Off design performance of divergent ejectors

7/28/2019 Off design performance of divergent ejectors

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RESEARCH MEMORANDUMOFF-DESIGN PERFORMANCE OF DIVERGENT EJ ECTORS

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By M ilton A . BeheimL ewis Flight Propulsion L aboratoryCleveland, Ohio

C ~ D o C u ? . m r nThis materlal contains informationaffectingth, Nntional Defenseof tbe United States within tbe meaningof the espi o~g~awa, TYtl s 18 , U.S.C., Sea. 793 and W , tbe trpIyImk38onor revelationof whi ch in mmanner to anunauthoricedp s o n s pmhtblted by l aw

NATIONAL ADVISORY COMMITTEEFOR AERONAUTICS

WASHINGTONSeptember 30, 1958I . . . 0 .. ... .....


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OFF- DEI GN PERFORMANCE OF DrVERGENT EJECPORS*By Milton A . Beheim

SUMMARYThe off-design performance of fixed- and of variable-gemetry di -vergent ejectors was investigated. The ejectors, which were designedfor turbojet operation at Mach 3, were investigated i n the Mach numberrange 0.8 to 2. The performance of a fixed-geometry ejector wi th hi ghsecondary-flow rates was competitive with that of more complex variable-geometry ejectors. Variable-geometry ejectors with compromises to re-duce mechanical complexity produced performance reasonably close to thatof an ideal variable ejector.

INTRODUCTIONSimple fixed-geometry divergent ejectors designed f or good perform-ance at hi gh flight speeds (e.g., Mach 3) suf fer l arge performance lossesat low speeds.on the geometry and the j et and stream interaction.that the performance of such an ejector c m be so poor at low speedsthat an airplane would not be able t o accelerate to the high designspeed. In other cases where suf f icient thrust was available duringacceleration, excessive fuel consumption occurred.

This loss results f rom j et overexpansion, which dependsAnalyses have shown

The following techniques of solving the problem are considered i nthi s investigation:off-design performance; (2) employ variable geometry; (3) employ largeamounts of secondary airflow to f i l l i n the excess area of the exit.These schemes were investigated i n the NACA Lewis 8- by 6- f oot tunneli n the Mach number range 0.8 to 2.

(1) Compromise the design performance to improve

SYMBOLSCDD boattai l plus base drag

boattai l drag coefficient based on maximum cross-sectional area

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m m m mm m m m m o mm m m m mm m o om m m m m ommo

om m mrno m m o m m m m m m m m om m m m m.moo 0 0 m mm mom m m

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maximum f orebody di ameterpr i mary- nozzl e di amet erspoi l er di amet ersecondary- nozzl e di ameterej ector gross thrustgross thrust of i deal compl et el y expanded pr i mary f l owaxi al di stance f r ompr i mar y- nozzl e exi t t o ej ector exi tMach numberbypass mass- f l ow r atesecondar y mass- f l ow r atemaximum capt ur e mass- f l ow r at e of i nl etpr i mar y t otal pr essur esecondar y t ot al pr essur ef r ee- st r eamt otal pr essur e ( upst r eamof model )l ocal Pi t ot pressurebase st at i c pr essur eboat t ai l stati c pr essur eexi t - pl ane st at i c pr essur ef r ee- st r eam st at i c pr essur e ( upst r eam of model )pr i mary t ot al t aper at wesecondary t ot al t emper at ur ef r ee- str eamvel oci t y


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............................................ ........... 0 . 0 .0 . . 0 . 0 .W p r i m e.....f&-fcl'cwjratq :..................... ....wS secon&& ;ei&t-flow rateYU divergence angle, degP boattai l angle, degSubscripts:ab afterburninga localnb no af terburning

normal distance from body surface

3

Ejector ModelsThirteen di fferent ejectors were used i n this investigation, eachidenti f ied by number.

i , and each sketch i s accompanied w th a table of the geometrical param-eters.12 were mounted on the cyl indrical section of the model, which had an8-inch outside diameter. With ejector 13 the outside diameter of thecylinder was reduced from 8 to 6.4 inches by an abrupt step 22 inchesupstream of the exi t plane.

Sketches of the ejectors are presented i n figureEjectors 1 ohese parameters are also summarized i n table I .

Ejectors 1 o 9 and 13 had low boattai l angles representative ofnacelle-type instal lations.as with certain fuselage-type instal lations.Ejectors 10 to 12 had high boattai l angles

Ejectors 1 o 9 were investigated with ei ther of two primary-nozzle-exit diameters corresponding to operation with f ul l afterburningand with no afterburning. "he rati o of nonafterbuming to afterburningprimary-nozzle diameter was 0.75.Ejectors 1 o 6 (figs. l(a) to (d)) were fixed-geometry types withvarious values of the geometrical parameters that affect ejector per-formance (such as expansion rati o, secondary diameter rati o, divergenceangle, etc.). Ejector 3had a divergent wal l contoured (by the method of ref . 1)to producenearly axi al flow at the exi t plane.

A l l ejectors except ejector 3 were conical.

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T w~M ~d i f l p ? t $ P o n b~y j ec tp ~+~tiproye ?;y$es$gn performanceare sho& f i Tlg& , f e r . : k#Zg w e J ):spotler r-q $0 pcourage j etseparatio"; A ??(7 ir'ih';fectfbn %fkbughMfrfulbf. sloes i h the divergentw a l l to encourage j et separation and to fill n excess flow area at theexi t plane.simultaneously.These techniques were investigated independently and al so

One type of variable-geometry ejector (7) that was investigated i sillustrated in figure l(f). he divergent portion was assumed to be com-posed of several leaves that could be rotated i n such a manner as to varythe e x i t area while maintaining a f ixed secondary diameter.Mach number (and simultaneously nozzle pressure ratio) decreased, the exitarea would be decreased to provide the correct ex psi on ratio. The two-step boattai l geometry that i s shown would resul t i n bigher boattai l dragat Mach 3 than would occur i f a single boattail angle had been selected,but i t would incur l ess drag with low-speed positions.ejector of thi s type was not constructed; but rather various posi tions ofthe movable portion corresponding to operation at various Mach numberswere selected, and models were constructed to simulate these conditions.

