JT9D-7A (SP) jet engine performance deterioration trends

NASA Technical Memorandum 81459 JT9D-7A ( S P ) JET ENGINE PERFORMANCE . DETERIORATION TRENDS G . Paul Richter Lewis Research Center Cleveland, Ohio and W. J. Olsson P r a t t & Whitney Aircraft Group 400 Main St.

East Hartford, Connecticut and N. B. Andersen Pan American World Airways J. F. K. International Airport Jamaica, New York Prepared for the International Aircraft Maintenance Engineering Exhibition and Conference sponsored by Hamilton Burr Publishing Company Dallas, Texas, April 8-10, 1980 (HAS&-Ta-81459) JT9D-78 (SP) JET E N G I N E N80-20274 P E R P O B A A I C E D E T E B l O R A ' I I O I T R E N D S ( N A S A ) 24 p HC A02/UP A01 CSCL 21E Unclas G3/07 47617

JT9D-7A (SP) J e t Engine Performance D e t e r i o r a t i o n Trends

G . Paul R i c h t e r -- NASA Lewis Research Center

W. J. Olsson - - P r a t t a n d W h i t n e y A i r c r a f t

N. B. Andersen -- Pan American World Airways

ABSTRACT The c o n t i n u i n g e s c a l a t i o n o f f u e l c o s t s and t h e decreasing a v a i l a b i l i t y o f f u e l s u p p l i e s have l e a d t o an i n c r e a s e i n t h e importance o f m a i n t a i n i n g good s p e c i f i c f u e l consumption over t h e l i f e c y c l e o f j e t engines, A b e t t e r understanding o f t h e trends o f engine d e t e r i o r a t i o n which l e a d t o h i g h e r fuel consumption can be used t o develop technology and apparatus t o minimize such losses. The P r a t t & Whitney JT9D Engine D i a g n o s t i c s Program b e i n g sponsored by t h e N a t i o n a l Aeronautics and Space A d m i n i s t r a t i o n (NASA) Lewis Research Center has t h e o b j e c t i v e s o f i d e n t i f y i n g and q u a n t i f y i n g t h e 1 eve1 s, trends, and causes o f engine performance d e t e r i o r a t i o n .

As p a r t o f t h i s program, a s e r i e s o f i n s t a l l e d engine c a l i b r a t i o n s ( b o t h on-the- ground and i n - f l i g h t ) were performed on b.to new Pan American World Airways 747 SP a i r c r a f t . The performance data gathered covered fnom b e f o r e t h e f i r s t f l i g h t through approximately 1000 f l i g h t c y c l e s and 6900 f l i g h t hours. To accompl i s h t h e c a l i b r a t i o n s a s p e c i a l -i n s t r u m e n t a t i o n system f o r ground t e s t i n g o f i n s t a l l e d engines o v e r a broad power range was used; along w i t h performing c o n c u r r e n t i n - f l i g h t engine c a l i b-ations under revenue ser- v i c e c o n d i t i o n s .

This paper presents a d i s c u s s i o n o f t h i s s p e c i f i c t e s t program and t h e r e s u l t s o f t h e a n a l y s i s o f t h e data, which p r o v i d e a b e t t e r under- s t a n d i n g o f s h o r t and 1 ong term performance d e t e r i o r a t i o n o f both engines and modul es.

INTRODUCTION The r a p i d r i s e i n t h e c o s t o f o i l s i n c e t h e OPEC o i l embargo i n 1973 and t h e d e s i r e t o decrease t h e U n i t e d S t a t e s ' dependency on f o r e i g n s u p p l i e r s f o r f u e l suppl i e s has r e s u l t e d i n a n a t i o n a l e f f o r t t o increase the a v a i l - a b i l i t y o f domestic o i l , develop a1 t e r n a t e sources o f energy, and develop near- and long-term means t o reduce f u e l consumption. To c o u n t e r a c t the ad- verse impact o f t h e world-wide f u e l c r i s i s on t h e a v i a t i o n i n d u s t r y , NASA i s conducting t h e A i r c r a f t Energy E f f i c i e n c y (ACEE) program. Included i n t h i s program a r e major p r o p u l s i o n p r o j e c t s which a r e addressing both near-term and 1 ong- term goal s. The near-term a c t i v i t i e s i n c l ude t h e Engine Component Improvement (ECI) P r o j e c t , which i s d i r e c t e d toward improving t h e f u e l con- sumption o f c u r r e n t h i g h bypass r a t i o t u r b o f a n engines and t h e i r d e r i v a t i v e s by 5 p e r c e n t over t h e . 1 i f e o f these engines. Inasmuch as commercial a i r c r a f t i n t h e f r e e w o r l d a r e u s i n g f u e l a t a r a t e i n excess o f 80 b i l l i o n l i t e r s o f fuel per year, t h i s f i v e p e r c e n t represents s i g n i f i c a n t f u e l cavings. The E C I P r o j e c t has two main p a r t s , Performance Improvement and Engine Diagnos- t i c s . The Perforqance Improvement program, which i s n o t covered herein, i s intended t o i d e n t i f y and e v a l u a t e improved component concepts which a r e tech- n i c a l l y and economically v i a b l e f o r t h e 1980-1 982 t i m e p e r i o d , and then de- velop and demonstrate these concepts through ground and f l i g h t t e s t s . . The Engine Diagnostics program i s d i r e c t e d toward i d e n t i f y i n g and q u a n t i f y i n g engine performance losses t h a t occur d u r i n g s e r v i c e use and t o develop c r i t e r i a f o r m i n i m i z i n g these l o s s e s ,

