矿井综采作业面毒害气体积聚现象的数值模拟研究

Numerical simulation on the phenomena of harmful gas accumulation near the fully mechanized mining face in an underground coal mine

本文研究矿井综采作业面附近毒害气体的积聚过程和分布规律。由"U"型通风作业面实际情况出发,提出作业面几何模型和气体流动的动力学控制方程,运用数值分析方法跟踪以CH_4和CO为代表的毒害气体在正常通风作业面的积累和分布情况。计算结果证实,作业面煤层和采空回填区释放出的CH_4和CO因局部涡流作用在回风巷隅角积聚,气体浓度经历升高而后逐渐稳定的过程;设备附近的毒害气体积聚过程与回风巷隅角类似,但积聚速度较快。迎风面附近CH_4和CO气体浓度相对较低;受上浮效应影响,背风面的毒害气体浓度积聚过程主要发生在背风面中上部。在常规通风条件下,局部CH_4浓度已超出安全规程允许的最高值,CO浓度亦达到危害人体健康的水平。本项工作获得的认识为作业面附近毒害气体监测和控制提供指导。

The present work aims to discover the accumulation process and distribution of harmful and toxic gases near the fully mechanized mining face by using numerical simulation method.In light of the actual situation of an ＂U＂type working face,a geometric model and dynamic governing equations were developed to trace the transient accumulation and distribution of the gases such as CH_4 and CO.The calculation results show that CH_4 and CO sourced from the goaf and the mining seams enter in the mainstream by following the airflow and then accumulate in the return corner,with their concentrations gradually growing and eventually reaching the steady values.The process of gas accumulation near the mining equipment is similar to that observed in the return corner,but the accumulation process is even faster.Mainly influenced by the floating effect,the gas concentrations are lower at the windward side of the equipment.The process of gas accumulation at the leeward side is mainly influenced by the vortex,and the harmful gases accumulate in the upper part of the leeward side in principal.It was found that,under normal ventilation condition,CH_4 concentration has exceeded maximum allowable value and CO concentration can also reach the level of doing harm to human＇s health in some particular locations.The established understanding provides guidance for the monitoring and control of the harmful gases near the working face in an underground coal mine.