A s f l ight

An actual variable

Another variable-geometry ejector (8) that was investigated i s showni n figure l (g).be constructed of leaves that could be rotated to vary exi t area whilemaintaining a constant secondary diameter. However, i n this case theboattai l was kept fixed. A s a result, as exi t area decreased, base areaincreased. The model was designed with a removable base plate t o i nvesti -gate the effect of base bleed flow. Again, fixed-geometry models wereconstructed to simulate various positions of interest of the movable por-tion of the ejector.

A s with ejector 7, the divergent portion was assumed to

A thi rd ty-pe of variable-geometry ejector (9) that was investigatedi s shown i n figure l (h) .both fixed and tne secondary diameter was variable.was assumed to be constructed of leaves that were hinged at the exi t plane.A t the design Mach number the secondary diameter would be at i ts minimumvalue and would be large enough to permit the passage of the cool ingsecondary airf low.eter would be increased to permit the flow of suf f ici entl y large quantitiesof secondary ai r to f i l l i n the excess flow area at the exi t plane andprevent overexpansion of the primary flow. A s with the other variableejectors, fixed-geometry models simulated posi tions of i nterest of thehypothetical variable ejector.

I n thi s case the boattai l and exi t area wereThe divergent w a l l

A t lower than design Mach numbers the secondary diam-

A s indicated earl ier, ejectors 10 to 12 (figs. l(i) nd ( j ) ) hadhigher boattai l angles than those discussed thus far. They simulated afami ly of fixed-geometry ejectors with various values of the geometricalparameters.afterburning) was investigated with these models.only one primary-nozzle position tcorresponding to f ul l


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Tunnel I nstal lationA schematic sketch of the instal lati on of the model i n the tunnel i sshown i n f igure 2. The downstream portion of the wal l s of the 8- by6-foot test section have been perforated t o permit operation at any Machnumber from 0.6 to 2.1.attain a more continuous blockage area distribution for more uniform flowat transonic speeds. Primary and secondary air were ducted separately tothe model through the support struts.

The support struts were swept forward 45O to

Pi tot pressure prof i les normal to the body j ust upstream of the boat-tail are shown i n figure 3 for several tunnel Mach numbers.were placed i n the plane of the strut and also nor mal to it.location i s indicated i n figure 2.profiles, it appears that boundary-layer thickness was about 0.8 inch atMach numbers 2, 1, and 0.8, and about 1.3 inches at Mach 1.35.

Survey rakesTheir axialIgnoring unusual di storti ons of thy

Local Mach numbers (denoted by Mz) computed by means of the Fbyleighequation fram the local body stati c pressure and the Pi tot pressure far-thest from the body are shown i n figure 3. These Mach numbers show acircumferential variation that probably was due to the wake from thesupport strut. A t tunnel Mach numbers 2, 1, and 0.8, the l ocal Mach numberwas lower i n the region behind the strut, and at Mach 1.35 it was lower i nthe plane normal to the strut. The reason for this shift of the l ow Machnumber region as tunnel Mach number i s varied i s not apparent.

Boattai l static-pressure distributions also indicated a varying de-gree of circumferential variation. This variation was greater at highertunnel Mach numbers (e.g., Mach 1.35 compared with Mach 0.8) and alsogenerally with higher boattai l angles. The worst condition investigated(ejector 5 or 6) i s shown i n figure 4 at several tunnel Mach numbers.The boattai l angle i n this case was 7.5O. The region of lowest pressurewas behind the strut at Mach 1.35, but at Mach 1 t was i n the plane nor malto the strut. A t Mach 0.8 the pressures were fairly uniform,ejectors 10 to 12 had higher over-all boattai l angles ( i n two steps) thanejector 5, the pressures were more uniform. The pressures of other ejec-tors w i t h lower-angle single-step boattai ls were al so more uniform.

Although


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Al l ejectors were investigated at several Mach numbers. With ejectors1 o 12 several values of primary-nozzle pressure rati o were employed ateach Mach number, and with each pressure rati o several values of secondaryflow were investigated.several values of secondary flow was investigated at each Mach numberwith ejector 13.Only one primary-nozzle pressure rat i o w i t h

For ejectors 1 o 9 f ul l afterburning was assumed for Mach numbers1.35 and greater, and no afterburning for Mach numbers 1.35 and less.The assumption of the Mach number at which afterburning was turned on di dnot af fect the generality of the conclusions. For ejectors 10 to 13 f u l lafterburning was assumed to occur over the Mach number range of the in-vestigation.about 80 F. Total temperature of both primary and secondary ai r was

Data ReductionWeight-flow rates were obtained with standard ASME orifices.mary total pressure was cmputed from the primary weight-flow rate andmeasured stati c pressures i n the primary nozzle upstream of the con-vergent- portion. Secondary total pressure was measured with rakes up-stream of the primary-nozzle-exit station.

Pri-

Because the force-measurement apparatus did not perform with con-si stent accuracy during the test, ejector gross thrust (exit-plane totalmomentum) was generally computed from the sum of the total mamentum ofthe primary and secondary streams at reference stations within the ejectorplus the sum of w a l l forces i n the axial di rection between the referencestati ons and the exi t plane. I n general, this procedure gave satisfactoryresul ts. Ekceptions occurred when large quanti ti es of secondary airflowwere used (speci fical ly, the exceptions were ejector 8, Mach 1.35 with noafterburning, and ejector 9, bkch numbers 1.35 and 1.0 with no afterburn-ing).ceeded the maximum theoretical value with the given secondary and primaryweight-flow rates and total pressures.i n fi gure 5 for ejector 8.of adjusted thrust rati o (computed frm the gross thrust obtained by theprocedure described) exceeded the maximum possible value at very highvalues of secondary-flow ratio. Thi s did not occur at Mach 1.0 (fig.5(b)), which was the more typical situation. I t i s believed that thiserror was a resul t of circumferential variations of the secondary flowthat were not detected with the instrmeotati on employed and that became

I n these cases the thrust computed by this procedure slightly ex-This discrepancy i s illustratedA t Mach 1.35 (fig. 5(a)) the measured value


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important only when the secondary-flow rate was unusually large. For theseexceptional cases, the maximum theoretical values were used i n the A.NALYSISsection.With the modified versions of ejector 1(i .e., with spoi lers and withair injectionj the wai i surfaces were too irrzg-L lar to evsl i ~tehe v a ~force.strai n gage and bellows arrangement) were used of necessity.configurations the apparatus appeared to be operating reasonably well.

