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以瓦斯径向非线性流动理论为基础,对钻孔径向物理网格均匀化处理,选取预估—校正差分算法推导线性差分方程组,获得钻孔径向瓦斯压力分布曲线,比较物理网格和网格均匀化差分迭代的计算误差.为使钻孔径向瓦斯压力分布曲线光滑、降低差分迭代的计算误差,选取拉伸-压缩变换函数使钻孔周边自然生成的非均匀物理网格经过对数变换变成均匀的计算网格,选取预估—校正平均稳式差分算法推导径向瓦斯不稳定流动线性差分方程组,并模拟不同透气性、不同时间钻孔径向瓦斯压力分布;钻孔径向6 m范围内物理网格与网格均匀化瓦斯压力最大差值达到1 MPa.
Based on the theory of non-linear flow of gas in the radial direction, the radial physical grid of the borehole is homogenized, the linear difference equations are derived by using the prediction-correction difference algorithm, and the radial pressure distribution curve of the borehole is obtained. The physical grid And meshing homogeneity differential iteration.In order to make the radial gas pressure distribution curve of the borehole smooth and reduce the calculation error of the differential iteration, the non-uniform physical grid around the borehole naturally The logarithmic transformation is transformed into a uniform computational grid, and the prediction-correction mean steady-state difference algorithm is used to derive the linear gas instability flow linear difference equations and to simulate the radial gas pressure distribution with different gas permeability and drilling time. Hole diameter 6 m range of physical grid and grid uniform gas pressure maximum difference of 1 MPa.