LAUSR

Abstract Gas explosions causing heavy casualties in the goaf of coal mine occasionally occurred in China. The goaf in the coal mine is a multi-scale complex medium with pores in remaining coal, the gaps among rock blocks that don’t meet the characteristics of the porous medium. The propagation of flames and shock waves induced by the gas explosion in the goaf is very complicated. Based on the spatial structure characteristics of the goaf, the numerical model of a gas explosion is established by using the OpenFOAM open-source CFD source code. The flame and shock wave propagation characteristics induced by the gas explosion are analyzed under the conditions of different arrangements for gradient diameter rocks. The results reveal that the initial flame propagation speed, shock wave and the pressure rise speed all increases firstly, while the values show a decreasing trend when the diameter of the rocks increases in the gradient rocks diameter model. The research results will be of great guiding significance for the prevention and control of gas explosions in the goaf, and the investigation of gas explosion accidents.