壁面抽吸条件下的爆震波传播特性

Propagation characteristics of detonation wave influenced by wall suction

为研究静止气中壁面抽吸对爆震波传播特性的影响,采用数值模拟方法研究了多孔抽吸壁面条件下爆震波的流场结构、传播速度等特性的变化规律。结果表明多孔抽吸壁面对爆震波传播特性有两方面的影响。首先,流场与多孔壁面发生碰撞产生弧形激波,弧形激波对爆震波的横波结构造成直接破坏,导致靠近多孔壁面区域的爆震波产生明显的速度亏损,爆震波强度削弱甚至熄爆;其次,多孔壁面作用导致了流场不稳定性增强,流场与孔板碰撞产生高温高压点,对爆震波的传播有促进作用,尤其在临界条件下,可能导致爆震波熄爆后重新起爆。在保持抽吸压力和边界条件不变情况下,对不同活性及不同抽吸距离时的爆震波传播特性进行研究,发现预混气活性降低、抽吸距离增长时,爆震波结构和传播速度受壁面抽吸影响增强。在加长抽吸距离条件下,随着预混气活性的降低,存在3种爆震波传播现象,即自持传播、熄爆后重新起爆以及完全熄爆。将相应工况下的实验研究与数值模拟结果进行对比,验证了数值模拟结果的正确性。

In order to investigate the characteristics of the detonation influenced by porous wall suction,the structure and velocity of the detonation waves are studied by means of numerical simulation,which shows that there exit two kinds of effects on detonation.On the one hand,part of flowfield is sucked into the suction chamber,colliding with the porous wall,with a series of arc shocks being formed.The interaction of arc shocks and tranverse waves leads to the attenuation of transvers waves and even failure of detonation.On the other hand,instability of the flowfield is enhanced,and there is a series of hot spots formed during the collision between flowfiled and porous wall,which may promote the detonation,especially in the critical state and reignition may occur.Different activity and distance are investigated,while the boundary conditions and initial state remain the same.The results show that,as the activity decreases and the distance increases,the influence of porous wall suction becomes stronger.When the suction distance is longer,three phenomena of propagation are observed with the decrease of the activity of mixture：self-sustained detonation,reignition after failure and complete failure.Finally,the corresponding experiments are conducted and the results of numerical simulation are validated.