瓦斯爆炸冲击波扰动后毒害气体云团运移特性

Study of the migration characteristics of noxious gas cloud after shock wave disturbance of a gas explosion

为了研究煤矿瓦斯爆炸后毒害气体的致灾影响,建立了井下巷道内毒害气体运移模型,分析了不同风流速度、不同转角角度下,CO浓度随运移时间的变化规律及毒害气体云团运移速度和尺寸的变化特性.认为风流速度主要影响毒害气体云团达到最大长度的时间,但对其最大长度没有明显影响;转角处毒害气体浓度峰值有突增现象,经过转角后其运移速度逐渐衰减.研究结果表明:风流速度越大,CO的滞留时间越短,其浓度峰值越高,如扩散距离80 m处,当风流速度从1 m/s增加至3 m/s时,CO的滞留时间减少了130 s,而浓度峰值增加了9.97×10^(-4);随着转角从30°增加至60°,毒害气体云团的运移速度衰减加快,在巷道内存在的时间减少了120 s;毒害气体云团的长度随运移时间呈倒U型的变化趋势,风流速度的增加明显缩短毒害气体云团达到最大长度的时间,但对最大长度大小影响较小,如风流速度为3 m/s时云团达最大长度的时间比1 m/s时减小了近1倍,但最大长度均约为245 m.

In order to study the disaster-causing effects of noxious gas after a gas explosion in a coal mine,a model of noxious gas migration in the underground roadway was established.The variation law of CO concentration with migration time and the variation characteristics of migration velocity and size of noxious gas cloud were analyzed under different airflow velocities and turning angles.It is considered that the airflow velocity mainly affects the time when the noxious gas cloud reaches its maximum length,but it has no obvious effect on its maximum length.There is a sudden increase in the peak concentration of noxious gas at the turning corner,and the migration velocity of the noxious gas cloud decreased gradually after passing the corner.The research results show that the greater the airflow velocity is,the shorter the CO retention time is,and the higher the CO peak concentration is.For example,when the airflow velocity increases from 1 to 3 m/s,the CO retention time decreases by 130 s at the diffusion distance of 80 m,while the peak concentration increases by 9.97×10^(-4).With the turning angle increasing from 30°to 60°,the migration velocity of the noxious gas cloud decreases faster,and the existence time in the roadway decreases by 120 s.The length of the noxious gas cloud shows an inverted U-shaped trend with the increasing migration time.The increase of airflow velocity obviously shortens the time for the noxious gas cloud to reach the maximum length,but it has little effect on the maximum length.For example,with the airflow velocity increasing from 1 to 3 m/s,the time for the noxious gas cloud to reach the maximum length reduces by nearly one time,but the maximum length is both about 245 m.