多颗粒在Giesekus流体Poiseuille流场中的异常迁移

Abnormal migration of multi-particles in Poiseuille flow of Giesekus fluid

该文采用虚拟区域法对多个颗粒在黏弹性流体Poiseuille流场中的侧向迁移进行了数值模拟。在数值模拟结果的基础上,比较了单颗粒与多颗粒运动的差异,分析了在不同流变性质的流体中颗粒运动的轨迹与趋势。研究结果表明,由于颗粒间相互作用的影响,多颗粒的运动轨迹和方向与单颗粒情形有着较大差异;在流道中心线与壁面之间存在一条分界线,当颗粒的初始位置位于分界线与中心线之间时,颗粒最终将运动至中心线,反之则运动到壁面;在同样的条件下,单颗粒朝中心线运动,而多颗粒则会朝向壁面运动,且这种现象随着颗粒间距离的减小而增强。

The lateral migration of particles in the Poiseuille flow of a Giesekus viscoelastic fluid is investigated numerically using the direct fictitious domain method. In the paper, the trajectories of three particles and the single particle under different conditions are analyzed in detail. Due to the hydrodynamic interparticle interaction, the trajectory of one particle among the three particles does not coincide with that of the single particle, even the migration direction of three particles is different from that of the single particle. The results show that there is a separatrix between the centerline and the wall. When the initial position of particle is between the centerline and the separatrix, the particle would eventually migrate to the centerline,otherwise the particle would migrate to the wall. Under the conditions that the single particle can move towards the centerline,some particles in multi-particles could migrate to the wall.