挡板偏心度对振荡流反应器三维流场对称性影响的研究

借助商业计算流体力学软件CFX,运用有限容积法离散振荡流反应器（OFR）的单个腔室,对具有理想对称几何边界和轻微挡板偏心度的OFR在系列振荡雷诺数（Reo）下的三维流场进行了仿真模拟,并将其可视化计算流场与实验流场进行比较,研究了OFR几何边界上的非对称因素对其内三维流场流型的影响.模拟结果表明在有效消除计算随机误差以及误差积累的情况下,几何边界理想对称OFR内的三维层流流场呈现出良好的中心对称性和周向均匀性,而湍流流场中心对称的同时呈现出周向非均匀结构--在圆周上生成8个中心对称排列的横向漩涡,其形态与Couette流中的泰勒涡类似.另外,挡板偏心度对OFR内的振荡流场的对称性有重要影响：在较大的下,其三维流场生成非对称性显著的大尺度漩涡对;并且随的增大,流场的非对称程度加大而增加.

Effects of Baffle Eccentricity on Flow Patterns of 3-D Flow Field in an Oscillatory Flow Reactor

Finite volume discretization was carried out for one single cell of oscillatory flow reactor (OFR) with perfect symmetric geometrical boundaries and slight eccentricity of baffles by using CFX, and the effects of asymmetry-geometrical factors on the flow patterns of 3-D flow field in OFR were studied by comparing the computational flow fields with experimental flow fields under a series of oscillatory Reynolds number( Re o).The results show that, when the computational error and its accumulation are eliminated effectively, the laminar flow in OFR with perfect-symmetric boundaries behaves in a pattern of central symmetry and circumferential uniformity while the turbulent flow field presents a centrally symmetric and circumferentially non-uniform structure with 8 transverse vortices arrayed circumferentially in a way of central symmetry, similar to Taylor vortices in Couette flow. It also is found that the asymmetry-geometrical boundary ?? the eccentricity of baffles has obvious effects on the symmetry of the flow field in OFR: at a relatively high Re o, two large-size vortices with obvious asymmetry are generated in the 3-D flow filed of OFR; and the greater the Re o, the more obvious the asymmetry of the oscillatory flow field with certain eccentricity of baffles.