Numerical simulation of gas drainage with high position boreholes in goaf

Gas distribution and flowing in Qinan Mine were calculated and analyzed by means of the Navier-Stocks formula based on the Darcy law and then the method of CFD numerical simulation was used to visually display the result.The gas collection course in the falling porous media at the upper corner of goaf was simulated theoretically, which clearly illustrated the gas movement and flow pattern in goaf when the gas was drained.Based on the simulation result, the gas was drained through high-position boreholes placed in the fracture area in Qinan Mine, and it was proved to prevent the gas from flowing to the upper corner.As a result, piping measurements show, the gas concentration in the drainage pipeline reached to about 30% to 80% and the gas concentration of return air was lowered to as low as 0.3%.