Abstract:
Given that the current real-time monitoring range of methane concentration does not cover the area where the “three machines” in fully mechanized mining face are located, and it is difficult to determine the locations for manual inspections, the methane diffusion law in the working face is studied on the basis of the grid division by changing the position of the coal mining point and the wind speed conditions, and by combining the on-site measurements with the simulation experiments, so as to provide a reference for optimizing the arrangement of methane sensors and the strategy of manual inspection in the working face. Firstly, the restricted space of the working face is divided into 294 grids, and then the software FLUENT is used to set the boundary conditions of the three-dimensional model of the working face and carry out simulation experiments, according to the experimental results of the diffusion of methane in the different grids to carry out statistical analyses, and by comparing the on-site measured results with the experimental data to verify the validity of the results of the simulation experiments. The research results indicate that methane diffusion reaches its widest range when coal mining operations are carried out in the central area of the working face. Wind speed affects the diffusion range of methane in different regions, but the diffusion intensity of coal falling methane resulting from transportation against the airflow direction is far less than that along the airflow direction. Moreover, the maximum methane concentration in the working face area is only related to the position of the coal mining point. Considering the methane diffusion patterns under different coal mining point positions and wind speed conditions, methane sensors should be primarily deployed or inspection frequencies should be increased at the overlapping locations of the horizontal-1 region and the vertical-2, vertical-3 regions. The research findings reveal the methane diffusion mechanism in the fully mechanized mining face, which is of great significance for determining the key location of gas monitoring in the working face and safeguarding the safety of the operators, and provides powerful support for improving the ability of preventing and controlling gas disasters in the working face.