The Study On The Shock Wave Propagation Rules And Numerical Simulation Of Gas Explosion In The Tunnel Of High Gas Coal Mine

The explosion occurred in the tunnel of coal mine belongs to the typical gas explosion. It is the most serious disaster in the production of coal mine. The computational fluid dynamics software Fluent is used for simulating the explosion of gas in the tunnel. The physical and mathematical models were established on the base of theoretical analysis. The initial conditions of the numerical simulation was given. The model of Finite-Rate/Eddy-Dissipation was used to describe the process of gas-air mixture explosion, using the SIMPLEC algorithm to handle the pressure and speed of the explosion. For improving the accuracy of the numerical simulation, the unbalanced function method near the wall was used to handle the flow field.The results of thesis were concluded that the high temperature and overpressure were significantly higher in the closed tunnel by simulating the gas explosion under the open and closed conditions in tunnels. The propagation of gas explosion in different concentrations in the tunnel was simulated. Through analyzing the explosion characteristics in different gas concentrations, the thesis concluded that the most violent explosion under the gas and air for combustion completely. Combined with the environment of coal mine tunnel, the gas explosion in tunnel section narrows and bifurcation conditions were simulated. The influence of tunnel changed on the explosion propagation process of gas was analyzed, the result shows that the temperature and pressure shock value at the tunnel narrows rising sharply and bifurcation of the flame propagation induced by the obstacle-type making turbulence led to flame acceleration and a significant rise in temperature. Research and analysis results show that the degree of gas explosion in a closed significantly stronger than in an open tunnel. The same tunnels were filled with gas in different concentrations but certain length. The gas explosion flame propagation distance is three to six times than the length of gas filled. The range of explosion is far greater than the gas concentration range, due to the formation of the triple point mutations, the overpressure increased significantly in the tunnel section narrows. and aggravated the explosion. When the gas explosion flame front propagation reached to the bifurcation of the tunnel, the explosion exacerbated by the burning rate increased, making the temperature rose sharply and leading to the degree of damage in the bifurcation of the gas explosion severely than other locations. The results have certain reference value in the area of gas explosion propagation and accident prevention.