Abstract: In order to explore the applicability and accuracy of the prediction method of shock wave overpressure of methane-air premixed gas explosion at different fixed-point distances, a self-made gas pipeline explosion device was used to study the variation characteristics of shock wave overpressure with distance at different concentrations.TNT equivalent method and TNO multi-energy method were used to analyze the difference of shock wave overpressure of methane-air premixed gas explosion at different fixed-point distances, and the formula of shock wave overpressure of gas explosion at different fixed-point distances was modified based on TNT equivalent method.The results show that the attenuation of shock wave of methane-air premixed gas explosion is proportional to the overpressure of shock wave and inversely proportional to the fixed-point distance.With the increase of methane-air premixed gas concentration,the shock wave overpressure curve gradually evolved from intermediate between TNT equivalent method and TNO multi-energy method to higher than TNT equivalent method at the proximal end and lower than TNO multi-energy method at the distal end.When the concentration of methane-air premixed gas is 9.5%,11.5% and 13.5%, the absolute value of the deviation between the corrected shock wave overpressure and the measured value is less than 25%.

Key words: gas explosion, deflagration, TNT equivalent method, shock wave overpressure, percentage of absolute deviation