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1 ; c C X U PERFORMANCE ~GHARAGTERISTICS O F SEVERAL DIVERGENT S H R O U D AIRCRAFT EJECTORS By William K. Greathouse and William T. Beale Lewis Flight Propulsion Laboratory C leveland, Ohio CLASSIFIED DOCUMENT This matertal contalns information affecting the National Defense of the United States wlthln the meanin!3 of the espionage laws, Title 18, U.S.C., Secs. 793 and 784, t t e transmission or revelation of which in any marmer to an unauthorized p r s o n i s prohibited by law.
NATIONAL ADVISORY COMMITTEE
F O R AERONAUTICS
WASHINGTON September 8, 1955
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NACA RM E55G21a " CONFIDE~IAL
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS PERFORMANCE CHARACTE8ISTICS O F S m
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u~ v m u m L- annuuu ALKLM'I' JW ;JBC;'I'UXS By W i l l i a m K. Greathouse and Wi-1-liam T , Reale S U M M A R Y Ten divergent- and two cylindrical-shroud e j e c t o r s were investiga- t e d t o determine i n t e r n a l e j e c t o r performance over a range of pressure r a t i o s and expansion a r e a r a t i o s representative of f l i g h t Mach numbers up t o about 3. Cold d r y a i r was used f o r both t h e primary and secondary flows.
Experimental data and camputed n e t - t h r u s t c h a r a c t e r i s t i c s i n d i c a t e t h a t v a r i a b l e shroud geometry i s necessary f o r an e j e c t o r t o a t t a i n near-optimum t h r u s t performance over a t y p i c a l range of f l i g h t condi- t i o n s of current i n t e r e s t .
An e j e c t o r i n s t a l l a t i o n having a fixed p r i - mary nozzle could maintain near-optimum n e t t'-mst i f t h e shroud were v a r i a b l e f'rom a c y l i n d r i c a l shape at low subsonic Mach numbers t o a d i - vergent shape a t supersonic Mach numbers. A p r a c t i c a l e j e c t o r f o r an afterburning t u r b o j e t i s perhaps t h e conventional double-iris design modified s o t h a t t h e shroud could be e i t h e r conical, c y l i n d r i c a l , or divergent.
The e j e c t o r has shown merit a s an a i r c r a f t j e t - e x i t configuration because of i t s a b i l i t y t o expand t h e engine gases e f f i c i e n t l y and t o provide cooling from t h e flow of secondary a i r . As p a r t of an o v e r - a l l program t o study various j e t e x i t s , several types of model and W l - s i z e e j e c t o r s have been investigated a t the NACA Lewis laboratory.
Published r e p o r t s present performance d a t a f o r conical e j e c t o r s ( r e f s . 1 t o 7 ) , c y l i n d r i c a l e j e c t o r s ( r e f s . 8 t o ll), double-shroud e j e c t o r s ( r e f s . 12
t o 1 5 ) , and divergent e j e c t o r s of low divergence angles ( r e f . 16) . In
addition, various e j e c t o r configurations have been i n v e s t i g a t e d with e x t e r n a l flow ( r e f s . 17 t o 21) .
A desirable j e t e x i t , of course, i s one t h a t can maintain high thrust performance over a wide range of operation. Such could be re- alized if the high thrust of the convergent-divergent nozzle a t design pressure r a t i o s could be combined with ejector t h r u s t characteristics a t below-design pressure r a t i o s . Thus, it i s reasoned that divergent- shroud ejectors might have good t h r u s t performance over a certain de- sired range of operation. Analysis of divergent-ejector data i n r e f - erence 16 indicates s l i g h t l y b e t t e r t h r u s t f o r divergent shrouds than f o r cylindrical shrouds, even though the divergence angles were only about 3'. However, the data were limited t o only four divergent ejec- t o r s , representing expansion r a t i o s f o r f l i g h t Mach numbers up t o about 1.3. Therefore, the purpose of t h i s investigation i s t o determine and study the internal performance of ejectors with divergence angles up t o about 12O and expansion r a t i o s f o r f l i g h t Mach numbers up t o about 3.
Ten divergent-shroud ejectors were investigated, and two cylindri- c a l ejectors are included f o r comparison. Exit diameter r a t i o s of about 1.23, 1.45, and 1.82 were selected f o r the divergent ejectors t o repre- sent design Mach numbers of about 1.5, 2.0, and 2.8, respectively. For each e x i t diameter r a t i o , the shroud divergence angle and annular secondary-flow area were v&ried, while shroud length (spacing r a t i o ) was constant. A divergent ejector of 1.70 e x i t diameter r a t i o i s a l s o included t o simulate a geometry that may be encountered with a fixed- shroud ejector when the primary nozzle of a turbojet i s positioned f o r nonafterburning operation. E x i t diameter r a t i o s of the two cylindrical ejectors were 1.10 and 1.46. For most configurations, primary pressure r a t i o ranged * o m 1.5 t o above 20, and the weight-flow r a t i o ranged from 0 t o about 0.20. Dry a i r (-20' F dewpoint) a t about 540' R (80' F) was used f o r both primary and second.a,ry flows.
Jet-thrust and air-handling performance data are presented for each configuration. Net t h r u s t of certain configurations i s shown a t typical operating conditions t o indicate the internal performance of fixed and variable ejector geametry a t design and off-design Mach numbers.
