INVESTIGATION ON THE PRESSURE MATCHING PERFORMANCE OF THE CONSTANT AREA SUPERSONIC-SUPERSONIC EJECTOR. Jian CHEN, Zhenguo WANG*, Jiping WU, Wanwu XU

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1 INVESTIGATION ON THE PRESSURE MATCHING PERFORMANCE OF THE CONSTANT AREA SUPERSONIC-SUPERSONIC EJECTOR by Jan CHEN, Zhenguo WANG*, Jpng WU, Wanwu XU Scence and Technology on Scramje Laboraory, Naonal Unversy of Defense Technology, Changsha, Chna The pressure machng performance of he consan area supersonc-supersonc ejecor has been suded by varyng he prmary and secondary Mach numbers. The effec of he prmary flud njecon confguraons n ejecor, namely perpheral and cenral, has been nvesgaed as well. Schleren pcures of flow srucure n he former par of he mxng duc wh dfferen sagnaon pressure rao of he prmary and secondary flows have been aken. Pressure raos of he prmary and secondary flows a he lmng condon have been obaned from he resuls of pressure and opcal measuremens. Addonally, a compuaonal flud dynamcs analyss has been performed o clarfy he physcal meanng of he pressure machng performance dagram of he ejecor. The obaned resuls show ha he pressure machng performance of he consan area supersonc-supersonc ejecor ncreases wh he ncrease of he secondary Mach number, and he performance decreases slghly wh he ncrease of he prmary Mach number. The phenomenon of boundary layer separaon nduced by shock wave resuls n weaker pressure machng performance of he cenral ejecor han ha of he perpheral one. Furhermore, based on he observaons of he expermen, a smplfed analycal model has been proposed o predc he lmng pressure rao, and he predced values obaned by hs model agree well wh he expermenal daa. Key words: ejecor, hgh-energy chemcal laser, pressure recovery sysem, pressure machng 1. Inroducon Supersonc ejecors are flud devces n whch wo flud sreams are allowed o perform he mxng and recompresson. One flud wh hgher oal energy s he prmary flow, and he oher flud wh lower oal energy s he secondary flow. In a supersonc ejecor, ransfer of mechancal energy from he prmary flow o secondary flow s accomplshed by mxng of hese wo sreams, and supersonc ejecor s operaed whou movng pars. Is smplcy makes supersonc ejecors found many applcaons n engneerng, such as hgh-alude es facles [1], ejecor ramjes [2] and * Correspondng auhor; 137 Yanwach Sree, Changsha, Hunan, , Chna. e-mal: nud_cj@sna.cn

2 ejecor based refrgeraon cycle [3], ec. However, he prmary movaon for hs nvesgaon s he applcaon of he supersonc ejecor as he pressure recovery sysem n he hgh-energy chemcal laser. In he connuous-wave chemcal laser, he flow a he laser cavy ex s supersonc and wh low sac pressure (~400 Pa) [4]. To sar and susan he lasng process, he laser cavy flow mus be pumped o he amben condon. Thus, he pressure recovery sysem s necessary for he hgh-energy chemcal laser sysem. The subsonc-supersonc ejecor s used as he convenonal approach o solve he pressure recovery problem n he pas decades, see fg.1(a). However, he requremen of hgh flexbly on he ransporable accal hgh-energy laser expecs a furher reducon on he wegh and volume wh a beer performance of he pressure recovery sysem [5]. The supersonc-supersonc ejecor (SSE), see fg.1(b), seems o be a very suable means o sasfy he requremen of he accal hgh-energy laser menoned above [6]. In he supersonc-supersonc ejecor, he dffusers beween he laser cavy ex and he ejecor are elmnaed, and he supersonc laser cavy flow s pumped drecly by he supersonc ejecor. Fgure 1. Approaches o he pressure recovery problem: (a) subsonc-supersonc ejecor; (b) supersonc-supersonc ejecor However, Invesgaons on he supersonc-supersonc ejecor [7] have been rarely repored. In 1980s, Mkkelsen e al. [8] and Duon e al. [9] performed one-dmensonal analyses of he consan area supersonc-supersonc ejecor (CASSE), and a seres of small-scale CASSE expermens have been conduced o valdae he heorecal resuls. Recenly, researches concerned wh he SSE have no been avalable n he open leraure unl he work of Dvorak e al. [10, 11] on a wo-dmensonal CASSE, and he flow srucures n former par of he mxng duc and he ransonc nsably of he ejecor were analyzed. For a supersonc-supersonc ejecor, he Mach number of he secondary flow a he mxng duc nle mus be greaer han uny. However, f he prmary-o-secondary nle sac pressure rao s grea han uny, he secondary flow s compressed by he muual neracon of he prmary and secondary flows whn he mxng duc, hs process s lmed, and a condon s evenually reached for whch he secondary flow s compressed o aerodynamc chokng condon, see fg.2. The nle sac pressure rao of he prmary and secondary flows (= P p /P s ) a hs lmng condon s called he lm pressure rao. When he value of exceeds he value of, separaon lm lm

