几何粗糙对岩体裂隙非线性流动的影响机制

破断岩体裂隙的几何粗糙使得其中的流体流动行为呈现出显著的非线性。借助粗糙裂隙的平行板离散模型和COMSOL软件,分析了离散模型单元体内部的流体流速及压力分布规律,获得了岩体裂隙中非线性流动产生的物理机制;研究了裂隙几何特征对非线性流动的影响规律,提出岩体裂隙非线性流动的流量计算方法,并与数值模拟结果进行了对比。结果表明:隙宽突变处的附加压力降损耗是导致粗糙裂隙流体流动产生非线性的主因;裂隙壁面粗糙和雷诺数的耦合作用显著影响裂隙中流体的非线性流动行为,裂隙中隙宽明显收缩处是附加压力降损耗的主要位置;提出的粗糙裂隙非线性流动的流量计算方法显著提高了分析结果的准确度,显示出较好的实用性。

Effect mechanism of geometry roughness on no-linear flow in rock fractures

Geometry roughness of rock fractures affects the non-linear behavior of fluid flow through it.Com-bining with the series-parallel plate discrete model for rough fractures and COMSOL software,this paper analyzed the fluid flow velocity and pressure distribution in discrete model unit,and the physical mechanism of non-linear fluid flow occurred in fractures was obtained.By studying the law of geometry characteristic parameter effect on non-linear flow,a mass flow calculation method was proposed,and was compared with numerical results.It shows that the excess pressure loss taken place at aperture mutation position led to non-linear flow in rough fractures；it is the roughness of fracture wall coupled with Reynolds number which significantly influenced the non-linear flow behavior in rock fractures,and the max value of excess pressure loss arose in place which aperture obviously narrow；the proposed calculation method improved the analysis accuracy of results,displayed a better applicability.