煤与瓦斯突出发生前后煤层温度演化规律研究

Evolution law of coal seam temperature before and after coal and gas outburst

为研究煤与瓦斯突出发生前后煤层温度演化规律,利用多场耦合煤矿动力灾害物理模拟试验系统,开展了气-固耦合条件下的煤与瓦斯突出物理模拟试验,并监测了突出发生前后的煤层瓦斯压力与温度。研究表明:在突出发生之前,煤层在吸附瓦斯过程中煤体温度随着瓦斯压力的增大而逐渐升高,煤层在达到吸附平衡后,煤体温度上升了2.6℃,位于煤层中心位置处的煤体温度明显高于边缘位置处;突出发生后,距离突出口较近的断面内煤体温度会出现突降现象,断面中心位置处温度下降量明显较大,而在距离突出口较远的断面,温度变化趋势与之相反;突出过程为热力学多变过程,煤体温度降低是由游离瓦斯膨胀做功和吸附瓦斯解吸造成的,煤体温度下降量和瓦斯膨胀能随着瓦斯解吸量的增加而增大。

In order to study the evolution law of coal seam temperature before and after coal and gas outburst,the multi-field coupling coal mine dynamic disaster physical simulation test system was used to carry out the physical simulation test of coal and gas outburst under gas-solid coupling.The gas pressure and temperature of coal seam before and after outburst were monitored.The research results have revealed that before the outburst,the coal mass temperature gradually increases with the gas pressure during gas adsorption process.After the coal seam reaches the stage of adsorption equilibrium,the coal mass temperature rises by 2.6℃.The coal mass temperature at the center of the coal seam is significantly higher than that at the edge.After the outburst,the coal mass temperature in the section close to the outburst orifice suddenly drops.The decrease of temperature at the center of the cross-section is significantly larger,while in the section farther away from the outburst orifice,the temperature change trend is opposite.The outburst process features a thermodynamic polytropic process.The decrease of coal mass temperature is caused by the work of free gas expansion and desorption of adsorbed gas.At the same time,the decrease of coal mass temperature and gas expansion energy increase with the increase of gas desorption.