3 of he secondary flow occurs. Thus, s used as he creron o esmae he pressure machng lm performance of he CASSE. Fgure 2. Schemac of he flow feld a he lmng condon Due o he low cavy pressure of he hgh-energy chemcal laser, hgh compresson rao P b /P s s requred. Fgure 3 llusraes a ypcal operaon plane for he CASSE, and he uppermos boundary of he plane defnes he maxmum compresson rao of he ejecor. In fg.3, s observed ha he value of he maxmum compresson rao a he lmng condon s greaer han ha a he mached pressure condon. However, when exceeds, performance of he ejecor declnes because of he lm separaon of he secondary flow [9]. Therefore, he pressure machng performance of he consan area supersonc-supersonc ejecor should be nvesgaed n deal. Fgure 3. Typcal operaon plane for he CASSE 2. Expermenal Seup and Numercal Mehods 2.1. Expermenal Seup In hs sudy, he recangular CASSE wh he deph beng 80mm are nvesgaed. Fgure 4 shows he schemac vew of he model ejecors, he supersonc prmary flow s symmercally njeced along he op and boom walls, and he secondary flow s njeced hrough a consan area solaor wh s lengh beng 270mm. Then, he prmary and secondary flows mx n he 840mm long consan area mxng duc whch s 84mm hgh. The prmary and secondary nle heghs a he enrance of he mxng duc are 20mm and 40mm, respecvely. Boh he prmary and secondary nozzles are desgned by he mehod of characerscs o produce unform dsrbuons of velocy and pressure a he confluence pon of wo sreams. Pressure aps are nsalled a sx locaons, namely, wo sagnaon

4 pressures of he prmary flows (P p_u and P p_d, respecvely), sagnaon pressure of he secondary flow (P s ), and sac pressures of he prmary and secondary flows a he enrance of he mxng duc (P p_u, P p_d and P s ). Pezopressure ransducers wh an operang range of 0-1MPa and an accuracy of 0.5% are used o measure P p_u and P p_d, and he ransducers wh a range of 0-100kPa and an accuracy of 0.05% are used for he measuremen of he pressure a he oher pons. The daa raes of all he pressure measuremens are 1000Hz. Fgure 4. Schemac of he nvesgaed model ejecors The Mach numbers of he prmary and secondary a he enrance of he mxng duc are calbraed by he measured pressures va eq.(1): P P π(, M ) (1) where 1 π(, M) 1 M (2) The calbraed Mach numbers a he mxng duc nle are lsed n ab.1. Table 1. Inle Mach numbers for he ejecor expermens No. M p_u M p_d M s Ejecor 1# 1.58 Ejecor 2# % 1.74 Ejecor 3# 1.91 Ejecor 4# 1.58 Ejecor 5# % 1.74 Ejecor 6# 1.91 The schemac of he es facly s llusraed n fg.5. Boh he prmary and secondary fluds are he compressed ar from a pressure ank, and hese wo fluds are led hrough he closng and conrol valves o he ejecor. Then he mxed flow s led hrough a fnal sagnaon chamber wh back pressure conrol valve, whch s locaed downsream from he ejecor ex. However, he back pressure conrol valve s fully open n he curren sudy. The characersc of flow n he supersonc ejecor s raher complex, shock waves, mxng layers, he neracon beween shock waves and he neracon beween shock waves and mxng layers occur frequenly, and he schleren mehod seems o be very suable for nvesgaon. Schleren pcures are aken wh urnng he knfe edge o horzonal poson (0 degree), so he opcal measuremens are sensve o changes of densy n drecon perpendcular o he symmercal plane of he ejecor, and he rgh-mos border of he regon vsble a opcal measuremens s approxmaely 100mm downsream from he mxng duc nle.

