高温区碰并诱导气相爆轰二次起爆的数值研究

Numerical study on re-initiation phenomenon of gaseous detonation induced by the coalescence of high temperature regions

针对心形管内气相爆轰二次起爆过程进行了数值研究。采用二阶附加半隐的龙格-库塔法和5阶WENO格式求解二维欧拉方程,采用基元反应来描述爆轰化学反应过程。结果表明:气相爆轰在心形管中传播,由于壁面几何结构的作用,爆轰波熄灭后会发生二次起爆。该二次起爆由高温区碰并所诱导,且在管道不同位置诱导了两处二次起爆。爆轰流场中存在未反应气囊、射流、爆轰波马赫反射、激波与火焰作用及其所诱导的不稳定性等现象。计算得到的二次起爆过程胞格结构演变与实验基本一致。

The re-initiation phenomenon of gaseous detonation in a heart-shape tube was numerically studied. The 2nd additive semi-implicit Runge-Kutta method and 5th order WENO scheme were used to solve two-dimensional reactive Euler equations. Detailed chemical reaction model was utilized to describe the heat release of detonation. The results show that, when gaseous detonation propagates in a heart-shape tube, influenced by the wall geometry, detonation falls and then re-initiates. Detonation re-initiation is induced by the coalescence of high temperature regions twice at the different place in the tube. Some complicated phenomena such as the formation of unreacted gas pockets and jets, Mach reflection, shock-flame interaction and the resultant flame instabilities exist in the current detonation flow field. The computed evolution of cellular pattern in the process of detonation re-initiation is qualitatively consistent with that from the experiments.