The f i r s t phase o f t h e engine d i a g n o s t i c p r o j e c t was t h e c o l l e c t i o n , docu- mentation, and a n a l y s i s o f h i s t o r i c a l engine performance and p a r t s usage data.

That e f f o r t was completed i n 1978 and t h e r e s u l t s reported i n NASA CR- 135448

(Reference 1 ) . That study establ ished average JT9D engine performance dete-

r i o r a t i o n causes, and produced p r e l iminary a n a l y t i c a l models o f both engine and module performance d e t e r i o r a t i o n w i t h s e r v i c e usage.

The e f f o r t r e p o r i e d i n t h i s paper was p a r t o f t h e second phase o f t h e engine d i a g n o s t i c p r o j e c t and was d i r e c t e d a t expanding the understanding o f engine d e t e r i o r a t i o n by the c o l l e c t i o n o f performaqce data from a selected sample o f new i n - s e r v i c e JT9D engines, under c l o s e l y monitored c o n d i t i o n s .

This paper presents the r e s u l t s o f these studies concerning a group o f new production engines, conducted d u r i n g the p e r i o d A p r i l 1977 t o January 1979. The source o f l'ata f o r these studies has been Pan American World Airways JT9D-7A SP engines which were i n s t a l l e d on two o f t h e i r 747 SP, a i r c r a f t .

entered s e r v i c e i n May 1977 and June 1978, r e s p e c t i v e l y .

These a i r c r a f t

DATA ACQUISITION SYSTEMS P l us- In-Console (PIC) System Test Data The PIC System was developed and operational l y checked o u t by P r a t t 6 Whitney A i r c r a f t as a quick and accurate system f o r measuring i n s t a l l e d s t a t i c engine performance. The P I C System provided high q u a l i t y data on 15 engine performance parameters. With the exception o f t h r u s t , the P I C sys- tem recorded a l l t e s t data t h a t a r e normally obtained i n an engine t e s t stand.

The engine performance parameters obtained are shown i n Figure 1 . The sys-

tern i s shown schematically i n Figure 2, and consists o f : an engine i n t e r f a c e harness, i n c l u d i n g the necessary e l e c t r i c a l 1 ) .

cables and t u b i n g t o the pressure transducers 2 ) a modified " t r i m mast" t o guide the cables and tubing through the fan stream 3) a temperature-control 1 ed pressure transducer box 4 ) a data recording system 5 ) a portabl e minicomputer f o r reducing the data t o engineering u n i t s , applying standard day corrections, and c a l c u l a t i n g p r e l i m i nary modul e per- formance.

I n preparation f o r these PIC t e s t s , the a i r c r a f t systems and the o u t - I board and inboard engines on the l e f t s i d e ( p o s i t i o n s 1 and 2 r e s p e c t i v e l y ) f o r two Pan American 747(SP) a i r c r a f t (N536PA and N537PA), were equipped w i t h expanded instrumentation.

The f i r s t P I C t e s t s were performed a t the Boeing Commercial Airplane Company, Everett, Washington, p r i o r t o the f i r s t f l i g h t o f each a i r c r a f t , and were conducted i n a Quick Engine Change (QEC) c o n f i g u r a t i o n which i n - cluded the normal f l i g h t i n l e t , n a c e l l e and nozzles. Ten sets o f P I C c a l i - brations were performed on a i r c r a f t N536PA d u r i n g i t s f i r s t 6900 hours and

F i g u r e 3 shows t h e dates, engine age, and l o c a - 1000 c y c l e s o f o p e r a t i o n .

t i o n s f o r t h i s s e r i e s o f t e s t s . Engine S/N Po695745 was removed f o r cause p r i o r t o t h e l a s t PIC t e s t . This engine was r e p a i r e d and r e - I n s t a l l ed on S i x s e t s o f PIC c a l i b r a t i o n s were performed o n a i r - a d i f f e r e n t a i r c r a f t .

c r a f t N537PA. F i g u r e 4 shows t h e comparable data f o r t h i s s e r i e s o f t e s t s .