Therefore, the data from the force-measurement apparatus (aFor these

Thrust RatioIn the ANALYSIS section of the report an effective thrust rati o

(F - msVg - D)/Fithrust rati o F/Fi and the boattai l plus base drag D. A t some Machnumbers where these data were not obtained, an estimated value for smallsecondary-flow rati o was computed by the following procedure: (1) fthe expansion rati o was correct for the particular nozzle pressure rati o(ful l y expanded), a 2-percent loss i n gross-thrust rati o was assumed toaccount for f ri cti on l osses i n the nozzle.gross-thrust rati o due to flow divergence at the exit plane were computedassuming F/Fi = (1+cos a)/2. (3) I f the primary flow was underex-panded, the additi onal loss i n gross-thrust rati o was computed from acalculation of exit-plane momentum.expanded, estimates of gross-thrust rati o were made based on earlier un-published data.(6) The configurations for which these estimates were made did not havebases; therefore, base drag was not needed.

i s evaluated that required a knowledge of the gross-

(2) Additional losses i n

(4) I f the primary flow was over-(5) B o a t t a i l drag was computed from reference 2.

The basic data are presented i n figures 6 to 22, Parameters pre-sented are thrust ratio, ejector pressure ratio, boattai l drag coeff i -cient, and either base pressure rati o ( i f a base existed) or exi tstatic-pressure rati o as functions of secondary-flow ratio.static-pressure rati o i s useful as an indication whether or not the pri -mary flow i s overexpanded.

The exit

ANALYSISThe data of figures 6 to 22 have been used i n an analysis of theperformance of the ejectors over a Mach number range to obtain a compar-ison of the solutions considered for the off-design ejector problem. A s

a basis for canparison, nozzle pressure-ratio schedules with Mach numberwere assumed as shown i n figure 23. Two schedules were used: the


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currently or planned f or the near future, and the schedule f or ejector13 i s f or an advanced, hypothetical, low-pressure-ratio turboj et usinga transonic compressor with a design Mach number of 4.The performnce parameter upon which the analysi s i s based i s aneffective thrust rati o (F - msVO - D)/Fi, defined as the ejector gross

thrust minus the free-stream momentum of secondary ai r minus the drag ofthe boattai l and base (if here i s one) divided by gross thrust of theideal ful ly expanded primary flow. W i t h this parameter, configurationsdesigned for a given engine and nacel le si ze but having di f ferent after-body geometries and secondary flows can be compared di rectly.

Fixed Geometry and Low Secondary FlowI f a fixed-geometry ejector i s designed to provide peak performanceat a particular design Mach number, and i f off-design performance i s nota consideration, then the ejector of necessi ty must have the correctexpansion rati o f or that Mach number, and the flow divergence at theexit plane must be smal l . Ejectors 1 o 3 are of this type with a designMach number of 3. Assuming that a 2-percent secondary-flow rati o i ssuf fici ent f or cooling purposes over the Mach number range 0.8 to 3, theperformance of these ejectors i n thi s Mach number range i s shown i n f ig-ure 24.speed range with no afterburning operation. Ejector 2, which had alarger secondary diameter than ejector 1, showed better j et separationcharacteri stics than ejector 1only at h c h 0.8.ejector 3 with a contoured divergent wal l was about the same as that ofthe conical ejectors.

Performance of al l three ejectors was very poor i n the transonic

The performance of

The off-design performance of these fixed-geometry ej ectors can beimproved, at the expense of on-design performance, i f the divergenceangle i s increased or i f the expansion rati o i s decreased. A higherdivergence angle would improve the j et separation characteristics andthus reduce the degree of j et overexpansion (although the pressures i nthe separated region may sti l l be lower than i s desirable because of thebase-pressure phenomenon (ref. 3)),. With a smaller expansibn rati o, thef low would not be as badly overexpanded at off-design conditions.With ejector 4 the expansion rati o was the correct value for Mach 3operation, as with ejector 1, but the divergence angle was increased from

9' to 25O. The performance of this ejector i s compared with that ofejector 1 n f igure 25, again for a flow ratio of 0.02.number afterburning performance of ejector 4 was estimated to be somewhatless than that of ejector 1because of the higher divergence angle, butlarge improvements i n performance occurred at Mach numbers 0.8 and 1.0.However, no improvement was attained at Mach 1.35 with no afterburning.the afterburning had been continued to some lower Mach number than Mach

The high Mach

I f


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......................... . 0 . . . .. ................ ...............................NAcARME5&1ba.... . e .e 0 . c Q N F . I e i 0 . 0 . . 9With ejectors 5 and 6 the expansion ratio i s decreased to that cor-With 2-percent flow rati oesponding to complete expansion at Mach 2.2.the performances of ejectors 5 and 6 were identi cal and are also com-

pared h3th tkt ~f e;ezt=r 1 i n figlze 25.underexpansion losses were appreciable (near Mach 3), ejector 5 or 6provided higher performance than ei ther ejector 1or 4. The loss i nperfomnee of the compromised ejectors ( 4 to 6) wits about the same atMach 3, but ejectors 5 and 6 were superior at al l other Mach numbers.Therefore, i t appears that a decreased expansion rati o i s a much bettercompromise than an increased divergence angle.