APPARATUS AND INSTRUMENTATION Ejector Configurations The gemetries of the t e n divergent and two cylindrical ejectors used i n the investigation .me l i s t e d i n table I. The three groups of divergent ejectors having e x i t diameter r a t i o s D,/D~ of about 1.23, 1.45, and 1.82 represent typical expansion r a t i o s f o r design Mach num- Shroud divergence angle bers of about 1.5, 2.0, and 2.8, respectively.
P , approach angle a, and secondary diameter Ds were. varied within each group. Shroud length L was increased with e x i t diameter r a t i o t o keep the divergence angle under 12O and thereby avoid rapid expansion within the ejector shroud. The ejector with 1.70 e x i t diameter r a t i o represents a geometry t h a t could occur i n a fixed-shroud divergent ejec- t o r designed for afterburning but operating a t nonafterburning condi- tions (closed primary nozzle). Two cylindrical ejectors ( ~ ~ 1 % of 1.10 and 1.46) are included f o r comparison with divergent-ejector performance.
The ejectors were i n s t a l l e d i n the t e s t chamber photographed i n figure l ( a ) and shown schematically i n figure l j b ) . The ejector and air-supply l i n e s were freely suspended i n the chamber by four flexure rods. The resultant a x i a l force acting on the ejector i n s t a l l a t i o n was transmitted through a flexure-plate-supported b e l l crank and linkage t o a null-type force-measuring c e l l . Any pressure gradient on the diffuser portion of the primary-air l i n e was prevented by a vent between the labyrinth seals t h a t kept a i r flow through the second s e a l a t a minimum.
Details of t h i s nozzle t e s t f a c i l i t y are presented i n reference 22.
Instrumentation Pressures and temperatures were measured a t the various stations indicated i n figures l ( b ) and 2. The type of measurement a t each lo- Ambient exhaust pressure was measured i n cation i s given i n table 11.
several places near the outside of the ejector e x i t .
The performance of each ejector was obtained over a raage of p r i - a t various constant values of corrected
mary pressure r a t i o s P Ip
p O - weight -f low r a t i o (ws/w ) ~ T , / T ~ . For most configurations the range P of P ~ / ~ ~ was frm 1.5 t o above 20, with (ws/w ) P about 0.20.
Prelimiaary t e s t s indicated no essential difference between average t o t a l pressure measured a t station p and s t a t i o n 3. Also, there was no difference between plenum-chamber pressure and t o t a l pressure a t s t a t i o n s . Therefore, primary t o t a l pressure Pp m d secondary t o t a l pressure Ps were evaluated f o r subsequent t e s t s from measurements a t s t a t i o n and the plenum chamber, respectively.
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Ejector thrust ratio Fej/Fip is defined herein as the ratio of the actual ejector jet thrust to the thrust available f ' r o m the primary stream,if primary mass flow were ideally expanded to exhaust pressure.
Actual ejector jet thrust Fecj was obtained from the measured force after accounting for inlet momentum forces, bellmouth forces, and labyrinth-seal forces. The ideally expanded primary thrust Fip was computed as the product of measured primary mass flow and isentropic velocity at the existing primary pressure ratio and temperature. The was about A .5 percent.
accuracy in obtaining thrust ratio F ~ ~ / F ~ ~ Details of the conventional computation method used for reduction of the test data are given in reference 22. Symbols and nomenclature used herein are defined in appendix A.
FSSULTS AND DISCUSSION Jet-Thrust and Air-Handling Characteristics Jet-thrust and air-handling characteristics for the ten divergent ejectors investigated and for the two cylindrical ejectors are presented in figures 3 and 4, respectively. A calibration of the primary nozzle in figure 5 indicates the consistent thrust and weight-flow measurements obtained during the investigation.
Jet thrust. - Thrust characteristics in figure 3(a) are typical of
all the ejectors investigated. Each jet-thrust curve peaked at a cer- tain value of P ~ / ~ ~ , which indicates that the flow was fully expanded.
A for the higher weight- These peaks occurred at lower values of pplPO flow ratios simply because less flow area was available for expansion Consequently, the design pressure ratio (P P /p 0 of the primary stream.
for peak thrust) of an ejector depends upon both the physical size of the shroud and the amount of secondary flow.
Air-handling. - Typical air-handling characteristics of the ejec-
tors investigated are also shown in figure 3 ( a ) . For any given weight- flow ratio, the ejector total-pressure ratio became a flmction of only the upstream flow conditions (stations p and s) over .a wide range of This is characteristic of aircraft ejectors primary pressure ratios.
and can result with a stable supersonic primary flow and a "choked" A di- secondary flow before or at the ejector shroud exit (ref. 8 ) .
vergent ejector operates in a similar manner; but, when the secondary passage is small enough, the flow can choke at the shroud entrance (station s) rather than farther downstream as for a cylindrical or conical ejector .
Such a choked-shroud entrance existed f o r most of the divergent ejectors investigated, and the approximate weight-flow r a t i o a t which choking occurred i s noted f o r each configuration on the graphs of a i r - handling performance. Also, a method of computing the air-handling per- formance of a choked-shroud ejector i s described i n appendix B, and com- puted and experimental r e s u l t s a r e compared. Thus, f o r a divergent ejector, it appears t h a t the secondary flow can be limited t o a desired value by sizing the annular passage a t the shroud entrance.
0.1 N Net-Thrust Performance Net-thrust performance of an ejector system should include the in- herent drag imposed by taking secondary a i r aboard the a i r c r a f t .
