Document
NASA Technical Memorandum 100952
AIAA-88-3025
II
Hot Gas Ingestion Testing of an Advanced
STOVL Concept in the NASA Lewis
9- by 15-Foot Low Speed Wind Tunnel
With Flow Visualization
189-15078 (bASA-TB-lGQ952) HOT G A S I N C L S I I G Y TESTING C E Aabl A D V A I C L L STGYL CCNCEPI 3 E 1 'IBE N A S A Y l T B PLOY V I S U A L I Z A I I C N ( N A Z A ) 27 p Uaclas LEYIS 9- B Y I S - P O C T LCIY SPEEI; E X I C TUNNEL CSCL 01A 63/02 0179881
moert L. Johns
Lewis Research Center
Cleveland, Ohio
and
Joseph D. Flood, Thomas W. Strock, and Kurt C. Amuedo
McDonnell Douglas Corporation
St. Louis, Missouri
Prepared for the
24th Joint Propulsion Conference
cosponsored by the AIAA, ASME, SAE, and ASEE
Boston, Massachusetts, July 11-13, 1988
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HOT GAS I N G E S T I O N T E S T I N G OF A N ADVANCED STOVL CONCEPT I N THE NASA LEWIS 9- BY 15-FOOT L O W SPEED WIND TUNNEL W I T H FLOW VISUALIZATION A 1 b e r t L . Johns N a t i o n a l A e r o n a u t i c s and Space A d m i n i s t r a t i o n Y Lewis Research C e n t e r C l e v e l a n d , O h i o 44135 and
i -
Joseph D . f l o o d , Thomas W . S t r o c k , and K u r t C . Amuedo M c D o n n e l l A i r c r a f t Company M c D o n n e l l D o u g l a s C o r p o r a t i o n S t . L o u i s , M i s s o u r i 63166 SUMMARY Advanced S h o r t T a k e o f f i v e r t i c a l L a n d i n g (STOVL) a i r c r a f t c a p a b l e o f o p e r - a t i n g from r e m o t e s i t e s , damaged r u n w a y s , and s m a l l a i r c a p a b l e s h i p s a r e b e i n g p u r s u e d f o r d e p l o y m e n t a r o u n d t h e t u r n o f t h e c e n t u r y . To a c h i e v e t h i s g o a l , i t i s i m p o r t a n t t h a t t h e t e c h n o l o g i e s c r i t i c a l t o t h i s u n i q u e c l a s s o f a i r c r a f t be d e v e l o p e d . R e c o g n i z i n g t h i s need, NASA L e w i s R e s e a r c h C e n t e r , M c D o n n e l l D o u g l a s A i r c r a f t , and DARPA d e f i n e d a c o o p e r a t i v e p r o g r a m f o r t e s t i n g i n t h e NASA L e w i s 9- b y 15-Foot Low Speed Wind Tunnel (LSWT) t o e s t a b l i s h a d a t a b a s e f o r h o t gas i n g e s t i o n , one o f t h e t e c h n o l o g i e s c r i t i c a l t o STOVL.
T h i s p a p e r w i l l p r e s e n t r e s u l t s from a t e s t p r o g r a m a l o n g w i t h a d i s c u s - s i o n o f t h e f a c i l i t y m o d i f i c a t i o n s a l l o w i n g t h i s t y p e o f t e s t i n g a t model s c a l e . These m o d i f i c a t i o n s t o t h e t u n n e l i n c l u d e a n o v e l g r o u n d p l a n e , an e l a b o r a t e model s u p p o r t w h i c h i n c l u d e d 4" of freedom, h e a t e d h i g h p r e s s u r e a i r for n o z z l e flow, a s u c t i o n s y s t e m e x h a u s t for i n l e t flow, and t u n n e l s i d e w a l l m o d i f i c a t i o n s . S e v e r a l flow v i s u a l i z a t i o n t e c h n i q u e s were employed i n c l u d i n g w a t e r m i s t i n t h e n o z z l e flows and t u f t s on t h e g r o u n d p l a n e . Headwind ( f r e e - s t r e a m ) v e l o c i t y was v a r i e d from 8 t o 2 3 k n .
I N T R O D U C T I O N S u p e r s o n i c Advanced S h o r t T a k e o f f i v e r t i c a l L a n d i n g a i r c r a f t c a p a b l e o f o p e r a t i n g from r e m o t e s i t e s , damaged r u n w a y s , and s h i p s ( f i g . 1 ) a r e b e i n g p u r - sued for d e p l o y m e n t a r o u n d t h e t u r n o f t h e c e n t u r y . To a c h i e v e t h i s g o a l , i t i s i m p o r t a n t t h a t t h e t e c h n o l o g i e s c r i t i c a l t o t h i s u n i q u e c l a s s o f a i r c r a f t be d e v e l o p e d . S e v e r a l o f t h e Advanced S h o r t T a k e o f f / V e r t i c a l L a n d i n g c o n c e p t s have t h e p r o b l e m o f h o t gas i n g e s t i o n ( d u r i n g v e r t i c a l f l i g h t o p e r a t i o n w h i l e .
i n g r o u n d e f f e c t ) as a k e y d e v e l o p m e n t i s s u e .
I n g e n e r a l , S h o r t T a k e o f f I V e r t i c a l L a n d i n g a i r c r a f t o p e r a t i o n n e a r t h e g r o u n d can be s u b j e c t t o s i g n i f i c a n t t h r u s t l o s s e s due t o t h e i n g e s t i o n o f h o t e x h a u s t gases and i n d u c e d j e t l a i r f r a m e i t e r a t i o n s ( r e f s . 1 and 2 ) . These i n t e r a c t i o n s o c c u r between t h e l i f t j e t s , e n t r a i n e d flow o v e r t h e a i r c r a f t s u r - f a c e s and a l o n g t h e g r o u n d , and a m b i e n t w i n d s ( f i g . 2 ) . I n t h e d e v e l o p m e n t o f e f f i c i e n t S h o r t T a k e o f f l V e r t i c a l L a n d i n g a i r c r a f t , i t i s e s s e n t i a l t o m i n i m i z e l o s s e s caused b y g r o u n d e f f e c t s t o p r e v e n t c o m p r o m i s i n g t h e p e r f o r m a n c e and o v e r a l l m i s s i o n o f t h e a i r c r a f t . T h e r e f o r e , t h o s e f a c t o r s w h i c h s u b s t a n t i a l l y a f f e c t h o t gas i n g e s t i o n and i n d u c e d l i f t must be i d e n t i f i e d and a comprehen- s i v e d a t a b a s e m u s t be e s t a b l i s h e d t o g u i d e t h e d e s i g n o f advanced s h o r t t a k e o f f i v e r t i c a l l a n d i n g a i r c r a f t . P e r f o r m i n g t h i s t y p e o f r e s e a r c h a t f u l l s c a l e , where i t has c l a s s i c a l l y been d o n e , i s d i f f i c u l t and e x p e n s i v e . A w i n d t u n n e l c a p a b i l i t y i s t h e r e f o r e b o t h d e s i r e d and r e q u i r e d . Hot gas t e s t i n g a t model s c a l e has been a t t e m p t e d p r e v i o u s l y i n a w i n d t u n n e l ( r e f . 1 ) b u t some- t i m e s w i t h l e s s t h a n s a t i s f a c t o r y r e s u l t s . Tunnel w a l l i n t e r f e r e n c e , p r e - m a t u r e model and t u n n e l h e a t i n g , and t e m p e r a t u r e s c a l i n g p r o b l e m s a l l have i n f l u e n c e d t h e r e s u l t s . Knowing t h e s e p a s t s h o r t c o m i n g s NASA L e w i s R e s e a r c h DARPA d e f i n e d a c o o p e r a t i v e p r o g r a m C e n t e r , M c D o n n e l l D o u g l a s A i r c r a f t , and f o r t e s t i n g i n t h e NASA L e w i s 9- b y 1 5 - F o o t Low Speed Wind Tunnel (LSWT) t o d e v e l o p a new model t e s t i n g t e c h n i q u e and e s t a b l i s h a r e q u i r e d d a t a b a s e f o r h o t gas i n g e s t i o n f o r advanced STOVL. T h i s p a p e r w i l l p r e s e n t r e s u l t s from t h i s t e s t p r o g r a m a l o n g w i t h a d i s c u s s i o n o f t h e f a c i l i t y m o d i f i c a t i o n s a l l o w - i n g a s u c c e s s f u l c o m p l e t i o n o f t h i s t y p e t e s t i n g a t model s c a l e . These m o d i f i - c a t i o n s t o t h e t u n n e l i n c l u d e a n o v e l g r o u n d p l a n e , an e l a b o r a t e model s u p p o r t w h i c h i n c l u d e d 4" o f f r e e d o m , h e a t e d h i g h p r e s s u r e a i r f o r n o z z l e flow, a suc- t i o n s y s t e m f o r i n l e t f l o w , and t u n n e l s i d e w a l l m o d i f i c a t i o n s . S e v e r a l f l o w v i s u a l i z a t i o n t e c h n i q u e s were employed i n c l u d i n g w a t e r m i s t i n t h e n o z z l e flows and t u f t s o n t h e g r o u n d p l a n e .