As can be seen from F i g u r e 3 and 4, these c a l i b r a t i o n s were spaced i n a manner t o e s t a b l i s h engine i n i t i a l f l i g h t performance, s h o r t - , and medium- term f l i g h t performance d e t e r i o r a t i o n trends.

During t h e PIC t e s t i n g , a l l c o r r e c t e d parameters were c a l c u l a t e d by t h e minicomputer, p l o t t e d for data v a l i d a t i o n , and compared w i t h data from t h e p r e v i o u s t e s t . The i n i t i a l PIC t e s t d a t a was compared t o the produc- t i o n acceptance t e s t performance data f o r each engine, as a b a s e l i n e .

Typical data gathered d u r i n g two c o n s e c u t i v e c a l i b r a t i o n s o f engine P-695743 a r e presented i n F i g u r e 5, showing c o r r e c t e d f u e l f l o w as a f u n c t i o n o f engine pressure r a t i o (EPR). Extensive t a b u l a r r e s u l t s o f data were a l s o an o u t p u t o f t h e PIC system.

I n - F l i g h t Performance Cal i b r a t i o n Data I n an e f f o r t t o e s t a b l i s h a r e l a t i o n s h i p between i n s t a l l e d ground and i n - f l i g h t engine performance, a s e r i e s o f i n - f l i g h t c a l i b r a t i o n s were con- ducted o n each o f t h e f o u r engines on a i r c r a f t N536PA and N537PA. These c a l i b r a t i o n s were performed by P A Engineering personnel c o n c u r r e n t l y w i t h t h e PIC t e s t program, o n r e g u l a r revenue 747 SP f l i g h t s , u s i n g normal f l i g h t deck i n s t r u m e n t a t i o n .

C a l i b r a t i o n c o n d i t i o n s were standardized t o t h e e x t e n t p o s s i b l e by con- d u c t i n g them a t steady s t a t e c r u i s e c o n d i t i o n s . F i g u r e 6 shows t h e engine and a i r p l a n e parameters t h a t were recorded a t each i n - f l i g h t c a l i b r a t i o n p o i n t . A c a l i b r a t i o n c o n s i s t e d o f a t l e a s t f o u r complete data p o i n t s e t s where engine pressure r a t i o (EPR) on each engine was v a r i e d between 1 . 2

and 1.5. Constant Mach nurcber ( M ) and a1 ti tude were maintained throughout each c a l l b r a t i o n procedure; and w i t h one o r two exceptions, a1 t i t u d e and M were duplicated f o r a l l f l i g h t c a l i b r a t i o n s . I n addition, a f u e l sample was taken a t the end o f each f l i g h t t o e s t a b l i s h the f u e l heating value.

ANALYSIS OF DATA 81 DISCUSSION O F RESULTS PIC Data

-

The P I C data taken a t sea-level s t a t i c c o n d i t i o n s were immediately corrected t o standard day c o n d i t i o n s u t i l i z i n g t h e p o r t a b l e m i n i ~ o m p u t e r .

Additional c o r r e c t i o n s were subsequently appl i e d t o account f o r v a r i a t i o n s i n f u e l lower heating value and water c o n t e n t o f t h e ambient a i r . An ad- d i t i o n a l c o r r e c t i o n was made t o t h e data taken d u r i n g t h e i n i t i a l c a l i b r a t i o n a t Boeing t o account f o r t h e apparent presence o f , vortex being ingested i n t o the engine. This c o r r e c t e d was based on the analysis o f t h s data f o r a l l f o u r engines i n t h i s program which i n d i c a t e d unl i k e l y improvements i n fan and low-pressure compressor performance bettween t e s t s a t boeing and sub- sequent t e s t s . Boeing requires a1 1 engine ground runs t o be conducted w i t h p r o t e c t i v e screens placed i n f r o n t and p a r t i a l l y t o the sides o f t h e engines t o reduce t h e p o s s i b i l i t y o f f o r e i g n o b j e c t damage t o the engine.

Experience a t P&WA i n d i c a t e d t h a t the presence o f such a device i n r e l a t i v e l y c l o s e p r o x i m i t y t o the engine produced a weak vortex t h a t was ingested by the engine, r e s u l t i n g i n losses i n fan and low-pressure compressor performance.

The performance d e t e r i o r a t i o n f o r each o f t h e four engines, as determined from the P I C t e s t s , was referenced t o the i n i t i a l Production Acceptance Test (PAT) data.

