Abstract: The large eddy simulation (LES) is used to study the fully developed flow fields in Kenics statics mixer. The formation inducement and evolution process of secondary flow is analyzed. Simulated data coincide well with experimental data. The results based on the current researched contents show that there are three kinds of longitudinal vortices in the area of the seventh twisted element. They are designated as merged-vortex, internal- vortex and detour-vortex. Merged-vortex produces by merging two vortices from the entrance of element. And internal- vortex grows by the rotation of the twisted blade. The detour-vortex is induced by the Coriolis force caused by high twist rate of the twisted blade. And the Coriolis force will lead to the unbalance pressure distribution and the separation of boundary layer, thus the induced vortices will come into being. The area of the seventh element is divided into four segments along the axial direction. There are five vortices in the first and second segments, and the values of vorticity and turbulent intensity are 23.0% and 8.93% higher than that in the third and fourth segments respectively. The vorticity increases suddenly near the pipe wall on the interface of the neighboring elements, which is 73.0% higher than the average values, because the energy dissipation is caused by breakup and coalescence of vortices.

Key words: Kenics statics mixer, large eddy simulation, longitudinal vortices, evolution, fully developed

摘要： 为分析Kenics型静态混合器内充分发展段沿轴向二次流纵向涡的形成诱因及演变过程，运用大涡模拟对混合器内流场进行研究，数值模拟结果与实验结果吻合较好. 结果表明，在第7个扭旋叶片所在区域内含3种旋涡，分别为叶片入口分割上一段流体后产生的合并旋涡、随扭旋叶片一起旋转的内流旋涡和绕流旋涡. 绕流旋涡是扭旋叶片高扭率产生的科氏力导致单侧流体压力不平衡，使边界层产生分离形成的诱导旋涡. 沿轴向将第7个扭旋叶片所在区域流场平均分成4段，第一和第二段的横截面上存在5个纵向涡，涡量和湍动强度平均值分别比第三和第四段高23.0%和8.93%. 在相邻叶片的分界面处，旋涡破碎和聚合产生能量损耗，使近壁面的涡量陡增，高出平均值73.0%.

关键词: Kenics型静态混合器, 大涡模拟, 纵向涡, 演变, 充分发展