Secondary-air drag could be f u l l free-stream momentum or some fraction thereof, depending on the source of air. Only a fraction of free-stream momentum would be chargeable t o the ejector system i f energy of the sec- ondary a i r were p a r t l y expended f o r some other purpose.
However, subse- quent net-thrust evaluations charge the ejector with f u l l i n l e t momentum drag, which tends t o make the r e s u l t s conservative. Other factors be- yond the scope of t h i s report are the effects of external flow, i n l e t - scoop drag, and drag due t o fuselage or nacelle shape near the ejector e x i t .
Assumed operating conditions. - Net-thrust performance was based on
the operating schedule shown i n figure 6. The curve of primary pressure r a t i o P ~ / ~ ~ typically represents accelerating climb t o 35,000 f e e t and 0.8 Mach number and then operation above 35,000 f e e t a t Mach numbers from 0.8 t o 3 .O. The curve of (P,/P~),, represents an upper l i m i t of - ejector operation (maximum ejector total-pressure r a t i o ) with assumed pressure losses through the secondary system. Secondary a i r was consid- ered t o enter a t eee-stream t o t a l temperature and t o experience a t e m - perature r i s e before reaching the ejector.
Complete d e t a i l s of the method used i n evaluating net-thrust r a t i o a r e given i n appendix C.
Performance a t design Mach number. - Net-thrust performance of the
various ejectors a t design Mach numbers of 1.5, 2.0, and 2.8 i s shown i n figure 7 f o r afterburning conditions ( T ~ = 3500° R ) . Each curve repre- sents operation over a range of secondary flows and total-pressure ra- t i o s from ws/wp = 0 a t the respective design Mach num- t o ( P ~ / P ~ ) ~ ~ ~ ber. As shown by the sketches and curves i n figure 7, the highest net- t h r u s t r a t i o a t each design Mach number was attained by the divergent ejector having the largest divergence angle and the smallest secondary- flow passage (configurations 3, 5, and 10). I n other words, a higher net t h r u s t occurred a s the ejector geometry approached t h a t of a simple convergent-divergent nozzle.
At maximum total-pressure ratio (P,/P~)~~~, ejectors 3, 5, and 10
could handle small secondary flows ( ( w s / u p ) 2/T,/Td * o m 0.02 to about
0.04 and maintain a net thrust of only about 1 percent less than that of a good uncooled convergent-divergent nozzle (velocity coefficient of 0.98). Cooling a convergent-divergent nozzle would certainly produce a net-thrust decrease (about 1-percent thrust decrease for each percent of compressor air used). Thus, it appears that, for a fixed jet-exit configuration at design Mach number, a divergent-shroud ejector design cu l .
could produce a net thrust equal to or slightly higher than a cooled t - convergent-divergent nozzle. However, if for some reason cooling of a M convergent-divergent nozzle were unnecessary, the convergent-divergent nozzle would of course be superior to the ejector charged with f ' u l l free-stream inlet momentum of the secondary air.
The net-thrust performance of the Mach 2.0 design cylindrical ejec- tor is lower than for any of the divergent ejectors (fig. 7 ( b ) ) , because the cylindrical ejector requires greater secondary flows (and hence a larger inlet momentum drag) for efficient expansion of the primary stream. The peak shown in the cylindrical-ejector thrust curve indi- cates that, for corrected weight-flow ratios above 0.04, the inlet mo- mentum drag exceeded any jet-thrust increase produced by flowing addi- tional secondary air.
Performance over range of Mach numbers. - Net-thrust performance of
the three divergent ejectors that previously showed the best net thrust at design Mach numbers of 1.5, 2.0, and 2.8 (configurations 3, 5, and 10, respectively) is presented in figure 8(a) over a ra'nge of flight conditions up to design Mach number. For each configuration, peak net thrust occurred very near the design Mach number, and large overexpan- sion losses are indicated at below-design Mach number. Thus, the high net-thrust characteristics of a fixed-shroud divergent ejector are re- alized only for operation near design conditions. This undesirable characteristic could not be relieved by control of secondary air but could be eliminated by use of variable shroud geometry.
Net-thrust performance of the two cylindrical ejectors investigated is shown in figure 8 ( b ) over a range of Mach number. Ejector 11 shows good net-thrust characteristics up to Mach number of about 1.0, above which underexpansion losses become excessive as in the case of a simple conical nozzle. Ejector 12 shows higher net thrust than a comparable divergent ejector (configuration 5, fig. 8 ( a ) ) up to Mach number of Above Mach 1.3 the secondary air handled by the cylindrical about 1.2.
ejector increased rapidly and thus produced a sharp net-thrust decrease By progressively throttling the due to excessive inlet momentum drag.
secondary flow to a corrected weight flow of about 0.04 at Mach 2.0, the net thrust could be maintained at about 91 percent, as shown by the . . . . . . .........................
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Throttling the flow below 0.04 would de- dashed curve i n figure 8(b).
crease the net thrust a t Mach 2.0 below 91 percent, u n t i l a t zero sec- ondary flow the net thrust would be about 86 percent.
It has long been realized t h a t fixed-shroud ejector characteristics are i n direct contrast t o those desired when primary-nozzle area i s mod- ulated f o r an afterburning turbojet engine. To further i l l u s t r a t e t h i s point f o r the case of a fixed-shroud divergent ejector, the net-thrust w performance - of such an i n s t a l l a t i o o i s represented i n figure 9. The camparison i s between a divergent ejector [configuration 5 ) represerltiiig N a design f o r afterburning (3500' R ) a t Mach 2.0 with a corrected weight- fiow r a t i o of about 0.04, acd t h z efectzr r e s l d t i r g fro111 closing the primary nozzle (configuration 7 ) for nonafterburning operation (1600~ R ) .
