The mathematical model of gas flowing in porous medium based on the homogenization method

Considered the characteristics of porous medium in coal seam and goaf, order to reflect accurately influence various media against gas flow, mathematical model discrete multi-scale network macroscopic CFCM (Coal-Fracture-Cavity-Model), was presented. The is classified into matrix, fracture hole systems based on size, matrix system includes micro fractures micro-porous. can be regarded as diffusion percolation areas; a free-flowing area. computation flow field micro-scale, small-scale large-scale are obtained according Fick’s law, Darcy’s permeability law Forchheimer generalized Darcy respectively, homogenization method used analyse by scale upgrading equivalent fluid equation got describe accurately. An example calculated shows that most influential factors goaf two above would prevent airflow. study validates correctness classification equation.