Study on methane explosion overpressure evolution law and flame propagation characteristics in diagonal pipe networks

In order to explore the overpressure evolution law and flame propagation characteristics after methane explosion in a complex underground network of coal mines, a methane explosion test system was built in the laboratory, the propagation law of the deflagration wave of a gas explosion with a methane volume fraction of 9.5% has been experimentally studied, and the overpressure and flame propagation process of the gas explosion have been numerically simulated. The test and numerical simulation results show that in the diagonal branch of the pipe network, the methane-air premixed gas explodes due to the superposition of the explosion pressure wave, forming an area of increased overpressure, but the flame wave generated is very weak and the temperature is low. In the parallel branch, with the increase of the propagation distance of the deflagration wave, the peak overpressure and the propagation velocity of the flame surface gradually decrease, while the flame duration first increases and then decreases. The maximum propagation distance of flame in the experiment is 18.75 m, while the propagation distance of the numerical simulation is 21.25 m，but the overall change law of experimental value and simulation value is the same. The research conclusions can provide theoretical support for the prevention, control and disasters in complex roadways in coal mines