5 Fgure 5. Tes nsallaon of he nvesgaed model ejecors 2.2. Numercal Model In he curren compuaonal analyss, he wo-dmensonal Reynolds Averaged Naver Sokes (RANS) equaons are solved wh he densy based solver of FLUENT [12]. The k RNG urbulence model wh he enhanced wall reamen s employed o smulae he urbulen flow feld n he ejecor, and he k RNG model s seleced for gves good resuls for he shock phase and srengh [13]. The equaons are solved usng a fne-volume negraon scheme, he second order spaally accurae upwnd scheme wh he advecon upsream splng mehod (AUSM) flux vecor splng s ulzed. The cold ar s consdered o be a calorcally perfec gas wh a consan rao of specfc heas, namely 1.4. The ar, usng he dea gas approxmaon, and he oal emperaure s K, s used as he workng flud. The Suherland law of vscosy s employed. The soluons can be consdered as converged when mos of he resduals reach her mnmum values afer fallng for more han hree orders of magnude, and he compued n flow and he ouflow mass flux s requred o drop below kg/s. The doman of he ejecors s consdered o be symmercal abou he cenral plane. Boundary condons are defned by nle pressure n enrances of he ejecor and by oule pressure a he ex of he ejecor, and no-slp condons are appled along he sold walls by seng he velocy componens o zero and nullfyng he energy conrbuons of he wall faces o he dsspave fluxes. The srucured quadrlaeral mesh conanng approxmaely 90,000 cells s creaed by he commercal sofware Gamb. The concenraon of grd densy s focused on he areas where sgnfcan phenomena s expeced [14], also he grd s densely clusered near he walls of he mxng duc, and he hegh of he frs row of cells s se a a dsance o he wall of 0.01mm, whch resuls n a value of y+ smaller han 1.0 for all of he flow feld. 3. Resuls and Dscusson 3.1. Supersonc flow srucures wh vared pressure rao The essenal of he pressure machng beween he prmary and secondary flows n he CASSE s he neracon of wo supersonc jes n a confned duc. In hs secon, he near feld flow srucures

6 of he prmary and secondary jes wh vared are suded. Snce he prmary and secondary nle sac pressures, P p and P s, are dffcul o be obaned when opcal measuremens are performed, hus, he sagnaon pressure rao deermned by usng eq.(1). dfferen (=P p /P s ) s also used n hs paper, and he correspondng can be Fgure 6 shows he supersonc flow feld n former par of he mxng duc of he Ejecor 3# for. Fgure 6. Flow srucures n former par of he mxng duc of he CASSE wh dfferen In fg.6(a), when 6.6, and he correspondng 1.6, he secondary flow s compressed and wo oblque shock waves, namely A1 and A2, nersec a he symmerc plane, and wo shock waves B1 and B2 go on. The angles of shock waves A1 and A2, ogeher wh her refleced shock waves B1 and B2, ncrease wh he ncrease of, see fg.6(b)-(d). However, s observed from he numercal resuls shown n fg.6(a)-(d), he refleced shock waves B1 and B2 are srong oblque shock waves when 13.1, and he shock waves B1 and B2 are weak ones n he oher cases. As depced n fg.6(e), when ncreases o 14.0, a Mach dsc appears n he secondary flow. As ncreases

