超燃冲压发动机凹腔火焰稳定器阻力分析

Investigation on drag of cavity flame holder in scramjet

关键词:  超声速燃烧冲压发动机  凹腔火焰稳定器  凹腔阻力  纹影

Key words:  Scramjet  Cavity flame holder  Cavity drag  Schilieren system

摘要:

为了研究凹腔火焰稳定器在超燃冲压发动机燃烧室内的阻力情况,采用了试验和数值仿真的方法,结合已有的研究结果、纹影图像和阻力测量等进行了分析。结果表明:在冷流中凹腔阻力受自由剪切层与后壁作用情况决定,来流总压高,作用面积大,凹腔阻力大;在反应流中,凹腔阻力小于冷流阻力,在高当量比条件下凹腔可能产生正推力;凹腔附近最强燃烧放热区对凹腔阻力影响较大,当最强放热区分布在凹腔前壁附近时凹腔可能产生推力;当最强燃烧放热区分布在凹腔后壁时,凹腔可能产生阻力。

Abstract:

Numerical and experimental methods,schilieren images and drag measurement were adopted to illustrate the drag of cavity flame holder in scramjet combustor.Results revealed that for cavities in supersonic cold flow,the cavity drag was determined by the contact tough between supersonic flow and the cavity aft wall,higher inflow stagnation pressure and larger contact area can lead to higher cavity drag.For cavities in supersonic reaction inflow,the cavity drag was less than cold flow,the cavity may produce positive force for some suitable equivalence ratio,and the strongest reaction zone near the cavity have great influence on the cavity drag.Once the strongest reaction zone near the cavity front wall,the cavity may produce positive force.When the strongest reaction zone near the cavity aft wall,the cavity may produce negative force.