Study On Gas Explosion Propagation Characteristics In Abnormal Structure Tube

Gas explosion is the main form of the coal mine disasters in China. Gas explosion in abnormal structure tube cause a lot of damage and casualties, it can still cause secondary disasters. It’s important to have a good command of the propogation characteristics of gas explosion in abnormal structure tube, which have guiding significance to mesasures of prevent, control and reduce the disasters.Based on the pipe system devlopmented by China University of Mining&Technology, this paper study gas explosion propagation characteristics in abnormal structure tubes by means of experiments and theoretical analysis. Obtained the main innovation achievements as follows:(1)Gas explosion under different filling ratios were studied in detail. The relationship between filling ratios and gas explosion propagation law was revealed. When the filling ratio is small, the peak overpressure reduces with the increase of propagation distance, the trajectory can be described as △P =ax2+bx+c. With the increase of filling ratio, the peak overpressure firstly decreases and then increases with increase of propagation distance, and falls again near the exit. The relation between maximum peak overpressure and the filling ratio can be described as △ Pmax=-0.003+0.16 β-0.08904 β2. The flame speed firstly increases and then decreases with the increase of propagation distance. The relation between maximum flame speed and the filling ratio can be described as vmax=31.02+428.09β-237.39β2.(2)This paper studied gas explosion in different bend pipes, revealed the influence of bend angles on gas explosion propagation. It is found that both of the peak overpressure, flame speed and the overpressure growth in the acute angle bend are greater than the ones in right and obtuse angle pipe. After divided into sections, the peak overpressure and the flame speed can be described as △P=a+be-x/c,v=a+be-x/c. The fitting parameters are also given in this paper, which have guiding significance to estimate the peak overpressure in pipes.(3)Gas explosion in different bifurcation pipes were studied in detail. This paper reveals the influence of two obtuse-angle bifurcation and obtuse angle-acute angle bifurcation pipe on gas explosion propagation. It was found that the peak overpressure and flame speed in obtuse branch are greater than the ones in acute branch in obtuse angle-acute angle bifurcation pipe. The explosion in two right-angle bifurcation pipe is greater than two obtuse-angle bifurcation and obtuse angle-acute angle bifurcation pipe. After divided into 2 sections, the peak overpressure can be described as △P=a+be-x/c,△P=d+d1x+d2x2. The flame speed can be described as v=a+be-x/c. The fitting parameters are also given in this paper, which have guiding significance to estimate the peak overpressure in pipes.(4)The distance between the bend, bifurcation and the ignition source have great influence on gas explosion propagation. The distance between the ignition source and the position where overpressure sudden increase grows with the increase of the distance between the bend, bifurcation and ignition source. In this process, the flame speed and the flame acceleration grows, while the maximum peak overpressure has little change.Gas explosion in confined space need extra attention.This paper anylized the gas explosion propagation law in abnormal structure, and hope to provide certain support to the coal mine gas explosion accident and management work. In addition, 4 papers about research results were published, in which 1 has been indexed by SCI, 1 has been indexed by EI.