Numerical Simulation Study On The Propagation Characteristics Of Gas Explosion Shock Wave In Different Types Of Tubes

The overpressure and impulse of gas explosion shock wave is one of the deadly fatal factors of underground coal mine,and it will also cause the damage of the roadway structure,and even affect the safety of the building and personnel on the ground.The structure of the roadway network is complex,the propagation of the shock wave in the straight roadway meets the special structure of the various types of roadway will be changed.Therefore,it is necessary to study the propagation characteristics of gas explosion shock wave in different types of tubes.This thesis is based on numerical simulation,four models of tubes with straight,"L" type,"T" type and cross type are established,the software Fluent is used to solve the pressure variation parameters of the blast wave in different types of tubes,through the pressure contours and pressure changed with time and distance curve,the propagation characteristics of gas explosion shock wave in various types of tubes are analyzed and compared.After study found that the propagation of gas explosion shock wave in the "L" type,"T" type and cross type tubes,the high and low pressure vortex,high pressure region exist in local tubes.Their occurrence is caused by diffraction,regular reflection and irregular reflection in the special structure of shock wave in the tubes.Among the results,the pressure peak is the highest in the high pressure region at the corner of the"L" type tube,and the damage effect on the wall is the strongest;the bifurcation structure of "T" type and cross type tubes can effectively improve the local high pressure in "L" type tube,but the degree of improvement with cross type tube is less than the "T" type tube.The bend and bifurcation structures of the tubes complicate the flow field,and also attenuate the pressure and velocity of shock wave.According to the degree of attenuation from large to small,followed by the cross tube,"T" type tube,"L" type tube.The bifurcation structure of the "T" and cross tubes makes the shock wave split,and the pressure and velocity of shock wave in the main tube are larger than those of the branch tube.At the same time,when the end of the main tube is closed,the damage of the shock wave on the end wall is greater than that at the end of the branch tube.In addition,appropriately increasing the length of the closed tube section can prolong the reverse time of the shock wave and reduce the damage degree of the reverse shock wave to the pipeline.