超声速来流中燃料喷注与凹腔相互作用流场分析

Experiment Research on Flowfield of Fuel InjectionInteraction with Cavity in Supersonic Crossflow

关键词:  超声速流场  凹腔  超声速喷注  回流区  穿透

Key words:  Supersonic flowfield  Cavity  Supersonic jet  Recirculation zone  Penetration

摘要:

利用基于纳米粒子的PIV(Particle image velocimetry)速度测量系统研究超声速流场中不同喷注Ma的横向喷注与开式凹腔内气体相互作用的流场，主要研究了相同喷注总压下横向喷注穿透的影响因素，分析了喷注动压比影响凹腔内气体和喷注相互作用的表现形式。通过研究发现，喷注动压比为6～8工况下由于凹腔内气体出现大范围回流使得凹腔前缘局部空间出现回流区，影响凹腔上部局部空间剪切层的形成，有效降低喷注与凹腔内气体之间流体的速度，增强了喷注 CVP (Counter-rotating vortex pair)对凹腔内气体的卷吸效果；超声速喷注与凹腔混合研究中，喷注出口欠膨胀程度是必要的考虑因素；相同喷注总压条件下，低Ma数更有有利于喷注展向扩展及穿透，以及和凹腔内气体的混合。

Abstract:

In order to study the influence of transverse jet penetration with the same total pressure and the behavior of jet interaction with fluid in cavity influenced by dynamics pressure ratio (DPR)， we take a measurement on the flow field of the interaction by transverse jet which has different Mach number with the fluid of open cavity in supersonic crossflow by particle image velocimetry (PIV) system based on nano-particles. There is a regional recirculation zone before cavity because the fluid in cavity has a strong recirculation when DPR is 6～8， which influences formation of shear layer beyond the cavity so that the fluid’s velocity between jet and cavity reduces effectively and CVP (Counter-rotating vortex pair) of transverse jet does a strong entrainment with fluid in cavity. Besides， the jet’s under-expended level is a necessary factor in the research of fuel injection interaction with cavity. The low-Mach injection has a better extension and penetration than high-Mach injection， which makes contribution to the interaction of injection and cavity， with a same total pressure.