The very low net thrust a t nonafterburning i s the combined r e s u l t of overexpansion and excessive secondary i n l e t momentum drag. Throttling the secondary flow i n t h i s case would reduce the net thrust even more, because the overexpansion losses would increase more than the i n l e t mo- mentum drag would decrease.
Variable ejector geometry. - Fram previous curves of fixed-ejector
performance, it i s apparent t h a t variable gemetry i s required f o r an ejector t o maintain near-optimum net thrust over the range of operating conditions of current interest.
An ejector i n s t a l l a t i o n using a fixed primary nozzle could a t t a i n near-optimum thrust i f the shroud could be varied from cylindrical a t low Mach number t o divergent a t high Mach number. The performance of such an ejector i s i l l u s t r a t e d i n figures 10(a) and (b) f o r afterburning (3500' R ) and nonafterburning ( 1 6 0 0 ' R ) , respectively. The curves are the locus of net thrust a t design pressure r a t i o for several fixed ejec- t o r s investigated and thus represent maximum ejector thrust performance over the assumed f l i g h t schedule. The over-all shroud variation indi- cated ( f i g . 10(a)) for the typical schedule used herein would be from a cylindrical ejector with 1.10 diameter r a t i o a t low subsonic Mach num- bers t o a divergent ejector with 1.82 e x i t diameter r a t i o a t Mach 2.8.
For a different f l i g h t schedule, the over-all shroud variation w i l l , of course, depend on the schedule i t s e l f and on the upper Mach number l i m i t , since the divergent shroud must provide the proper expansion ra- t i o f o r the combined flows. A t the largest expansion r a t i o (largest shroud e x i t ) , the shroud divergence angle should be s m a l l enough t o pre- vent rapid expansion of the flow.
Divergence angles f o r the ejectors investigated were l e s s than 12O, but a shorter ejector resulting *om angles up t o 15O or 20° might represent a reasonable design compromise with respect t o weight and size.
To a t t a i n near-optimum net thrust f o r a turbojet-afterburner ejec- n /n t o r instailation, b o u l a "erZ&ie s ~ ~ ~ & - ~ ; ; l & s m . e t e r rat.io - s / -p I and a variable e x i t diameter r a t i o D , / D ~ would be necessary. However, such a configuration might be impractical because of complex mechanical design. A more p r a c t i c a l design would be t h e conventional double-iris conical e j e c t o r modified so t h a t t h e shroud could f b t h e r expand t o form c y l i n d r i c a l and divergent shrouds when t h e a f t e r b u r n e r i s i n operation.
General trends t h a t can be expected f o r t h i s type of i n s t a l l a t i o n a r e The curve abc i l l u s t r a t e d by t h e curves and sketches i n f i g u r e 1 0 ( c ) .
i s f o r conical-ejector shroud v a r i a t i o n between an e x i t diameter r a t i o The curve of about 1.10 and 1.30 with t h e afterburner o f f (1600' R ) .
defg i s f o r shroud v a r i a t i o n from an e x i t diameter r a t i o of 1.10 (cy- Net- l i n d r i c a l ) t o 1.82 (divergent) with t h e a f t e r b u r n e r on (3500' R ) .
t h r u s t r a t i o i s lower f o r nonafterburning than f o r afterburning because i n l e t momentum of both t h e primary and t h e secondary system i s a g r e a t e r I n proportion of t h e a v a i l a b l e j e t t h r u s t a t 1600' than a t 3500' R .
general, t h e e j e c t o r net t h r u s t i s indicated a s about 1 percent l e s s than optimum nozzle net t h r u s t f o r afterburning conditions and about percent l e s s f o r nonafterburning conditions.
CONCLUDING RENARKS Ten divergent- and two cylindrical-shroud e j e c t o r s were investiga- t e d . The r e s u l t s i n d i c a t e t h a t variable shroud geometry i s necessary f o r an e j e c t o r t o maintain near-optimum t h r u s t performance over a t y p i - c a l range of f l i g h t conditions of c u r r e n t i n t e r e s t .
The afterburning t u r b o j e t and e j e c t o r i n s t a l l a t i o n r e q u i r e s both a variable shroud e x i t and a v a r i a b l e shroud entrance (which involves com- p l e x mechanical design) i n order t o maintain optimum t h r u s t ~ h a r a c t e r i s - t i c s as t h e primary nozzle i s varied. A more p r a c t i c a l e j e c t o r f o r an afterburning t u r b o j e t i s perhaps t h e conventional double-iris design modified so t h a t t h e shroud could be e i t h e r conical, c y l i n d r i c a l , o r divergent.
An e j e c t o r i n s t a l l a t i o n having a f i x e d primary nozzle could a t t a i n near-optimum t h r u s t over a range of f l i g h t Mach numbers i f t h e shroud geometry were variable from c y l i n d r i c a l t o divergent. A c y l i n d r i c a l shroud of about 1.10 diameter r a t i o would serve f o r low subsonic Mach numbers. A t supersonic Mach numbers, a divergent shroud providing t h e necessary expansion r a t i o with divergence angles up t o 15' o r 20' would have adequate performance.
