通风管网中瓦斯爆炸火焰波传播特性三维数值模拟

Flame propagation characteristics of gas explosion in 3D ventilation pipe network by numerical simulation

针对当前瓦斯爆炸传播规律研究主要集中在无通风状态的单条管路或简单分叉管路,对通风管网中的瓦斯爆炸传播研究极少的现状,采用数值模拟的方法,利用FLUENT软件对三维通风管网模型进行模拟,并利用TECPLOT 360和ORIGIN软件对模拟数据进行处理,用于研究通风管网中瓦斯爆炸火焰波的传播特性。研究结果表明:初期爆炸中火焰波的传播主要发生在瓦斯混合区且传播过程相对较慢;高温、高压发生耦合作用造成管网内左侧直管与底部直管的连接处发生二次爆炸,火焰波的传播速度快且传播路径复杂;通风动力恢复后,火焰波在管网内多因素的复合作用下重新进行传播;底部直管存在的多种结构变化,使得火焰波在其内部的传播过程中速度相对较慢且形态发生多次明显变化。得出相关结论:通风管网内瓦斯爆炸过程中火焰波传播的复杂性源于瓦斯爆炸过程中冲击波、通风动力、火焰波以及管网结构变化产生的扰动源等多因素的耦合作用;通风动力的存在使得管网内瓦斯爆炸传播过程更加复杂,通风动力系统与爆炸冲击波的耦合作用在这个过程中占据主导地位;瓦斯爆炸过程中,通风管网内增加了通风动力系统恢复并占据主导的传播演变过程,该过程中火焰波自身的发展传播特性同样受到影响,相比无通风时发生了变化;模拟结果为研究瓦斯爆炸的次生灾害的发生与防治、有毒有害气体的分布以及事故应急救援工作提供了参考。

The current study of gas explosion propagation law mainly focuses on a single pipe or a simple bifurcated pipe without ventilation. However, the research that concentrates on gas explosion propagation in a ventilation pipe network is rare. In this study, the three-dimensional ventilation network model is simulated by FLUENT software, and the simulation data are processed by TECPLOT 360 and ORIGIN software, which is used to study the propagation characteristics of gas explosion flame wave in a ventilation network. The results show that the propagation of flame wave in the initial explosion mainly occurs in the explosion chamber. And the process of flame propagation is relatively slow due to the pressure accumulation in the explosion chamber. Secondary explosion occurs at the connection between the intake pipe and the bottom straight pipe in the pipeline network due to the coupling effect of high temperature and high pressure. In this stage, the propagation speed of flame wave is fast and the propagation path is complex. When the ventilation power is restored, the flame wave propagates again in the pipe network under the combined action of multiple factors in the pipe network. There are many structural changes in the bottom straight tube, which make the propagation process of flame wave relatively complex. It is concluded that the complexity of flame wave propagation in the process of gas explosion in a ventilation network is due to the coupling of shock wave, ventilation power, flame wave and disturbance source caused by the change of pipe network structure. And the existence of ventilation power makes the process of gas explosion propagation more complex in the pipe network, and the coupling effect of ventilation power system and explosion shock wave occupies a dominant position in this process. In the gas explosion process, the ventilation power system is recovered and dominated by the ventilation power system is added in the gas explosion process. In this process, the development and propagation characteristics of the flame wave itself are also affected, which is changed compared with the case of no ventilation. The simulation results provide a reference for the study of the occurrence and prevention of secondary disasters of gas explosion, the distribution of toxic and harmful gases and emergency rescue work.