An Experimental Study of Coaxial Jet Spray Flame Structure and Soot Formation under High Pressure(Thermal Engineering)

Abstract

CoaXial let spray Ilarries of kerosene and oxygen are studied exp ｛／ riment ． ally in the alnbien 亡 prcssure range uf O ． 1 − 1 ． OMPa ． The luminescence spcctra of the flames are mcasulled by spectros ・ copic measurement ， and the flame 亡 emperature is rIleasured by a tw 〔 〕 − color methvd ． S〔〕ot pr 〔， duct沁 n regioll and soot vQlu τ ne fraction are rneasured by ！ aser induced incaiidescence ( LII＞． Spect1 ・ 〔 ) scopic lneusurel 皿 ent resu ！ Ls show bluc chemilumincscencc i【1 け1e combusti 〔，ll reacLio冂 rcgion and soot emissioll i副 し 1mlnous 日ame kg observed d ∩ wn 需 tream of the combust め n reacti 〔 )n region 、 CO2 en ' lissiol ［ is alsc 〕 observcd downstream of thc lunninous〔 lame ． The tcmperature measurement results sho 、厚 high − te1ユユ perature regi 〔 )ns near the buTner． The flame temperature decrcases drastically a 玩，ng the ce ； 〕tral axis and a Mi1 ユimum temperature point apPears ． ． T ］ ris po ｛ nt movcs ups し ream with increase 正 naml 〕ient pressure because vaporization 〔 )f droplets occurs fur亡 her upstream due to the change in droplet dispersion ． LII measurements show that soot concentration increases t川 0， 5MPa alld decreasos above O ， 7MPa ． This lrend agrees with ［ he spectroscopic arld ternperature meusurements ， because the fuel vapor concentration distributions changew 辻h increa ． ge in ambient pressure due to thc changc in droplet dispersio τ 1 and mixing betwcen fuc ' 1 vapor and oXidizer ． These results sh 〔 〕w that the drop 正 ot behavior changes with increase in prcssure and affects Hame structure and soot