Corrections (based on o t h e r engine t e s t i n g ) were appl i e d t o the PAT data to synthesize t h i s data t o a f l i g h t n a c e l l e t e s t c o n f i g u r a t i o n , thereby e s t a b l i s h i n g each engine's basel i n e performance.

I were then compared t o the base1 i n e t o determine the d i f f e r e n c e s i n engine !

performance. To complete t h e a n a l y s i s of each s e t of data, a performance a n a l y s i s was performed t o assess t h e modular performance losses corresponding t o t h e measured changes i n engine performance.

Each subsequent P I C engine t e s t was compared t o t h e previous t e s t f o r each s p e c i f i c engine, and a f u r t h e r a n a l y s i s o f t h e modular performance losses

F i n a l l y , the

was again made. cumulative modular performance losses were p l o t t e d versus engine f l i g h t c y c l e s t o e s t a b l i s h t h e o v e r a l l performance d e t e r i o r a t i o n trends r e l a t i v e t o t h e r e f e r e n c e base1 ine.

P l o t s o f a l l engine parameters were made f o r each t e s t ( f i g u r e 5 i s a t y p i c a l example). Changes ( d e l t a s ) i n a1 1 parameters were read a t an EPR o f 1.43. F i g u r e 7 presents t h e d e l t a s i n a l l t h e parameters o c c u r i n g between two consecutive c a l i b r a t i o n s , and t h e r e s u l t s o f t h e a n a l y s i s o f t h i s p a r t i c u l a r data set. C a l c u l a t e d parameters have been adjusted t o c o r r e c t any discrepancies i n t h e data caused by EGT p r o f i l e s h i f t s , e t c .

The performance a n a l y s i s of t h e P I C data y i e l d s estimated e f f i c i e n c y and flow c a p a c i t y losses f o r i n d i v i d u a l engine modules. F i g ~ i r e s 8 through 1 2 show t h e estimated module performance losses f o r engines P-695745 and P-695743 ( a i r c r a f t N536PA. p o s i t i o n s 1 and 2, r e s p e c t i v e l y ) and engines P-695760 and Po695763 ( a i r c r a f t N537PA, p o s i t i o n s 1 and 2, r e s p e c t i v e l y ) .

Fan modules (Figure 8 ) o f b o t h a i r c r a f t d e t e r i o r a t e very r a p i d l y a t f i r s t .

' The engines on a i r c r a f t N536PA show a h i g h e r i n i t i a l f a n module l o s s . No marked d i f f e r e n c e between inboard and outboard engines i s noted.

Low-pressure compressor modules (FIqure 9) e x h i b f t a s i m i l a r c h a r a c t e r - i s t i c d e t e r i o r a t i o n t r e n d as t h a t f o r t h e fan, b u t t h e e a r l y performance l o s s i s s l i g h t l y l e s s than i n t h e f a n module. Here again, t h e engines on a i r c r a f t N536PA show a h i g h e r i n i t i a l loss, and t h e r e i s no apparent tnboard/outboard e f f e c t .

The high-pressure compressor modules ( F i g u r e 10) o f engines on a i r c r a f t N537PA e x h i b i t t h e c h a r a c t e r i s t i c d e t e r i o r a t i o n trend, b u t t h e engines a i r - plane N536PA e x h i b i t v e r y 1 i tt l e s h o r t - t e r m high-pressure compressor p e r f o r - As can be seen, no we1 1-defined engine p o s i t i o n e f f e c t i s apparent.

mance l o s s .

The engines of b o t h a i r c r a f t show some i n i t i a l l o s s o f high-pressure t u r b i n e e f f i c i e n c y and flow c a p a c i t y ( F i g u r e 11). No s i g n i f i c a n t d i f f e r e n c e s between a i r c r a f t o r engine p o s i t i o n a r e apparent.

The d e t e r i o r a t i o n of t h e low-pressure t u r b i n e modules ( F i g u r e 1 2 ) i s almost n e g l i g i b l e f o r b o t h a i r c r a f t .

To v a r y i n g degrees, a l l modules except. t h e low-pressure t u r b i n e show t h e same d e t e r i o r a t i o n t r e n d ; performance d e t e r i o r a t e s r a p i d l y f o r t h e f i r s t 50 cycles o r so then l e v e l s o f f and d e t e r i o r a t e s g r a d u a l l y over t h e longer term.

The r a p i d e a r l y 9css i s most l i k e l y t h e r e s u l t o f blade t i p i n t e r f e r e n c e and w e a r i n g - i n o f seals; t h e gradual long-term l o s s i s due t o b l a d e and vane e r o s i o n .

