论文部分内容阅读
渗透率是指在一定压差下,多孔介质材料允许流体通过的能力,是描述多孔介质渗透性的重要物理参数。依据连续介质力学和唯象理论,在细观尺度上考虑了超声二次损伤对颗粒煤岩渗透率的重要影响,建立了超声激励过程中机械及热效应导致的有效应力和损伤量的理论模型。开展了不同气体压力下颗粒煤岩渗透率测定试验,拟合得到了渗透率与气体压力之间的经验公式,建立了煤岩气测渗透率、有效应力和二次损伤量间的关系模型。结果表明:超声作用能够有效提高颗粒煤岩体系的渗透率,有效应力的逐渐增大是超声增渗的主要原因;接触颗粒面元间损伤的增加和显著的热效应是渗透率增长率下降的主要影响因素。研究工作对煤层气增渗机理及优化开采具有重要的科学意义和工程实用价值。
Permeability refers to the ability of a porous media material to allow fluid to pass at a certain pressure differential and is an important physical parameter that describes the permeability of porous media. According to the theory of continuum mechanics and phenomenology, the important influence of ultrasonic secondary damage on the permeability of granular coal and rock is considered in the meso-scale, and the theoretical model of effective stress and damage caused by mechanical and thermal effects during ultrasonic excitation is established. The experiments of permeability of granular coal and rock under different gas pressures were carried out. The empirical formula between permeability and gas pressure was fitted and the relation model between permeability, effective stress and secondary damage of coal and gas was established. The results show that the ultrasonic effect can effectively improve the permeability of the granular coal and rock system, and the increase of the effective stress is the main reason of the ultrasonic increase. The increase of the damage and the significant thermal effect between the interfacial elements of the contact grain are the main factors of the decrease of the permeability growth rate Influencing factors. The research work has important scientific significance and engineering practical value to CBM infiltration mechanism and optimized mining.