Research On Methane-coal Dust Compound Explosion Pressure In Horizontal Pipe

Along with the urbanization speeding up in our country, people’s demand andconsumption for coal also increase. Coal production also increase. Although we strengthensupervision and management, and increase investment of science and technology in coalmines， the major accidents of gas explosion and coal dust explosion happened sometimesshock people. The major accident also caused great physical and mental harm to people andhuge economic losses to the country. Due to gas and coal dust in coal mine roadway arecoexisting, so the enclosed horizontal pipe of0.7m long and diameter of140mm, simulatingcoal mine roadway, is used to research detailedly on methane-coal dust compound pressureand pressure rise rate. The purpose is to provide theoretical basis for prevention and control ofgas and coal dust explosion in coal mine.Using our experimental device, experiment results show that:（1） Under the condition of fixed methane concentration, as coal dust concentration rising,the maximum explosion pressure (P_max) first increase then descend, existing a peak point. Andmethane concentration is different, then the coal dust concentration, producing the peak point,is different. Regularity of the maximum rate of pressure rising [（dP/dT）_max] and P_max is thesame. Under the condition of fixed coal dust concentration, as methane concentration rising,the maximum explosion pressure first increase then descend, existing a peak point. The mostdangerous methane concentrations corresponding to the peak point is5%.（2） Coal particle diameter impact on P_max and [（dP/dT）_max]obviously. When coal particlediameter vary from43μm to125μm, with the decrease of coal particle diameter, P_maxand（dP/dT）_max of methane-coal dust compound increase, and increasing trend is a linearrelationship.（3） Ignition delay time have important influence on P_max and （dP/dT）_maxWhen ignition delay time change from50ms to120ms, as ignition delay time rising, the maximum explosionpressure first increase then descend, existing a peak point. Coal dust particle diameter isdifferent, and ignition delay time producing the peak point is different.（4） To fit the experimental data, the fitting equation indicate that, within a certain range,P_max and （dP/dT）_max is quadratic function with coal dust concentration, is a linear functionwith coal dust particle diameter. P_max is cubic function with methane concentration.（5） Methane-coal dust compound explosion experimental research indicate that, in thisexperiment, the most dangerous condition of methane-coal dust compound explosion is thatmethane concentration is5%, coal dust concentration is500g/m³, coal dust particle diameteris <43μm, ignition delay time is100ms. In this condition, the maximum explosion pressurecan reach to0.69MPa, and the maximum rate of pressure rising can reach to15.82MPa/s.