F A C I L I T Y The t e s t s were c o n d u c t e d i n t h e NASA L e w i s 9- b y 1 5 - F o o t LSWT w h i c h i s l o c a t e d i n t h e r e t u r n l e g o f t h e 8- b y 6 - F o o t S u p e r s o n i c Wind T u n n e l ( f i g . 3 ) .
Some t e s t s were c o n d u c t e d a t h e a d w i n d v e l o c i t i e s from 30 t o 9 0 k n . These v e l o c i t i e s were o b t a i n e d u s i n g t h e c o m p r e s s o r and b y s l i d i n g d o o r s 1 and 2 from f u l l o p e n t o f u l l c l o s e d . The m a j o r i t y o f t h e t e s t s were c o n d u c t e d from 8 t o 2 3 k n . These l o w e r v e l o c i t i e s were o b t a i n e d u s i n g t h e b l o w e r s l o c a t e d i n t h e d r y e r b u i l d i n g and b y c h a n g i n g t h e o p e n i n g o f d o o r s 4 and 5 . D u r i n g t h e f o r e - g o i n g o p e r a t i o n , d o o r s 1 and 2 r e m a i n c l o s e d .
MODEL AND CONFIGURATIONS The model shown i n f i g u r e 4 i s a 9 . 2 p e r c e n t s c a l e model o f t h e M C A I R 2 7 9 - 3 C c o n c e p t . The model i s b a s i c a l l y made up o f t h r e e m a i n s e c t i o n s ; t h e ~ f o r w a r d , c e n t e r , and a f t f u s e l a g e .
F o r w a r d F u s e l a g e The f o r w a r d f u s e l a g e s e c t i o n c o n s i s t s o f t h e nose c o n e , t h e i n l e t s ( b o t h m a i n and a u x i l i a r y ) , nose g e a r , c a n a r d s , canopy, and c o m p r e s s o r f a c e r a k e I a s s e m b l y . D e t a i l s o f t h e c o m p r e s s o r r a k e a r e shown i n f i g u r e 4 ( b > . The com- p r e s s o r f a c e r a k e i n s t r u m e n t a t i o n l o c a t i o n s a r e shown i n t a b l e I.
I 2
C e n t e r F u s e l a g e The c e n t e r f u s e l a g e s e c t i o n c o n s i s t s o f b o t h f o r w a r d and a f t n o z z l e s and the r e l a t e d p l e n u m s , t h e i n l e t s u c t i o n d u c t , t h e m a i n l a n d i n g g e a r , and t h e l i f t improvement d e v i c e s ( L I D S ) (when so i n s t a l l e d ) ( f i g . 5 ) .
The L I D S c o n s i s t o f a f o r w a r d f e n c e , s i d e w a l l s , and l o n g i t u d i n a l s t r a k e s l o c a t e d a r o u n d t h e n o z z l e s p e r i m e t e r ( f i g . 5 ) .
A f t F u s e l a g e The a f t f u s e age c o n s i s t s o f a c o v e r and ower b o d y .
C o n f i g u r a t i o n F i g u r e 6 ( a ) shows t h e f r o n t v i e w o f t h e f o r w a r d n o z z l e s . I n t h i s p l a n e , t h e n o z z l e s can be r o t a t e d i n b o a r d t o form a n e g a t i v e s p l a y a n g l e (from t h e s t r a i g h t down p o s i t i o n , 0" s p l a y ) . The a f t n o z z l e s were a l w a y s a t 0" s p l a y .
From t h e s i d e v i e w ( f i g . 6 ( b > ) , t h e n o z z l e s ( f o r w a r d and a f t ) can be r o t a t e d from 0" ( f u l l a f t ) t o 100" ( n o z z l e s a r e p o i n t e d s l i g h t l y f o r w a r d ) . The a n g l e c r e a t e d i n t h e s i d e v i e w i s r e f e r r e d t o as v e c t o r a n g l e .
MODEL-SUPPORT SYSTEMS - INSTRUMENTATION A v i e w o f t h e model i n t h e t e s t s e c t i o n i s shown i n f i g u r e 7 . Also shown a r e t h e model s u p p o r t s y s t e m , w h i c h i n c l u d e s t h e h i g h p r e s s u r e hot (500" F ) a i r t o p r o v i d e i n l e t a i r f l o w , and t h e g r o u n d p l a n e w i t h t h e l i n e s ; a s u c t i o n l i n e The model h e i g h t was v a r i e d b y c h a n g i n g t h e number o f s l i d i n g t r a p d o o r o p e n .
s p a c e r s between t h e u p p e r and l o w e r f l a n g e s and a d j u s t i n g t h e j a c k s c r e w s .
The h i g h p r e s s u r e a i r l i n e s p r o v i d e d t h e a i r flow f o r t h e model n o z z l e s .
The s u c t i o n d u c t a l s o p r o v i d e d s u p p o r t f o r t h e h o t a i r and i n s t r u m e n t a t i o n l i n e s . P i t c h , r o l l , and yaw were a d j u s t e d b y c h a n g i n g t h e p o s i t i o n o f t h e b a l l j o i n t , l o c a t e d below t h e lower f l a n g e .
Ground P l a n e A s seen i n t h e p h o t o g r a p h o f f i g u r e 7 and shown i n t h e s c h e m a t i c o f f i g - u r e 8 , an e l e v a t e d g r o u n d p l a n e was i n s t a l l e d i n t h e t e s t s e c t i o n w h i c h i n c o r - p o r a t e d a u n i q u e t r a p d o o r f e a t u r e . The g r o u n d p l a n e was i n s t a l l e d 18 i n .
above t h e t e s t s e c t i o n f l o o r . T h i s k e p t t h e h o t a i r f l o w o f f t h e t u n n e l f l o o r and a l l o w e d i n s t r u m e n t a t i o n f o r p r e s s u r e and t e m p e r a . t u r e measurement o n t h e g r o u n d p l a n e .
T u f t s were p l a c e d o n t h e g r o u n d p l a n e ( f i g . 7 > , f o r flow v i s u a l i z a t i o n .
Ground p l a n e i n s t r u m e n t a t i o n l o c a t i o n s a r e g i v e n i n t a b l e 11.
T r a p Door S c a v e n g i n g S y s t e m A t r a p d o o r s c a v e n g i n g s y s t e m was i n s t a l l e d t o p r e v e n t t h e model s u r f a c e s a n d g r o u n d p l a n e from a r t i f i c i a l l y h e a t i n g w h i l e t h e n o z z l e s t e m p e r a t u r e and p r e s s u r e c o n d i t i o n s were b e i n g s e t between d a t a p o i n t s . The u n i q u e t r a p d o o r s y s t e m c o n s i s t s o f t h r e e m a i n components: s l i d i n g t r a p d o o r ( f i g . 8 > , d u c t i n g , and e j e c t o r s ( f i g . 9 ) . Model n o z z l e flow was s u c k e d t h r o u g h t h e t r a p d o o r o p e n i n g , down t h e d u c t u n d e r t h e g r o u n d p l a n e ; and e x h a u s t e d d o w n s t r e a m o f t h e t e s t s e c t i o n b y t h e e j e c t o r s ( f i g . 9 ) . When a d a t a p o i n t was t a k e n , t h e t r a p d o o r was c l o s e d and t h e e j e c t o r s were a u t o m a t i c a l l y s h u t o f f . A f t e r t a k i n g t h e d a t a p o i n t , t h e t r a p d o o r was opened and t h e e j e c t o r s were a u t o m a t i c a l l y t u r n e d o n . The t r a p d o o r was p n e u m a t i c a l l y a c t u a t e d , and i t c l o s e d i n a p p r o x i m a t e l y 0.5 s e c .
