| Mechanized coal caving technology is used by Tiefa coal mine, which have a lot of shortcoming, such as great strength of this mining method of extraction, the residual coal mined-out area left more than caving height and large, serious leakage. In the conditions of high gas and spontaneous combustion easily, Fire and gas problem in goaf is particularly prominent, and it serious threat to the safety of mine production. For the complex situation of Tiefa group, gas migration law in goaf is studied. The main contents are as follows:(1) In order to clearly understand the state of air flow and gas component concentration distribution, based on AutoCAD and CFD technology, software coupling wind, fire& gas is developed, which have a lot of advantage such as easy drawing, primitives including ventilation, nitrogen injection, closed walls, gas drilling and other elements.(2) Cross three zones are calculated by simulation software. And cross three zones changes are modeled before and after injection of nitrogen(3) Components distribution(including gas, oxygen, carbon monoxide), temperature, velocity and pressure field are analyzed by the software developed.(4) Coupling limit for gas and fire control is calculated in N2706 of Daxing mine.(5) dynamic adjust velocity method for fire prevention is summarized. Gas flow state is analyzed after measures. |
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