi ng component te ch no lo gi es were i n c l u d e d i nt h i s e n g i n e and e x e r c i s e d d u r i n g t h e g r o u n d t e s t i n g . While ont e s t , t h i s unique eng ine ach ieved over 162 ,360 N (36,500 l b f )t h r u s t . When t h e e n g i n e d a t a i s c or r ec t ed f o r i n s t a l l a t i o n ,

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instrumentation, and flight vs. ground effects, the researchengine is projected to have a cruise specific fuel consumptionof 0.056 kg/hr-N ( .55 lbm/hr-lbf), uninstalled. Corrected forinstallation, the projected cruise specific fuel consumptionwould be 13.5 percent better than the baseline averageproduction CF6-50C. That would make this set of researchhardware the world's most fuel efficient turbofan engine.F U E L SAVINGS SUMMARY

Figure 10 summarizes the results of the program. If allthe EEE technologies were applied to a new engine and thecycle and configuration of that engine optimized for today's$0.264/liter ($l.OO/gallon) fuel prices, the benefits of theEEE would be 17-19% in fuel savings. If the commercial fleetcould obtain half this benefit, it would translate in tonearly 4 billion liters (1 billion gallons) of jet fuel savedeach year. (Currently more than 38 billion liters (10 billiongallons) of jet fuel are burned each year.)reduction in direct operating cost would also be realized

A ten percent

along with acoustic and environmental improvements.The fuel savings are achieved through the four main areas

shown in the pie chart in figure 10. Improved componentsusing advanced aerodynauics, active clearar.2.e control, reducedgas-path leakage, higher temperature materials, and reducedcooling flows account for about half of the fuel savings. Thehigher pressure, temperature, and bypass ratio cycle accountsfor approximately a quarter of the benefit. The efficient

10


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mixed f l o w exhaus t a c c o u n t s f o r a b o u t a f i f t h and the improvedn a c e l l e i n s t a l l a t i o n , t h e remainder .TECHNOLOGY APPLICATION

A s t h e EEE program was p r o g r e s s i n g , b o t h General E l e c t r i cand P r a t t & Whitney saw immediate b e n e f i t f o r t h e EEEt e c h n o l o g y . So e ve n b e f o r e t h e EEE c o n t r a c t s are o f f i c i a l l ycomple te , w e f i n d a p p l i c a t i o n of t h e EEE t e c h n o l o g i e soccu r ing . Wi thou t g e t t i n g i n t o s p e c i f i c d e t a i l s , f i g u r e 11i n d i c a t e s t h e num be rs o f te c h no l og y a p p l i c a t i o n s as a p p l ie d t onew and de r iv a t i ve h igh bypass tu r bo f ans o f bo th companies.What counts as a t ec hn ol og y f o r f i g u r e 11 would be items l i k ef an and compresso r t i p t r e n c h e s , h i g h compresso r b l adeloa d in g , improved compresso r ae rodynamic des ign to o l s ,compressor vane uncamber ing a t e n d w a l l s , e t c . T a b l e s I and I1p r o v i d e t h e complete l i s t t h a t went i n t o f i g u r e 11.

I t can be cla imed % h a t a p p r o x i ma t e l y h a l f of th e f u e ls a v i n g s b e n e f i t s of t h e PW2037 a re a t t r i b u t a b l e t o t h e EEEprogram. A s bo th compan ies deve lop eng ines such as t h e PW4000and t h e CF6-80C2, s u b s t a n t i a l p o r t i o n s of t h e i r f u e l s a v i n g sb e n e f i t s can be a t t r i b u t e d t o t e c h n ol o g y d e ve lo pm e nt si n i t i a t e d by t h e EEE. G e n e r a l E l e c t r i c has a l s o i d e n t i f i e d as u b s t a n t i a l number of t e c h n o l o g i e s t h a t are a p p r o p r i a t e f o rt h e i r m i l i t a r y p ro du ct s and a r e i n c o r p o r a t i n g them.TH E FUTURE

When funds were r e s t o r e d i n 1 9 8 3 , i t was d e ci d ed t o u s esome of t h e f u n ds t o e v a l u a t e t u r b o f a n e n g i n e t e c h n o l o g i e s andc y c l e s of t h e f u t u r e bu i ld ing upon t h e EEE. The s t u d i e s w o u l d