S i d e w a l l B l e e d S y s t e m A s i d e w a l l b l e e d s y s t e m p r e v e n t e d t h e h o t a i r f l o w o f t h e n o z z l e s from r e c i r c u l a t i n g i n t h e t e s t s e c t i o n . Two rows o f a c o u s t i c p a n e l s were removed from each s i d e w a l l a t t h e g r o u n d p l a n e h e i g h t a l o n g t h e l e n g t h o f t h e t e s t sec- t i o n ( f i g . 1 0 ) . T h i s a l l o w e d t h e g r o u n d a i r f l o w m o v i n g t o t h e s i d e w a l l s t o f l o w out o f t h e t e s t s e c t i o n i n t o t h e s u r r o u n d i n g c a v i t y as shown i n f i g u r e 10.
Water I n j e c t i o n S y s t e m i n j e c t i o n s y s t e m was used t o c o n d u c t f l o w v i s u a l i z a t i o n t e s t i n g .
A w a t e r Water was i n j e c t e d i n t o u n h e a t e d n o z z l e flow where i t was a t o m i z e d . P o r o u s p l a t e s l o c a t e d i n t h e n o z z l e a i r s u p p l y l i n e s h e l p e d t o a t o m i z e t h e flow.
W h i t e l i g h t i l l u m i n a t i o n was used t o a l l o w t h e f l o w f i e l d t o be v i s u a l i z e d . A s i m p l i f i e d s c h e m a t i c o f t h e w a t e r i n j e c t i o n s y s t e m i s shown i n f i g u r e 1 1 .
I n s t r u m e n t a t i o n A p r o p e l l e r anemometer was u s e d t o measure a i r f l o w v e l o c i t y i n t h e t e s t s e c t i o n as shown i n f i g u r e 1 2 . The p r o p e l l e r anemometer i s c a p a b l e o f measur- i n g h e a d w i n d v e l o c i t i e s from 1 t o 98 k n . The p r o p e l l e r m e a s u r i n g a c c u r a c y was i0.6 k n .
The t u n n e l r e f e r e n c e t e m p e r a t u r e , a g a i n s t w h i c h a l l t e m p e r a t u r e r i s e s were computed, was measured i m m e d i a t e l y u p s t r e a m of t h e t e s t s e c t i o n ( i n t h e v i c i n i t y o f d o o r 3 ( f i g . 3 ) ) . Two i r o n l c o n s t a n t a n (I/C> t h e r m o c o u p l e s , one o n e a c h w a l l of t h e t u n n e l , were u s e d t o measure t h e f r e e s t r e a m t e m p e r a t u r e and were a v e r a g e d t o compute t h e r e f e r e n c e t e m p e r a t u r e .
Seven 20 ft s t r i p s o f 10 t h e r m o c o u p l e s were mounted w i t h i n t h e t e s t sec- t i o n ( f i g . 1 3 ) . One s t r i p had I/C's and t h e o t h e r s were c h r o m e / a l u m e l ( C / A > t h e r m o c o u p l e s . These s t r i p s measured t h e h e a t i n g i n t h e t e s t s e c t i o n . Two s t r i p s were p l a c e d o n e a c h s i d e w a l l and t h r e e s t r i p s i n t h e c e i l i n g . The c e i l - i n g a l s o c o n t a i n e d a 8 . 5 f t s t r i p o f s t a t i c p r e s s u r e i n s t r u m e n t a t i o n s f o r o b t a i n ng s t a t i c measurements. D e t a i l s o f t h e t h e r m o c o u p l e s and p r e s s u r e s t r i p s a r e shown I n f i g u r e 1 4 .
The g r o u n d p l a n e and t r a p d o o r t h e r m o c o u p l e s measured a i r t e m p e r a t u r e .
P r e s s u r e t a p s were l o c a t e d o n b o t h t h e g r o u n d p l a n e and t r a p d o o r .
The g r o u n d p l a n e c o o r d i n a t e s y s t e m i n r e f e r e n c e t o t h e model i s shown i n f i g u r e 1 5 .
The NASA L e w i s ESCORT I11 d a t a s y s t e m was u s e d f o r d a t a a c q u i s i t i o n . T h i s s y s t e m has a scan u p d a t e r a t e e v e r y second w h i c h i n c l u d e s a l l d a t a r e d u c t i o n c o m p u t a t i o n s and f a c i l i t y and model measurements. The e l e c t r o n i c a l l y scanned p r e s s u r e s y s t e m ( E S P ) c o n s i s t s o f f o u r t e e n m o d u l e s , each o f w h i c h c o n t a i n e d 32 i n d i v i d u a l t r a n s d u c e r s . T h r e e r a n g e s o f t r a n s d u c e r s were u s e d : ( 1 ) k5 p s i d w i t h an a c c u r a c y of k0.007 p s i , ( 2 ) i 1 5 p s i d w i t h an a c c u r a c y o f k0.02 p s i , (3) +250 p s i d w i t h an a c c u r a c y o f k 0 . 1 7 p s i .
T E S T PROCEDURE A l l t e s t r u n s were c o n d u c t e d a t s t e a d y s t a t e c o n d i t i o n s w i t h t h e model c o n f i g u r a t i o n and a t t i t u d e f i x e d . The model c o n f i g u r a t i o n and a t t i t u d e ( p i t c h , yaw, r o l l , and h e i g h t ) were s e t m a n u a l l y . A s s t a t e d e a r l i e r , most o f t h e t e s t was c o n d u c t e d from 8 t o 23 k n . T h i s i s t h e h e a d w i n d v e l o c i t y r a n g e f o r v e r t i - c a l l a n d i n g . I n g e n e r a l , t h e f o l l o w i n g d e p i c t s a t y p i c a l t e s t r u n : ( 1 ) A p r e t e s t t a r e r e a d i n g was t a k e n t o v e r i f y i n s t r u m e n t a t i o n o p e r a t i o n .
( 2 ) The t r a p d o o r - e j e c t o r s y s t e m was a c t i v a t e d ( t r a p d o o r open and e j e c - tors r u n n i n g ) .
(3) The i n l e t s u c t i o n f ow was s e t t o t h e maximum c o m p r e s s o r f a c e Mach number.
( 4 ) The n o z z l e a i r supp y s y s t e m was a c t i v a t e d and e a c h n o z z l e was s e t t o a n o z z l e p r e s s u r e r a t i o of a p r o x i m a t e l y 4.0 t o h e a t t h e m o d e l .
(5) The n a t u r a l gas h e a t e r was b r o u g h t up t o maximum t e m p e r a t u r e a t t h e n o z z l e s p l e n u m ( 9 6 0 " R ) .
( 6 ) A f t e r r e a c h i n g t h e d e s i r e d n o z z l e t e m p e r a t u r e , t h e i n l e t s u c t i o n f l o w , n o z z l e p r e s s u r e r a t i o s and t e m p e r a t u r e w e r e s e t t o a t e s t c o n d i t i o n .
The d e s i r e d h e a d w i n d v e l o c i t y was s e t and a r e f e r e n c e d a t a p o i n t was t a k e n w i t h t h e t r a p d o o r o p e n .
(7) The t r a p d o o r was t h e n c l o s e d and t h e i n l e t t e m p e r a t u r e r i s e v e r s u s t i m e was m o n i t o r e d on a s c r o l l i n g v i d e o p l o t t o e s t a b l i s h s t e a d y s t a t e c o n d i - t i o n . A t s t e a d y s t a t e c o n d i t i o n d a t a a r e t a k e n . I t can t a k e 15 t o 45 sec t o r e a c h s t e a d y s t a t e c o n d i t i o n s a t t h e c o m p r e s s o r f a c e r a k e .
(8) A f t e r t h e c o m p l e t i o n of t h e d a t a r e c o r d i n g , t h e t r a p d o o r i s opened and t h e n e x t c o n d i t i o n i s s e t .
( 9 ) A t t h e c o n c l u s i o n o f a t e s t r u n a p o s t t a r e r e a d i n g i s t a k e n .