7 furher, he secondary nle a he mxng duc enrance s no longer occuped by he supersonc secondary flow compleely, he boundary layer of he secondary flow separaes n he solaor, and a shock ran runs no he mxng duc, see fg.6(f). Thus, here exss a lmng pressure rao, lm_ 01 when exceeds, separaon of he secondary flow occurs. However, lm_ 01 s hard o lm_ 01 be obaned accuraely va schleren pcures, an alernae lmng pressure rao,, s se n lm_ 02 hs paper when he Mach dsc jus dsappears, as depced n fg.6(d). Thus, he value of lm_ 02 can be deermned expermenally, n hs case, 3.11, and he value of lm_ 02 s lm_ 01 deermned by numercal compuaon n he followng secons Effec of he prmary and secondary Mach numbers on he pressure machng performance The lmng pressure raos of he CASSEs wh dfferen nle prmary and secondary Mach numbers are presened n fg.7, and he lmng pressure raos calculaed by he heorecal model proposed by Duon e al. [9] are also gven. I s observed from fg.7 ha, he pressure machng performance of he CASSE ncreases wh he ncrease of he secondary Mach number, and he performance decreases slghly wh he ncrease of he prmary Mach number. Fgure 7. Comparson of he lmng pressure raos The effec of he secondary Mach number on he pressure machng performance can be explaned by he model proposed by Duon e al. The flow model s shown n fg.2 wh he followng assumpons [9]: (1) The prmary and secondary sreams reman dsnc and do no mx beween saons and 2. (2) The flow s senropc for boh he prmary and secondary flows beween saons and 2. (3) The Mach number of he secondary flow a saon 2 s uny, namely M s2 = 1.0. M p, A p and A s keep consan, and P s s assumed o be unalered when M s ncreases. Fgure 8 shows he conrol volume of he secondary flow n secon -2.

8 Fgure 8. Conrol volume of he secondary flow Applyng he momenum conservaon equaon o hs conrol volume yelds A s d 1 P A M P A M P A P A M P A A (3) s s s s s2 s2 s s2 p s2 s2 s s2 p s s2 As2 Rearrangng eq.(3) as A 2 2 s As2 1 sms Ps2 Ps 1 sm s2 Pp P A A s s s2 where P P π, M 1 s2 s s (5) π, M s s s2 (4) A A s 1 2 s Ms M 1 2 s2 s s s 1 2 s 1 (6) Fgure 9 shows he varaon of P P wh he ncrease of M s when s 1.4. p s Fgure 9. P P versus M s when s 1.4 p s I s llusraed n fg.9 ha Pp P s s a monooncally ncreasng funcon of M s. When M s ncreases, he slplne moves oward he symmercal plane, and he cross-seconal area of he prmary flow beween -2 ncreases. Snce P s s assumed unalered and prmary flow beween -2, an ncrease of Pp P p s he average sac pressure of he P can be obaned only when P p ncreases. Therefore, s he lmng pressure rao of he CASSE ncreases wh he ncrease of he secondary Mach number.

9 Alhough he model proposed by Duon e al. shows good applcably n explanng he nfluence of he secondary Mach number, he heorecal value of calculaed by hs model s lm much smaller han and lm_ 01, see fg.7. I s learned from he fundamenal of he lm_ 02 aerodynamcs ha shock wave s nevable when decelerang a supersonc flow, and he supersonc srucures n he former par of he mxng duc gven n las secon also show ha, he srengh of he shock waves n he secondary flow s farly srong when keeps near o he lmng condon. However, he assumpon of an senropc compresson of he secondary flow s used n he model proposed by Duon e al., he devaon of hs assumpon from he acual compresson process of he supersonc flow resuls n a large underesmae of he lmng pressure rao The pressure machng performance of he cenral CASSE As for a supersonc ejecor, here are wo ypes of ejecors, namely he perpheral and cenral ejecors. Fgure 10 llusraes he cross seconal vew of he mxng duc nle for boh he perpheral and cenral ejecors. Fgure 10. Cross seconal vew of he mxng duc nle for he perpheral and cenral ejecors Fgure 11 shows he comparson of he predced lmng pressure raos calculaed by he model proposed by Duon e al. wh he expermenal resuls of he cenral CASSEs (adaped from reference [9]). I s observed from fg.11 ha he expermenal lmng pressure raos of he cenral CASSE are smaller han he heorecal values, and hs s jus oppose for he perpheral ones, see fg.7.