As can be szen from t h e f i g u r e s , d e t e r i o r a t i o n t r e n d s appear t o be d i f f e r e n t f o r t h e two a i r c r a f t . The scope of t h i s t e s t program d i d n o t p e r m i t a s a t i s f a c t o r y understanding o f these d i f f e r e n c e s . Also, t h e c u r r e n t d a t a does n o t suggest any d i f f e r e n c e s i n d e t e r i o r a t i o n trends between inboard and outboard engines.

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,.-- ---71SwTl - -- -IC c - -F-F --Ym-T- - - - -

- - - - .--. - Overall Engine D e t e r i o r a t i o n The influence o f these i n d l v i d u a l module performance !asses cn engine TSFC l o s s a t sea l e v e l s t a t i c conditions versus f l i g h t cycles can be assessed by the use o f engine i n f l u e n c e c o e f f i c i e n t s , The r e s u l t s o f t h i s assessment a r e presented i n Figure 13. The data show a r a p i d l o s s i a TSFC of abort t percent d u r i n g t h e i n i t i a l 50 cycles, and a more gradual long-term l o s s t o abCut 2.2 percent a t 1000 cycles. A usage-oriented breakdown o f each module's c o n t r i b u t i o n t o the TSFC l o s s shown on Figure 13 i s presented on Figure 14 f o r 50, 150, and 500 A t 50 cycles, t h e TSFC l o s s i s dominated by t h e high-pi-essure t u r b i n e cycles.

d e t e r i o r a t i o n w i t h l e s s e r impacts by t h e low-pressure compressor, fan, and high-pressure compressor. A t 500 cycles, the high-pressure t u r b i n e and low- pressure compressor d e t e r i o r a t i o n e f f e c t s a r e dominant and a r e equal i n t t h e i r c o n t r i b u t i o n t o the t o t a l loss; the fan and high-pressure compressor impact I continues t o increase; and t h e impact o f t h e low-pressure t u r b i n e i s p r a c t i c a i l y I

i

n e g l i g i b l e . i

E

Over the s h o r t term, the TSFC losses are n e a r l y e q u a l l y s p l i t between the

i

c o l d section (fan, LPC, HPC) and h o t s e c t i o n (HPT L LPT) as we1 1 as between I I the high-pressure spool and the low-pressure spool. A t 500 cycles, the c o l d s e c t i o n dominates the TSFC losses, and the low-pressure spool e x h i b i t s m r e d e t e r i o r a t i o n than does t h e high-pressure-spool .

S i m i l a r t o the i n f l u e n c e on engine TSFC loss, the i n d i v i d u a l module performance losses can be t r a n s l a t e d i n t o engine E G T d e t e r i o r a t i o n a t sea l e v e l s t a t i c conditioos.

i

a as shown i n Figure 15.

I n - F l i g h t Data Using the data taken d u r i n g the i n - f l i g h t c a l i b r a t i o n s , Figure 16 presents e l g i n e f u e l flow and E G T versus E P R f o r a t y p i c a l c a l i b r a t i o n made on engine P-695738 on a i r p l a n e N536PA. It can be seen t h a t the data are c o n s i s t e n t i n t h a t

very l i t t l e s c a t t e r e x i s t s across t h e range o f power a t which data were r e - corded.

Using the type o f data shown i n f i g u r e 16, t h e change I n E G T and Fuel Flow f o r an EPRof 1.40 a r c shown I n f i g u r e 17 f o r a l l f o u r engines on a i r - plane N536FA. The i r r e g u l a r i t i e s i n the data a r e be1 ieved to be r r c s u l t of instrumentation d r i f t an* non-uniformity i n the amount o f bleed a i r from each engine. An example o f the l a t t e r c h a r a c t e r i s t i c appears t o have occurred between 130 and 370 f l i g h t cycles when engines 3 and 4 showed a s u b s t a n t i a l r i s e i n fuel flow i n EGT w h i l e engines 1 and 2 were showing a corresponding decrease.

Using the average values from a1 1 f o u r engines y i e l d s t h e trends shown i n f i g u r e 18 where changes i n EGT and Fuel Flow a r e shown as a f u n c t i o n o f f l i g h t cycles f o r two airplanes, N536PA and N537PA. These f i g u r e s show a 5 t o IOC r i s e i n EGT and about 0.3 percent r i s e i n Fuel Flow over t h e range o f f l i g h t cycles from 0 t o 700. These type o f data a r e useful f o r i n d i c a t - i n g r e l a t i v e l y l o n g term trends i n performance, b u t because o f the data qua1 i t y , s h o r t term v a r i a t i o n s a r e n o t w e l l defined.

