复燃对液氧煤油发动机尾焰冲击特性影响研究

Effects of Afterburning on Impact Properties of

关键词:  复燃  液氧煤油发动机  尾焰  冲击  数值计算

Key words:  Afterburning  LOx/kerosene engine  Exhaust plume  Impact  Mathematical computation

摘要:

为了研究复燃对液氧煤油发动机尾焰冲击特性的影响，建立了液氧煤油发动机尾焰冲击数值计算模型，并基于模型研究了喷管出口距离平板3m，5m两种工况下复燃对尾焰冲击特性的影响。结果表明:模型考虑了发动机内部燃烧对尾焰冲击特性的影响，计算得到了主射流区的激波结构；复燃增大了尾焰自由射流区和壁面射流区的高温区域，改变了自由射流区和滞止区的形状结构；平板壁面压力随着径向距离增大而逐渐减小，并且3m工况时在1.8m和2.5m处分别出现2.5倍环境压力和1.5倍环境压力的波动，5m工况时在2m处出现1.5～2倍环境压力的波动，在波动之后平板壁面上压力很快降为环境压力，复燃对5m工况的波动较3m工况影响大。

Abstract:

Aimed at studying the effects of afterburning on impact properties of LOx/kerosene engine exhaust plume，the mathematical computation model of LOx/kerosene engine exhaust plume impact was founded. Based on this model，the effects of afterburning on impact properties of LOx/kerosene engine exhaust plume in two different cases of 3m and 5m，respectively，from nozzle exit to the plate were studied. It is found that，the influence of engine internal combustion on impact properties was taken into account in the model，the shock wave structure of the main jet zone is contained. Afterburning can not only increase the high-temperature region of the free jet region and the wall-jet region，but also change the structure of the free jet region and the stagnation zone. Besides，the pressure of the plate wall decreases gradually as the radial distance increases，fluctuations of 2.5 times and 1.5 times the ambient pressure occur at about 1.8m and 2.5m radial distances in the 3m case，while the fluctuation of 1.5～2.5 times the ambient pressure occurs at about 2m radial distance in the 5m case. The pressure on the plate soon reduced to ambient pressure after fluctuations，the afterburning gives a greater impact on fluctuations in the 5m case than 3m case.