瓦斯爆炸燃烧波与冲击波相互关系及影响研究

瓦斯被点燃发生爆炸后,燃烧产物膨胀,火焰阵面前形成冲击波,压缩未反应的混合物,这种冲击波阵面到火焰阵面之间面积收敛,形成了较大的附加压缩,其最终的流场性质从冲击波到火焰是逐渐增加的。冲击波作用产生的涡旋造成燃烧火焰的严重变形以及火焰破碎和湍流燃烧都将极大提高燃烧及扩展速率,从而改变燃烧、爆炸过程。冲击波在衰减前与燃烧波是伴生的,燃烧波的存在为燃烧波、冲击波的传播提供了加速的能量。反应完结后燃烧波消失,不在为爆炸冲击波提供传播的能量,冲击波在内摩擦、壁面吸热及摩擦的作用下开始衰减。燃烧波与冲击波在传播过程中存在着相互作用、相互加速的正反馈机制,使得瓦斯爆炸后冲击波的破坏效应十分显著;火焰传播速度越大,冲击波阵面到火焰阵面之间面积收敛越急剧,超压值就越大,引起的破坏效应越大。

Study on Influence and Interrelation between Shock Wave and Combustion Wave of Gas Explosion

The shock wave is formed ahead of the combustion wave front after the gas is ignited to explosion.The gas mixture without reaction is compressed by the expanded combustion products which causes the touching areas reduced between the shock front and the combustion wave and then the additional compression is formed.The flow field is increased gradually from shock to the flame.The vortex by the shock will result in the serious deformation,broken flame and turbulent combustion,which can accelerate combustion and expansion rate and change the combustion and explosion process.The shock and combustion wave is associated with each other before attenuation.The combustion wave will provides accelerating energy for the propagation of combustion and shock wave.The combustion wave will be vanished after the chemical reaction is finished which,at the same time,can not provide any energy.Under the action of inner friction,roadway wall decalescence and friction,the shock wave begins to be attenuated.The positive feedback mechanism of interaction and inter-acceleration is in the process of propagation,which makes the damage effect obviously remarkable.The more the flame is propagated,the sharper the areas between the shock wave and flame front are restrained and the greater the overpressure is,which also cause great damage.