冲压发动机进气道压力振荡过程的数值研究

Numerical simulation of pressure oscillation in ramjet inlet

针对来流马赫数3.5,0°迎角飞行条件下冲压发动机的简化模型,数值模拟了进气道整流罩开启过程的非定常流动。计算采用AUSMPW有限体积格式,基于结构与非结构的混合网格技术,求解了非定常N-S方程。计算结果表明,在进气道整流罩打开以后,超声速气流会在燃烧室通道内形成振幅衰减较慢的低频剧烈振荡。在同样计算条件下采用Euler方程进行对比性研究,数值实验发现对这类大雷诺数、强非定常性的问题,Euler方程和N-S方程得到的结果相差不大。

Unsteady flows in the opening of inlet cover are investigated numerically, based on a simplified ramjet model with a Math number 3.5 and angle of attack 0. The AUSMPW scheme is used in finite volume method to solve unsteady Navi- er-Stokes equations on mixed structured-unstructured grids. The results demonstrated that supersonic airflows will form a low- frequency oscillation in the combustor after the inlet cover is open, and the attenuation of the oscillation is very slow. To be a contrast, Euler equations were solved in the same condition, and the numerical experiments demonstrated that for such strongly unsteady flows with a high Reynold number, the Euler solution is comparable to the N-S solution.