摘要
煤体是一种多孔介质,其内部孔隙结构十分复杂,准确评价煤体的孔隙特征对研究瓦斯的吸附解吸和高效瓦斯抽采具有重要意义。根据分形理论,研究了一种描述多孔介质孔隙空间分布的随机分形模型,并根据其构造方法,建立了煤体多孔介质孔隙度和分形维数之间的关系。通过压汞实验,验证了分形模型的正确性。对煤体多孔介质孔隙度进行了分形描述,结果表明:分形维数决定了孔隙度,分形维数越大,孔隙度越小;观测尺度越小,孔隙度越大,同一阶次孔隙平均直径越小,孔隙度越小,同一阶次孔隙数量越少,孔隙度越小;相同孔隙度条件下的孔径分布不尽相同,这也导致了瓦斯流动和吸附解吸规律的不同。因此,煤体多孔介质的分形维数反映了煤体内部孔径分布特征,对研究煤体孔隙类型和探讨煤层内瓦斯流动有重要意义。
Coal is a kind of porous media, in which the pore structure is very complex. Thus, the accu- rate evaluation of the pore characteristics of coal mass has great significance to research the adsorption and desorption of gas and the efficient gas drainage. In this paper, based on fractal theory, a kind of random fractal model which can be use to describe the pore space distribution of porous was researched, and on the basis of its construction method, the relationship between porous media porosity and fractal dimension was established. In addition, by mercury injection experiment, the correctness of fractal model was verified, and the fractal description of porosity for porous media of coal mass was carried out. The results show that porosity is determined by fractal dimension, and the porosity decreases with the increase of fractal dimension. Meanwhile, the smaller the observing scale, the bigger the porosity, the smaller the average diameter of the same order pore, the smaller the porosity, and the less the amount of the same order pore, the smaller the porosity. Moreover, the pore size distribution can be different with the same porosity, which leads to different gas flow, and adsorption and desorption laws. Therefore, the fractal dimension can reflect the characteristics of pore size distribution in coal mass, which has great significance to the study of pore types of coal mass and gas flow in the coal seam.
出处
《采矿与安全工程学报》
EI
北大核心
2013年第3期437-442,448,共7页
Journal of Mining & Safety Engineering
基金
国家重点基础研究发展计划(973)项目(2011CB201205)
国家自然科学基金项目(51074161)
煤炭资源与安全开采国家重点实验室自主研究课题项目(SKLCRSM08x03)
关键词
多孔介质
孔隙度
分形维数
压汞实验
porous media
porosity
fractal dimension
mercury injection experiment
