Study On Energy Change Characteristics Of Coal And Gas Outburst Based On Jet Theory

Coal and gas outburst is one of the most serious disasters in coal mine production in China.Combined with the theoretical analysis of coal and gas outburst,the simulation test of coal and gas outburst in laboratory and numerical simulation,the energy change characteristics of coal and gas outburst are studied.It has important theoretical and practical significance for prediction and prevention of coal and gas outburst.According to the characteristics of gas solid two phase jet in the field,it was proposed that the coal and gas outburst can be regarded as the process of gas-solid two-phase jet flow,and the energy formula of coal and gas outburst was deduced.Using the simulation device of coal and gas active jet outburst,the experimental study was carried out to study the variation of critical gas pressure,pulverized coal pulverization and fragmentation of coal and gas outburst in coal with different particle size,different water content and different coal uncovering area.The theoretical formula of jet energy was compared with the experimental results,and it was found that the results were consistent with the previous qualitative research.The jet outburst of coal and gas under different gas pressure was studied by AN AYS Fluent,the simulation results were incorporated into the energy formula,and the feasibility of the simulation was verified compared with the field examples.The energy change characteristics of coal and gas outburst are analyzed,and the results showed that with the increase of water content,the decrease of the particle size and the coal uncovering area,the outburst energy had volatility.The experimental and numerical simulation data were used to calculate the jet energy,it was concluded that with the increase of critical gas pressure,the outburst energy was larger.Both the experimental and numerical results show that the energy of gas was 3-4 orders of magnitude larger than that of coal,which was in accordance with the results of previous studies.The results could be used as a reference for the prediction of coal and gas outburst energy.