- Av.-- - . & ~ x - - - - - - ~ - ~ ? = = - - CONCLUSIONS The i n - s e r v i ce engine performance d e t e r i o r a t i o n study was the second phase o f the NASA 3190 Diagnostics Program t o be completed. Two performance data acquisi t i o n systems, i n - f l i g h t c a l i b r a t ions and PIC t e s t i n g , were used, Analysis o f these data r e s u l t e d i n a refinement o f p r e l i m i n a r y performance d e t e r i o r a t i o n models

I 1

and has provided a more comprehensive understanding of performance d e t e r l o r a t i o n l e v e l s and trends i n these engines.

I n general, the f l i g h t data was useful i n d e f i n i n g a i r p l a n e average engine performance trends but was the l e a s t r e l i a b l e o f the two data sources i n i d e i ~ t i f y i n g I i n d i v i d u a l engine d e t e r i o r a t i o n trends and l e v e l s . fhe PIC t e s t i n g provided

i

b e t t e r measurement o f i n s t a l l e d ground data on engine and module performance i !

and performance changes, and i n the came time frame as the i n - f l i g h t c a l i b r a t i o n s .

! 1

These PIC data were l i m i t e d t o approximately 1000 f l i g h t cycles, and were there- k i

!

f o r e valuable i n e s t a b l i s h i n g the short-term performance d e t e r i o r a t i o n trends f o r the JT9D-7A SP engine, b u t d i d not provide ( i ~ o r was intended t o provide) a b a s e . f o r

I I !

d e f i n i n g longer term performance d e t e r i o r a t i o n trends.

I

E

, Thus, t o o b t a i n the desired understanding of engine performance d e t e r i o r a t i o n required in-depth analyses of the data systems, knowledge o f t h e i r 1 i m i t a t i o n s , !

I I and f i n a l l y , a comparison of the r e s u l t s w i t h the h i s t o r i c a l data study r e s u l t s , i w i t h the proper judgemental weighting of each.

From these analyses, i t can be I concluded t h a t there are a number of c o n t r i b u t i n g causes o f p e r f [ rmance d e t e r i o r a - t i o n i n the JT90-7A SP engine.

> i Estimation of engine performanct :?ss based on sea l e v e l PIC data Indicates t h a t s i g n i f i c a n t losses occur very early, followed by a more gradual l o s s over the longer term. A TSFC loss of about 1.0 percent occurs w i t h i n the f i r s t 50 cycles,

i

I increasing to about 2.2 percent by 1000 cycles.

!

The TSFC l o s s t n the f i r s t 50 cycles i s dominated b y low-pressutuc compressor and hfgh-pressure t u r b i n e d e t e r i o r a t l o n w i t h s m ~ l l e r , b u t s i g i ~ i f i c a n t contributions from the f a n and high-pressure comressor. Over t h i s short term, TSFC losses are * n e a r l y e q u a l l y s p l i t between the hot and c o l d sections and between the high- and low-pressure spools. No s i g n i f i c a n t d i f f e r e n c e i n engine a e t e r i o r a t i o n trends due t o wing p o s i t i o n i s apparent from the data obtalned.

I n - f l i g h t c a l i b r a t i o n data proved t o be o f l i m i t e d value i n e v a l u a t i n g i n d i v i d u a l engine deter f o r a t i o n . These d c t a were obtained frm a i r c r a f t s t a r t i n g a t about 20 cycles, aqd t h e r e f o r e do n o t provide any i n f o m a t i o n about very s h o r t - term engine d e t e r i o r a t i o n . Nor can any conclusions be d r ~ w n concerning I n d l v i d u c l engine d e t e r i o r a t i o n trends over the long term because o f appreciable s c a t t e r i n tnesr data.

I

D e t e r i o r a t i o n averaging f o r the four engines on an a l r p l a n e eliminates a

I

considerable amount o f s c a t t e r , suggesting t h a t a i r p l a n e systems misy be i n f l u e n c i n g i n d i v i d u a l engine trends. Thus, the usefulness o f i n - f l i g h t c a l i b r a t i o n data i s l i m i t e d t o i n d i c a t i n g gross average d e t e r i o r a t i o n trends.

RWWWCE 1 . Sallee, O . P . : Report on Performance Deterioration Baaed on Existing b (historical) data. NASA CR-135448, 1980.