10 Fgure 11. Comparson of he heorecal and expermenal lmng pressure rao of he cenral CASSE wh M p = 2.5. (adaped from reference [9]) Fgure 12 shows flow srucures n former par of he mxng duc of a cenral CASSE (Ejecor 3# cenral CASSE) wh dfferen, and Ejecor 3# cenral CASSE has he same nle prmary and secondary Mach numbers as Ejecor 3# perpheral CASSE lss n ab.1. I s observed from fg.12(c) ha he secondary flow separaon occurs when 12.7, however, he secondary nle of he Ejecor 3# perpheral CASSE s sll occuped by he complee supersonc secondary flow when 14.0, see fg.6(e). Fgure 12. Flow srucures n he former par of he mxng duc of he Ejecor 3# cenral CASSE wh dfferen The sreamlnes n he former par of he mxng duc of he cenral CASSE are shown n fg.13. I s observed from fg.13 ha a recrculaon zone s formed because of he boundary layer separaon, and hs separaon s nduced by shock waves. The recrculaon zone reduces he effecve area of he secondary flow, and hs resuls n a sronger compresson of he secondary flow. Thus, he pressure graden along he flow drecon of he secondary flow ncreases. And hs means ha he local back pressure of he secondary flow a he mxng duc nle ncreases. Therefore, he pressure machng performance of he cenral CASSE s reduced by boundary layer separaon nduced by shock waves.

11 Fgure 13. Sreamlnes n he former par of he mxng duc of he Ejecor 3# cenral CASSE 3.4. A modfed model for predcng he lmng pressure rao of he CASSE Snce he srengh of shock waves n he secondary flow jus downsream he mxng duc nle s farly srong when keeps near o he lmng condon, he effec of he shock waves mus be consdered n he heorecal model for predcng he lmng pressure rao. Fgure 14 s a schemac of he flow feld n concern. Fgure 14. Dagram of saons and nomenclaure used n he heorecal analyss When wall shear sresses are neglgble, he momenum conservaon equaon can be appled o he prmary and secondary flows as a whole conrol volume beween saons and 2. I s assumed ha he mxng of he prmary and secondary flows s neglgble beween saons and 2, hus, he mass conservaon equaon can be appled o he prmary and secondary flows, respecvely. By applyng he mass and momenum conservaon equaons ogeher wh he followng assumpons, he lmng pressure rao of he CASSE can be deermned. (1) The flow beween saons and 2 s seady, adabac and one-dmensonal. (2) The workng fluds are deal gases wh consan specfc hea rao, namely p and (3) The prmary and secondary flows are pecewse unform a saon. (4) The sac pressures are such ha P p >P s. (5) The prmary flow s senropc beween saons and 2. (6) The secondary flow s choked a saon 2. (7) The secondary flow experences an oblque shock wave A, he shock wave angle max s deermned by he maxmum urnng angle for gven Mach number upsream of he oblque shock wave. (8) The oblque shock wave A affecs only he properes of he secondary flow afer saon 1. (9) The secondary flow s unform a saon 1, and s senropc beween saons 1 and 2. One consequence of assumpon (7) s ha he shock wave sandng a he ex of solaor s a srong oblque shock wave. Of course, he rue oblque shock wave nduced by he urnng angle s a s.

