Study on sealing effect of pre-drainage gas borehole in coal seam based on air-gas mixed flow coupling model

The low gas extraction concentration is one of the main factors that affect the prevention and control effect of coal and gas outburst. Based on this, the factors of air leakage around the roadway and borehole are analyzed. The effect of extraction time, seal length and air leakage on the gas concentration is discussed by the fluid-solid coupling model, which is proved by the borehole environmental parameter instrument.The research findings show...