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h a v e a n o u t p u t s imilar t o t h e i n i t i a l EEE s t u d y , t h a t i s ad e f i n i t i o n o f a c o mp l e t e t u rb o fa n p ro p u l s i o n s y s t e m , b u t f o rt h e y e a r s 2000-2010. The s t u d i e s would t r y t o a ns we r i ft u rb o fa n t e c h n o l o g y I s an area of f ~ d i m i n l s h i n g e t u r n s " and,i f n o t , e s t a b l i s h t h e b a s i s f o r a follow-on program a f t e r EEE.

F i g u r e 1 2 I s t h e r e s u l t of t h e P r a t t & Whitney s tudyc a l l e d t h e "Target Engine". P r a t t & Whitney used technologye x t r a p o l a t i o n s and l i m i t e d p a r a m e t r i c c y cl e m a l y s e s t o a r r i v ea t t h i s c o n c e p t u a l e n g i n e . The Targe t Engine has agear -d r i ven swept b lad e N 1 2 : l b yp as s r a t i o f a n and s e p a r a t ef l o w e x h a u s t . ( A m i x e r b e n e f i t a t rn 1 2 : 1 b yp as s r a t i o c o ul dn o t be i d e n t i f i e d . ) The ot he r ma jor impac t i s t h e h i g h ,~ 6 0 : 1 , y c l e p r e s s u r e r a t i o w hich r e q u i r e s small and hight e m p e r a t u r e rear s t a g e s o f t h e h i g h p re s s u re c o mp re s s o r .Because of the Improved (approx im ate ly one po in t po l y t r op ic )c o mp r es s or e f f i c i e n c y , o n l y a modest r i s e i n t u r b i n e r o t o ri n l e t t e mp e ra t u re o f a p p ro x i ma t e l y o ne hu nd re d d e g re e s i sr e q u i r e d .

The b a s i c t e c h n o l o g i e s r e q u i r e d are a d v a n c e d , c o n t r o l l e dd i f f u s i o n , h i g h e r e f f i c i e n c y c o mp r es s or ; low p r e s s u r e d r o pd i f fu s e r - c o mb u s t o r ; h i g h a n n ul u s - sp e e d -s q u are d , f u l lt h r ee - d i me n s io n a l d e s i g n t u r b i n e s ; c l o s e d - l o o p a c t i v ec l e a r a n c e c o n t r o l ; c om po si te i n t e g r a t e d s t r u c t u r e s ; s h o r t ,s h o c k - f r e e i n t e g r a t e d f a n co wl ; a s w e p t , s h o c k - f r e e f a n ; andh i g h e f f i c i e n c y r e d u c t i o n g e a r.

When t h i s type of eng ine i s e v a l u a t e d , t h e p o t e n t i a l f u e ls a v i n g s i s 1 5 . 5 p e r c e n t I n c r u i s e s p e c i f i c f u e l c o ns um pt io n

1 2


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o v e r t h e EEE. T h i s t r a n s l a t e s t o a 2 4 p e r c e n t s a v i ng s I n f u e lb u r n e d f o r a 3700 km (2000 n a u t i c a l m i l e ) m i s s i o n 500p a s s e n g e r q u a d j e t . T he se b e n e f i t s a re s p l i t r ou gh ly e q u a l l ybetween thermal ef f i c i ency improvemen t s and p ropu l s ivee f f i c i e n c y i mp ro ve me nt s. B ec aus e o f t h e c o n t r i b u t i o n s o f t h es we pt f a n t o t h e e f f i c i e nc y improvemen ts , some p re l im ina ryd e s i g n s t u d i e s ha ve b ee n s t a r t e d u s i n g EEE f u n d s .