12 weak one. Applyng he momenum conservaon equaon o he prmary and secondary flows beween saons and 2 ogeher wh assumpons (1, 3) yelds P A M P A M P A M P A M (7) p p p p s s s s p2 p2 p p2 s2 s2 s s2 Rearrangng eq.(7) as P P A f, M A f, M P A f, M 1 P P A f, M A f, M P A f, M p s2 s2 1 s s2 p 1 p p p2 p2 1 p p2 s where s s 1 s s s 1 s s p s 1 s s (8) f (, M) M (9) The equaon sn M M M M max 2 s used o solve for he angle of he oblque shock wave max correspondng o he maxmum urnng angle for gven Mach number upsream of he oblque shock wave. Snce max s obaned, M s1, P s1 /P s and P s1 /P s can be deermned. By applyng assumpon (9), hen Ps2 Ps2 P π s1 s, Ms1 Ps1 (11) P P P π, M P s s1 s s s2 s By assumpon (6), M s2 = 1.0, and applyng he mass conservaon equaon o he secondary flow beween saons and 2 12 (10) P q(, ) q(, ) P q(, ) A P W K A M K A M M q(, ) s s2 s2 s s s s s s s s s s2 s s2 Ts T A s s Ps2 s Ms2 where q(, M ) M 1 M Accordng o assumpon (9), P s2 = P s1, herefore, As2 Ps q( s, Ms ) A P q(,1.0) s s1 s The senropc area rao funcon s expressed as 1 2( 1) 2 1 M f 2, A Acr M 2 1 and he subscrp cr sands for he aerodynamc chokng condon. M (12) (13) (14) (15)

13 For a consan area ejecor, p p 2 p p Ap2 Ap A f s As2 2 p, M p2 (16) A A f, M The prmary Mach number a saon 2, M p2 s he supersonc soluon of eq.(16). Snce M p2 s obaned, by assumpon (5), hen P P p2 p p p2 π p, M p (17) π, M Combnng eq.(8), eq.(11), eq.(14), eq.(17), and wh M s2 = 1.0, M p2 s obaned by solvng eq.(16), ogeher wh he ejecor parameers p, s, M p, M s and A p /A s, hen he lmng pressure rao of he consan area supersonc-supersonc ejecor s found. Fgure 15 shows he comparson beween he calculaed by he presen model and he lm model proposed by Duon e al. and lm_ 01, whch are used as he benchmark o lm_ 02 esmae he precson of he heorecal value, are also gven n fg.15. I s observed from fg.15 ha he presen model gves a superor agreemen beween he calculaed and he expermenal lm compared o he model proposed by Duon e al. Whn he range of parameers lm_ 02 nvesgaed n he curren sudy, he calculaed by he presen model agrees well wh he lm expermenal, especally when he prmary Mach number s relavely hgh. However, he lm_ 02 calculaed by he presen model s sll 14-21% less han lm when M lm_ 01 p = 2.85, and 6-18% less han when M lm_ 01 p = 3.2. Ths dscrepancy may be caused by he smplfcaon of he complex and srong shock waves, and he gnorance of he complex physcal phenomena, such as mxng of he prmary and secondary flows, shock wave/mxng layer neracon, ec. Fgure 15. Comparson beween he heorecal and expermenal/numercal 4. Conclusons lm The neracons beween he prmary and secondary flow n a confned mxng duc have been nvesgaed expermenally and numercally, he physcal meanng of he pressure machng performance of he consan area supersonc-supersonc ejecor has been clarfed. Influences of he

14 prmary and secondary Mach numbers on he pressure machng performance of he ejecors have been examned, and he prmary flud njecon confguraon n ejecors has been suded as well. Based on he resuls of expermens and numercal smulaons, a smplfed analycal model has been proposed o predc he lmng pressure rao of he consan area supersonc-supersonc ejecor. From hese nvesgaons, we have come o he followng conclusons: (1) When he pressure rao of he prmary and secondary flows keeps near o he lmng condon, he complex shock wave srucures are generaed n he secondary flow, and hese shock waves mprove he pressure machng performance of he consan area supersonc-supersonc ejecor. (2) The lmng pressure rao of he consan area supersonc-supersonc ejecor ncreases wh he ncrease of he secondary Mach number, and hs lmng pressure rao decreases slghly wh he ncrease of he prmary Mach number. (3) The pressure machng performance of he cenral consan area supersonc-supersonc ejecor s lower han ha of he perpheral one, and hs s due o boundary layer separaon nduced by shock wave n he cenral supersonc-supersonc ejecor. (4) By nroducng a srong oblque shock wave no a prevous senropc compresson model, he gap beween he heorecal value of he lmng pressure rao and he expermenal one s reduced from 30-35% o approxmaely 10%. Acknowledgmen Ths work was suppored by he Naonal Naural Scence Foundaon of Chna (Gran No ). Also he auhors are ndebed o Dr. We HUANG for hs valuable suggesons when wrng hs paper. Nomenclaure A cross-seconal area,[m 2 ] V RT M Mach number(= 0.5 P T pressure, [Pa] emperaure, [K] R gas consan, [Jkg 1 K 1 ] V velocy, [ms 1 ] W mass flow rae, [kgs 1 ] Greek symbols ), [-] oblque shock wave angle, [ ] specfc hea rao, [-] pressure rao, [-] Subscrps, 1, 2 saon, 2 n fg.2 and saon, 1, 2 n fg.14 lm lmng condon

