Research on the gas migration trend and mechanism of the transition flow regime in coal based on MRT-LBM simulation

In order to reveal the process and mechanism of gas flow in a low-permeability coal seam, new multiple-relaxation-time lattice Boltzmann method (MRT-LBM) model migration micro/nanopores based on Langmuir monolayer adsorption theory, slip boundary scheme Bosanquet effective viscosity was established. The software MATLAB used carry out simulation study uniform pore MRT-LBM model, results were compared verified with porous anodic alumina membrane experimental results. On this basis, pores different micro/nanopore sizes considering simulated. show that dimensionless permeability coefficient increases decreasing size under same pressure, which reflects subsequent enhancement microboundary constraint effect reveals system becomes main controlling factor seam within matrix middle late stages extraction, while role needs be considered. layer weakens capacity, but for radius greater than 16 nm, apparent change caused by is less 5%, can ignored. N 2 , CH 4, CO enter transition regime pressure conditions; decreases, difference characteristics three gases increases.