模型超音速燃烧室流场和性能的数值模拟

NUMERICAL STUDIES ON FLOWS AND PERFORMANCES IN SIMPLIFIED SUPERSONIC COMBUSTOR

关键词:  超音速燃烧  数值仿真  超音速冲压喷气发动机

Key words:  Supersonic combustion  Numrical simulation  Supersonic combustion ramjet engine

摘要:

研究了简化模型超音速燃烧室流场和性能的数值模拟方法，该燃烧室在支板后缘设置一缝隙式喷嘴，平行于超音速空气流喷射氢气。用椭圆型偏微分方程数学模型，ＭａｃＣｏｒｍａｃｋ差分格式成功地计算了两种不同后绿尺寸的流场及其性能，为了对照比较，还计算了另外两种流场。计算结果表明，支板后的流场存在回流区，因喷氢的压力高于超音速空气流的压力和壁面附面层的影响，燃烧室内将出现斜冲波和膨胀波，压力沿横向变化明显，由此证明流场与“边界层流动”有性质上区别。提出了全流场按性质不同分段进行数值模拟的方法，利用计算得到的流场节点状态参数（如温度、压力等），积分获得燃烧室的性能参数，和文献的实验数据对比，计算结果合理、可靠。

Abstract:

The gas flow field in a simplified supersonic combustor with a slot hydrogen injector mounting behind strut and injecting hydrogen parallelly to air now is numerically simulated by using elliptical partial differential equation module and MacCormack scheme. The results show that there is a recirculation zone behind the strut. Pressure of injecting H2 higher than air flow and effects of boundary-layer lead to oblique shock wave and expansive wave in combustor, and pressure will take place great changes along transverse. It can be concluded that such flow field has an obvious difference from boundary-layer flow in performance. Thus, it is suggested that the whole flow field in supersonic combustor should be separately calculated according to its character. And then, the combustor performance could be obtained by integrating over the given nodes value (such as temperature, pressure). Compared with experimental data of reference [5], the simulated results are reasonable and reliable.