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

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.