15 max p s maxmum value prmary secondary sagnaon condon Abbrevaons CASSE consan area supersonc-supersonc ejecor SSE supersonc-supersonc ejecor References [1] Kumaran, R. M., e al., Opmzaon of Second Throa Ejecors for Hgh-Alude Tes Facly, Journal of Propulson and Power, 25(2009), 3, pp [2] Nelson, K. W., Expermenal Invesgaon of an Ejecor Scramje RBCC a Mach 4.0 and 6.5 Smulaed Flgh Condons, Ph. D. hess, The Unversy of Alabama n Hunsvlle, Hunsvlle, USA, 2002 [3] Zhu, Y. H., e al., Numercal Invesgaon of Geomery Parameers for Desgn of Hgh Performance Ejecors. Appled Thermal Engneerng, 29(2009), pp [4] Snghal, G., e al., Pressure Recovery Sudes on a Supersonc COIL Wh Cenral Ejecor Confguraon, Opcs & Laser Technology, 42(2010), pp [5] Shwarz, J., Gerald, T. W., Joel, M. A., Taccal Hgh-Energy laser. Proceedngs (Basu, S., Rker, J. F.), Laser and Beam Conrol Technologes, San Jose, USA, 2002, Vol 4632, pp [6] Zme, E., Seady Sae and Transen Operaon of an Ejecor for a Chemcal Laser Cold Flow Mxng Expermen, Repor No. TR , Whe Oak Laboraory, MD., USA, 1976 [7] Gule, R. N., US Paen, , 1983 [8] Mkkelsen, C. D., Sandberg, M. R., Addy, A. L., Theorecal and Expermenal Analyss of he Consan-Area, Supersonc-Supersonc Ejecor. Repor No. UILU-ENG Unversy of Illnos a Urbana-Champagn, IL., USA, 1976 [9] Duon, J. C., Mkkelsen, C. D., Addy, A. L., A Theorecal and Expermenal Invesgaon of he Consan Area, Supersonc-Supersonc Ejecor, AIAA Journal, 20(1982), 10, pp [10] Dvorak, V., Safark, P., Supersonc Flow Srucure n he Enrance Par of a Mxng Chamber of 2D Model Ejecor. Journal of he Thermal Scence, 12(2003), 4, pp [11] Dvorak, V., Safark, P., Transonc Insably n Enrance Par of Mxng Chamber of Hgh-Speed Ejecor, Journal of Thermal Scence, 14(2005), 3, pp [12] Fluen Inc., Fluen 6.3 User s Gude, 2006 [13] Barosewcz, Y., e al., Numercal and Expermenal Invesgaons on Supersonc Ejecors, Inernaonal Journal of Hea and Flud Flow, 26(2005), pp [14] Srveerakul, T., Aphornraana, S., Chunnanond, K., Performance Predcon of Seam Ejecor Usng Compuaonal Flud Dynamcs: Par 1. Valdaon of he CFD Resuls, Inernaonal Journal of Thermal Scences, 46(2007), pp

16 Appendx fg.a. Calculaon flow char for deermnng he lmng pressure rao of he CASSE s llusraed n Fgure A. Flow char for deermnng he lmng pressure rao