论文部分内容阅读
为了研究岩体裂隙面的粗糙程度与渗流机制间的相互关系,将裂隙沿长度方向均匀分割成若干段,通过设置每一段末端的随机高度,生成两侧对称的粗糙裂隙面。基于格子Boltzmann方法,采用不可压缩流体的D2G9模型,验证了经典的Poiseuille流,计算了不同相对粗糙度岩体裂隙的渗流特性,讨论了裂隙面粗糙度对渗流流态的影响。研究结果表明:裂隙结构壁面对流体的阻碍作用,使得流体在壁面附近的流动产生急剧调整,同时随着裂隙相对粗糙度的增加,在裂隙隙宽急剧变化的部位,局部伴随着旋涡的形成,导致流体内部摩擦阻力作用增大。在单位时间截面渗流流量及每一段平均隙宽相等的条件下,将本数值解与多平行板理论解进行了对比,对于相对粗糙度δ=0.01674的裂隙方案,由于多平行板理论解忽略了粗糙裂隙隙宽变化而引起的局部压降,其裂隙中线处压降产生的最大误差达到15.2%。当相对粗糙度较小时,裂隙中线处的压力与光滑平板流相类似,近似呈线性变化。随着裂隙相对粗糙度增大,压力变化偏离直线方向,且在断面由窄突然变宽的部位,压力变化偏离线性尤为显著。
In order to study the correlation between the roughness of rock fracture surface and the seepage mechanism, the fracture is divided into several sections along the length. By setting the random heights of each end, a rough fracture surface with bilateral symmetry is generated. Based on the Lattice Boltzmann method, the incompressible fluid D2G9 model is used to verify the classical Poiseuille flow, and the seepage characteristics of fractures with different relative roughness are calculated. The influence of roughness on the seepage flow regime is discussed. The results show that the wall of the crack structure obstructs the flow of fluid and makes the flow of the fluid near the wall sharply adjusted. Meanwhile, with the increase of the relative roughness of the crack, the vortex is locally formed along the sharp changes of the crack width, Resulting in increased friction within the fluid resistance. Comparing this numerical solution with the theory of multi-parallel plates under the condition of the percolation flow per unit time and the average gap width of each section, the theoretical solution of multi-parallel plates is neglected for the fracture scheme with relative roughness of δ = 0.01674 The maximum pressure drop caused by the pressure drop at the midline of the fracture reaches 15.2% due to the local pressure drop caused by the change of the rough crack width. When the relative roughness is small, the pressure at the midline of the fracture is similar to that of the smooth plate flow and changes approximately linearly. As the relative roughness of fracture increases, the pressure changes deviate from the straight line direction, and the pressure variation deviates linearly especially in the section where the section suddenly widens from narrow to narrow.