Except for the reginn wher e

Fixed Geometry and High Secondary FlowThe reason a fixed-geometry ejector performs poorly at Mach numbersless than design i s that the exi t area i s too large f or the avai lablepressure ratio. If the secondary flow were increased suff iciently atthis condition, it would f i l l i n the excess exi t area and prevent over-expansion of the primary flow. I n designing a fixed-geometry ejectorthat wi l l employ this technique to improve the off-design performance,it i s necessary to select a proper value of secondary diameter to opti -mize over-al l performance. It i s desirable that there be suff ici entsecondary flow to prevent primary-flow overexpansion and al so that thesecondary flow have as high a total pressure as possible so that over-al l performance wi l l be hi gh. If the secondary diameter i s too largefor the amount of secondary flow being used, then throttl ing losses ofthe secondary air would occur, with an accompanying l os s i n ejector per-formance. On the other hand, i f the secondary diameter i s too small,it may be impossible to pass suf f ici ent ai r at the available pressure."he effect of increased secondary f low on off-design ejector per-formance i s shown i n figure 26 f or ejectors 3 and 6 and for two posi-tions of the variable portions of ejector 9.Mach 1.35.mum values for the various exi t diameter ratios. The effective thrustrati os increased rapidly as flow rati o increased even though f ul l free-stream momentum of the secondary air was charged against the ejector.

Thus, large gains would be realized i f the drag and weight of the in letsystem that provides the additional ai r can be kept low.

These data were obtained atThe secondary diameter ratios were not necessari ly the opti-

One method of obtaining this additional air i s the use of auxiliaryinl ets. Another method that was considered i n detai l i s the use of theexcess air-handling characteristics of a fixed-capture-area mai n inletat lower than design speeds. Typical of i nlets of this type i s the onei l lustrated i n the sketch of f igure 27.surface i s varied at each Mach number soas to maintain an in let mass-flow ratio of 1, and excess air i s disposed of through some sort of by-pass system (see ref . 4).With this inlet the compression

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of t hi s type, the schedule of bypass mass-flow ratio i s shown i n figure27.and use it i n the secondary passage of the ejector (assuming an after-burning primary temperature of 3500' R and a nonafterburning temperatureof 1600 R), then maximum available secondary-flow rati o would be asshown i n f igure 27.tional total-pressure losses i n ducting the bypass ai r back to the ejec-tor, and taking the upper schedule of nozzle pressure rati o of figure 23,the maximum available ejector pressure rati o becames that shown also i nfigure 27. In the analyses that follow, where secondary air i s assumedto be obtained from the i nl et bypass, the limits of available weightflow and of avai lable pressure shown i n this f igure wi l l apply.i cal problems of ducting large quanti ties of high-pressure ai r aroundthe engine are not considered.

If i t were possible to duct al l of this bypass air around the engine

Estimating inl et pressure recovery, assuming addi-

Mechan-

Figure 28 shows the improvement i n performance of ejector 6 whenlarge amounts of secondary air are supplied by the i nl et bypass. I nthi s case the secondary-flow rate (also shown i n the figure) was re-stricted by the pressure l i m i t . Although the secondary diameter rati oselected f or thi s ejector was not necessarily the optimum, the -rove-mentin performance was large.compromised version of a Mach 3 ejector (i.e., the expansion rati o i sless than ideal at Mach 3). I3ata at high secondary-flow rates were notobtained with ejectors that were not compromised (e.g., ejector Z) , butthe beneficial effects of high secondary flow would be obtained withthese ejectors also.

A s discussed earl ier, ejector 6 i s a

The effect on performance of using spoi lers with ejector 1 s showni n figure 29. The spoi lers were assumed to be retracted f or high-speedafterburning operation and extended for transonic nonafterburning oper-ation. A t Mach numbers 0.8 and 1 he spoi lers caused j et separation asthey were intended to do, and hence improved performance relative to thebasic unmodified configuration, but fai l ed to do so at Mach 1.35. Evenwhen the j et did separate, however, the pressures i n the separated re-gionwere st i l l less than po because of the base pressure phenomenondescribed i n reference 3. Thus, performance remained rel ativel y low.Usi ng i nl et bypass air, air injection with the spoi lers eliminated theloss i n performance at Mach 1.35 as shown i n the figure, but the result-ing performance was no better than that of the basic ejector, At Machnumbers 0.8 and 1 he performance was about the same with air injectionplus spoilers as with the spoi lers alone. With air injection alone( w i t h the air again supplied by the i nl et bypass) , about the same im-provement i n performance was attained at Mach numbers 0.8 and 1as withthe spoilers, but there was no improvement over the basic ejector atMach 1.35, The secondary-flow rates again were l imited by the pressureavailable.


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Although the level of performance was low, a further comparison ofthe performance of the basic ejector 1with the performance with ai r in-jection i s presented i n figure 30. A t Mach 1.35 (f ig. 30(a)) the per-formance of the basic ejector was higher at a given flow rati o than thatwith air injection. Therefore, at this Mach number it would be betternot to use the air-injection sl ot s and to pass ai l am.ils%leaec~z&~qy30(b)) sl ightly higher performance was obtained at a given flow rati owhen air injection through the s l ot s was employed. A t Wch 0.8 (fig.30(c)), the performance was higher when the slots were employed, even

l air through the secondary passage of the basic ejector. A t Mach 1(fig.

I w i t h zero secondary f low, than with the basic ejector. Increasing sec-ondary flow through the slots produced relatively small improvements i nperformance.open the primary f l o w did not overexpand internal ly as much as w i t h thebasic ejector.

Wal l pressure distributi ons showed that with the sl ots

Variable Geometry and Low Secondary FlowAn ideal ized variable-geometry ejector would have the followingfeatures:ratio, (2) variable secondar y diameter t o produce a divergent shr oud f oreach exi t position, (3) variable boattai l angle to avoid base area asexi t diameter i s varied, with leaves suff iciently long that boattai ldrag i s negligible. An exit of this type m s not tested, because withthe nozzle always on design and with negligible drag the effective thrustratio i s known to be about 0.97.