P R E S E N T A T I O N OF EXPERIMENTAL RESULTS The p r i m a r y o b j e c t i v e s of t h i s paper a r e t o convey t h e m o d i f i c a t i o n s t o t h e 9- b y 15-Foot Low Speed Wind Tunnel and some o f t h e r e s u l t s o b t a i n e d f o r t h e STOVL h o t gas i n g e s t i o n t e s t . I n o r d e r t o show t h e s e r e s u l t s , i t i s neces- s a r y t o s t a r t t h e d i s c u s s i o n w i t h t h e t u n n e l m o d i f i c a t i o n s , f o l l o w e d b y t h e model H G I r e s u l t s . A d i s c u s s i o n o n t h e g r o u n d p l a n e t e m p e r a t u r e and p r e s s u r e d i s t r i b u t i o n s w i l l follow. The f i n a l f i g u r e s w i l l show a few frames from t h e w a t e r f l o w v i s u a l i z a t i o n .
S e v e r a l p a r a m e t e r s a r e i m p o r t a n t i n h o t gas i n g e s t i o n . For example, t h e i n l e t t e m p e r a t u r e d i s t o r t i o n can cause e n g i n e s t a l l ; and t h e i n l e t p r e s s u r e r e c o v e r y i s i n d i c a t i v e o f t h e e n g i n e t h r u s t . However, t h i s r e p o r t w i l l use t h e i n l e t t e m p e r a t u r e r i s e , w h i c h i s t h e i n c r e a s e i n t h e compressor f a c e tem- p e r a t u r e o v e r a r e f e r e n c e t e m p e r a t u r e . The e f f e c t o f t h e i n l e t t e m p e r a t u r e r i s e i s a r e d u c t i o n i n t h e e n g i n e t h r u s t . I n l e t t e m p e r a t u r e can be i n f l u e n c e d by s e v e r a l f a c t o r s such as h e a d w i n d , h e i g h t above t h e g r o u n d , s p l a y a n g l e between t h e f o r w a r d n o z z l e s , n o z z l e t e m p e r a t u r e l e v e l s , and n o z z l e p r e s s u r e r a t i o .
T h i s r e p o r t w i l l a d d r e s s t h e e f f e c t o f s p l a y a n g l e , l i f t i m p r o v e m e n t d e v i c e s ( L I D S ) , and m a i n l a n d i n g g e a r h e i g h t above t h e g r o u n d p l a n e .
RESULTS AND D I S C U S S I O N A s was d i s c u s s e d p r e v i o u s l y i n f i g u r e 2 , h o t gas i n g e s t i o n ( H G I ) i s caused b y two s o u r c e s . The f i r s t i s t h e n e a r f i e l d i n g e s t i o n w h i c h i s a r e s u l t o f t h e f o u n t a i n upwash. W i t h m u l t i n o z z l e s , t h e n o z z l e j e t s i m p i n g e on t h e g r o u n d s p r e a d i n g i n a l l d i r e c t i o n s . The i n w a r d f l o w i n g g r o u n d flow (from a n o z z l e ) e n c o u n t e r s o t h e r i n w a r d f l o w i n g g r o u n d f l o w from a n o t h e r n o z z l e . These f l o w s m e e t f o r m i n g a f a n shape upwash or " f o u n t a i n . " Once i t e n c o u n t e r s a n o t h e r j e t , b o t h flow upward f o r m i n g a f o u n t a i n . A t some g i v e n model h e i g h t above t h e g r o u n d , t h e f o u n t a i n flow w i l l i m p i n g e on t h e u n d e r s u r f a c e o f t h e m o d e l . A t t h i s p o i n t , t h e n e a r f i e l d h o t gas i n g e s t i o n o c c u r r e d . T h i s h o t gas can flow f o r w a r d and g e t i n g e s t e d i n t o t h e i n l e t .
The a i r f l o w i n g a l o n g t h e a x i s has n o t m i x e d and g e n e r a l l y r e s u l t s i n a h i g h i n l e t t e m p e r a t u r e r i s e . The f o u n t a i n upwash s t r e n g t h i s d e t e r m i n e d , i n p a r t , b y t h e f o r w a r d n o z z l e s t h r u s t s p l a y a n g l e , t h e n o z z l e s e x i t p l a n e spac- i n g , and t h e h e i g h t o f t h e model above t h e g r o u n d p l a n e . A v a r i a t i o n o f any one o f t h e s e can change t h e s t r e n g t h o f t h e f o u n t a i n . The e x i t p l a n e s p a c i n g e s t a b l i s h e s t h e r e l a t i v e flow a r e a a v a i l a b l e f o r t h e c e n t r a l f o u n t a i n t o flow f o r w a r d a l o n g t h e u n d e r s i d e o f t h e model. T h i s w i l l d e t e r m i n e t h e amount o f h o t gas t h a t i s i n g e s t e d i n t o t h e i n l e t flow f i e l d and g e t p u l l e d i n t o t h e i n l e t .
The o t h e r s o u r c e o f h o t gas i n g e s t i o n i s t h e f a r f i e l d . The h i g h v e l o c i t y g r o u n d j e t from t h e n o z z l e s flow ahead o f t h e model u n t i l , due t o b u o y a n c y and t h e h e a d w i n d , t h e flows s e p a r a t e from t h e g r o u n d . The f l o w i s t h e n b l o w n b a c k t o t h e model i n l e t flow f i e l d where t h e h o t gas i s i n g e s t e d i n t o t h e i n l e t .
T h i s form o f H G I g e n e r a l l y c a u s e s a l o w e r i n l e t t e m p e r a t u r e r i s e i n c o m p a r i s o n t o t h e n e a r f i e l d H G I . The e x c e p t i o n i s when t h e f a r f i e l d s e p a r a t i o n o c c u r s a t t h e i n l e t .
The c l e a n c o n f i g u r a t i o n was t e s t e d t o p r o v i d e a b a s e l i n e c o n f i g u r a t i o n t o compare t h e e f f e c t o f L I D s . The c l e a n c o n f i g u r a t i o n w i l l g e n e r a l l y have a h i g h e r i n l e t t e m p e r a t u r e r i s e because i t has n o way o f d i v e r t i n g t h e n e a r f i e l d i n g e s t i o n . A p a r a m e t e r o f c r i t i c a l v a l u e f o r v e r t i c a l l a n d i n g c o n c e p t i s t h e h e i g h t t h e m a i n l a n d i n g g e a r i s above t h e g r o u n d p l a n e . D a t a p r e s e n t e d i n t h i s p a p e r a r e f o r t h e d e s i g n c o n d i t i o n o f a n o z z l e p r e s s u r e r a t i o o f 3 . 0 2 and com- p r e s s o r f a c e Mach number of 0.40. The n o z z l e p r e s s u r e r a t i o was v a r i e d from 1 . 1 t o 4 . 0 0 .
The i n l e t t e m p e r a t u r e r i s e a t t h e c o m p r e s s o r f a c e v e r s u s t h e d i s t a n c e o f t h e m a i n l a n d i n g g e a r wheel above t h e g r o u n d p l a n e i s shown i n f i g u r e 1 6 .
The r e s u l t s a r e shown f o r t h e c l e a n c o n f i g u r a t i o n ; - 6 " s p l a y o n t h e f o r - ward n o z z l e s and 0" s p l a y o n t h e a f t n o z z l e s . The d a t a shown f o r n o z z l e p r e s - s u r e r a t i o o f 3 . 0 2 , c o m p r e s s o r f a c e Mach number o f 0 . 4 0 , a n o z z l e e x h a u s t t e m p e r a t u r e o f 960 O R , and a h e a d w i n d v e l o c i t y o f 10 k n . I n l e t t e m p e r a t u r e r i s e i n c r e a s e s w i t h d e c r e a s i n g h e i g h t above t h e g r o u n d p l a n e . The most s i g n i f - i c a n t p o i n t i s t h e g r o u n d e f f e c t r a n g e b e i n g r e l a t i v e l y s m a l l . I n g e n e r a l , an i n c r e a s e i n h e a d w i n d v e l o c i t y w i l l r e s u l t i n a h i g h e r l e v e l o f h o t gas i n g e s - t i o n . T h i s i s caused b y t h e f a r f i e l d s e p a r a t i o n o c c u r r i n g c l o s e r t o t h e i n l e t .
