Abstract: Based on high-speed synchronous acquisition of flame dynamic propagation and overpressure signal,an experimental study on the coupled relationship between flame shape and overpressure of gas explosion under different conditions was performed.The experimental results showed that if there was no obstruction,flame front was always relatively smooth and its shape gradually developed into a finger-like shape from initial hemisphere appearance,generating a peak overpressure of 3.9 kPa.If there were central continuous obstacles,flame front changed into a tongue-like shape,and finally into wave-like shape,resulting in a peak overpressure of 12.5 kPa.With continuous obstacles on both left and right walls,flame front gave rise to a mushroom-like shape and at last to Christmas tree shape,producing a peak overpressure of 11.4 kPa.Once flame shape was folded or curled,flame surface area increased and then the burned and unburned gas mixtures were blended rapidly,so that combustion reaction rate and overpressure increased.Furthermore,a theoretical analysis clarified the interaction between flame shapes with transient overpressure.

Key words: gas explosion, flame shape, overpressure, coupled relationship

摘要： 基于火焰动态传播和超压信号的高速同步采集,实验研究了不同湍流激励条件下瓦斯爆炸火焰结构与压力波的耦合关系。实验结果表明:在无障碍物条件下,火焰阵面较为光滑,由初始的半球状逐渐演变为手指状,最大超压为3.9 kPa。在中间连续障碍物条件下,火焰发展为舌状,最后呈现波浪状,最大超压为12.5 kPa。在两侧连续障碍物条件下,火焰转变为蘑菇状,最终发展为树状,最大超压为11.4 kPa。当火焰结构发生褶皱或卷曲时,火焰表面积增大,已燃气体与未燃气体快速掺混,导致燃烧反应速率和超压上升。进一步的理论分析阐明了火焰结构与瞬态超压的相互作用。

关键词: 瓦斯爆炸, 火焰结构, 超压, 耦合规律