振动频率对含瓦斯煤渗透特性的影响及模型验证

Influence of vibration frequency on permeability characteristics of coal containing gas and model verification

为了研究振动频率对含瓦斯煤渗透特性的影响,采用“振动—三轴—渗流”试验装置,开展含瓦斯煤在不同振动频率和瓦斯压力下的渗透试验,并将流固耦合模型代入软件进行验证。研究结果表明:含瓦斯煤的渗透率随瓦斯压力的逐渐增加呈现出先下降后上升的变化规律,该曲线的克林伯格瓦斯压力临界点在1.0 MPa左右;含瓦斯煤的渗透率随振动频率的增加先逐渐变大,当振动频率超过10 Hz后,渗透率缓慢减小并最终趋于稳定;考虑振动对煤岩的影响,推导出孔隙率与渗透率动态演化方程,代入Ansys模拟软件验证了方程的准确性。

In order to study the influence law of vibration frequency on permeability characteristics of coal containing gas,the“vibration-triaxial-seepage”device was used to carry out the permeability test of coal containing gas under different vibration frequencies and gas pressures,and the fluid solid coupling model was brought into the software for verification.The results show that the permeability of coal containing gas decreases first and then increases with the increasing gas pressure,and the critical point of Klinberg gas pressure of the curve is about 1.0 MPa;the permeability of coal containing gas increases gradually with the increase of vibration frequency,when the vibration frequency exceeds 10 Hz,the permeability decreases slowly and finally tends to be stable;considering the influence of vibration on coal and rock,the dynamic evolution equations of porosity and permeability are derived and brought into the Ansys simulation software to verify the accuracy of the equations.