Use of an e j e c t o r f o r a fixed j e t - e x i t a p p l i c a t i o n depends somewhat - on cooling-air requirements. For no cooling a i r , a f i x e d convergent- divergent type nozzle could provide about 1 percent more t h r u s t than an e j e c t o r . With corrected cooling-air-flow r a t i o s of about 0.02 t o 0.04, t,he divergent e j e c t o r a2parently can provide a n e t t h r u s t equal t o o r s l i g h t l y b e t t e r than t h e n e t t h r u s t expected from a cooled convergent- For most of the divergent ejectors investigated, secondary flow was choked in the annular passage at the ejector entrance for high values of weight-flow ratio. Air-handling characteristics for such choked opera- tion can be computed from one-dimensional flow theory within an accuracy of about 0.01 weight-flow-ratio unit.
Lewis Flight Pr~pulsion Laboratory ......... AT,.c:-...-~ ~ 2 - - 2 --,,- ~,,--LL-- a_-- n L: I Y ~ U U L L ~ L f i u v L ~ U L y ~ U I I I I ~ I I b ~ l c t : IUL n c r u L l s u b A C s Cleveland, Ohio, July 27, 1955
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lo*** .**. NACA RM E55GZla SYMBOLS area, sq f ' t coefficient diameter, in. or ft thrust, lb acceleration due to gravity, 32.17 ftlsec 2 distance between exits of primary nozzle and ejector shroud, in. or ft Mach number total pressure, lb/sq ft static pressure, lb/sq ft gas constant, 53.3 f't-lb/(lb) (%) total temperature, ?R static temperature, ?R velocity, ft/sec weight flow, lb/sec half cone angle of upstream shroud section, deg wall divergence angle of ejector shroud, deg ratio of specific heats ratio of local pressure to NACA standard sea-level pressure of 2ll6 lb/sq ft ratio of local temperature to NACA standard sea-level temper- ature of 518.7O R density, lb/cu ft .........................
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Subscripts : b bellmouth c cold e ejector exit ej ejector F thrust h hot isentropic primary expansion jet net primary stream or station p P s secondary stream or station s v velocity 0 free stream or ambient exhaust Parameters: actual jet thrust thrust 'Oefficient, (actual mass flow) (isentropic velocity j actual exit velocity velocity coefficient, isentropic velocity exit diameter ratio secondary diameter ratio thrust ratio spacing (length) ratio primary pressure ratio ejector total-pressure ratio ejector temperature ratio ejector weight-flow ratio
- ws fi corrected weight-flow ratio
W P APPENDIX B AIR-HANDLING CHARACTERISTICS OF CHOKED EJECTOR Consider the choked ejector system in sketch (a) : Sketch (a) Since both primary and secondary Mach numbers are 1.0 at a known flow area, the flow through each system can be expressed for the primary stream as and for the secondary stream as where C is the flow coefficient of the corresponding passage. Cornbin- ing the two equations, corrected weight-flow ratio is expressed as Thus, the pumping characteristics of such an ejector axe defined if flow areas, flow coefficients, and specific-heat ratios are known.
Computed and experimental weight-flow ratios a r e compared in figure 11 for several choked divergent ejectors.
Agreement is generally within 0.01 ws/wp unit.
NACA RM E55G21a CONFIDENTIAL CALCULATION O F NET-THRUST RATIO FOR ETECTOR Net-thrust r a t i o ( F , ~ / F ~ ~ ) , i s defined herein a s the r a t i o of t h e net t h r u s t of the ejector system t o t h e net. t h r ~ s t ay.~ilz$le 2a;;i the primary system i f t h e a c t u a l mass flow w e r e expanded isentropically t o exhaust pressure. In equation form, For computation purposes, t h e equation w a s rearranged by using W~
Fej = (%)J Fip and Fip = Yip and d i v i d i % t h r o ~ & by ; Yip t o
g obtain In order t o evaluate the performance of a hot (hot primary stream) ejec- tor f'rm the cold data herein, the following two assumptions were made:
(1) The corrected weight-flow r a t i o (ws/wp) l\lT,/Tp of a hot ejector i s
equal t o t h e corrected weight-flow r a t i o of a cold ejector, and (2) t h e J e t - t h r u s t r a t i o of a hot e j e c t o r is the same as f o r a cold ejector a t the same over-all operating pressure r a t i o s .
Thus, equation ( ~ 2 ) becmes and net-thrust ratio can be evaluated for a t y p i c a l schedule of f l i g h t conditions.
The net-thrust values computed herein are based on a ty-pical sched- u l e of primary pressure r a t i o and maximum ejector +,:tal--qeggse~-tlo ...................... 0 . .
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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.......
CONFIDENTIAL ......................... . . . . . . .
. .
. . . . . 0 . . . . . a * . . .
. . . * . . . . . . . . . . . . . . ......
.
. . 0 . .
.......
....
16**. *'** **. ....cbM~&e : : NACA RM E55G21a
with flight k c h number and altitude as shown in figure 7. The proce- dure for computing (Fej/Fip), f r m equation ( ~ 3 ) is as follows.
(1) Choose Mach number and primary temperature. Determine pplPO and (ps/pP ImaX from schedule.
From its cold performance (2) Select an ejector to be evaluated.
data at P /p , get values of (F . / F ~ ~ ) J c
P 0 e J and ( : E l c from
ws/wp = 0 to (P,/P~)~~~.
(3) Compute (v0/vip) as follows :
where to is the altitude temperature in OR and ( ~ / m ) ~ is a ve-
locity parameter from tables of reference 23 corresponding to the pp/pO at a typical yp of 1.3.