To put a l l t h e EEE and t h e f u t u r e i n t o one p e r s p e c t i v e ,f i g u r e 13 is prov ided . T h i s f i g u r e s h o w s th e t r e n d o fu n i n s t a l l e d , bare s p e c i f i c f u e l consumption s t a r t i n g w i t h t h eJ T3 ty p e t u r b o j e t as a f u n c t i o n of year of i n i t i a lc e r t i f i c a t i o n . The n e x t s p o t on t h e c u r v e is t h e J T 3 D / J T 8 Dt y p e e n g i n e s w i t h a b o u t a 1 5 pe rc en t improvement. The ne xts p o t , t h e f i r s t JT9D/CF6 typ e hig h bypass e ng in es , ag ai n madea s u b s t a n t i a l i mpr ov emen t on t h e o r d e r of 1 9 p e r c e n t o v e r t h ep r e v i o u s e n g i n e s . N e x t comes t h e PW2037 w i t h an improvementon t h e o r d e r o f 1 2 p e r c e n t o v e r t h e JT9D/CF6. The PW2037r e p r e s e n t s t h e f i r s t s i g n i f i c a n t us e of EEE t echnology .

Two s po ts f o r E E E are shown. The h i g h e r i s a b o u t 1 5p e r c e n t b e l o w t h e JT9D/CF6 s po t and re p r e s e n t s t h e f i n a lr e s u l t s f o r t h e EEE FPS eng ines . The l o w e r s p o t r e p r e s e n t sa p p l i c a t i o n of EEE t e c h n o l o g i e s b u t w i t h some re-op t imizat ionof t h e e n g in e c o n f i g u r a t i o n s uc h as t h e number of compressorand t u r b i n e s t a g e s . I t is about 1 8 percen t be low t h e J T g D / C F 6s p o t . The T ur bo fa n F u t u r e P o t e n t i a l s p o t r e p r e s e n t s t h er e s u l t s of t h e Targe t Engine s t ud y j u s t shown, ag ai n showingt h a t s u b s t a n t i a l g a in s e re s t i l l p o s s i b l e . T h i s is v e r y


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i mp o r t a n t b e c a u s e i t i s n o t c l e a r t h a t t u r b o p r o p s w i l l bea v a i l a b l e i n t h e h i g h t h r u s t s i z e n or ma ll y f i l l e d by t u r b of a n sd u r in g t h i s time p e r i o d .

F i n a l l y , are tw o s p o t s f o r a d va n ce d p r o p f a n t y p et u r b o p r o p s y s t e m s which in c lu de advanced t echno logy co r es .The h i g h e r s p o t u s e s a n EEE t echno logy co re and low p ressu ret u r b i n e and t h e l o we r s p o t u s e s t h e advanced Tar g e t Enginec o r e a nd low p r e s s u r e t u r b i n e t e c h n o l o g i e s . Thus e ve n t h ep r op f an g a i n s s u b s t a n t i a l l y f r om t u r b o f a n c o r e t ec h no lo g ydevelopments .CONCLUS N SThe E EE program was h i g h l y s u c c e s s f u l and p r o vi d e s a ne x c e l l e n t t e c h n o l o g y base f o r much improved tu rbo fan eng inef u e l e f f i c i e n c y . As a r e s u l t , b ot h G e ne r al E l e c t r i c and P r a t t& Whitney a r e r a p i d l y t r a n s l a t i n g t h e s e t e c h n o l o g i e s i n t ot h e i r products making t h e EEE program a g r e a t s u c c e s s .

Although no funding has b e e n i d e n t i f i e d , a fo l low-ont u r b o f a n r e s e a r c h progra m c o ul d o b t a i n s u b s t a n t i a l a d d i t i o n a lf u e l s a v in g s b e n e f i t s .would ha ve d i r e c t a p p l i c a t i o n t o p r o p f a n t u r b o p ro p p r o pu l s i o ns y s t e m s p r ov i di n g s u b s t a n t i a l b e n e f i t t o them a l s o .

