随着矿井开采深度的增加和综采技术的发展，煤矿采空区面积显著增大，煤自燃灾害形势更加严峻。采空区漏风是产生煤自燃的重要原因之一，因此研究采空区内部气体渗透特征及采空区风流运移特征十分重要。本文选取三种煤样为主要研究对象，搭建了松散煤体气体渗流综合实验平台，对不同温度条件下松散煤体内的气体渗流特征进行系统分析，以物理实验为基础，通过COMSOL数值模拟方法研究采空区松散煤体内温度升高与渗流规律的关系。主要结论如下：

       （1）基于自主搭建的松散煤体气体渗流综合实验平台，进行了不同温度下的松散煤体气体渗流实验。煤体温度从30 ℃升高至80 ℃过程中，气体低速通过粒径范围在3～5 mm松散无烟煤、烟煤及褐煤时均遵循达西渗流定律，当温度升高时，气体通过松散煤体的渗透率逐渐减小，且三种煤样渗透率无烟煤＞烟煤＞褐煤，30 ℃与80 ℃时的渗透率值分别为：无烟煤9.79×10^-10 m²、8.35×10^-10 m²；烟煤6.56×10^-10 m²、5.39×10^-10 m²；褐煤5.71×10^-10 m²、3.27×10^-10 m²。

       （2）进行了恒温条件与连续升温条件下气体在松散煤体中渗流数值模拟研究。以物理实验为基础、烟煤为研究对象，分别模拟30 ℃至80 ℃时恒温条件下的渗流过程，分析渗流速度变化，进而模拟30 ℃～80 ℃连续升温6 h时的气体渗流过程，分析得到在外部热源逐渐升高过程中模型管内的温度分布与渗透率分布呈“椭球形壳体”，模型管中心温度低于外侧，中心渗透率高于外侧，且渗透率随温度增加而减小，变化值为30 ℃至80 ℃时外壁渗透率从6.25×10^-10 m²减小至5.74×10^-10 m²，中心的渗透率从6.21×10^-10 m²减小至5.72×10^-10 m²，变化规律及数值与物理实验吻合性较好。

      （3）进行了采空区气体渗流数值模拟研究。以平煤八矿某工作面的现场数据为基础建立采空区渗流模型，模拟采空区温度影响条件下的温度分布、渗透率分布及氧气浓度分布，随着工作面从第10天推进至第35天时，高温区域高温点的温度从34.2 ℃升高至47.2 ℃时渗透率从6.3×10^-10 m²减小至6.07×10^-10 m²。随着温度的升高，煤体渗透率减小，高温区域的氧浓度逐渐减小，氧气运移路径发生变化。

       研究采空区松散煤体内气体渗流规律变化，有效掌握了采空区风流的运移特征，为煤自然发火的监测以及防治等工作提供了一定的理论基础。

       With the increase of mine mining depth and the development of fully mechanized mining technology, the area of coal goaf has increased significantly, and the disaster situation of coal spontaneous combustion has become more severe. Air leakage in the goaf is one of the important reasons for spontaneous combustion of coal. Therefore, it is very important to study the characteristics of the gas permeability and air flow in the goaf. In this paper, three coal samples are selected as the main research objects, and a comprehensive experimental platform for gas seepage in loose coals is built, and the characteristics of gas seepage in loose coals under different temperature conditions are systematically analyzed. Based on physical experiments, the COMSOL numerical simulation method is used to study The relationship between the temperature rise in the loose coal in the goaf and the seepage law. The main conclusions are as follows:

       (1) Based on the self-built loose coal gas seepage experiment platform, the loose coal gas seepage experiment at different temperatures was carried out. When the temperature of the coal body rises from 30 ℃ to 80 ℃, the gas passes through the loose anthracite, bituminous coal and lignite at a low velocity in the particle size range of 3～5 mm. Darcy's law of percolation is followed. When the temperature rises, the gas passes through the loose coal. The permeability of the three coal samples is gradually decreasing, and the permeability of the three coal samples is anthracite>bituminous>lignite. The permeability values at 30 ℃ and 80 ℃ are respectively: anthracite 9.79×10^-10 m², 8.35×10^-10 m²; bituminous coal 6.56 ×10^-10 m², 5.39×10^-10 m²; lignite 5.71×10^-10 m², 3.27×10^-10 m².

       (2) The simulation of gas seepage in the loose coal mass under constant temperature conditions and continuous heating conditions was carried out. Based on physical experiments and bituminous coal as the research object, the seepage process under constant temperature conditions from 30 ℃ to 80 ℃ is simulated, and the change of seepage velocity is analyzed. Furthermore, it simulates the gas permeation process when the temperature is continuously increased from 30 ℃ to 80 ℃ for 6 h, and analyzes the temperature distribution in the model tube in the process of the gradual increase of the external heat source. The permeability distribution is like an "ellipsoidal shell", and the center temperature of the model tube is lower than the outer side, the permeability of the center is higher than that of the outer side, and the permeability decreases with increasing temperature. When the change value is 30 ℃ to 80 ℃, the permeability of the outer wall decreases from 6.25×10^-10 m² to 5.74×10^-10 m². The permeability decreases from 6.21×10^-10 m² to 5.72×10^-10 m², and the change rule and value are in good agreement with the physical experiment.

       (3) The simulation of gas seepage in the goaf when there is heat storage and temperature rise somewhere in the goaf. Based on the field data of a working face of Pingdingshan No. 8 Coal Mine, a goaf seepage model is established to simulate the temperature distribution, permeability distribution and oxygen concentration distribution under the influence of the goaf temperature. As the working face progresses from day 10 to day 35, when the temperature of the high temperature point in the high temperature area increased from 34.2 ℃ to 47.2 ℃, the permeability decreased from 6.3×10^-10 m² to 6.07×10^-10 m². As the temperature increases, the coal permeability decreases, the oxygen concentration in the high temperature area gradually decreases, and the oxygen migration path changes.

       The study of the influence of the gas seepage law in the loose coal in the goaf effectively grasps the characteristics of air flow in the goaf, and provides a certain theoretical basis for the monitoring and prevention of coal spontaneous combustion.

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