Research On Mixing Process Of Gaseous Fuel Jet In Supersonic Crossflow

This paper makes a research on the effects of jet’s dynamic pressures radio(DPA),inclined angles,jet Mach number and cavity in injection downstream on the jet’s mixture process.With the aid of SPIV(Stereoscopic Particle Image Velocimetry)system based on Nano-particles,we got the stereoscopic space’s velocity vector and also acquired the flow field’s density distribution with NPLS(Nanoparticle-Based Planar Laser-Scattering)system based on the scatter effect of condensed vapor in main flow.The research implies that jet’s penetrability will be intensified by the increase of DPA,which causes the jet wake not to close timely.There is a recirculation zone in the upstream cavity,which has an influence on the cavity’s shear layer formation so that the counter rotating vortex(CVP)can entrain the fluid in cavity to enhance its own size and intensity.The research indicates that as the inclined angle increases in the range of 0-90°,it will enlarge jet’s normal direction momentum,which will enhance jet’s penetrability and the shear effect between jet and crossflow,so that jet’s penetration depth will be larger and jet’s dissipative effect will be strengthened.The penetration depth of the tilted injection can be calculated by covering its injection DPR in the normal direction into a vertical injection.Besides,the increase of inclined angles will enlarge CVP’s influence zone and strengthen CVP’s contribution to mixture.At the same time,it will weaken the contribution of CVP’s induced vortex to the mixing effect.The research believes that under the condition of the same total temperature and total pressure,with the increase of Mach number,DPR has a maximum value,where Ma=1.414,and it will promote jet’s penetration accordingly.The static pressure radio(SPR)has a significant contribution to CVP’s development as well.SPR will decrease as jet’s Mach increases under the condition of the same total temperature and total pressure,which results in jet’s outlet pressure potential energy’s decrease and CVP’s kinetic energy’s weakening.On the contrary,SPR’s increase will have reinforcement on CVP entraining cavity’s fluid,which can promote CVP’s vortex development and enlarge the affected area of CVP.Therefore,SPR’s increase can strengthen flow field’s mixing effect.Based on the existing experiment data,there comes to the conclusion that a strong dissipative effect is on the injection on plate with different SPRs.However,the dissipative effect will be weakened for CVP could entrain cavity’s fluid when there is a cavity at the downstream of jet.Besides,there is little difference in the flat jet to CVP’s size under different SPRs;however,CVP’s size will have an obvious difference when the cavity is added to the downstream of the jet and the rotating vortex could be cast for the different fluids in the cavity.