曲面激波诱导斜爆轰的数值模拟

Numerical Simulation on Shock-Induced Detonation

关键词:  曲面激波  斜爆轰  诱导  燃烧波  数值模拟

Key words:  Surface shock  Oblique detonation  Induce  Combustion wave  Numerical simulation

摘要:

为了研究恰当比预混氢气-空气斜爆轰流场的波系结构和流动特征，基于带化学反应的Navier-Stokes方程，对弹头及楔穿越预混气体时诱导的斜爆轰进行了数值模拟。对流项的离散采用Steger-Warming格式，时间项采用二阶Runge-kutta方法。结果表明，对于弹头：（1）在亚爆轰条件下，能够模拟氢气-空气预混诱导爆轰流场的精细结构；（2）在超爆轰条件下，通过精细调整网格，能够很好地分辨强烈耦合的激波和燃烧波，且与Lehr实验吻合良好。对于楔结构：捕获到了清晰的三波点及其复杂精细的斜爆轰流场结构，预测的诱导燃烧距离、激波角和斜爆轰角与实验吻合良好；通过对流场波系结构变化过程的研究，获得了流场三波点随时间的演化过程。

Abstract:

Numerical simulations were performed on the oblique detonation wave structures and features induced by hypervelocity conical projectile and wedge while passing through premixed stoichometric hydrogen-air flowfield based on Navier-Stokes equations considering chemical reaction. The numerical methods used here were Steger-Warming scheme for the convection fluxes discretization and second-order Runge-Kutta iterate for time discretization. Results show that, for the projectile： (1) under subdetonative speed condition, the method mentioned above and the grid can describe the fine detonation structure， (2) under superdetonative speed condition, the strongly coupled shock and combustion wave can be resolved with carefully adapted mesh, well in accordance with Lehr’s experimental data. For the wedge detonation, distinct triple point and complicated oblique detonation structure can be captured, the predicted induction distance, shock wave angle and oblique detonation angle are in consistent with experiment data; the evolution process of the oblique detonation wave is represented based on the method mentioned above, and the variation of the triple point location with time is obtained.