正向爆轰驱动高焓激波风洞的数值模拟

Numerical simulation of forward-running detonation drivers for high-enthalpy shock tunnels

对充满氢氧可燃气体、带扩容腔的正向爆轰驱动的激波风洞进行了数值模拟。计算采用了欧拉方程,频散可控耗散差分格式(DCD)和改进的二阶段化学反应模型。在扩容腔附近采用二维轴对称计算模型,而在驱动段和被驱动段的直管道部分则采用一维计算模型。本文分析了爆轰波在管道中的传播、反射和绕射过程。计算结果表明扩容腔的尺寸对爆轰波的传播、反射、汇聚等起着决定性的作用;带扩容腔的正向爆轰驱动的激波风洞能够得到平稳的持续时间较长的气流,提高了实验的精确度和可重复性。

In this paper the numerical simulations of detonation wave propagation in a tube with a cavity ring are conducted by solving axis-symmetric Euler equations. The Dispersion Controlled Dissipation （DCD） scheme is adopted and the modified two-step chemical reaction model of stoichiometric oxygenhydrogen mixture is accepted. Two-dimensional Euler equations are used in the cavity ring and onedimension Euler equations are used in others. The propagation, reflection and focus of the detonation wave are analyzed. The numerical results show that the ratio of the cavity radius to that of detonation tubes plays an important role in detonation wave interaction in the cavity. A strong up-stream traveling shock wave can be formed through detonation wave reflections and shock wave focus, which can elevate the flow pressure that has decreased because of expansions waves effect. Results show also that a steady, long-drawn flow can be got at the end of the shock tube, which contribute to experimentation.