(1)variable exi t diameter to obtain the ideal expansion

A simpler version of this exit was investigated and i s designatedThe secondary diameter was kept fixed as exi t area varied,jector 7.and internal and external l ines were varied w i t h a single set of leavesthat were short, and therefore boattai l drag was not negligible. Theschedule of exi t diameter rati o employedis shown i n figure 31.ejector was designed so that the ideal expansion rati o was attainablefor afterburning operation between Mach numbers 1.35 and 3.assumed that during the transiti on from afterburning to nonafterburningoperation at Mach number 1.35 the exi t area was not changed.sul ted i n overexpansion at Mach 1.35 (nonafterburning) .1and 0.8, the exi t diameter was near the ideal value.numbers 1and 0.8 the exit diameter was less than the secondary diam-eter (since the l atter was kept fixed), with the result that the shr oudwas convergent rather than divergent.relatively low thrust particularly at low secondary-flow ratios and highprimary pressure ratios.at least as large as the secondary diameter and permit overexpansion (asat Mach 1.35, nonafterburning) or to determine some optimum intermediateexit position.that would permit secondary diameter to vary as the leaves rotated mightavoid this problem.

TheI t wasThis re-

A t Wch numbersHowever, at MachSuch a configuration can have

A lternatives would be to keep the exi t diameter

The selection of a different pivot point of the leaves

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The performance of ejector 7 i s presentedin figure 32 f or 2-percentflow ratio. Also shown for reference i s the estimated performance of theideal variable ejector described earlier. Although ejector 7 would have


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shown i n f igure 36 where this problem occurred. The performance at Mach3 again would be less than that of the ideal ejector because of boattai ldrag and because the flow was slightly underexpanded (de/$ = 1.6) . Thedrop i n performance f or nonafterburning operation occurred because thesecondary total pressure was less than free-stream total pressure as aresul t of the losses ass-med i n the maxi -pressure-rati o schedule offigure 27.Comparison

The best performing ejectors of those considered thus far are com-pared i n figure 37.high secondary flow was within the range of performance encompassed bythe more cmplex variable-geometry ejectors.i n the low Mach number range was obtained w i t h ejector 9.The performance of fixed-geometry ejector 6 with

The highest performance

Ejectors with N l fterburningqectors 10 to 13were investigated with f ul l afterburning over theenti re speed range. The supersonic performance of ejectors 10 to 12 hasbeen obtained i n an earl ier investigation, and the speed range i s ex-tended i nto the transonic range i n the present report.of these ejectors based on the same pressure-ratio schedule as that ofthe previous ejectors i s shown i n f igure 38 f or 2-percent flow rati o.Ejector 10, which differed from ejector 11only i n that it had a smallersecondary diameter, had about the same performance as ejector 11.cause these ejectors had high boattail angles representative of somefuselage-type instal lations, boattai l drag was high, and thus the generallevel of performance was low.(corresponding to complete expansion at Mach 3) than ejectors 10 and l l .For a given engine and fuselage size, an increase i n expansion rati owould resul t i n an increase i n exit area and hence a reduction i n boat-tai l area.ratio at off-design conditions would at least be partly compensated f orby the decreased boattail drag.construction, ejector 12 had a smaller primary-nozzle area than ejectors10 and 11; whereas exit area, fuselage area, and boattai l geometry wereidentical. Hence the data of figure 38 do not show the net ef fect of asimple change i n expansion ratio, but rather show the effect of Machnumber on the performance of various ejector geometries. As with ejec-tors 10 and 11, the level of performance of ej ector 12 was low becauseof high boattai l drag, but additional losses occurred with ejector 12because of the greater degree of overexpansion of the primary flow.

"he performance

Be-

Ejector 12 had a higher expansion rati o

The increased overexpansion losses w i t h the higher expansionHowever, because of details of model


15/62

The ef f ect of secondar y f l ow on t he perf ormance of ej ect ors 10 t o12 at Mach 1 i s shown i n f i gur e 39.f or mance occur r ed as f l ow r at i o i ncreased.Agai n, appr eci abl e i ncr eases i n per -

The ef f ect of secondar y f l ow on t he perf ormance of ej ector 13 i s Ishown i n f i gur e 40.t hat f or t he pr evi ous nozzl es ( see f i g. 23).crease i n p e r f o mc e as a resul t of i ncreasi ng t he f l ow r at i o di f f er edw th Mach number but was appr eci abl e at al l Mach number s. The gr eat esti mprovement occur r ed at Mach 15

The nozzl e- pr essur e- r at i o schedul e was l ower thanThe magni t ude of t he i n-

SUMMARY OF RESULTSThe of f - desi gn per f or mance of f i xed- and var i abl e- geomet r y di ver gentej ectors has been i nvest i gat ed.operat i on at Mach 3 and wer e i nvest i gat ed i n t he Mach number r ange 0.8t o 2 The f ol l ow ng r esul t s wer e obt ai ned: I

The ej ect or s wer e desi gned f or t ur boj et

1. Lar ge per f ormance l osses occur r ed at of f - desi gn Mach number swith si mpl e f i xed- geomet r y ej ectors desi gned f or peak perf ormance atMach 3.2. Compr omsi ng desi gn per f ormance by i ncr easi ng the di ver genceangl e or by decreasi ng t he expansi on r at i o pr oduced l ar ge gai ns i n of f -desi gn per f ormance.t han an i ncr eased di ver gence angl e.A decr eased expansi on r at i o was a bet t er compr omse3 I ncreasi ng t he secondar y ai r f l ow t o f i l l i n t he excess exi t ar eaof f i xed- geomet r y ej ect or s at of f - desi gn condi t i ons pr oduced l ar ge gai nsi n perf or mance and made themcompet i t i ve wi t h f ai r l y compl ex var i abl e-geomet r y t ypes.4. Var i abl e- expansi on- r at i o ej ect or s wi t h compr om ses t o r educe Imechani cal compl exi t y pr oduced per f ormance r easonabl y cl ose t o t hat ofan i deal var i abl e ej ect or. I5. An ej ector wi t h a f i xed exi t ar ea and a var i abl e secondar y di ameter w th high secondary ai r f l ow pr oduced t he best perf ormance of t het ypes i nvest i gat ed.

Lew s Fl i ght Pr opul si on Labor at or yNat i onal Advi sory Comm t t ee f or Aer onaut i csCl evel and, Ohi o, J ul y 15, 1958


16/62

1. Cl j . ppi nger , R. F.: Supersoni c Axi al l y Symmet r i c Nozzl es. Rep. No.794, Bal l i s t i c Res. Labs. , Aber deen Pr ovi ng Gr ound, Dec. 1951.Coni cal Boat t ai l s .2. zaCk, john x. ; yL ieoretical&zaa-L-e n4 n + r i h . r + i nna nni4 Wn i r e rtraI u u I ~ Y u " I v I I " W Y U ..I._--gs f orNACA TN 2972, 1953.