The co re po r t io n o f these t e c h n o l o g i e s

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T A B L E IPW E 3 TECHNOLOGIES - APPLICATION TO COMMERCIAL ENGINES

TECHNOLOGY-:OMPRESSOR INT ERM EDI ATE CASE WITH THROUGH STRUTS:AN AND COMPRESSOR T I P TRENCHES(EDUCED LPC INNER CAVITY VOLUMES.ow C X I U L c)RUM COMPRESSOR ROTORS WITH INTEGRAL KNIFE EDGES:OMPRES SO R A I RF O I L S WITH E L L IP T I CA L L E A DING E DG EI I N I S HROUDE D HP CMUBLE WALL COMPRESSOR ACTIVE CLEARANCE CONTROL:ONTROLLED DIFFUSION COMPRESSOR AIRFOILS[NCREASED COMPRESSOR STAGE LOADINGSrANGENTIAL COMPRESSOR BLADE ATTACHMENTS:ANTED COMPRESSOR EX IS T GUID E VANE /DIFFU SERrwo BEARNG HIGH SPOOL WITH DAMPING AND SPRINGSIO N- ME TA L L IC TURB INE O UTE R A IRS E A L% L L R I N G TU R B I N E S ID E P L A T E SIMPROVED TURBINE FEATHERSEAL SLOTSME RMA L B A RRIE R CO A TING ON TURBINE VANE PLATFORMIMPROVED GASPATH STATIC SEALSr U R B I N E A I R F O I L I N T E R N A L T R I P S T R I P Sr URB INE A I RF O I L INTE RNA L TURNING VA NES3-D DESIGN TURBINE VANES[MPRO VE D S UCTIO N S IDE F IL M CO OL INGi I G H A N2 T U R B I N Er H I N T U R B IN E A I R F O I L T R A I L I N G E D GE Si I G H S T AG E L O A D IN G T U R B I N E A I R F O I L SU G H R E A C T IO N HP T U R B I N ELOW CX/U TURBINET U R B I N E A I R F O I L S W I T H E L L I P T I C A L L E A D I N G E D G E STWIST RESTRAINED HP TURBINE VANESB O L TL E S S TURB INE D IS K S IDE P L A TELP TURBINE FLOW GUIDESLOW LOSS CONTOUR TUR BIN E E X IT GUID E VANETHREE BEARING LOW SPOOL

IT9 D- 7 R4 P W 2 0 3 7e_XXXXXXXXXXXXXXXXXXX

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P W4 0 0 0XXXXXXX

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T A B L E I 1

6E E3 T EC H N OLOGIES - A P P L I C A T I O N T O C O M M E R C I A L /M I L I T A R Y E N G I N E STECHNOLOGY

IMPROVED COMPRESSOR AERODYNAMICD ESIGN T OOLS:OMPRESSOR VANE UNCAM BERING ATENDWALLSIMPROVED BETWEEN SHINGLE SEALS FORSHINGLE COMBUSTOR LINERStEDUC E0 THROUGH-FLOW VEL OCIT Y HPT U R BIN E D ESIGNYIGH STAGE REACTION HP T U R BIN EIMPROVED HP TURBINE FLOWPATH OVERLAPSHP TURBINE CONVERGED STATOR BANDSHP TURBINE IMPROVED A IR FO IL SURFACEV E L O C I T Y D I S T R I B U T I O N SCERAMIC HP TURBINE SHROUDSLIGH T WEIGH T R AD IAL ST R U T T ED T U R BIN EFRAME WITH POLYGONAL CASINGIMPROVED LP TURBINE FLOWPATH OVERLAP:IMPR OVED LP T U R BIN E A I R F OI L SU RF ACEV EL OC I T Y D I S T R I B U T I O N SFADEC FAULT IND IC AT IO N AND CORRECTIVEAC T ION SYST EM

F 6- 80C 2 'F M 56-3-110-

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16


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REFERENCES

1.

2.

3 .

4.

5.

6.

7.

ETHELL, J. L. (19831, Fuel Economy In Aviation, NASASP-462

JOHNSTON, R. P., et. al. (19801, Energy Efficient Engine -Flight Propulsion System Preliminary Analysis and Design(General Electric), NASA CR-159583GARDNER, W. B. (19791, Energy Efficient Engine - FlightPropulsion System Preliminary Analysis and Design (Pratt &Whitney), NASA CR-159487SULLIVAN, T. J. and HAGER, R. D. (1983), The AerodynamicDesign and Performance of the General Electric/NASA E3-an, AIAA-83-1160GARDNER, W. B. (1982), Energy Efficient Engine (E3)Technology Status, AIAA-82-1052BEITLER, R. S., SAUNDERS, A. A., and WANGER, R. P. (1980),Fuel Conservation Through Active Control of RotorClearances, AIAA-80-1087KUCHAR, A. P., and CHAMBERLIN, R. (19841, Comparison ofFull-scale Engine and Subscale Model Performance of aMixed Flow Exhaust System for an Energy Efficient EnginePropulsion System, AIAA-84-0283


19/28

F i g u r e 1 - Overv iew o f a i rc ra f t energy e f f i c i ency p rogram.

