Optimization of Dynamic Nitrogen Injection Parameters in Fully Mechanized Working Face of Liuzhuang Coal Mine

In order to study the influence of nitrogen injection on the distribution of residual coal spontaneous combustion of "three belts" in the goaf, based on the "O" type slump compaction and the model of Bachmat nonlinear seepage, the distribution of air leakage in the stope of 171101 working face in Liuzhuang Coal Mine was numerically simulated by using Fluent software.The simulated air volume distribution of the working face was basically consistent with the result of field measurement. On this basis, the component transport model was used to simulate and analyze the concentration fields of multicomponent gas under different nitrogen injection sites. The results showed that the oxygen concentration in the goaf changes obviously before and after nitrogen injection, the oxygen concentration decreases particularly significant especially in the vicinity of the nitrogen injection port, and there is no great change in methane concentration. By comparing multiple programs, it can be concluded that when the nitrogen injection port is set 10 m to 30 m from the working face, the effect of nitrogen injection is better.