Simulation Study On Propagation Law Of Gas Explosion Shock Wave In Coal Mining Face With Different Ventilation Modes

Based on the previous gas explosion experiment and the 11.28 gas explosion accident case in Chenjiashan,Shaanxi,the paper uses numerical simulation software Fluent to study the gas explosion shock wave propagation law in coal mining face with different ventilation methods.The research results have certain theoretical guiding significance for improving the safety of mine production.Combined with the pipeline gas explosion experiment,the paper verifies the reliability of the LES+ED calculation model in the gas explosion simulation from both experimental and theoretical calculations;Secondly,the paper studies the influence of key parameters such as grid size,iteration step length and ignition temperature on the peak overpressure and explosion time,and determines the most reasonable grid size,iteration step length and ignition temperature to be 0.5m,0.0005 s and 1600 k,respectively;Based on the analysis of the attenuation coefficient and the overpressure difference between adjacent measurement points,the paper concludes that the gas explosion shock wave in the roadway starts at 40 m and spreads stably in the form of a single shock wave.The effective length of inlet / return air roadway is determined to be 40 m in the simulation study of gas explosion in U-type,Y-type and W-type ventilation faces.Establish a full-scale three-dimensional physical model of coal mining face with U-shaped(different cross-sections),Y-shaped and W-shaped ventilation methods on the basis of the previous stage,carry out simulation research on gas explosion in different ventilation methods,and compare and analyze the explosion shock wave propagation cloud diagram and the peak overpressure And the curve of peak attenuation rate with distance: The curve of the peak overpressure and the peak attenuation rate with distance shows that: The peak attenuation rate of overpressure in the inlet tunnel of the U-shaped ventilation method changes from low to high to low,while the peak attenuation rate of overpressure in the return air tunnel is a process from high to low to high.The peak overpressure at the working face and its attenuation The trends are in the form of power functions,and when the cross-section shape of the roadway is trapezoidal,the peak and attenuation rate of overpressure in the roadway and working face are the largest,followed by rectangular and semi-circular arches;The attenuation trend of the peak overpressure of the inlet tunnel 1# and the working face of the Y-type ventilation method is in the form of a power function.The attenuation trend of the peak overpressure of the inlet tunnel 2# and the return air tunnel is the same,however,the peak value of overpressure in return air roadway is generally 10.6% higher than that in inlet air roadway,and the attenuation speed is from low to high to low;The peak attenuation trend of overpressure in W-type ventilation roadway 1# and 2# conforms to the form of power function,and the peak attenuation trend of overpressure in return airway conforms to the form of exponential function.The peak overpressure of working face decreases with the distance from the explosion source,The decay rate is gradually reduced.