PROPULSION SYSTEMDEFINITION (Ir UPDATES

COMPONENTTECHNOLOGIES

SYSTEMS INTEGRATIONTECHNOLOGIES

CALENDAR YEAR77 I 78 I 79 [ 80 I 81 I 82 I 83 I 84 I 85

FLIGHT PROPULSiON SYSTEM DESIGNI I I I I I

ICLS - INTEGRATED COREILOW SPOOLGENERAL ELECTRIC0 RATT (IrWHITNEYF i g u r e 2. - E n e r gy e f f i c i e n t e n g i n e p r o g r a m .


20/28

I-TWO-ZONE COMBUSTORI /4 -STAGE ISL AND BOOSTER7\\ 1 rFIVE-STAGE L. P TURBINESINGLE-STAGE FAN7

I \ I \I '\

;TEN-STAGE H. P. COM PRES SORJ L l W O - S T A G E H. P. TURBINECS-80-2098Figure 3. - Energy efficien t engine, General Electric configura tion.

FOUR-STAGC L P. COMPRESSOR1I IISINGLE-STAGE FA N 7I I 1

,-TWO-ZONE COMBUSTORI ,-FOUR-STAGE L P. TURBINEI ,-MIXERIt ! !

fTEN-STAGE H. P. COMPRESSOR' SINGLE-STAGE H. P. TURBINEc s -80-2099Figure 4 - Energy efficien t engine, Pratt & Whitney configuration.


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32 BLADE / 6 .8 BY PASS RATIO / 1.65 PRESSURE RAT IO0.55 S PAN , AFT MOUNTED LOW LOSS SHROUD89.2 BYPASS, 89.5 CORE EFFICIENCYQUARTER STAGE BOOSTER I FOD SEPERATIONINTEGRAL STATOR-FAN FRAME / WIDE ROTOR-STATOR SPA CING

Figure 5. - EEE fan technology.


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(a ) Genera l E lec t r i c . 10 -s tage ; 23 : 1p r e s s u r e r a ti o ; H i g h s pe ed , e n d b e nd t r e a t m e n t ;90.5 poly. ef f .

(b ) P r a t t & Whitne y. 10-stage; 14: 1 r e s s u r e r a t i o ; H i g h l o a d i n g c o n t r o l l e d d i f f u s i o n ;

F i g u r e 6 - EEE c o m p r e s s or t e c h n o l o g y ; A c t i v e a n d p a s s iv e c l e a r a n c e c o n t r o l ; s h o r t , s t i f f91.5 poly. eff.

r o t o r ; low aspec t ra t i o b lades.


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i. . . .


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GE

P & W

r3. 0RATIO

L na

PHASE

GE P&w

mHASEiiiMI D 70s 1978 1980 1981183TECHNOLOGY READINESSFEATURES GE P & W NEW E3 TECHNOLOGY

0 NUMBER OF LOBES 18 18 0 SHORT EFFICIENT MIXERS COMBININGPENETRATION, % 45 15 HIGH M IXI NG EFFECTIVENESS WITH LCVY0 MIXING LENGTH, LID .5 2 .61 PRESSURE LOSS0 MIXING EFFECTIVENESS, % 79 85 0 M I X E R S A T H I G H B Y P A S S R A T IO S

0 REDUCED WEIGHT MIXER DESIGNSF i g u r e 8. - EEE exhaus t m ixer techno logy .

F i g u r e 9. - EEE e x p e r i m e n t a l e n g i n e o n t e s t stand.