(4) Compute Ts as follows: where To is the free-stream total temperature, and (AT), is the tem- perature rise through the secondary system for a specific secondary flow. In this report ( A T ) , was evaluated by the methods of refer- ence 24.
(5) Solve equation (~3) for (Fe j/~ip)n and plot : T = constant
I
(6) Repeat (1) t o (5) a t other values of Mach number t o obtain per- formance curves over t h e desired range of Mach number.
REFERENCES 1. Huddleston, S. C., Wilsted, H. D., and E l l i s , C . W . : Performance of Several Air E j e c t o r s with Conical Mixing Sections and Small Second- a r y Flow Rates. IWCA FM E8D23, 1948.
2 . Wilsted, H. D . , Huddleston, S. C., and E l l i s , C. W . : E f f e c t of Tem- perature on Performance of Several Ejector Configurations.
NACA RM E9E16, 1949.
3. E l l i s , C . W . , H o l l i s t e r , D. P., and Sargent, A. F., Jr.: Preliminary I n v e s t i g a t i o n of Cooling-Air Ejector Performance at Pressure Ratios from 1 t o 10. NACA RM E5lH21, 1951.
4. Wallner, Lewis E., and Jansen, W e r t T.: Full-Scale I n v e s t i g a t i o n
of Cooling Shroud and Ejector Nozzle f o r a Turbo j e t Engine - After-
burner I n s t a l l a t i o n . NACA RM E51J04, 1951.
5 . Greathouse, W. K., and H o l l i s t e r , D. P.: Preliminary Air-Flow and Thrust Calibrations of Several Conical Cooling-Air Ejectors with a Primary t o Secondary Temperature Ratio of 1.0.
I - Diameter
Ratios of 1.21 and 1.10. NACA RM E52E21, 1952.
6. Greathouse, W. K., and H o l l i s t e r , D. P.: Preliminary Air-Flow and Thrust Calibrations of Several Conical Cooling-Air Ejectors with a
Primary t o Secondary Temperature Ratio of 1.0. I1 - Diameter Ra-
t i o s of 1.06 and 1.40. NACA RM E52F26, 1952.
7. Ciepluch, C . C., and Fenn, D. B . : Experimental Data *om Four Full- Scale Conical Cooling A i r Ejectors. NACA RM E54F02, 1954.
8. Kochendorfer, Fred D., and Rousso, Morris D . : Performance Character- i s t i c s of A i r c r a f t Cooling Ejectors Having Short Cylindrical Shrouds.
NACA R M E5lEO1, 1951.
9. Greathouse, W. K., and H o l l i s t e r , D. P.: Air-Flow and Thrust Charac- t e r i s t i c s of Several Cylindrical Cooling-Air E j e c t o r s with a P r i - mary t o Secondary Temperature Ratio of 1.0. NACA RM E52L24, 1953.
10. Kochendorfer, Fred D.: Effect of P r o p e r t i e s of Primary Fluid on Performance of Cylindrical Shroud Ejectors. NACA RM E53L24a, 1954.
11. Greathouse, W. K.: Preliminary Investigation of Pumping and Thrust Characteristics of Nl-Size Cooling-Air Ejectors at Several Exhaust-Gas Temperatures. NACA RM E54A18, 1954.
12. Ellis, C. W., Hollister, D. P., and Wilsted, H. D.: Investigation of Performance of Several Double-Shroud Ejectors and Effect of NACA RM Variable-Area Exhaust Nozzle on Ejector Performance.
E52D25, 1952.
13. Hollister, Donald P., and Greathouse, William K . : Performance of Double-Shroud Ejector Configuration with Primary Pressure Ratios from 1.0 to 10. NACA RM E52K17, 1953.
14. Reshotko, Eli: Performance Characteristics of a Double-Cylindrical- Shroud Ejector Nozzle. NACA RM E53H28, 1953.
15. Greathouse, William K.: Performance Characteristics of Several Full- Scale Double-Shroud Ejector Configurations over a Range of Primary Gas Temperatures. NACA RM E54F07, 1954.
16. Huntley, S. C., and Yanowitz, Herbert: Pumping and Thrust Charac- teristics of Several Divergent Cooling-Air Ejectors and Cmparison of Performance with Conical and Cylindrical Ejectors. NACA RM E53J13, 1954.
17. Allen, John L.: Pumping Characteristics for Several Simulated Variable-Gemetry Ejectors with Hot and Cold Primary Flow. NACA RM E54G15, 1954.
Effects of Secondary-Air Flow on Annular Base 18. Vargo, Donald J.: Force of a Supersonic Airplane. NACA RM E54G28, 1954.
Thrust and Pumping 19. Hearth, Donald P. , and Valerino, Alfred S . : Characteristics of a Series of Ejector-Type Exhaust Nozzles at Subsonic and Supersonic Flight Speeds. N.ACA RM E54H.19, 1954.
20. Salmi, Reino J.: Experimental Investigation of Drag of Afterbodies with Existing Jet at High Subsonic Mach Numbers. NACA RM E54113, 1954.
21. Beke, Andrew, and Simon, Paul C.: Thrust and Drag Characteristics of Simulated Variable-Shroud Nozzles with Hot and Cold Primary Flows at Subsonic and Supersonic Speeds. NACA RM E54J26, 1955.
22. Krull, H. George, and Beale, William T.: Effect of Plug Design on Performance Characteristics of Convergent-Plug Exhaust Nozzles.
NACA RM E54H05, 1954.
.......... ..........*.*..........
. . . 0 . . . .... . 0 . . * .