The e f f e c t o f s p l a y a n g l e i s shown i n f i g u r e 1 7 . These r e s u l t s show t h e i n l e t t e m p e r a t u r e r i s e o v e r a r a n g e o f h e a d w i n d v e l o c i t i e s . Two c l e a n c o n f i g u - 0" s p l a y and a n o t h e r w i t h - 6 " s p l a y ( f o r w a r d noz- r a t i o n s a r e shown, one w i t h z l e s ) . A g a i n , t h e d a t a a r e shown f o r t h e d e s i g n c o n d i t i o n and a n o z z l e e x h a u s t t e m p e r a t u r e o f 960" R . The 0" s p l a y c o n f i g u r a t i o n i n l e t t e m p e r a t u r e r i s e was a t h i g h e r t h a n t h e -6" s p l a y c o n f i g u r a t i o n . The d i f f e r e n c e r a n g i n g from 22" 10 k n t o 12" a t 23 k n . The 0" s p l a y c o n f i g u r a t i o n maximum c o m p r e s s o r f a c e tem- p e r a t u r e r i s e o c c u r r e d a t t h e 8 k n h e a d w i n d c o n d i t i o n . I t was o b s e r v e d from t h e f l o w v i s u a l i z a t i o n t h a t t h e f a r f i e l d s e p a r a t i o n p o i n t o c c u r r e d n e a r t h e nose g e a r . A s t h e h e a d w i n d v e l o c i t y i n c r e a s e d t h e s e p a r a t i o n zones ( f a r and n e a r f i e l d ) moved u n d e r t h e m o d e l , hence p r o d u c i n g a r e d u c t i o n i n t h e compres- sor f a c e t e m p e r a t u r e r i s e .
When t h e L I D s a r e i n s t a l l e d o n t h e - 6 " s p l a y c o n f i g u r a t i o n ( f i g . 1 8 > , t h e i n l e t t e m p e r a t u r e r i s e i s s i g n i f i c a n t l y r e d u c e d . T h i s r e d u c t i o n was caused b y t h e L I D s e f f e c t i v e n e s s a t c o n t a i n i n g t h e f o u n t a i n upwash and d e f l e c t i n g t h e h o t gas away from t h e i n l e t flow f i e l d . The L I D s r e d u c e d t h e i n l e t t e m p e r a t u r e r i s e b y a p p r o x i m a t e l y 52" o v e r t h e h e a d w i n d v e l o c i t y r a n g e from 10 t o 23 k n .
MODEL TEMPERATURE PROFILES The a i r a r o u n d t h e model f u s e l a g e was measured w i t h t h e r m o c o u p l e s w h i c h p r o t r u d e 0.10 i n . beyond t h e model s u r f a c e . D a t a a r e shown f o r t h e -6" s p l a y c o n f i g u r a t i o n w i t h and w i t h o u t L I D s . A i r t e m p e r a t u r e was measured a t 43 d i f - f e r e n t l o c a t i o n s a r o u n d t h e m o d e l .
T e m p e r a t u r e measurements made 0.10 i n . beyond t h e u n d e r s u r f a c e o f t h e model a r e shown i n f i g u r e 19. These measurements a r e made a l o n g t h e model c e n t e r l i n e . The d a t a a r e p r e s e n t e d f o r a 10 k n h e a d w i n d , a n o z z l e p r e s s u r e r a t i o o f 3.02, c o m p r e s s o r f a c e Mach number o f 0.40, and m a i n g e a r h e i g h t o f 0 . 1 0 i n . B o t h c o n f i g u r a t i o n s had maximum t e m p e r a t u r e n e a r t h e m a i n l a n d i n g g e a r o f 900 O R . The t e m p e r a t u r e l e v e l was t h e same f o r b o t h c o n f i g u r a t i o n s u n t i l u p s t r e a m of t h e L I D s f o r w a r d f e n c e (model s t a t i o n 2 4 ) . The l o c a l temper- a t u r e was r e d u c e d b y 200 O R a t t h e f o r w a r d f e n c e . I n t h e r e g i o n o f t h e i n l e t (model s t a t i o n s 10 t o 1 5 ) , t h e L I D s r e d u c e d t h e t e m p e r a t u r e b y a p p r o x i m a t e l y 100 t o 150 O R . T h e r e f o r e , t h e L I D s were e f f e c t i v e i n c o n t a i n i n g and d e f l e c t i n g t h e h o t a i r flow w h i c h i m p i n g e d o n t h e u n d e r s i d e of t h e m o d e l , t h e r e b y r e d u c i n g o f H G I .
t h e d e g r e e T e m p e r a t u r e measurements made a r o u n d t h e p e r i m e t e r o f t h e m a i n i n l e t sec- t i o n a r e shown i n f i g u r e 20. The r e s u l t s a r e shown w i t h and w i t h o u t L I D s con- f i g u r a t i o n s a t t h e d e s i g n c o n d i t i o n . The L I D s c o n f i g u r a t i o n i s 100 t o 150 O R l o w e r t h a n t h e c l e a n c o n f i g u r a t i o n .
GROUND PLANE A I R TEMPERATURE AND PRESSURE MEASUREMENTS A s n o t e d i n t h e i n s t r u m e n t a t i o n s e c t i o n , t h e g r o u n d p l a n e t h e r m o c o u p l e s measured a i r t e m p e r a t u r e . The g r o u n d p l a n e t e m p e r a t u r e d i s t r i b u t i o n a l o n g t h e c e n t e r l i n e i s p r e s e n t e d i n f i g u r e 21 f o r t h e d e s i g n c o n d i t i o n , a n o z z l e e x h a u s t t e m p e r a t u r e o f 960 O R , a m a i n l a n d i n g g e a r h e i g h t o f 0 . 1 0 i n . , and a h e a d w i n d v e l o c i t y o f 10 k n . F i g u r e 21 shows a c o m p a r i s o n o f t h e c o n f i g u r a t i o n s w i t h and w i t h o u t L I D s . The p u r p o s e of t h e L I D s i s t o r e d i r e c t t h e f o u n t a i n flow b a c k o n t o t h e g r o u n d p l a n e r e g i o n . A s a r e s u l t , t h e g r o u n d flow i s s l i g h t l y i n t e n s i f i e d between 10 and 50 i n . u p s t r e a m o f t h e m i d n o z z l e s l o c a t i o n . The g r o u n d p l a n e a i r t e m p e r a t u r e u p s t r e a m o f t h e L I D s i n c r e a s e s as shown i n f i g u r e 2 1 . T h i s d a t a t e n d s t o i n d i c a t e t h a t t h e L I D s can a l s o m o d i f y t h e f a r f i e l d i n g e s t i o n .
A t y p i c a l p r e s s u r e change d i s t r i b u t i o n a l o n g t h e c e n t e r l i n e o f t h e g r o u n d p l a n e i s p r e s e n t e d i n f i g u r e 2 2 f o r a 10 k n h e a d w i n d , and d e s i g n c o n d i t i o n .
The n o z z l e e x h a u s t f l o w i m p i n g e s o n t h e g r o u n d p l a n e b e t w e e n -10 and +10 i n . , r e s u l t i n g i n a l o c a l s t a g n a t i o n p r e s s u r e n e a r t h e n o z z l e t o t a l p r e s s u r e a t i m p i n g e m e n t . The n e g a t i v e p r e s s u r e change r e g i o n l o c a t e d u n d e r t h e model i s a r e s u l t o f t h e g r o u n d flow a c c e l e r a t i o n away from t h e i m p i n g e m e n t zone and o v e r - e x p a n d i n g . These n e g a t i v e p r e s s u r e s a f f e c t t h e model u n d e r s u r f a c e , r e s u l t i n g i n n e g a t i v e suckdown forces w h i c h a r e seen i n t h e j e t i n d u c e d l i f t ( r e f . 1 ) .
However, t h e f o u n t a i n i m p i n g i n g o n t h e u n d e r s u r f a c e o f t h e model w o u l d r e s u l t i n an upwash f o r c e . I n g e n e r a l , t h e f o u r p o s t e r c o n f i g u r a t i o n t e s t e d has a n e t upwash f o r c e ( u s i n g e m p i r i c a l l y p r e d i c t e d j e t - i n d u c e d l i f t c h a r a c t e r i s t i c s ) when i n g r o u n d e f f e c t s a t a n o z z l e p r e s s u r e r a t i o o f 3.02.
