Numerical Analysis on Propagation Characteristics and Safety Distance of Gas Explosiona

Abstract

Through a roadway model with cross-section area of 80×80 mm2 and length of 100 m, the changing laws of overpressure, temperature, density, combustion rate and gas velocity after the explosion of methane-air mixtures with concentration of 9.5% and filling lengths of 2 m, 6 m, 10 m and 14 m were simulated by using AutoReaGas software. The results show that in the explosion propagation process, the peak overpressure firstly decreases, then increases, and then attenuates until to zero. However, flame propagation speed firstly increases, then begins to reduce and decreases until to zero. With the increase of methane filling length, the safety distance firstly increases and then decreases slightly, and the maximum distance of flame propagation increases linearly. With the increase of methane filling length, the initial peak overpressure and the maximum peak overpressure obviously increase, the peak overpressure and the maximum temperature in other points almost continually increase, and the distance where peak overpressure begins to rise and obtains its maximum value also increases. The time of flame arrival in the same point at various filling lengths is almost the same before flame speed begins to decrease, indicating that flame speed is almost the same before it decreases. Research results can be used to provide guidance for the safety of underground persons, the disaster relief and treatment of gas explosion in underground coal mines.