漩涡合并过程中颗粒运动的数值模拟

漩涡合并不仅影响着流场的演化，还制约着颗粒相的运动．基于涡团分裂合并机制，以一种改进的涡核扩散方法(CCSVM)计算了二相流中的漩涡合并与演化，在此基础上采用单颗粒轨道模型计算、分析了漩涡合并过程中的颗粒运动轨迹．研究结果表明:漩涡合并过程中的颗粒轨迹是一条螺旋线，并且保持与漩涡相同的旋转方向，合并后的漩涡中心即为达到稳定状态后的环状颗粒群中心；合并时间与环量初始值、漩涡半径与涡心距比值的初始值有关；特定条件下，颗粒群中会生成一条拉伸的尾迹，尾迹的产生与黏度系数、颗粒与漩涡的相对位置、合并漩涡环量的不对称性有关．

Simulation on Motion of Particles in Vortex Merging Process

In two-phase flow, the vortex merging influences both flow evolution and particles motion. With the help of the blobs-splitting-and-merging scheme, the vortex merging was calculated by using a corrected core spreading vortex method (CCSVM); based on these, the particles motion in vortex merging process was calculated according to the particle kinetic model. As the results indicate, the particle traces are spiral lines, keeping the same rotation direction with the spinning vortex; the center of particles group is in agreement with that of the merged vortex; the merging time is determined by the circulation and initial ratio of the vortex radius and vortex center distance; and in a certain initial condition, a stretched particle trail is generated, which is determined by the viscosity, the relative position between particles and vortex, and the unsymmetrical circulation of the two merging vortexes.