隔板深度对激波聚焦起爆影响的数值模拟研究

考虑几何结构参数对激波聚焦触发爆轰波的复杂影响,对H2/Air预混气的环形射流激波聚焦起爆现象开展了数值模拟研究,详细分析了不同隔板深度条件下的激波聚焦过程、流场演化特征以及爆轰波参数变化规律。研究结果表明,凹腔内激波聚焦诱导的局部爆炸以及隔板前缘处射流形成"卷吸涡"是引起爆轰波触发的两个重要机制,而隔板深度是影响环形射流激波聚焦起爆性能的关键因素。随着隔板深度的增加,凹腔内激波聚焦的强度逐步增强,回传的能量损失有所减小,进而导致爆燃转爆轰的距离与时间显著缩短。此外,当隔板深度由1 mm逐渐增加至3 mm时,爆轰波自持传播稳定性呈现出先降低后升高的变化趋势,产生这一现象的主要原因是爆轰波强度与三波点运动的相互作用。

Numerical Investigation of the Effects of Diaphragm Depth on Shock Waves Focusing Detonation

Considering the complex effects of geometric structure parameters on shock waves focusing detonation,a numerical investigation was carried out to study the toroidal shock waves focusing detonation phenomena in this paper.The changing characteristics of shock waves focusing process,flow field evolution features and detonation wave parameters were analyzed in detail by using different diaphragm depths.The results showed that both the local explosion caused by shock waves focusing in cavity and the"entrainment vortex"formed due to,the jet of shock waves or flame in front of diaphragm were very important mechanisms for detonation initiation.And diaphragm depth was a key parameter to affect the deflagration to detonation transition(DDT)performance of toroidal shock waves focusing detonation.With the increase of diaphragm depths,the shock waves focusing strength in cavity could be enhanced.The energy loss backed into circular seam by local explosion was decreased.The interaction between shock wave and flame was improved.All of these leaded that the DDT distance and time were shortened significantly.Besides,when the diaphragm depths were changed from 1 mm to 3 mm,the self-sustaining propagation stability of detonation waves could decrease firstly and then increase.The main reason of this phenomenon was the interaction effects of the strength and triple-point detonation waves.