Simulation of tunnel methane dispersion and airflow using three-dimensional lattice Boltzmann method based large-eddy simulation

The lattice Boltzmann method (LBM) and large-eddy simulation (LES) were combined with a scalar subgrid-scale model to simulate the tunnel air velocity field and methane dispersion. The presented model was validated by comparing its results with the published experimental results and the results of other numerical models (the OpenFOAM-K-Epsilon model and the OpenFOAM-LES model). Four local ventilation systems of a coal mine tunnel were evaluated based on the presented model. This demonstrated that the time-averaged results of the LBM-LES model agree well with the experimental results. Both the LBM-LES model and the OpenFOAM-LES model can capture the transient velocity fluctuation of the tunnel airflow. In diluting the methane near the heading face, the forced ventilation system performs the best. The exhaust ventilation system can prevent methane from spreading further from the heading face.