A model for gas diffusion based on the pore structure in coal
AN Fenghua1，2，JIA Hongfu2，LIU Jun1，2
(1. Collaborative Innovation Center of Coal Safety Production and Clean and Efficient Utilization，Henan Polytechnic University，Jiaozuo，Henan 454000，China；2. School of Safety Science and Engineering，Henan Polytechnic University，Jiaozuo，Henan 454000，China)
Abstract：For the microscopic mechanism research of the effect of pore distribution on gas diffusion，toward the problems of coal gas states and diffusion forms diversity，a mass transfer model for multiscale porous media was established；based on pore sizes distribution determinations，the roulette algorithm was used to generate random numbers in accordance with pores¢ spatial distribution probability，and then pore spatial structure was inversed approximately through the interpolation of these numbers. On the basis of this geometric model，numerical software Comsol was utilized to solve the equations of the new diffusion model，and the results were compared with the gas desorption experimental results of coal particles. Results show that tortuosity of coal is much larger than other porous materials，with the index in the exponential relationship between tortuosity and porosity reaching about 5.5，indicating worse diffusivity；with various pore sizes，Knudsen coefficients and diffusion coefficients are different in coal；the diffusion coefficient of coal particles calculated through the analytical solution of the unipore model has the same order of magnitudes with the internal diffusion coefficients obtained through the model，which are about 10－9 cm2/s，but they have different variation trends as gas desorption.
安丰华1，2，贾宏福2，刘 军1，2. 基于煤孔隙构成的瓦斯扩散模型研究[J]. 岩石力学与工程学报, 0, (): 339-339.
AN Fenghua1，2，JIA Hongfu2，LIU Jun1，2. A model for gas diffusion based on the pore structure in coal. , 0, (): 339-339.
