关键词: 瓦斯扩散, 双孔模型, 动扩散系数模型, 孔隙结构, 数值模拟

Abstract: Studying the law of gas desorption-diffusion in coal is of great significance for fully understanding the mechanism of gas migration in coal, scientifically utilizing gas resources, and preventing and controlling gas disasters. Based on the numerical simulation method, the applicability of the unipore model, the bidisperse model and the dynamic diffusion coefficient model in the gas desorption-diffusion of coal particles was compared and analyzed. The gas pressure distribution law of the bidisperse model and the dynamic diffusion coefficient model and the sensitivity of the model parameters to the metamorphic degree, particle size and adsorption equilibrium pressure of the coal sample were studied. The results show that compared with the unipore model, the bidisperse model and the dynamic diffusion coefficient model can more accurately describe the gas desorption-diffusion law in the whole stage. The bidisperse model and the dynamic diffusion coefficient model describe the gas desorption-diffusion process in different ways. Compared with the bidisperse model, the dynamic diffusion coefficient model has a larger radial gas pressure gradient. The degree of coal sample metamorphism, particle size, and adsorption equilibrium pressure have a significant impact on the various parameters of the model, and its essence is the difference in pore structure in coal. The research results can provide guidance for reasonable selection of gas desorption-diffusion model and its parameters.