超燃冲压发动机双凹腔燃烧室氢气燃烧流场分析

为了比较超燃冲压发动机中双凹腔燃烧窜相对于单凹腔燃烧室在促进燃烧方面的优势,运用高速摄影仪拍摄了氧气当量比为0.07时燃烧室中的火焰情况,结合数值仿真结果,得出如下结论:小当量比情况下氢气燃烧很稳定,燃烧区域主要集中于前凹腔的剪切层和该凹腔所围成的三角区以及该凹腔下游壁面位置,燃料喷口周围没有火焰;无论是串联凹腔燃烧室还是并联凹腔燃烧室,相同条件下燃烧时壁面压力均比单凹腔燃烧室高,串联凹腔之间的回流区为燃烧提供了有利的条件;在一定范围内,串联凹腔之间的距离越近,燃烧放热越集中,壁面压力越高.

Analysis of the hydrogen combustion field in scramjet dual-cavity combustor

In order to compare dual-cavity combustor with single-cavity combustor on enhancing the combustion,high-speed photography was employed to investigate hydrogen flame structure when fuel equivalence ratio is 0.07 in scramjet.The results show that,hydrogen flame is stable under small fuel equivalence ratio;the combustion region of upstream-cavity near the orifice is a triangular zone formed by the cavity and its shear layer,and another stable zone is beside the downstream wall,while there is no obvious flame around the injection exit;under the same incoming situation,the wall pressure of single cavity combustor is lower than that of combustors with cavities in parallel and cavities in tandem;and the recirculation zone with slow velocity and high pressure between cavities in tandem is good for the process of combustion;for cavities in tandem,the nearer the cavities' distance is,the higher the wall pressure and more concentrated the heat released from combustion is.