障碍物角度对氢–空气混合物爆燃转爆轰影响的数值研究

Numerical Study of the Effect of Solid Obstacles at Different Angles on Flame Acceleration and Deflagration-to-Detonation Transition

摘要: 为了研究在封闭通道内增强爆轰的最佳障碍物角度，本研究采用在OpenFOAM平台上实现的大涡模拟(LES)方法，对障碍物角度(30˚、60˚、90˚、120˚、150˚)对火焰加速和爆轰起爆的影响进行了详细的数值研究。结果表明，在燃烧室中间设置障碍物可以形成更多的局部火焰。同时，障碍物角度的变化也会产生不同的涡结构和回流区。这些差异会影响燃烧反应速度，从而影响火焰加速效果。从结果来看，障碍物角度越大，火焰加速效果越好。在爆轰起爆过程中，倾斜障碍物确实可以更早地诱导涡流过早分离，同时增强旋涡结构与火焰前缘的耦合，但一旦障碍物角度超过临界值，越来越开放的几何形状抑制了障碍物附近有效热点的形成，由此产生的压力波更容易向下游排出，而不是局部能量沉积。它不能在障碍物附近进行主动反射和聚焦，因此需要较远的距离才能加速并实现爆轰。本研究可为障碍物对可燃气体爆轰影响的研究进行了补充，为实际防爆设计提供参考。

Abstract: To investigate the optimal obstacle angel for enhancing detonation within a closed channel, this study employs the Large Eddy Simulation (LES) method, implemented on the OpenFOAM platform, to perform a detailed numerical investigation of the influence of obstacle angle (30˚, 60˚, 90˚, 120˚, 150˚) on flame acceleration and detonation onset. The results show that setting obstacles in the middle of the combustion chamber can form more local flames. Meanwhile, the change in the angle of the obstacle will also generate different vortex structures and reflux zones. These differences will affect the combustion reaction rate, thereby influencing the flame acceleration effect. Judging from the results, the larger the Angle of the obstacle, the better the flame acceleration effect. During detonation initiation, inclined obstacles can indeed induce premature vortex detach earlier and simultaneously enhance the coupling between vortical structures and the flame front, but once the obstacle angle exceeds a critical value, the increasingly open geometry suppresses the formation of effective hotspots in the vicinity of the obstacle, and the resulting pressure wave is more prone to vent downstream rather than contribute to localized energy deposition, therefore, it can not actively reflect and focus near obstacles, so requires a longer distance to accelerate and achieve detonation. This study can supplement the research on the influence of obstacles on the detonation of flammable gases and provide a reference for actual explosion-proof design.