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为了建立能够表征煤体真实孔隙结构的数字模型,进而进行数值模拟研究,通过μCT225k VFCB高精度CT系统扫描得到了大柳塔煤矿长焰煤CT数据,可观测到的最小孔隙直径为1.94μm。使用基于Matlab语言的三维重建程序结合逆向工程技术,提出了一种将煤体CT三维数据转换为CAD数字模型的方法。以Ansys建立的煤体有限元模型为例,对煤体瓦斯渗流进行了模拟,分析了煤体孔隙内的速度及压力分布规律,并计算了沿X、Y、Z方向的渗透系数。计算结果表明:在微观尺度下(<100μm)煤体渗透系数呈现各向异性,其受煤体结构的影响较明显。提出的基于CT三维重建结合逆向工程技术构建的煤体CAD数字模型不仅可进行有限元分析,同时也可以被EDEM等离散元分析软件所使用,拓宽了煤体CT三维数据的应用范围,丰富了煤体在微观尺度上的研究方法。
In order to establish a digital model that can characterize the real pore structure of coal, and then carry out numerical simulation studies, the CT data of long-flame coal in Daliuta coal mine was obtained by scanning with a high-precision CT system of μCT225k VFCB. The smallest observed pore diameter is 1.94μm. Using the three-dimensional reconstruction program based on Matlab language combined with reverse engineering technology, a method of transforming three-dimensional data of coal body CT into CAD digital model was proposed. Taking the finite element model of coal body set up by Ansys as an example, the gas flow in the coal seam is simulated. The velocity and pressure distribution in the pores of the coal body are analyzed. The permeability coefficients along the X, Y and Z directions are calculated. The calculation results show that the anisotropy of permeability coefficient of coal at microscopic scale (<100μm) is obvious, which is obviously influenced by the structure of coal. The proposed CAD model of coal body based on CT three-dimensional reconstruction and reverse engineering not only can be used for finite element analysis but also can be used by EDEM and other discrete element analysis software to broaden the application range of three-dimensional data of coal CT and enrich Research methods of coal on the micro scale.