3. Baughman, L. Eugene, and Kochendor f er , Fred D: J et Ef f ect s on BasePressures of Coni cal Af t er bodi es at Mach 1.91 and 3.12.E57E06, 1957. NACA RM4. Ger t sma, L. W, and Behei m M A: Per f or mance at Mach Number s 3,07,1.89, and 0 of I nl et s Desi gned f or I nl et - Engi ne Mat chi ng Up t o

Mach 3. NACA RM E58B13, 1958.


17/62

16

MIt

* B-Pcd

a3r l

U

9N

Lorl"0.0.r l

-0N

Inr l

0 u!r l

coM??

9N-r l

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20

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18/62

Ej ect o r 2 Te7

( a ) Ej ect o rs 1 and 2: dp, nb/ dp, ab = 0. 75; dm dp, ab = 2.0.

L

de/ dp, ab = 1. 8ds/ dp, ab = 1.05.- 1. 21' / dp, ab = 2. 37

7 vdp, ab 0. 875B = 3. 50a = 23

5 = 20 e j e ct o re j e ct o r

L

de/ dp, ab = 1. 75dg ds/ dp, ab = 1. 057 l / dp, ab = 2. 37

7L 0 = 20dg/ dp, ab = 1. 78( b ) E j ec t or 3: dp, nb/ dp, ab = 0. 75; d,/dpab = 2 . 0 .

de/ dp, ab = 1. 45ds/dp,ab = 1. 05 ( e j ec t o r 5)= 1. 21 ( e j ec t o r 6)L/ dp, ab = 1. 26

B = 7. 50a = g o (e j ec to r 5, )- 6.5' ( e j ec t o r 6)

( d ) Ej ec t or s 5 and 6: dp, nb/ dp, ab = 0 . 7 5 ; dmdp, ab = 2. 0.F i gure 1. - Ej ect or geometr i es.

e j e ct o re j ect o r


19/62

18. . . . . ................................................ ....................... 0 . 0 .0 .. : *e : e NJCAiRM E58GlOa0 .

( e ) E j e ct o r 1 wi t h s po i l e r s a nd ai r i nj ec t i on.C . 0 6 2 5 dp, ab ( a l l Slots)

de/ dp, ab = 1. 8 ( a t M = 3)ds/ dp, ab = 1.05. / dp, a b = 1.55 , = 7'

.-6, = -11.5' ( at M = 3)1- 1' I= 14 ( a t M = 3)( f ) Ej ec t o r 7: dp, nb/ dp, ab = 0.75; d,,/dpab = 2. 0.

de/ dp, ab = 1.6 ( a tds / dp , ab = 1.05

B = 6.5'

M = 3 )l / dp, ab = 1.69a = 9.5' ( at M = 3)-dJ dp, a b = 2.0.

de/ dp, ab =ds/ dp , ab = 1 OSl /dp,; b = 1.69p = 5a = 9.5O ( a t MI -( h) Ej ec t o r 9: dp, nb/ dp, ab= 0.75; dm dp, ab = 2.0 .

F i gur e 1. - Co nt i n ue d. E j e c t o r g eo me t r i e s .

( a t M = 3)

= 3)

.......................... .................. ................. 0 . 0 . 0 .. . .. 0 . 0 .0 . 0 .......0 . . . . ..........................


20/62

= 1. 21 (e j ec to r

a = 125 ( ej ector 10)8. 50 ( ej ect or 11)dB/ dp, ab = 1 5(I) Ej ect ors 10 and 11: dp, nb/ $, ab = 1.0; d, J dp,ab = 2.5.

I -1. -k) Ej ector 13: dp, nb/ dp, ab = 1.0; d, , , /dp,ab = 1. 45.Figure 1. - Concl uded. Ej ect or geometr i es.

19


21/62

20. . . . . . . .......................... . 0 . 0 . ........................ ...................... . t w a m~. t :..WCq RM E58G10a. .... . 0 . 0 .

br l

.......................... .................. . ................ 0 . 0 . 0 .. . 0 . . 0 . 0 .a 0 . 0 .......a 0 . 0. ..........................


22/62

......................... . 0 . . . ........... .................................... 0 . . 21. e....ACA RM E58G10a : .e: CbNE I i I &p~~. . ~. 0 . . . .

L1A ( a) Mach number , 2.0.

0 .1 .2 .3 .4 .5 .6 .l .9 1. 0Rati o of Pi tot t o fr ee-st reamtotal pressure, P1/Po( b) Mach numher , 1.35

Fi gure 3. - Pi t ot pressure prof i l es upstr eamof boatt ai l .

.................................................. . . . . .... e . 0 . .0 .......................... 0 . . 0 . . ............... . . . .CONFI DENTI AL


23/62

22

.

I

0 .* . CONFIDENTIAL

T i-rlLd-P-PLd0P+0Ekt-'r nPI7 t0 :a,r iv ik0kPIa,k30ma,kPI-P0-P

i

Gaa,a7r-lVe0uI

Ma,2l.dR


24/62

NACA RM E58G10a COWIDENTIAL I 23

.9(

0-%8 .94

.9c

.86

.82

.78

( a)Mach number, 1.35.F&ur e 4. - Boattail static-pr essure distribution with 7.5O boattall angle.

CCI NFI DENTI AL


25/62

Crn ID ENT IAL NACA RM E58G10a

1. 14

0P:.98

*82

.7 4

.660 1 2 3 4

L ocatlm- 0 Aar mal to strut0 Behind S t N t

6 I- ~ Station froas beginning of boattai l angle, in.(b) MBch number, 1.0.

p&ure 4. - Continued. Boattail stati c- peeure diatrlbutlon with 7.S0 boattall angle.


26/62

NACA RM E58G10a

Flow

......................... . 0 . . . .. 0 . 0 . 0 0 . . ....................... ....... 0 . 0 . . 0 . 0 . .......... .......................... .

