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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摘要为揭示煤孔隙结构对瓦斯扩散的微观作用机制，针对煤中瓦斯赋存形态和扩散形式多样性，构建多尺度孔隙介质瓦斯传质模型；基于煤孔径分布测试结果，采用赌轮盘算法随机生成符合其空间分布概率的随机数，通过插值近似反演，获得了煤孔隙空间分布模型。在此几何模型基础上，利用Comsol数值软件对扩散模型进行解算，并与粒煤解吸实验结果进行对比分析。结果表明，煤的扩散能力较差，曲折因子远大于其他多孔材料，曲折因子与孔隙率关系负指数为5.5左右时模拟结果与实测结果基本一致；随孔径变化，煤内部努森系数、扩散系数不同，并在解吸过程中发生变化，煤粒内部扩散以过渡型扩散为主；由单孔隙模型解析解所得煤粒整体的扩散系数与模型所得内部扩散系数量级相同，为10－9 cm2/s，但随解吸进行其变化趋势有差异。

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	安丰华1
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	贾宏福2
	刘军1
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关键词 ：采矿工程, 孔隙分布, 扩散系数, 努森系数, 瓦斯解吸

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

引用本文:

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, 2021, 40(5): 987-996.
AN Fenghua1，2，JIA Hongfu2，LIU Jun1，2. A gas diffusion model based on the pore structure in coal. , 2021, 40(5): 987-996.

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http://rockmech.whrsm.ac.cn/CN/10.13722/j.cnki.jrme.2020.0901 或 http://rockmech.whrsm.ac.cn/CN/Y2021/V40/I5/987

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