多障碍物通道中激波诱导气相爆轰的数值研究

NUMERICAL INVESTIGATION ON SHOCK-INDUCED GASEOUS DETONATION IN A DUCT WITH MULTI-OBSTACLES

应用数值模拟方法,研究了直通道中激波经过多块矩形障碍物时诱导H_2/O_2混合气体起爆的物理机制．研究表明：在前导激波强度不足以诱导波后气体直接起爆的条件下,经过激波压缩的可燃气体也可能在远离激波的障碍物之间的凹槽部位起爆；障碍物表面产生的压缩波、膨胀波和气流滑移面对可燃气体的起爆、爆轰波的形成和传播过程有重要的影响；添加不同稀释比的氮气可以影响爆轰波后流场的温度分布；增加障碍物的间距可以改变可燃气起爆位置．

Numerical simulation was carried out to investigate the shock-induced detonation initiation of the premixed H2/O2/N2 gas mixture in a duct with multi-rectangular-shaped obstacles. Numerical results show that even if the incident shock is not strong enough to induce a direct initiation of combustible mixtures behind the shock, the onset of detonation may take place in the cavity between obstacles which are far behind the shock front. Compression waves, expansion waves and contact surfaces generated from the obstacles surface play important roles on the chemical reaction that triggers the DDT process. Increasing N2 dilution of combustible mixtures, the wall temperature distribution behind detonations becomes non-uniform and increasing the distance between obstacles results in a delay of detonation initiation.