Design and preliminary evaluation of inlet concepts selected for maneuver improvement

Cawthon, J.

doi:10.2514/6.1976-701

Cited by 3 publications

(2 citation statements)

References 1 publication

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“…The larger mass flow ratio required for blowing through the larger slot height (m B /m f = 0.021) falls far outside the core-compressor bleed capability reported in Ref. 8.…”

Section: Some Criteria For Selecting Lip Blowing Parametersmentioning

confidence: 89%

Investigation of tangential blowing applied to a subsonic V/STOL inlet

Burley

Hwang

1983

Journal of Aircraft

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Engine inlets for subsonic V/STOL aircraft must operate over a wide range of conditions without internal flow separation. An experimental and an analytical investigation were conducted to evaluate the effectiveness of tangential blowing to maintain attached flow to high angles of attack. The inlet had a relatively thin lip with a blowing slot located either on the lip or in the diffuser. The height and width of these slots were varied. Experimentally determined flow separation boundaries showed that lip blowing achieved higher angle-of-attack capability than diffuser blowing. This capability was achieved with the largest slot circumferential extent and either of the two slot heights. Predicted (analytical) separation boundaries showed good agreement except at the highest angles of attack. xlO 4 Nomenclature A = area CR = contraction ratio D = diameter h = blowing slot height L -inlet length m = mass flow rate P = total pressure p = static pressure , 'R = Reynolds number m R [/Pa \ (T-//T) "1 RBP = relative blowing power,--( --) -1\ fflf L.\PQ / J T = total temperature V.= velocity x = axial length from inlet highlight y = rake height 7 = ratio of specific heats 6 = blowing slot circumferential extent = viscosity p = density \l/-= circumferential location Subscripts B = blowing d = diffuser rake de = diffuser exit e^ = edge of boundary layer F -fan face HL = highlight / = inlet max .= maximum 0 -freestream t = throat

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“…The larger mass flow ratio required for blowing through the larger slot height (m B /m f = 0.021) falls far outside the core-compressor bleed capability reported in Ref. 8.…”

Section: Some Criteria For Selecting Lip Blowing Parametersmentioning

confidence: 89%

Investigation of tangential blowing applied to a subsonic V/STOL inlet

Burley

Hwang

1983

Journal of Aircraft

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“…area of inlet channel,cm 2 inlet entrance area, cm2 inlet entrance diameter, mm, R c Dc/2 average Mach number at inlet exit average Mach number at geometry throat of inlet Mach number before terminal shock in diffuser average total pressure at inlet exit, kg/cm2 surface static pressure of inlet, 2 kg/cm 2 free-stream total pressure, kg/cm average root mean square value of total pressure fluctuations in any annular area at inlet exit, kg/cm 2 average root mean square value of total pressure fluctuations in any 60"sector at inlet exit, kg/cm2 average root mean square value of total pressure fluctuations at inlet exit,kg/cm 2 root mean square value of static pressure fluctuations, kg/cm 2 average dynamic pressure at inlet exit, kg/cm radius, mm Lecturer Professor INTRODUCTION It is noteworthy that the lip flow separation of the supersonic inlet during airplane take-offs or flying at large angles of attack may reduce seriously the total pressure recovery and increase the flow distortion at the inlet exit (1,2,3,4)• In this paper the effects of blowing at the lip separation on the dynamic characteristics of inlet are presented, and some sources of the dynamic distortion are analysed by means of the coherence theory.…”

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Lip Separate Flow Blowing and Analysis of Coherence of Inlet

Zhang

1985

Volume 1: Aircraft Engine; Turbomachinery

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It is found in the experiments that blowing at the lip separation of the inlet obviously reduces the turbulences at the inlet exit, and apparently reduces the intensity of pressure fluctuations caused by the shock-boundary layer interaction down-stream of throat. The coherence between pressure in the interaction region and total pressure at the exit is also reduced. The coherence between the pressure in the lip separation region and total pressure at the exit is 0.32. If, in addition, there is a stronger shock down-stream of the throat the above mentioned coherence is reduced to 0.06.

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Optimum Subsonic, High–Angle–of–Attack Nacelles

Luidens

Stockman

Diedrich

1980

SAE Technical Paper Series

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ABSTRALTMany proposed advanced a i r c r a f t -b u t espec i a l l y t i l t -n a c e l le, subsonic-cruise, VlSTOL a i rc r a f t -r e q u i r e nacelles t h a t operate over a wide range o f aerodynamic conditions. The optimum design o f such n a c e l l e s and t h e i r i n l e t s i s described, i n c l u d i n g how t h e i n l e t low-speed design c o n d i t i o n s a r e selected, t h e c o o d i t i o n s f o r which f t h e various regions o f t h e i n l e t a r e designed, and appropriate c r i t e r i a o f merit. For lor-speed o p e r a t i o n t h e optimum i n t e r n a l surface v e l o c i t y d i s t r i b u t i o n s and s k i n f r i c t i o n d i s t r i b u t i o n s a r e described f o r t h r e e categories o f i n l e t s : those without boundary-layer c o n t r o l (BLL), those w i t h BLC, and those w i t h blow-in door s l o t s and r et r a c t a b l e slats. Experimental r e s u l t s a r e presented t h a t show t h e performance o f the various types o f i n l e t s . At c r u i s e speed t h e e f f e c t o f f a c t o r s t h a t reduce t h e n a c e l l e e x t e r n a l surface area and t h e l o c a l s k i n f r i c t i o n i s i l l u s t r a t e d .These f a c t o r s are c r u i s e Mach number, i n l e t t h r o a t size, fan-face Mach number, and n a c e l l e contour. The i n t e r r e l a t i o n o f these cruise-speed f a c t o r s w i t h t h e design requirements f o r good low-speed performance i s discussed. F i n a l l y an i n l e t design without BLL and an optimized i n l e t design w i t h s l o t s and s l a t s a r e compared t o i l l u s t r a t e t h e p o s s i b l e reductions i n n a c e l l e size.

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Design and preliminary evaluation of inlet concepts selected for maneuver improvement

Cited by 3 publications

References 1 publication

Investigation of tangential blowing applied to a subsonic V/STOL inlet

Investigation of tangential blowing applied to a subsonic V/STOL inlet

Lip Separate Flow Blowing and Analysis of Coherence of Inlet

Optimum Subsonic, High–Angle–of–Attack Nacelles

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