. . . . . . . . . . . . . . . . . ......
. . . . 0 . . 0 . . ........
......................... . . . . . . *
CONFIDENTIAL 23. W n e r , L. Richard, Addie, Albert N., and Zimmerman, Richard H.: Charts f o r the Analysis of One-Dimensional Steady Compressible Flow. NACA T N 1419, 1948.
24. Koffel, W i l l i a m K., and % . m a n , Harold R . : Empirical Cooling Cor- r e l a t i o n for an Experimental Afterburner with an Annular Cooling Passage. NACA RM E52Ci3, 1952.
.........................
. . . 0 . . 0 . .
. . . .
. 0 . .
........
. . . . . . . . . . . . . . . ......
. .
. . . . .
20.** -- - 0 ....... * . . . C & & D B $ u * : : . . a .
NACA RM E55G21a
TABU I. - EJECTOR CONFIGURATIONS
Dp = 6.018 in. inside = 6.143 in. o u t s i d e
--TI
I
- .I
Data i n Approach Spacing Divergence I n l e t Shroud E j e c t o r E x i t angle, f i g u r e r a t i o , a n g l e , diameter diameter a r a t i o , r a t i o , I3 LIDp D,/Dp D e b p 15' 36' 0.45 2' 51' Divergent 3 ( a ) 1 1.24 1.20 17' 34' .47 5O 36' 1.14 ( b ) 2 1.23 20' 9 ' .47 1.23 11°31' 1.04 ( c ) 3 16' 1' 1.06 6 O 2 2 ' ( d ) 4 1.44 1 . 2 1 l g O 7' 1.06 go 25' ( e ) 5 1.45 1.09 90° g 0 3 9 ' 6 1.07 1.46 1.09 (f 11' 5 4 ' 7 1.07 go 23' 1.34 ( g ) 1.70 13' 53' 1 . 9 1 1.82 8O 20' 1.26 (h) 8 1 5 0 2 8 ' 8 O 5 9 ' 9 1 . 9 1 1 . 8 1 1 . 2 1 (i) 19' 4 ' 1.90 1 0 ° 3 4 ' ( j ) 1 0 1.82 1.10 90' 1 1 0.80 1.10 0° 1.12 C y l i n d r i c a l 90'
2.12 o0 1.46 1 1.46
1 2 .........................
. . a . . a . a . . . . . . * a . m . . . . . . . . . . . . . . . . . . . .
......
. . a . . .
....
.................
: a * @ * ~ y l L . . . m . a . 2 1
NACA RM E55GZla ' - -- Station o r location Total temperature Total pressure Static pressure -- -----I---- Two '4-probe 4 Wall taps radial rakes 8 -Probe 4 W a l l taps d i m t r i c e rake O n outside of Survey with bellmouth i n l e t 12 taps SProbe &Probe diametrical dianzetrical rake rake
-----------
Plenum chamber 8 Taps (secondary a i r ) c ircumferent id Orifice siagle (secondary a i r ) probe Three 3- probe rakes
eqY spaced
%ps tream pressure and or if ice differential pressure measured f o r calibrated orifice assembly.
b ~ n s t a l l e d during preliminary only.
(a) Photograph.
Figure 1. - Nozzle test facility.
Secondary-air orifice \_ To air- supply system
Force-measuring cell 4 3 ! ! ! ! +
(b) Schematic diagram.
. *.
Figure 1. - Concluded. Nozzle test facility.
Plenum chamber Station s ( ~ l l dimensions in inches ); Figure 2. - Schematic diagram of typical ejector assembly.
(see Table 1 for other values.)
Dp = 6.018 inches inside and 6.143 inches outside.
....................
NACA F i M E55GZla i i i o e i ~oJW~$$@~ ............ • . • . 25
. 0 . 0 . . . .
. ...* .
. . . .
..........
.......................
3 4 5 6 7 8 9 1 0 11 Primary pressure r a t i o , pp/po ( a ) Ejector 1.
Figure 3 . - Performance of divergent-shroud e j e c t o r s .
Primary pressure ratio, P /P P 0 (b) Ejector 2.
Performance o f divergent-shroud ejectors.
Figure 3. - Continued.
rrlrnary pressure r a t l o , F$po ( c ) E j e c t o r 3.
F i g u r e 3. - Continued. Performance of divergent-shroud e s e c t o r s .
Primary pressure ratio, P /p P 0 ( e ) Ejector 5.
Figure 3. - Continued. Performance of divergent-shroud ejectors.
....................... ..........
. 0 . 0 . . .... . 0 . . . . . .
. . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . .
................. .....: : C O N P n ~ m * . . , (f) Ejector 6.
Figure 3. - Continued. Performance of divergent-shroud ejectors.
a * . . . . . . . . .......................
. . . . . . . .... 0 . 0 . .
............. ;@wIPEwIAL; .......
...... . . . . . .
......................... . 0 . . 0 . .
( g ) E l e c t o r 7 .
....... F..ure3..Continued. Performance • a*. of $iy%r;rgen&t;s.ryd eJec&tgrp.
...........
. .
. . .
. . . . . . . . . . .
. . . . . . . . . . . . . . . .
.
......
. . . . . .
......
. . . . . . * :co&D~J-A&*... .................
1 3 5 7 $1 11 13 15 17 1 9 2 1 23 25 Primary pressure ratio, ' , " o (g) Concluded. Ejector 7.
Figure 3. - Continued. Performance of divergent-shrsud ejectors.
(h) Ejector 8.