CONFI DENTI AL 25

1,oo

.98

96

* 92

,go

LocationNormal to strutBehM strut

I-

. - 0 1 2 3 4 5 6 7 8Station frombeginning of boa t ta i l W e , i n.( c) Mach nr, 0.8.

F i gure 4. - Concluded. Boattail statio-preasure distri bution w i t h 7. 5O boattai l angl e.

.......... .......................0 . 0 . . . . ..... 0 . 0 . ................ ....... 0 . 0 . 0 . . ................................ . . . . .


27/62

................................ . . . 0 . 0 . 0 ....... . ....................................... ........... . . .. .. 0 . .... 0 . . 0 . 0 .26 CONFI DENTI AL NACA RM E58G10a

0.rlFr

k

4JmE5 ( a) Mach number , 1.35.

Secondar y- f l ow r at i o - i$' wP( b) Mach number , 1.0.

F i gur e 5. - Compar i son of measur ed and maximum t hrust ra t i os f or ej ec tor 8wi t h no af t er bur ni nR.

....................... ................ . ................. 0 . . 0 . . ............................. 0 . . 0 . 0 .. 0 . 0 . 0 .. 0 . 0 ......... . .CONFI DENTI AL


28/62

NACA FME58G10a

r- W In?

................... 0 . ............ . ....

. . .............. .Crn IDENTIAL

. . . . ............... 0 . ...........

27m

Sm

w .c mG O3 .ale- E

00

- .? ?m c

-rl N

A e

9rl

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30Ui

0

e-

rlh000(u.-,uu

CONFIDENTIAL


29/62

............................. . 0 . 0 .. 0 . 0 . 0 ... . . .......... . 0 ....... . ....................................... ..........0 . .28 CONFIDENTIAL NACA RM E58G10a

. 7

.6

.5

. 4

.3

.2.3 .6 .6

.2 . 4 .4

.1 .2 . 2

0 0 00 .005 . 01

d m . .l d ML. 4r f i a a ul d d a o n0 v uu ddc G nm -. 05 -m5 0

1.2 1.21. 4I O2 a?a L Qd r t Rm m .. 1.0e ou L -m Q4* r lw f i

1 .om 1 .o

.8 .80 .02 .04 .06 0 .02 .0 4 . 6 .08 0 .02 . 04dS ec o nda r y - f l o w r a t i o , -;E

( a ) No a f t e r b u r n i n g; Ma c h ( b ) No a f t e r b ur n i n g; Ma c h ( c ) No a f t e r -b ur n i n g; Ma c hnumber , 0. 8.

number , 1.35. number , 1.0.

F i gur e 7. - P e r f o r ma n c e of e j e ct o r 2........................ ........... 0 . 0 .. . . . .................... .. 0 . 0 ........ . . 0 .0 . . . . .............................. . CONFIDENTIAL


30/62

......................... . 0 . . . .. 0 . 0 . 0 . . ....................... . ................ ........................... . 0 . 0 . .. 0 . 0 . .NACA RM E58G10a 29ONFIDENTIAL

9r(kf43E.Md

Dal+P-v

.......... .......................0 . 0 . 0 . . 0 . 0 . .. . . . . . . . . . . . . . . ....... 0 . 0 . a . . ................................ . . . . ..... .


31/62

. 0 . . . . .........................30

.9

.8

.7

.6

.5

CONFIDENTIAL

.6

.5

. 4

.3

.2

NACA RM E58G10a

.9

.7

.6

.5

.9

.8

.7

.5.6 .3 .5 .6a%.

04m

.2 . 4 .54-3 .2 . 1 .3 . 4malah o 0 .2 . 3J0c)wa -.2 - . l .1 .2(11 . 04 .02 .04 . 04MU

L -ec,d ( u

*d* 4KILoa,

2; .02 . 01 .02 .020 0 0 0

.8 .8 1. 1 1.0I O2 a,?c) h 0KI2a

c ) mm010c) h dX dW k

. 6 . 9 .94 a*

A .4 . 7' - 0 . 02 . 04- 0 .02 . 04 . 06- ' 0 .02 . 04 .06'"0 .02 . 04

S ec o nd ar y - f l o w r a t i o , 2( d) No a f t e r -bur n i ng; Machnumber , 0.8.

( a) Af t e r b ur ni n g; ( b ) No a f t e r b ur n i ng; ( c ) No a f t e r b ur n i ng ;Mac h number , Mac h number , 1.35. Mac h number , 1.0.1.35.F i gur e 9. - Pe r f o r ma n c e of e j e c t o r 4........................ ..........

...... . . . . . . . . . . . . . . . . .e * e . . . ............................. 0 . 0 .0 . 0 .. . ..0 . 0 ......... . . 0 .CONFIDENTIAL


32/62

NACA RM E58GlOa

......................... . . . . .. 0 . 0 . 0 . . ........................ ....... 0 . .e.. 0 . 0 . .......... ........................ . a .

CONFIDENTIAL 31

Secondary-flow r a t l o , 2P y$( c) NO afterburning;Mach number, 0.8.

( a) No a f t e r bur n i ng; Mach number , 1.35. ( b) NO af t e rburni ng; Mach number, 1.0.

F i gur e 10. - Performance of ej ector 5.

.......... ........................ 0 . . . . ..... 0 . 0 . .. . . . . . . . . . . . . . . . ....... 0 . 0 . a . . ................................ . . . . .

CCTNFI DENTI AL


33/62

................................ . . e e . e . 0 ....... e . . . . . . . . . . . . . . . .. 0 . .... . e ........................ ..........e . . .. e e . 0 .32

3 3 3 3

CONFIDENTIAL

9 9

NACA RM E58G10a

i 4Y)

Y

=

N.

1

,. - 03

Y)

3

LD

?