A t y p i c a l f a r f i e l d s e p a r a t i o n i s shown u s i n g w a t e r flow v i s u a l i z a t i o n i n f i g u r e 23. The t u f t s o n t h e g r o u n d p l a n e p o i n t i n g t o w a r d t h e model a r e ' u p s t r e a m o f t h e g r o u n d j e t s e p a r a t i o n zone, u n d e r t h e i n f l u e n c e o f t h e h e a d w i n d v e l o c i t y . The t u f t s p o i n t i n g away from t h e model a r e d o w n s t r e a m o f t h e g r o u n d j e t f l o w s e p a r a t l o n zone, u n d e r t h e i n f l u e n c e o f t h e n o z z l e s f l o w . The i n f l u - ence o f t h e g r o u n d j e t i s c o n f i n e d l a t e r a l l y b y t h e f r e e s t r e a m ( h e a d w i n d ) v e l o c i t y , due t o t h e l a t e r a l v e l o c i t y d e c a y . T h i s c a n be o b s e r v e d a t t h e t o p o f f i g u r e 2 3 . The t u f t s i n t h e u p p e r r e g i o n a r e p o i n t i n g d o w n s t r e a m ( i n t h e d i r e c t i o n o f t h e m o d e l ) . The w a t e r m i s t flow v i s u a l i z a t i o n h a v e b e e n e f f e c - t i v e i n h i g h l i g h t i n g t h e f a r f i e l d i n g e s t i o n z o n e s / r e g i o n s o f g r o u n d p l a n e s e p a r a t i o n .
a
C h a r a c t e r i s t i c s t y p i c a l of t h e n e a r f i e l d h o t gas i n g e s t i o n a r e shown i n f l g u r e 24. T h i s i s a t h r e e - q u a r t e r v i e w of t h e c l e a n c o n f i g u r a t i o n w i t h a - 6 " s p l a y . When t h e g r o u n d a i r flow from two j e t s m e e t , a f o u n t a i n i s f o r m e d . I f t h e r e a r e more t h a n two j e t s , a f o u n t a i n i s f o r m e d between each p a i r and a cen- t r a l f o u n t a i n i s f o r m e d when t h e f l o w from a l l f o u r n o z z l e s m e e t .
Between t h e f o r w a r d and a f t n o z z l e s i s a s t a g n a t i o n l i n e . The c e n t r a l f o u n t a i n can a l s o be seen i n t h e a f t r e g i o n u n d e r t h e m o d e l . The w a t e r m i s t flow v i s u a l i z a t i o n i s v e r y e f f e c t i v e i n s h o w i n g t h e n e a r f i e l d h o t gas i n g e s - t i o n c h a r a c t e r i s t i c s . The e x p e r i m e n t a l and flow v i s u a l i z a t i o n r e s u l t s i n d i c a t e t h a t t h e m o d i f i c a t i o n s made t o t h e 9- b y 1 5 - F o o t LSWT e f f e c t i v e l y v a l i d a t e d t h i s f a c i l i t y as an a c c e p t a b l e w i n d t u n n e l , f o r STOVL h o t gas i n g e s t i o n t e s t i n g .
SUMMARY O F RESULTS An e x p e r i m e n t a l i n v e s t i g a t i o n was c o n d u c t e d i n t h e NASA L e w i s 9- b y 15-FOOt Low Speed Wind Tunnel t o d e t e r m i n e t h e e f f e c t s o f Hot Gas I n g e s t i o n o n a v e c t o r e d t h r u s t STOVL c o n c e p t , t o b u i l d a h o t gas i n g e s t i o n d a t a b a s e , and t o e s t a b l i s h t h e w i n d t u n n e l as an a c c e p t a b l e h o t gas t e s t i n g f a c i l i t y .
The t e s t was c o n d u c t e d w i t h a 9 . 2 p e r c e n t s c a l e m o d e l . D a t a were o b t a i n e d i n l e t Mach number r a n g i n g f o r n o z z l e p r e s s u r e r a t i o r a n g i n g from 1 . 1 t o 4 . 0 , from 0.1 t o 0 . 4 0 , and m a i n l a n d i n g g e a r h e i g h t above t h e g r o u n d p l a n e r a n g i n g from -0.20 ( w h e e l s removed) t o 1 5 . 4 7 i n . The model a t t i t u d e r a n g e was as f o l - lows: p i t c h a n g l e +6.5"; yaw a n g l e 0 " , 45", and 90"; and r o l l a n g l e 0 " . Head- w i n d ( f r e e s t r e a m ) v e l o c i t y was v a r i e d form 8 t o 2 3 k n . S e v e r a l m o d i f i c a t i o n s t o t h e 9- b y 1 5 - F o o t LSWT i n an e f f o r t t o v a l i d a t e t h i s h o t gas t e s t - were made The f o l l o w i n g r e s u l t s were o b t a i n e d : i n g f a c i l i t y .
( 1 ) The m o d i f i c a t i o n s made t o t h e 9- b y 1 5 - F o o t Low Speed Wind T u n n e l have p r o v e n t o be e f f e c t i v e i n t e s t i n g v e c t o r e d t h r u s t c o n c e p t s .
( 2 ) The 9- b y 15-Foot LSWT has been v a l i d a t e d as an a c c e p t a b l e w i n d t u n n e l f o r STOVL h o t gas i n g e s t i o n t e s t i n g .
( 3 ) L I D S s i g n i f i c a n t l y r e d u c e d t h e i n l e t t e m p e r a t u r e r i s e a t t h e compres- sor f a c e ( 4 ) I n l e t t e m p e r a t u r e r i s e i n c r e a s e s w i t h d e c r e a s i n g h e i g h t above t h e g r o u n d p ane.
(5) S p l a y a n g l e can r e d u c e t h e i n l e t t e m p e r a t u r e r i s e a t t h e c o m p r e s s o r f a c e .
(6) The w a t e r m i s t flow v i s u a l i z a t i o n r e s u l t s have been v e r y e f f e c t i v e i n s h o w i n g b o t h t h e n e a r and f a r f i e l d i n g e s t i o n z o n e s , r e g i o n s / l o c a t i o n s o f g r o u n d p l a n e s e p a r a t i o n , and j e t f o u n t a i n s .
b CONCLUDING REMARKS As a result of the successful program, a large data base has been estab- lished for supersonic and subsonic jets exhausting into a subsonic flow field.
A follow-on activity is, therefore recommended and should incorporate fur- ther improvements in the 9- by 15-Foot LSWT for HGI-type testing. For example: ( 1 ) A model Integrated Support System (MISS) will be installed. This sup- port system will have 4" of freedom (pitch, roll, y a w , and vertical variation) remotely actuated from the control room. The MISS will have the following fea- tures: pitch angle *ZOO, angle-of-yaw *180", and angle-of-roll *lo". The height variation will range from wheels-on-ground to approximately 4.5 f t above the present ground plane. The MISS will simulate both inlet and nozzle airflows.
( 2 ) Installation of a thermovision system with both video and digital output.
( 3 ) Installation of a laser sheet system coupled with a standard and U-matic video systems.
( 4 ) A new 1660 "R heated air supply system will be used.
(5) On-line acoustic analysis system will be used.
( 6 ) A new analog system will approximately double the present analog meas- urement capabilities of the 9- by 15-Foot Low Speed Wind Tunnel.
REFERENCES 1 . "Proceedings of the 1985 Ground-Effects Workshop," NASA Ames Research Center, Aug. 20-21, 1985, NASA CP-2462.
2. Strock, T., Amuedo, K . , and Flood, J . , "Hot Gas Ingestion Test Results o f
a Four-poster Vectored Thrust STOVL Concept," NASA CR-182115, July 1988.
TABLE I . - GROUND PLANE INSTRUMENTATION LOCATIONS [Dimensions a r e i n i n c h e s ; x measured f r o m t r a p d o o r l e a d i n g edge: y i s l o c a t e d 22 i n . above t h e ground p l a n e c e n t e r l i n e .
zl p a n e l y l p a n e l S t a t i c p r e s s u r e S u r f a c e a i r t e m p e r a t u r e S t a t i c p r e s s u r e S u r f a c e a i r t e m p e r a t u r e TABLE 11. - COMPRESSOR FACE RAKE I N S T R U M E N T A T I O N LOCATIONS
I Leg i d e n t i f i c a t i o n I Leg i d e n t i f i c a t i o n
I
Number A n g l e , R a d i u s , Number A n g l e , R a d i u s , R , I I deg I 2. I I deg i n .