I

NASA N a t i o n a l Aeronautics and Space A d m i n i s t r a t i o n P A Pan American Worl d Airways P&WA P r a t t & Whitney A i r c r a f t SYMBOLS & ACRONYMS A G W A i r c r a f t gross weight

EGT Exhaust Gas Temperature ( O C ) - measured a t HPT discharge

EPR Engine Pressure R a t i o F O D Foreign O b j e c t Damage HPC High-pressure Compressor HPT High-pressure Turbine LPC Low-pressure Compressor L PT Low-pressure Turbine M Mach Number N Rotor Speed Gage Pressure (I b / i n 2 ) ( s i g ) P

P P

Absolute Pressure ( l b / i n ) ( p s i a ) PIC Pl ug- In-Consol e Q u i c k Engine Change QEC SLS Sea Level S t a t i c Special Performance (SP) t Temperature (OF) (%) T Absol u t e Temperature (OR) (OK) TS F C Thrust Speci f i c Fuel Consumption ( I b/hr-1 b) W Mas; Flow ( I bm/sec)(l bm/hr. ) B Vane Angl e (degrees) a Change SUBSCRIPTS Undisturbed i n 1 e t (pressures and temperatures) 1 Low-pressure r o t o r ( r o t o r speeds) Fan i n l e t (pressures and temperatures) 2 High-pressure r o t o r ( r o t o r speeds) 2.4 Fan blade discharge 2.6 Fan e x i t guide vane discharge 3 LPC discharge 4 HPC discharge 5 HPT i n l e t 6 HPT discharge 7 LPT discharge a m Ambient avg Average f Fuel i nd I n d i v i d u a l s S t a t i c t s t a g n a t i o n ( t o t a l ) 13

TEMPERATURES PRESSURES O M t~ M PAM N1 tt3 p s 3 N2 114 "l3 FUEL FLOW

tb - avg

P ~ 4 VANE ANGLE

tb - ind(6)

P S S ~

$7 - " ! I

Pl7

tt7 - indl61

--

TOTALS 5 15 DATA PARAMETERS

Figure 1. - Engine performance parameters obtained

d u r i n g P I C testing.

OUTPUT: *OBSERVED DATA CORRECTED TO SEA LEVEL STATIC STP.NDARD DAY *CHANCES RELATIVE TO BASELINE PERFORMANCE

I/ TUBES. WIRES

CABLE . ' TRANSDJCER BOX-" Figure 2. - Schematic of PIC system.

DATE ENGINE HOURS CYCLES TEST LOCATION

- ---

4-2l-77 743. 745 0 0 BMING, SEATTLE 5.09-77 743, 745 18 11 JFK, N. f, 5-16-77 743, "45 110 19 JFK, N.Y.

5-19-77 743, 745 155 23 JFK, N.Y.

6-20-77 743. 745 614 91 JFK. N.Y.

7-18-77 743, 745 1021 133 JFK. N.Y.

11-02-77 743 lOBl 141 SF0 11-02-77 745 2686 365 SF0 2-11-78 743 2473 3 6 0 JFK. N.Y.

2-11-78 745 3878 584 JFK, N.Y.

4-18-78 743 3415 475 SF0 4-18-78 745 4820 700 SF0 12-04-78 743 6903 1078 U X Figure 3. - Chronology of PIC testing on aircraft N536PA, engines P-695743 and P-695745.

DATE HOURS CYCLES TEST LOCATION

- -

5-04-78 0 0 TBC 6-07-78 52 15 TBC 6-27-78 297 54 SF0 7-20-78 609 110 LAX 11-05-78 2 2 4 331 JFK, Y. Y.

1 4 - 7 9 3165 510 SF0

Figure 4. - Chronolqy ol PIC testing on aircraft

N537PA. engines P-695760 and P-695763.

475 cycles 0 6909 hr.

EkGINE PRESSURE RATIO,

Figure 5. - Typical data acquired on

two consecutive PIC performance checks, corrected fuel flow as a function d engine pressure ratio.

PARAMETER n

PRESSURE ALTllUDE Pam INLET AIR TOTAL TEMPERATURE INLET AIR STATIC TEMPERATURE M A C H NUMBER LOW-PRESSURE ROTOR SPEED N 1 HtGH-PRESSURE ROTOR SPEED HICH-PRESSURE TURBINE EXHAUST GAS TEMPERATURE FUEL FLOW wf EPR ENGINE PRESSURE RATIO

----

NUMBER OF AIR-CONDITICNING PACKS IN USE AGW AIRCRAFT GROSS WEIGHT

F i g u r e 6. - Performance parameters obtained d u r i n g i n - f l i g h t

calibrations.

MEASURED PARAMETER CHANGE I N ACJUSTED MEASURED CHANGE I N PARAMETER PARAMETER

LOW-PRESSURE ROTOR SPEED to. 21% 9 . 2 3 %

HIGH-PRESSURE ROTOR SPEED 9.29% 9. .B% H P C DISCHARGE TOTAL TEMPERATURE t 1 . 0 OR *20 OR HPT DISCHARGE TOTAL TEMPERATURE t z 8 OR t n OR LPT DISCHARGE TOTAL TEMPERATURE +11 O R + I 7 OR +I. 44% t 1 . 4 3 P ~ l Pt2 -0.65% -0.67% F d Z i R flow -0.41% -0.63%

FUEL FLOW t 1 . 0 7 k a. 99%

ANALYZED MODULE PARAMETER CHANGES: FAN EFFICIENCY 4 . 8 0 pts.

