Experimental study of new technology for preventing gas combustion in mining face

Based on analyzing the reasons and characteristics of gas combustion under coal mine and integrating the situation of gas combustion accident which frequently occured at present,the authors built the experimental platform with the ultra fine water mist to prevent gas combustion.A series of experiments with the ultra fine water mist to prevent gas combustion was conducted.Finally,the best operation parameter to study the water mist restrained gas combustion was obtained with the methane flow of 150 mL/min,the methane concentration of 90%,the atomization quantity of 220 mL/min,and the water spray particle size of 5-30 μm.The results show that after release ultra fine water mist,a closed spray ring is formed around the gas flame,and the gas flame interact with ultra fine water mist appears the process of restrained-cut flame-restrained again-cut flame again,with the gas flame gradual becoming smaller until to extinguish.Comparing with free combustion,the temperature and oxygen concentration around gas flame all reduced with different degree,and the whole process of flame extinguish is only 90 s.