多层采空区流场局部动态平衡数学建模分析

Mathematical model for the local dynamic balance of multi-goaf air ventilation systems

针对大同矿区浅埋深、多煤层群、近距离、两硬条件下开采形成的多层采空区极易发生自燃的问题,进行风流流场调压分析,以达到控制采空区遗煤自燃及防止有害气体流入工作面的目标。建立了多层采空区流场调压数学模型,得出工作面风压调节的最优参数,结合工程实际分析,确定了多层采空区流场调压需要达到的预期效果。提出多层采空区流场局部动态平衡的调压方法,结合达西线性渗流定律,确定了多层采空区流场达到局部动态平衡的调压允许范围,并提出调压自动控制方法。

In order to control the self-spontaneous combustion of the coal residual in the multi-strata goaf and prevent from large amounts of harmful gas invasion into the working face,this paper intends to develop a mathematical model for the local dynamic balance of the air ventilation system in the multi-strata goaf. For this purpose,we have first of all analyzed the air pressure regulations in such systems in the working face of Datong Mine. Based on our analysis,we have determined the desired effects of the air pressure regulation in such systems in regard to the security problems in the actual production process. As is known,traditional pressure-equalizing technology is poor in controlling coal residual＇s spontaneous combustion in the case of multi-strata goaf,the paper has thus attempted to put forward a regulation method for the air pressure dynamic balance in the air ventilation system of the said goaf. What we have done first is to drill an air pressure measuring hole from the airflow back-way to the adjacent overlying goaf or goafs,trying to adjust the air pressure dynamic balance for the air pressure variation and difference automatically. In so doing,we would like to prevent large amounts of air intrusion between the working face and such goafs. Combined with the Darcy linear percolation law,we have confirmed the air pressure adjustable range and developed an automatic control method for the air pressure regulation. In practical engineering projects,it is only when we obtained the air pressure adjustable range that we shall be able to adjust the fan inverter by consoling on the basis of the survey parameters from the pressure difference sensor,the mining multi-parameter collector and so on,so as to realize the automatic control of the fan ventilation process. Since the air pressure regulation method is of important theoretical and practical value to solve the residual coal spontaneous combustion problems in multilayer goafs,it can surely be made a highly valuable reference to the close-type coal seams mining production.