基于流固耦合的瓦斯抽采半径数值模拟研究

Study on Numerical Simulation of Gasdrainage Radius Based on Fluid and Solid Coupling

快速准确考察钻孔有效抽采半径一直是煤矿瓦斯高效防治的难题之一,常规数值模拟方法因未贴合真实抽采状态,模拟结果往往存在较大偏差。本研究基于瓦斯吸附、解吸特性和可压缩性,重点分析抽采时煤体的有效应力与孔隙率、渗透性的关系,对瓦斯流动综合偏微分方程进行修正,建立了流固耦合的偏微分控制方程组,随后借助COMSOL Multiphysics软件对不同点位瓦斯压力、孔隙率等变化进行数值模拟,根据阳泉矿区某矿实际拟合得到有效抽采半径公式,现场试验发现理论模拟和实际抽采达标时间偏差小于3天,验证方法可行有效。

Quick and accurate inspection of the effective drainage radius of the borehole has always been one of the difficult problems in the efficient prevention and control of coal mine gas, conventional numerical simulation methods often have large deviations due to the fact that the simulation results do not fit the real drainage conditions. Taking a mine in Yangquan mining area as the engineering background, based on the characteristics of gas adsorption, desorption and compressibility, this article focuses on the analysis of the relationship between the effective stress of the coal body during drainage and the porosity and permeability, and revises the comprehensive partial differential equation of gas flow by establishing a system of partial differential control equations for fluid-solid coupling, and numerically simulating changes in gas pressure and porosity at different points with the help of COMSOL Multiphysics, which obtains the effective extraction radius formula and proves that the verification method is feasible and effective, with the deviation between the theoretical simulation and the actual extraction standard time being less than 3 days.