Research On Flow Field Law In High Gas Goaf Of Duanwang Coal Mine

This paper research on the spontaneous combustion disaster and gas disaster in goaf of 150405 face of Duanwang coal mine in Shanxi province. The CFD simulation technology is used to research on it. The goaf model is constructed based on the reality condition. gravity and inhomogeneous caving characteristic are considered. The oxygen consumption is obtained from the closed oxygen consumption experiment. Spontaneous combustion and gas drainage volume are analyzed after simulation. In addition, some conditions are adjusted to research the flow field in goaf.At first, the simulation is conducted at angel 6 degree. The simulation result showed that the pressure difference in belt roadway and return airway is 140 Pa, the minimum velocity is 1.47 m/s, they accords with the actual measurement. At the same time, the result also accords with the nomal airleakage regulation. The gas "come-up" phenomenon appearance in goaf for the gravity. At the same time, the air in goaf has the "rush-down" phenomenon behind the working face, some air rushed out from goaf then come into goaf again, thus resulting in the "circulation-remain" phenomenon of air.When goaf angel is 6 degree, the drainage volumes are respectively set to be 82 m/min (gas drainage volume is 20.5 m3/min),100 m3/min(gas drainage volume is 25 m3/min),120 m3/min(gas drainage volume is 30m3/min). The results show that the gas range has decrease tendency at the transport roadway side; the gas concentration decreases with the increase of drainage volume; The oxygen range has decrease tendency at the belt roadway side and increase tendency at the orbit roadway side.