Study On The Influence Of Baffle On The Propagation Characteristics Of Explosion Shock Wave In Single Headed Roadway

In recent years,coal mining accidents still occur frequently,and the situation of coal mine safety production is still severe.At present,China is vigorously promoting the emergency refuge system,and most of the refuge locations are located in the bifurcated roadway next to the main roadway.In case of an accident,the refuge chamber or other materials in the bifurcated roadway are the necessary guarantee for the safety of underground personnel and material loss reduction.Therefore,this thesis adopts the method of combining numerical simulation and similar simulation to deeply analyze the influence of the baffle on the peak pressure,flame propagation structure and flame velocity in the bifurcated single heading roadway.The main work and conclusions are as follows:First of all,according to the scale and conditions of the laboratory,a scaled down pipe model was made.The five components of the model are explosion chamber,closure plate,main tunnel simulation pipeline,experimental tunnel simulation pipeline and cover plate.Secondly,the similar simulation experiment was used to study the propagation law of the baffle to the gas explosion under the mine inside the single heading roadway,summarizing the inhibition effect of the number and position changing of the baffle on the explosion effect by analyzing the change law of the explosion overpressure and flame speed.It is found that when the shock wave encounters a turning structure in the transmission process,the gas will expand due to the sudden increase of the cross section,forming Prandtl Meyer flow at the turning.When the shock wave is transmitted to the corner of the bifurcated roadway,the blocking effect of the corner will cause the shock wave in transmission to be divided into two parts,and the shock wave in the main roadway will continue to propagate,the shock wave in the bifurcated roadway will accumulate at the right corner,forming a high pressure zone,and continuously spread to the lower roadway,making the flow field in the single ended bifurcated roadway more complex.The baffles set in the single headed bifurcated roadway will weaken the peak pressure in varying degrees,among which the L type of single baffle and the RR type of double baffle have the best weakening effect,which are 46.4% and 64.5% respectively.Finally,the experimental results in the similar simulation are demonstrated by numerical simulation.The results show that the initial speed of L type and R type flame under the condition of single baffle is lower than that of no-load test,while the flame acceleration effect of RR type and LR type under the condition of double baffle is better than that of RL type and LL type as a whole.It is found that this phenomenon occurs because the baffle blocks the flow of a large number of combustible gas mixtures concentrated on the right side of the roadway due to inertia.At the same time,the sudden change of the flame surface in the pipe gap accelerates the gas flow,forming a stronger gas flow behind the baffle.After data co MParison.Therefore,in the design and layout of the refuge chamber or the one-head tunnel with important machinery and materials,two flameproof panels or other objects with equal spacing along the opposite side of the coal mining,half the width of the bifurcated tunnel and similar shape,can effectively spread to the bifurcated tunnel and reduce the overpressure by more than 65%,which is of great significance to support the safety of the mine,especially the safety avoidance system.