66.499 2 21.533 293.50 1 3 338.467 5 246.499 6 201.533 a 113.501 7 158.467
- 0.624 0.624
.646 1.081 1.119 1.396 1.396 1.56 1.444 1.651 1.651 1.81 1.709 1.938 S u r f a c e a I I I a S u r f a c e denotes s t a t i c p r e s s u r e l o c a t i o n .
b 1 1 AIR FORCE MISSIONS 1,500 I 10,000 n CARRIER OPERATION CD-84-15235 FIGURE 1. - STOVL IMPROVES OPERATIONAL EFFECTIVENESS.
Near Field Hot Gas Ingestion Due to Fountain Upwash Far Field Hot Gas Ingestion Due to Separated Ground Flow FIGURE 2. - THE SOURCES OF HOT GAS INGESTION.
NO. 2 DOO? 7 r/\ No. 3 Door-,, ,F Acoustical Muffler 2.74 by 4.58 meter \ \ \ (9 x 5) Low speed \ Test Section -, No. 4 Door -, NO. 5 Door-
K w / ' - 8 x 6 Diffuser
2.44 by 1.83 meter (8 x 6) Supersonlc
&/-- Test Section
- Balance Chamber
Flexible Nozzle CD-88-34998 FIGURE 3. - AN ILLUSTRATION O F THE 9- BY 15-FOOT LOW-SPEED WIND TUNNEL AND THE 8- BY 6-FOOT SUPERSONIC WIND TUNNEL.
(a) A THREE-QUARTERVIEW OF THE MODEL INSTALLED I N THE 9- BY E-FOOT LOW-SPEED WIND TUNNEL.
FIGURE 4 . - MODEL 279-3C AND COMPRESSOR FACE RAKE DETAILS.
TABLE I. - COMPRESSOR FACE RAKE INSTRUMENTAT ICJN LOCAT IONS.
L e g I d e n t i f i c a t i o n I Leg I d e n t i f i c a t i o n
Number Angle, Radius, Number Angle, :ad i 1-15 , deg . R, in. L , i n .
1 66.499 4 295. 501 S 246.499 0 113.501 0. 646 T o t a l Temperature 0.624 0 . 7 2 2 Fressur e F r e s s u r e 0 . 698 Temper a t c i r e 1.119 Temperature 1 .OB1 F'ressur e 1.251 Pressure 1.209 Temp et- a t LI r e 1.444 Temperature 1.396 F r e s s ~ t r e 1.615 Pressure 1.56
Temper a t c i r e 1 . 709
Temperature 1.651 1.875 F r e s s u r e 1.81 P r e s s ~ t r e 1.958
I Temperature 1.872 1 Temperature
2 . 038 2.038 S t a t i c Fressctr-e S t a t i c Pressure
Inlet Centerbody -. n
I I / / L Main and Auxiliary Inlets Face Rake
Nose Gear -
HA
0 Thermocouple 0 Total Pressure A Static Pressure Tap k y - E n g i n e Hub -Inlet Bifurcation View Looking Downstream ( b ) FORWARD FUSELAGE - COMPRESSOR FACE RAKE SCHENATIC.
FIGURE 4 . - CONCLUDED.
I 14 FIGURE 5 . - THE UNDERSURFACE OF THE HGI MODEL SHOWING L I D S AND NOZZLES.
i
X ( a ) NOZZLE SPLAY ANGLE.
Nozzle Side View z ( b ) NOZZLE VECTOR ANGLE.
FIGURE 6 . - D E F I N I T I O N OF FORWARD NOZZLES SPLAY AND VECTOR ANGLES.
ORJGlNAL PASF IS OF POOW QUALITY FIGURE 7. - THE HOT GAS INGESTION MODEL AND SUPPORTING SYSTEM INSTALLED I N THE 9- BY 15- FOOT LOW-SPEED WIND TUNNEL.
Table 11. - Ground plane Instrumentation locations.
1 37.33 22 ~ 1 37.31 18 2 28.37 21.98 2 28.34 18 3 2 2 . 4 21.94 3 22.36 17.97 4 16.4 21.97 4 16.36 16.04 5 i0.58 21.98 5 10.37 18.02 6 4 . 3 6 22 6 4.54 18.04 Tomperrturo Tomperrturs 1 31.38 21.97 1 31.36 17.99 2 25.34 21.98 2 25.33 18 3 19.37 21.98 3 19.38 17.99 4 1 3 . 4 1 22 4 13.38 18 5 7 . 3 7 21.97 5 7 . 3 4 18 6 3 . 3 2 6 3 . 3
I_ 336 6
40.75 7 \ \ D e c k in g opening 1 1 I I F L O W I, --
1 -
I I I I 1 8
t - I1 I1 I b 2
7-
FIGURE 8. - GROUND PLANE SCHEPV\TIC AND I N S T R U E N T A T I O N . (DIPIENSIONS I N INCHES.)
FIGURE 9. - AFT VIEW OF THE 9- BY 15-FOOT LOW-SPEED WIND TUNNEL TEST SECTION,
___-----
I (Left and Right Sides) , \ \ \ I \ -Ground Wind Tunnel Floor- I Trap Door \ Plane Scavenging System -I Surface FIGURE 10. - CROSS SECTION OF TEST SECTION SHOWING THE SIDEWALLS SCAVENGING SYSTEM, ,-Pressure Control Valve / i P, P.
Water FillA +, ? .
To NASA Lewis Nitrogen
Water Fill 4’
S y s t e m 1 System Supply System
A ‘I / ‘Shut Off Valve
Fill V a l v e d ‘ c -Vent Valve Check Valve--/ -Water Tank Line (4) (Allow for Vertical ,
Height Change) -’
To Test Nozzle FIGURE 11. - A SCHEMATIC OF THE MODEL FLOW V I S U A L I Z A T I O N WATER INJECTION SYSTEM.
\ Anemometer -Tunnel Ceiling .--)
Tunnel Wind - I
Trap Door Open W FIGURE 12. - TEST SECTION AIRFLOW VELOCITY MEASURING SYSTEM.
I ‘-North Wall
\
-
‘-Thermocouple strip @
-Tunnel Rake
,- Static Pressure Strip
A’
TunnelRake -
,-Thermocouple strip @
d 0- Propeller Anemometer
t - ~ e r m o c o u p ~ Strip @
1 -South Wall
/ Celllng (Looklng Down) c Ground Plane North Wall
-Thermocouple Strip @
/-Thermocouple Strip @
I c I
I
Ground Plane South Wall FIGURE 13. - TEST SECTION WALLS AND CEILING INSTRUPENTATIONS.
m J an 0 0 0 0 0 . 0 0 0
8.5 ft CI
I-
Individual Static Pressure Taps ,I 10 Installed
I I
a t 0 0 0 . 0 . . 0 0 FIGURE 14. - DETAILS O F THE TEST SECTION THERMOCOUPLE AND STATIC PRESSURE I N S T R U E N T A T I O N STRIPS.
0 . 0 Fuselage 30.51 5 Nozzle Midpoint Y-Axis 60 40 30 20 10 0 -10 -20 -30 Side View ///’/”////’/’‘//’/
cc&hii6di: ’’ ” ’ + ’ / / Y-Axis
k’ ” I”’ ’
c
t
Ground c- Plane
I
Top Vlow FIGURE 15. - GROUND PLANE COORDINATE SYSTEM AND MODEL LOCATION.
MAIN GEAR HEIGHT = 0.10 IN.
NOZZLE PRESSURE RATIO = 3.02 COMPRESSOR FACE MACH NUMBER = 0.40 FORWARD NOZZLE SPLAY = -6' MAIN GEAR HEIGHT = 0.20 IN.
PITCH ANGLE = 6.5' NOZZLE PRESSURE RATIO = 3.02 NOZZLE EXHAUST TEMPERATURE = 960 O R COMPRESSOR FACE MACH NUMBER = 0.40 HEADWIND VELOCITY = 10 KNOTS FORWARD NOZZLE SPLAY = -6' PITCH ANGLE = 6.5' NOZZLE EXHAUST TEMPERATURE = 960 O R I a m m k?
