Numerical analysis on influence of initial pressure on attenuation characteristics of gas explosion

Through a roadway model whose cross-section area is 80×80 mm² and length is 100m, the attenuation characteristics of explosive shock wave of methane-air mixtures with concentration of 9.5% and filling ratio of 10% were simulated by using AutoReaGas software at the initial pressure of 20 KPa, 60 KPa, 101.3 KPa, 150 KPa and 200 KPa. The results show that when shock wave propagates in roadway, the distances where peak overpressure and maximum gas velocity attenuate to zero are the same as those of maximum temperature and maximum density reduce nearly to their corresponding initial values. With the increase of initial pressure, the safety distance presents the change law of decrease, increase and decrease, the peak overpressure, the maximum density, the maximum combustion rate gradually increase, and their laws can be approximated by means of some linear functions, however, the changes of maximum temperature and maximum gas velocity are not obvious.