火焰加速产生压力锋面机理分析

Mechanism Analysis of Compression Front Produced by Flame Acceleration

基于定容燃烧弹研究预混层流火焰穿过孔板之后的加速过程。通过纹影法,观测到火焰之前压力锋面形成过程。分析火焰传播速率、火焰前锋结构变化、火焰加速对末端气体的影响以及从计算流体力学的角度分析了压力锋面的形成过程。结果表明,层流火焰穿过孔板会明显加速,火焰锋面之前形成清晰的压力锋面,这导致末端气体温度、压力升高,发生自燃,为小型化汽油机爆震研究提供借鉴。

The flame acceleration process after orifice plate was investigated based on constant volume combustion bomb. By schlieren method~ we observed the formation of compression front before turbulent flame. We studied the flame propagation speed, flame front structural changes, the influence of flame acceleration on the end gas and the formation mechanism of compression front from the aspect of computational fluid dynamics. The results shown that, the laminar flame will be accelerated through the orifice plate significantly and there is a clear compression front before the flame front. This may lead to high temperature and pressure in the end gas and auto-ignition consequently. Thus provides reference for knock phenomenon of downsized engine.