ErmM3EPuczm..-.Y

CL)k0c,0a,na,k0a,(dEk0kka,PII

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2

2l


34/62

......................... . 0 . . 0 . .. 0 . 0 . . 0 . . ......... . . . . . . . . . . . . . . . ................ .......................... . 0 . 0 . .. 0 . 0 . .NACA RM E58G10a CONFIDENTIAL 33

dek

.3 .3 .3aI l kd ;P,Re d\

- &. k .2 .2 .2.02 .02 .03

d lrl MdSc l l d % C I P

0 0 . 01i .0 1.0

0

2t a" .8 .9Q0d .+ od ++m .6 .8

A .7.-0 .02 .04 .06 0 .02 .04 .06 0 . 2 .04 .06Secondar y - f l ow ra t i o, -

( a) No aft erbur ni ngj Mach ( b) No af t erbur ni ngj Mach ( c ) No af t erbur ni ngj Machnumber , 1.35. number , 1. 0. number , 0.8.F i gu r e 12. - Per f or mance of ej ect or 1 wi t h spoi l er s .

.......... .......................0 . 0 . 0 . . 0 . . e .. . . . . . . . . . . . . . . ....... 0 . 0 . 0 . . ................................ . . . . ..... .C r n I D r n I A L


35/62

* a ..a * a . a * * * . *a a * * a * * . . * aa * . * . a a . a a . a . . a a .a . . a .a . * * a . a * .a . a . a a .a * . a * * a a . a .aa . a a. aa * . . a * a * * * *. a a * *. .a * * a . a * .. . . a * . a * . a34

c -- b?P i m?r(

CONFIDENTIAL NACA RM E58G10a

2I:a .c o3 .eF.ha ,ale EG 4 3c

..,5?

0z0h-

92r(

e35:9..bodE3PIm0ze--

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CONFIDENTIAL


36/62

.......................... . . . . . . . . . . . . . . ........... ..e me * ..e. 0 . e...... 0 .0 . .. 0 . .NACA RM E58G10a CONFI DENTI AL

* *

Y

0

N 0

N9 0

. 0 . . 0 . ..............0 . 0 . e...........

93

ce3.cc

3MC3

e,

0e

4

m--

COWIDENTIAL

35


37/62

.........................0 . 0 . 0 .0 . 0 .. . . 0 . ........ . .. 0 . 0 ....... . ....................................... .............. 0 . .NACA RM E58G10a6 CONFIDENTIAL

n ?.

N rl 0

m

(D v ) N.

u) M. r l rl I n

d N9 9

I9-r0

h9

N 9 m 0WD

4v

30rlI

a000I

m

....................... ........... . 0 . 0 .. 0 . 0 ........ . . 0 .. 0 . . . . ............................................ ....... 0 . . CO m DENT AL

chv0nc


38/62

......................... . . . . .. 0 . 0 . . ......... . . . . . . . . . . . . . . ....... 0 . . . . 0 . 0 . .......... ........................ .... .

NACA RM E58G10a CONFIDENTIAL 37d9

N9

09

1sO. . .a mmmU Z .r (G 0 .m .. 7 4b o -C G -Zda , a- E 9 92322

800

h 0 h0 9(

9 ? (0

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I

v)akrl. 1 .

0

m9W9

d9

N9

d 0mN. 9

r?'d

Be1

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02a-

9 9. .CONFIDENTIAL


39/62

38. . . . . . . ............................... . ................. . 0 . 0 .0 . . ........ . .. .... . . ........................ 0 . ..........

d 3 3 3

CONFI DENTI AL

3

3* N9 9

NACA RM ESBGlOa

3 3

F0ci0e,.T-Je,L

3 4

COIWIDENTIAL


40/62

em. eem mm ee e m m mm eem. meme

NACA RM E58G10a C O N F I D E N T I A L

m * 09 9

39

.030he3

i : .OMInz *dM -c aeCh m3-mU0zmhv

MDda%.I9rlhm1I:VzMC3mU0ze

e

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C O N F I D E N T I A L


41/62

.e 0 .0 e,. *e. e... e.. e... .e.. e . e* * m.e e . . . . e *

40

.9

.8

.7

CONFIDENTIAL NACA RM E58G10a

.9

.8

.7

.9

.8

.?

. 2 .3 .3ahln\w wh a2 I%@a ~ . 1 . 2 . 2::t ' c,V d( u kw3 0 .1 . 1

.03 .09 .04. - ? I'2hoc;Q d k C F1+ h aJ ( uvd a O d0 v u

.0 2 .07 .02v O .6 1. 0 1. 0

.r i a4 k F9d 3 c 4Plnmu ] -.w oa, k d(D P42d .9m . 5 0 .02 .04 0 .02 .04 0 .0 2 .04i n

Secondar y- f l ow r at i o, -s EP( a) No af t er bur ni ng; ( b) No af t er bur ni ng; ( c ) No af t er bur ni ngjMach number , 1. 35; Mach number , 1.0; Mach number , 0. 8;de/% 1. 53. de/ % 1. 53. de/ dp, 1. 53.F i gur e 17. - Per f or mance of ej ect or 8 wi t hout base f l ow.

.e 0 e ..e *.*e e 0 e.. ..e 0. . 0 0 .. ...e .e.

0 . e. e e. .*e .* e e.. e... e.. ...e . e *e... e . e . e . e .

e . .e .e . .e e ..e .. e e m e e . e *e 0 . e .. e . . .e e . . . . 0 . COKFIDENTIAL


42/62

......................... . . . . .. 0 . 0 . . 0 . . ....................... . ....... 0 . 0 . . . .... . 0 . 0 . .......... .......................

NACA RM E58G10a CONFI DENTI AL

N d rl

Lo M rl mrf rl 4

....... ........... . . .0 . 0 ................................. . .

rl In

................0 . 0 . .. . b 0 . .. ....... .........

41

mhwaa,4aGE

CONFIDENTIAL


43/62

. . . . ............. .. 0 . ...........

42

.........................0 . 0 0 . 0 . 0 .................... . 0 . . 0 . 0 ............. ..........CONFIDENTIAL NACA RM E58G10a

(Drl

..9rl9

rlF-aP5m

m

....................................-m2?3s ?TXZ0 ..... : . a W O a = :... 0 . . ............. . ........ .......................... 0 . 0 . 0 .. 0 . . 0 . . CONFIDENTIAL

Al daa,VI

M.iC3Pa40zav

dtmr-

a

Documents

Off design performance of divergent ejectors