Three-dimension Numerical Simulation of Residual Coal Spontaneous Combustion in Goaf in Fully Mechanized Caving Face

In order to study residual coal spontaneous combustion process,a 3D numerical model was built for residual coal spontaneous combustion in goaf in fully mechanized caving face.Methods for determining the relevant parameters were given.Taking 3123 working face of Wulong mine in China for an example,residual coal spontaneous combustion was studied through the method of 3D numerical simulation.The results show that the wind velocity field,the oxygen and gas concentration fields,the three zones division and the heat-up process of residual coal obtained using the method of 3D numerical simulation conform basically to the results of actual measurement,that the shape of oxidation zone is similar to reversed 7,that there may be a number of high temperature zones,and that the centre position of high temperature zone is higher than the floor.According to simulation analysis,the air-volume of working face both height of oxidation zone and the heat-up time of residual coal are roughly exponential functions of air-supply to working face when the air-supply to working face is small,the oxidation zone width is directly proportional to the supply.