Influence of Goaf Gas Emission on Gas Concentration and Spontaneous Combustion Zone Distribution

By using Fluent software, we carried out the numerical simulation for the gas concentration of goaf and spontaneous combustion zone distribution of different cases of gas emission including uniform emission, subsection uniform emission and continuous emission condition. The results show that: when the gas emission is uniform, the gas concentration in the shallow part of the goaf is lower than that of subsection uniform emission and continuous emission, and the gas concentration in the deep part of the goaf is higher than that of the two other cases. In view of the two conditions of the gas uniform emission and continuous emission, the gas concentration of the two cases in the shallow area of the goaf is not large, but, in the deep part of the goaf, the gas concentration that of the former is greater than that of the latter. When the gas emission is uniform, the width of spontaneous combustion zone is smaller than of the two other cases, but when the gas emission is subsection uniform, the width of spontaneous combustion zone is slightly larger than that of the continuous gas emission. So in the study of the flow field in the goaf, it is not accurate to consider the gas emission as uniform and subsection uniform, we should be study it based on the actual characteristics of gas emission.