基于煤孔隙构成的瓦斯扩散模型研究

doi:10.13722/j.cnki.jrme.2020.0901

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Abstract For revealing the microscopic influence mechanisms of pore distribution on gas diffusion， a mass transfer model for multiscale porous media was established considering coal gas state and diffusion form diversity. Based on pore size distribution determinations，the roulette algorithm was used to generate random numbers in accordance with pore spatial distribution probability，and then a pore spatial structure model was inversed approximately through the interpolation of these numbers. On the basis of the 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 the diffusivity of the coal is worse and the tortuosity of coal is much larger than other porous materials, and that the simulation and experimental results are approximately consistent with each other while the index in the exponential relationship between the tortuosity and the porosity reaching about 5.5. With various pore sizes，Knudsen coefficient and the diffusion coefficient are different in coal. The diffusion coefficient of coal particles calculated through the analytical solution of the uni-pore model has the same order of magnitude with the internal diffusion coefficient obtained through the model，about 10－9 cm2/s，but they have different variation trends as gas desorption.

Key words： mining engineering pore distribution diffusion coefficient Knudsen coefficient gas desorptio

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	AN Fenghua1
	2
	JIA Hongfu2
	LIU Jun1
	2

Cite this article:

AN Fenghua1,2,JIA Hongfu2, et al. A gas diffusion model based on the pore structure in coal[J]. , 2021, 40(5): 987-996.

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https://rockmech.whrsm.ac.cn/EN/10.13722/j.cnki.jrme.2020.0901 OR https://rockmech.whrsm.ac.cn/EN/Y2021/V40/I5/987

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