Three-dimensional numerical simulation of spontaneous combustion in goaf of fully mechanized top-coal caving longwall

摘要

In the fully-mechanized mining top-coal caving face spontaneous combustion accident, high temperature ignition sources are mostly away from the floor at a certain height over the spatial position, rather than the position of the flat floor currently considered. The spontaneous combustion in the three-dimensional goaf was studied. By using CFD software - Fluent, it establishes the spontaneous combustion three-dimensional mathematical model of the loosen coal in the goaf, and simulates the spontaneous combustion process in the model. The simulation results show that along the height direction of goaf, from the floor up, the oxygen concentration decreases progressively. The distribution of low oxygen concentration is just like an "O" district, while the distribution of high is just like a "U" zone. In the rear of the fully-mechanized mining top-coal caving face goaf, the spontaneous combustion not only exists along the strike direction but also in the vertical direction. The intersecting area in both directions constitutes the actual spatial spontaneous combustion "three zones" of the goaf.