瓦斯压力变化过程中煤体渗透率特性的研究

为了研究煤体渗透率与瓦斯压力之间的关系,以吸附瓦斯煤体变形的应力、应变研究为基础建立了煤体渗透率与瓦斯压力变化的数学模型,并在温度恒定、径向应变受到严格约束和水份不变的条件下进行了实验。采用测量不同吸附特性煤样在不同孔隙压力和不同压差条件下瓦斯渗透流量的方法测定渗透率,渗透流量测量采用排水法与气体微流量计法相结合的测量方法,将其测量结果与数学模型产生的曲线进行对比分析。研究结果表明:渗透率随瓦斯压力的变化而变化,且瓦斯压力对于不同吸附性能的煤样影响程度不同;煤样瓦斯渗透率的理论值与实验值的相对误差最大可达到8.62%。但是从总体的数据来看,理论值和实验值的变化趋势基本一致,因此,可以依据煤样的基本参数和渗透率数学模型计算出该煤样在某一瓦斯压力下的渗透率。

Study on Permeability Charatieristics of Coal Body with Gas Pressure Variation

To study the relationship between the permeability of coal body and gas pressure,we established the mathematical models of coal permeability and gas pressure variation based on the analysis of,stress and strain of coal body absorbing gas,and carried out the experiments in the condition that the temperature is constant,radial strain is restrained strictly and moisture remains invariable.Using the methods which measuring the gas seepage discharges of coal samples with different adsorptive characteristics under different pore pressures and pressure drops to determine the permeability.The seepage discharge was measured by water drainage method combined with the gas micro-flow meter method,and the measurement results were analyzed comparatively with the curve of mathematical model.The results show that the permeability changes with the gas pressure,and the influence degree of gas pressure is different for different adsorption of coal samples.The change trends of the theoretical gas permeability of coal samples and the experimental values are basically accordance,while the maximal relative error between the theory and experiment values reaches to 8.62%.Therefore,the permeability under a certain gas pressure can be calculated according to the basic parameters and mathematical permeability model of coal samples.