FAN FLOW CAPACITY -0.501 LOW-PRESSURE COMPRESSOR EFFICIENCY -0.65 p t ~ .

LOW-PRESSURE COMPRESSOR FLOW CAPACITY - 0 . 0 HIGH-PRESSURE COMPRESSOR EFFICIENCY -0.60 pts.

HIGH-PRESSURE COMPRESSOR FLOW CAPACITY -0.45% HIGH-PRESSURE TURBINE EFFICIENCY -0.4) pts.

HIGH-PRESSURE TURBINE FLOW CAPACITY 9.41% LOW-PRESSURE TURBINE EFFICIENCY 0. pts.

LOW-PRESSURE TURBINE FLOW CAPACITY 0. % F i g u r e 7. - Gas generator a n a l y s i s of P I C c a l i b r a t i o n data f o r e n g i n e P-695743.

N536PA

0 P-695745, ws. 1

P-695743, POS. 2 N537 PA A P-695760, POS. 1 0 P-695163, POS. 2

1 loo 200---m um UK: rn 770 0 800 1 m 1100

ENGINE FLIGHT CYCLES Figure 8. - Fan module performance deterioration.

0 P-695745. WS. 1 0 P-695743, POS. 2 N537 PA A P-695760. POS. 1 0 P-695763: POS. 2 Figure 9. - Low-pressure compressor performance deterioration.

N536 PA 0 P-69578. POS. 1 0 P-695743. POS. 2 N537 PA

a ~-695760. WS. 1

0 P-695763. POS. 2 U -1.0 -2 0 ENGINE FLIGHT CYCLES

Figure 10. - High-pressure compressor performance deteriora-

tion.

0 P-695745. POS. 1 P-695743. POS. 2 A P-695760, POS. 1 0 P-695763. POS. 2

a : -2.0 l , I I I I , , I ' U

1 100 am 300 410 500 600 700 800 900 1 m 1 1 0 0

ENGINE FLIGHT CYCLES Figure 11. - High-pressure turbine performance deterioration.

0 P-69576, POS. 1 0 P-695743, POS. 2 A P-695760, 0,s. 1 0 P-695763, POS. 2 Figure 1 2 - Low-pressure turbine performance deterioration.

N536PA 0 P-695745, POS. 1 0 P-695743, POS. 2 N537P A A P-695760, PDS. 1 0 P-695763, POS. 2

1 100 zm ~o ax, xu rn 700 sm ~ o o i a a o l ~ m

ENGINE FLIGHT CYCLES Figure 13. - Estimated sea level static TSFC deterioration.

MOOULEICOMPONENT CHANGE IN TSFC, % 50 CYCLES 1% CYCLES 500 CYCLES 0. K) FAN 0. a 0.25 .60 LOW-PRESSURE COMPRESSOR .a .a .K) HIGH-PRESSURE COMPRESSOR .10 .P

. % .a

HIGH-PRCSSURE TURBINE .O 1 5

.m

LOW-PRISSURE TURBINE O - -

I TOTAL

HICH-PRESSURE SWOL LOW-PRESSURE SPOOL deltrioralion.

N S M PA 0 P d 9 5 7 6 . WS. 1 0 P-695743, POS. 2 W37 PA A P-695760. WS. 1

0 P-bPS763, POS. 2 -

; 10

- 10

ENGINE FLIGHT CYCLES Figure 15. - Estimated sea l w e l static EGT deterioration.

i r m l I I i l I 1 1

1.22 1.30 1.36 1.46 1.26 1.34 1.42 1.50 ENGINE PRESSURE RATK)

Figure 16. - In-flight calibration d JTPD-

7A(SPJ engine P-695736 on airplane N536PA; fuel flow and ECT.

N536PA 0 fJ695745, POS 1 0 P695743, POS 2 0 W957QQ. POS 3 A W 9 5 ' 3 a POS 4 U + 0 W a -lC -3 0 l l l l l l l , 100 mmd00500600700 FLIGHT CYCLES

Figure 17. - Change in fuel flow and EGT

versus usage for airplane NSMPA.

---

10 * 3 l Y

/--== --.--

c O F -

W a 2 .1.0 1 1 1 1 j j 0 1 0 0 2 0 0 X r ) 4 1 0 5 0 0 6 0 0 ? 0 0 FLIGHT CYCLES Figure 18. - Comparison d airplane lour- engine werages d A luel flow and A EGT determined by in-llight calibrations.