8- 0 0' SPLAY 1oc - 0 -6' SPLAY c 4 t- 4 W m a 60 W m a Z 0 SPLAY - 6 ' 7 ' D = . u c 3O a . u c E Q FORWARD NOZZLES E Q 8 C w w c*u 3 4 4" w w c u D=v 4 3 4 t - u i a z W I s a P w o I L m aEm
e
20 I W W !
SI s g 4 u E ?
?
-.4 0 .4 .8 1.2 1.6 MAIN LANDING GEAR WHEEL HEIGHT ABOVE 10 15 20 25 GROUND PLANE, h, IN. HEADWIND VELOCITY. KNOTS FIGURE 16. - THE MODEL HEIGHT ABOVE THE GROUND PLANE FIGURE 17. - THE EFFECT OF FORWARD NOZZLE SPLAY ANGLE ON EFFECTS ON HOT GAS INGESTION. HOT GAS INGESTION.
FORWARD FENCE MAIN GEAR HEIGHT = 0.20 IN.
NOZZLE PRESSURE RATIO = 3.02 COMPRESSOR FACE MACH NUMBER = 0.40 FORWARD NOZZLE SPLAY = -6' PITCH ANGLE = 6.5' NOZZLE EXHAUST TEMPERATURE = 960 O R LANDING UNDERSURFACE OF MODEL 279-3C HEADWIND VELOCITY = 10 KNOTS GEAR MAIN GEAR HEIGHT = 0.10 IN.
0 CLEAN CLEAN CONFIGURATION NOZZLE PRESSURE RATIO = 3.02 A WITH L I D S COMPRESSOR FACE MACH NUMBER = 0.40 FORWARD NOZZLE SPLAY = -6'
8o t
c U PITCH ANGLE = 6.5' NOZZLE EXHAUST TEMPERATURE = 960 O R 2oa 60 HEADWIND VELOCITY = 10 KNOTS W E . ut- - 0 " l0OC E Q 0 CLEAN a WITH L I D S L I D S CONFIGURATION W Y
5 2 6 50010 15 20 25 30 35 40
s 0
5 10 15 20 25 HEADWIND VELOCITY. KNOTS MODEL FUSELAGE STATION, IN.
FIGURE 18. - THE EFFECT OF L I F T IMPROVEMENT DEVICES ON FIGURE 19. - THE EFFECT OF L I D S ON THE MODEL UNDER- HOT GAS INGESTION.
SURFACE CENTERLINE A I R TEMPERATURE DISTRIBUTION, - + t MAIN GEAR HEIGHT = 0.10 I N .
NOZZLE PRESSURE RATIO = 3 . 0 2 COMPRESSOR FACE MACH NUMBER = 0.40 MAIN GEAR HEIGHT = 0.10 I N .
FORWARD NOZZLE SPLAY = - 6 ' NOZZLE PRESSURE RATIO = 3.02 PITCH ANGLE = 6.5' COMPRESSOR FACE MACH NUMBER = 0.40 NOZZLE EXHAUST TEMPERATURE = 960 O R FORWARD NOZZLE SPLAY = -6' - HEADWIND VELOCITY = 1 0 KNOTS PITCH ANGLE = 6.5' CL - NOZZLE EXHAUST TEMPERATURE = 960 O R p: d 900 HEADWIND VELOCITY = 10 KNOTS p: 0 CLEAN a - + 4 g 900 WITH L I D S a 0 CLEAN 5 800 + 4 P a WITH L I D S -
2 800
5 700 1
+ 5 700 W U A 2 600 W CL a
- 600
I n CL I a 5 0 0 v) 1 2 0 100 80 60 40 20 0 -20 - 4 - 3 - 2 - 1 0 1 2 3 4 5 GROUND PLANE CENTERLINE DISTANCE FROM M I D FUSELAGE PERIMETER FROM LOWER CENTERLINE, I N . NOZZLES. I N .
FIGURE 20. - THE EFFECT OF L I D S ON THE TEMPERATURE FIGURE 21. - THE GROUND PLANE CENTERLINE A I R TEM- PERATURE DISTRIBUTIONS FOR THE CLEAN AND WITH DISTRIBUTION I N THE INLET PERIMETER REGION.
L I D S CONFIGURATIONS.
'\ CENTRAL FOUNTAIN - .1 0 CLEAN a WITH L I D S d P d C LD L
s
U M A I N GEAR HEIGHT = 0.10 I N .
- NOZZLE PRESSURE RATIO = 3 . 0 2 g -.l COMPRESSOR FACE MACH NUMBER = 0.40 v) (0 W FORWARD NOZZLE SPLAY = -6' p: a - PITCH ANGLE = 6.5' y -.1 NOZZLE EXHAUST TEMPERATURE = 960 O R U p: HEADWIND VELOCITY = 10 KNOTS z -. - . 3 : 1 4 0 1 2 0 100 80 60 40 20 0 - 2 0 GROUND PLANE CENTERLINE DISTANCE FROM MID NOZZLES. I N .
FIGURE 22. - THE GROUND PLANE CENTERLINE PRESSURE CHANGE DISTRIBUTIONS FOR THE CLEAN AND WITH L I D S CONFIGURATIONS.
i 24
FIGURE 23. ~ A FLOW V I S U A L I Z A T I O N VIEW SHOWING FAR F I E L D SEPARATION AHEAD OF THE MODEL.
FIGURE 24. - A THREE-QUARTER VIEW OF THE CLEAN CONFIGURATION SHOWING THE NEAR F I E L D CENTRAL FOUNTAIN/LOCAL FLOW F I E L D CHARACTERISTICS.
NASA
Report Documentation Page
National Aeronautics and Soace Administratior - 2. Government Accession No. 3. Recipient's Catalog No.
1. Report No.
NASA TM-100952 AIAA-88-3025 5. Report Date 4. Title and Subtitle Hot Gas Ingestion Testing of an Advanced STOVL Concept in the NASA Lewis 9- by 15-Foot Low Speed Wind Tunnel With Flow 6. Performing Organization Code Visualization 8. Performing Organization Report NO.
7. Author(s) Albert L. Johns, Joseph D. Flood, Thomas W. Strock, and Kurt C. Amuedo E-4250 10. Work Unit No.
505-62-7 1 9. Performing Organization Name and Address 11. Contract or Grant No.
National Aeronautics and Space Administration Lewis Research Center Cleveland, Ohio 44135-3191 13. Type of Report and Period Covered Technical Memorandum 2. Sponsoring Agency Name and Address National Aeronautics and Space Administration 14. Sponsoring Agency Code Washington, D.C. 20546-0001 5. Supplementary Notes Prepared for the 24th Joint Propulsion Conference cosponsored by the AIAA, ASME, SAE, and ASEE, Boston, Massachusetts, July 11-13, 1988. Albert L. Johns, NASA Lewis Research Center; Joseph D. Flood, Thomas W. Strock, and Kurt C. Amuedo, McDonnell Aircraft Company, McDonnell Douglas Corporation, St. Louis, Missouri 63166.
6. Abstract Advanced Short Takeoff/Vertical Landing (STOVL) aircraft capable of operating from remote sites, damaged runways, and small air capable ships are being pursued for deployment around the turn of the century. To achieve this goal, it is important that the technologies critical to this unique class of aircraft be developed.
Recognizing this need, NASA Lewis Research Center, McDonnell Douglas Aircraft, and DARPA defined a cooperative program for testing in the NASA Lewis 9- by 15-Foot Low Speed Wind Tunnel (LSWT) to establish a database for hot gas ingestion, one of the technologies critical to STOVL. This paper will present a few results from a test program along with a discussion of the facility modifications allowing this type of testing at model scale. These modifications to the tunnel include a novel ground plane, an elaborate model support which included four degrees of freedom, heated high pressure air for nozzle flow, a suction system exhaust for inlet flow, and tunnel sidewall modifications. Several flow visualization techniques were employed including water mist in the nozzle f l o w s and tufts on the ground plane. Headwind (freestream) velocity was varied from 8 to 23 knots.
7. Key Words (Suggested by Author(s)) 18. Distribution Statement STOVL Unclassified - Unlimited Vectored thrust Subject Category 02 Hot gas ingestion Flow visualization Unclassified Unclassi tied 26 A03 NASA FORM 1626 OCT 86 "For sale by the National Technical Information Service, Springfield, Virginia 221 61