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REFERENCE ENGINEOPR: 2 5 - 3 0BPR. 4.3.5.3

T (SLTO1' 2300~2400'F

I I " I IENERGY EFFICIENT ENGINE18% FUEL SAVINGS

OP R 36-37BPR: 6 6 - 6 8

1 SLTO)' 2450 - 250dF

SOURCES OF FUEL SAVINGSIMPROVED COMPONEN TS-, ,- MPROVED CYCLE

I HIGHER BYPASS RATIOI HIGHER TEMPERATURES

,/ HIGHER PRESSURE RATIODVANCED AERODYNAMICS .\ACTIVE CLEARANCE CONTROLREDUCED GAS-PATH LEAKAGEHIGHER TEMPERATURE MATERIALSREDUCED COOLING

,.I .IMPROVED NACELLE INSTALLATION '..- MIXED FLOW EXHAUST

F igure 10. - EE E bene f i ts sum m ary .


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c-79-2745

I A P P L I C A T I O N I CF6-8OC2 I CFM56-3 1 M I L I T A R Y INUMBER OFTECHNOLOG I ES 9 6 15

(a ) Gene ra l E lec t r ic .

A P P L I C A T I O NNUMBER OFTECHNOLOGIES

C-79-2743

JT9D-7R4 PW 2037 PW 4ooo7 28 30


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ADVANCED TECHNOLOGY REQUIREMENTSFOR M00 -2010A. D. TURBOFAN SYSTEMS

ADVANCED CYCLE

. 9

.8ece .72nY$, . 65z

v,W

J

. 5

. 4 *

55-65 OVERALL PRESSURE RATIO9 -12 BYPASS RATIO2700-2800 F COMBUSTOR EXIT TEMPERATURESEPARATE EXHAU STS

- CERTIFIED TURBOJETS

CERT. LOW-BYPASS FANS--TECHNOLOGY TREND-

CERT. H I -BY PAS S FANS-

ENERGY EFFICIENT ENGINE-

TURBOPROPS6 Q URBOFAN FUTURE POTENTIALI 1 I 0 DVANCED TURBOPROPSI

,-HIGH AN^, FULLYOW A P IP DIFFUSERCOMBUSTOR ~\ADVANCED CONTROLLED / 3-D DESIGN TURBINES\\

\ .I --DIFFUSION COMPRESSOR 7%.A.

SWEPT FAN ---CLOSED LOO P ACT IVECLEARANCE CONTROL

\ #\ -SHORT, SHOCK-FREE +\,INTEGRATED COWL \-COMPOSITE, INTEGRATED STRUCTURE

F i g u r e 12 - A d v a n c e d t u r b o f a n r e s e a r c h r e q u ir e m e n t s a n d b e n ef it s . P o t e n t i a l fuel s a v i n g s w e r E EE -15.5% SFC,-24% fue l bu rned.

F i g u r e 13. - T u r b o f a n t e c h n o l o g y t r e n d .


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1. Report No.N ASA TM-83741

2. Government Accession No. 3. Recipient's Catalog No.

17. Ke y Words (Suggested by Author(s) )Energy Conserva t ionS u b so n ic T r a n s p o r t T u r b i n e E n g ineA i r c r a f t T u r b i n e E n g i n eE ne rg y E f f i c i e n t E ng in e

4. Title and SubtitleE ne rg y E f f i c i e n t E n gi ne P ro gra m C o n t r i b u t i o n s t o A i r c r a f t F u elC o n s e r v a t i o n

18. Distribution Statement

5. Report Date

6. Performing Organization Code505-40-12C

U n c l a s s i f i e d - u n l i m i t e dSTAR Category 07

7. Author(s)P e t e r G. B a t t e r t o n9. Performing Organization Name and AddressN a t i o n a l A e r o n a u t i c s a n d S p a c e A d min i s t r a t i o nLewis Research Cen te rC leve land , Oh io 44135

12. Sponsoring Agency Name and AddressN a t i o n a l A e r o n a u t i c s a n d S p a c e A d min i s t r a t i o nWashington, D.C. 20546

8. Performing Organization Report No.E-2226

10. Work Unit No.

11. Contract or Grant No.

13. Type of Report and Period CoveredTe ch ni ca l Memorandum

14. Sponsoring Agency Code

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19. Security Classif. (of this report)U n c l a s s i f i e d

20. Security Classif. (o f this page) 21 . NO. of Pages 22. Rice'U n c l a s s i f i e d

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NACA TM 83741 Energy Efficient Engine Program Contribution to Aircraft Fuel Conservation

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