Characterization of the gas explosion under continuous disturbance by coal gangue in a coal mine gob

Abstract

Gas explosions in coal mine gobs caused by the spontaneous combustion of coal usually result in serious threat to energy security. The main feature is that the explosion flame is initially disturbed by the coal gangue. To recognize the characteristics of gas explosion under the continuous disturbance of gangue, based on the explosion accident of a certain coalmine, experiments under five blockage length-diameter ratios (BLRs) and four concentrations with the ignition located inside the gangue were carried out. The results show that the gangue could significantly influence the explosion intensity. The disturbance of gangue increased the flame deformation degree and the reaction rate, the combustion intensity increased with BLR. The relationship between overpressure ratios and BLRs showed a good logarithmic function trend. The impact intensity downstream of blockage region was the highest in 11.5 % condition, reaching 2.67 times of the no-obstacle condition. The disturbance of gangue should be an important factor in inducing high intensity catastrophe in Babao coal mine. For mines with similar status, reducing or eliminating the intensifying effect of coal gangue on explosion is necessary to guaranteeing safe production. The conclusion can help in guiding the assessment of gas explosion intensity and disaster prevention under similar scenarios.

Keywords

• Gas explosion
• Coal gangue
• Continuous disturbance
• Impact load
• Overpressure ratio