采空区遗煤自燃"三带"及有害气体分布数值模拟OA北大核心CSTPCD

In order to investigate the distribution of the"three zones"of spontaneous combustion of residual coal and the distribution of harmful gases in the goaf of Hanjiawan Coal Mine in Shaanxi,numerical simulation studies were conducted using"Fluent+UDF".The study focused on the numerical simulation of the distribution of the"three zones"of spontaneous combustion of residual coal and the flow field characteristics.The goaf is considered as a porous medium,and parameters such as porosity of porous media,viscous resistance and inertial resistance in porous media,oxygen consumption of residual coal oxidation,and harmful gas outburst from residual coal were calculated through user-defined equations.The results indicate that the residual coal in the working face and goaf can be divided into scattered zones,oxidation zones,and suffocation zones.When the oxygen concentration is 0.07≤C≤0.18 as the oxidation zone indicator,the width of the oxidation zone increases from 23 m to 40 m from the inlet side to the return side,and finally decreases to 13 m on the return side.The oxidation zone on the side of the return airway is smaller than that of the inlet airway,and the suffocation zone is the largest.As the height increases,the overall oxidation zone area moves towards the inlet direction of the air inlet roadway,and the coverage area first increases and then decreases.