Figure 3. - Continued. Performance of divergent-shroud ejectors.
. . . . . . . . . . . . . . . . . . . . . . * ..........
. . . . a . 0.0. . . . . . . . .
. 6 above about 0.18 .5 .4 .3 .2 .1
j I
I
9 11 13 15 17 19 1 3 5 7 21 23 25 Primary p r e s s u r e r a t i o , P /p P 0 ( h ) C8,ncluded. E,jector 8.
Figure 3. - Continued. performance of divergent-shroud e j e c t o r s .
Primary pressure ratio, pp/po ( 1 ) Ejector 9.
F i g u r e 3. - C o n ~ i n u e a . reriormance of alvergens-snroud eJectors.
.................... 36 . C ( ) ~ I B ~ I I T ~ ~ ~ . ~ : a: : : NACA RM E55G21a
. . . . . . .
......
.
. . . . . . . . . . . . . . . .
- - - - - . . - -
. a . 0 . .
. . a * * . ma..
. * 1 . . * q . 'a. 1 - q I l l I 1 I
C o r r e c t e d weight-flow r a t l o , I I I J e t t h r u s t 1 I I / , 4 - I I t I ( j ) E j e c t o r 10.
(a) Ejector 11.
Figure 4. - Performance of cylindrical-shroud ejectors.
.............
. • . . * * C Q N P Y ~ E N T ~ L O * * . .....* : *: : : NllCA RM E55G21a
. . . . . . . . . . .
0 . 0 . .
. . . . . ..*. .
.......................
...
I 1 I , 1 1 . j ; r- r -1 1 / Corrected welght-flow - ratio:-]
(b) Ejector 12.
I
.IJ!gvre $. f. Conc$udzd . . * P e ~ ? a m a p ~ ~ ?f y p l i ~ o i ~ p l - f i ~ e d $ ejectors .
.......... ......
. . . . . . "0 ~ ~ ~ ~ ~ I A I ; .......
*...*.......*......* . 0 . 0 . .
1 3 5 7 9 1 1 13 15 17 19 2 1 23 25 27 Primary pressure r a t i o , P /p P 0 Figure 5. - Primary-nozzle c a l i b r a t i o n .
.a. ...a ..a ...a ma. *.a ..a 0 . . a m .
a . a . . acmy*NT~L. . . a. .
a em : NACA RM E55GZla
40 : : mom a mom 0.
. ... a . . a .
. . a . . a . a
. ... a a .. . . a ..a am. am. . . ...a .a. . . ..
F l i g h t Mach number, % Figure 6. - Assumed o p e r a t i n g schedule f o r e v a l u a t i o n of e j e c t o r n e t t h r u s t .
. . . a a. .
a. em. 0.. ma. ..a. ..a ma.. ..a . .. . . . .
. a .
a . a . . .
.....
: C O m l r , ~ . . a : :a. . ..a .
4 1
. . NACA R M E55G21amam : : a m m a . ... e m . ... . ma. m a r n o .ma
Exit diameter ratio, 1.23; flight Mach number, 1.5 (a) Divergent ejectors 1, 2, and 3.
I I 1 1 I I I .84' I . 7 0 .1 .2 .3 .4 .5 .6 Ejector total-pressure ratio, PS/Pp Exit diameter ratio, 1.82; flight Mach number, 2.
(c) Divergent ejectors 8, 9, and 10.
Prj Figure 7. - Net-thrust performance of fixed-shroud ejectors at design Mach number.
mary gas temperature, 3 5 0 0 ' R.
. . a . a . . a * .....
. a a * . a
a a . a .
42 . . **: : .-*'cor~a;n& : . .
l l ~ C A RM E55G2La a * . ma.. m.. . . a 0.. . a . . a ma.. 0.. l a a .
(a) Divergent-shroud e.iectors.
Flight Mach number, Mo (b) Cylindrical-shroud ejectors.
Figure 8. - Net-thrust performance of fixed-shroud ejectors over range of flight Mach number.
Primary gas temperature, 3 5 0 0 ' R.
0 .2 .4 .6 .8 1 . 0 1 . 2 1 . 4 1.6 1.8 F l i g h t Mach number, Mg Figure 9. - Off-design performance of a fixed-shroud divergent e j e c t o r .
Primary gas temperature, 3 5 0 0 ' R.
(a) Fixed primary nozzle.
1.00
-
a rl
-%
.96 . .
.r- r d k r .92 4 0 .2 . 4 . 6 1.0 Flight Mach number, Mg (b) Fixed primary nozzle. Primary gas temperature, 1 6 0 0 ' R.
1.00 .96 .92 .88 2.8 3.2 0 . 4 .8 1.2 1.6 2.0 2.4 Flight Mach number, % Primary gas temperature, 1 6 0 0 ' and 3 5 0 0 ' R.
(c) Variable primary nozzle.
Figure 10. - Net-thrust performance of ejectors with variable shroud geometry.
. a . . a. .
. a m . * . . a . m . . . . . . . . . . . . . . . . . . . a .
• i C&~D~PPTIA%. : : . . . . . 45
NACA RM ~ 5 5 ~ 2 & : : a: : a.m. • a * . • • • •
.......................
..a am.. * * a
/ -- Computed from eq. ( ~ 3 ) for
and Cp = Cs = 1.0 yp = ys = 1.4
1 . .f
I' / . 3 - Ejector weight-flow ratio, ws/wp
Figure 11. - Comparison of computed and experimental weight-flow ratio
for choked ejectors.