岩石裂隙粗糙程度对渗流惯性效应的影响机制
The Influence Mechanism of Rock Fracture Roughness on Seepage Inertial Effect
申林方 1杨鸿忠 1陈积普 1王志良 1普姜超1
作者信息
- 1. 昆明理工大学建筑工程学院,云南昆明 650500
- 折叠
摘要
为研究粗糙裂隙渗流惯性效应的演化规律,采用分段线性法生成了粗糙裂隙面.基于格子Boltzmann方法,采用半反弹格式表征粗糙裂隙壁面与流体间的相互作用,建立了模拟粗糙岩石裂隙渗流过程的数值计算模型.根据有限差分方法对计算得到的渗流速度场进行数学离散,并结合动量守恒方程求解了粗糙裂隙渗流流体的黏性压降与惯性压降.探究了壁面粗糙程度、驱动压差、局部漩涡对裂隙渗流惯性效应演化规律的影响.研究结果表明:渗流惯性效应主要受控于流体的渗流流速及其空间变化率,粗糙壁面促使流体渗流流速大小、方向发生改变,从而产生惯性效应,截面平均压降与壁面起伏高度具有相似的变化趋势.随着裂隙渗流驱动压差的增大,渗流惯性效应加剧,截面平均压降增大,在壁面凸起处截面平均惯性压降的增大效果尤为显著.局部漩涡加剧了动能损耗,且漩涡结构内部的压力耗散以黏性压降为主,直至靠近漩涡边界时惯性压降才逐渐呈增长趋势.
Abstract
To study the inertial effect evolution of fluid seepage in the rough fracture,the piecewise linear method was adopted to generate the rough fracture surface.Based on the lattice Boltzmann method,the interaction be-tween the rough wall surface and fluid was characterized using the half-way bounce-back scheme,and a nu-merical model was proposed to simulate the fluid flow in the rough fracture.The seepage velocity was mathemati-cally discretized using the finite difference method,and the viscous pressure drop and inertial pressure drop of rough fracture seepage fluid were obtained according to the momentum conservation equation.Finally,the effects of surface roughness,driving pressure and local eddy flow on the evolution of seepage inertial effect were studied.The results show that the inertial pressure drop is mainly controlled by the seepage velocity and its spatial varia-tion.The rough wall changes the magnitude and direction of fluid flow velocity,resulting in the inertial pressure drop.The cross-section average pressure drop exhibits a similar variation trend to the wall surface height.As the driving pressure of fracture seepage increases,the seepage inertial effect intensifies,leading to an increase in the average pressure drop,and the increase in average inertial pressure drop is particularly significant at the convex regions of the wall surface.The local eddy flow intensifies the kinetic energy loss,the pressure dissipation inside the eddy zone is dominated by the viscous pressure drop,and the inertial pressure drop gradually increases until it is close to the eddy boundary.
关键词
粗糙裂隙/惯性效应/格子Boltzmann方法/渗流Key words
rough fracture/inertial effect/lattice Boltzmann method/seepage引用本文复制引用
基金项目
国家自然科学基金项目(42167022)
国家自然科学基金项目(41931294)
国家自然科学基金项目(42067043)
出版年
2024
NETL
NSTL
万方数据