颗粒在黏弹性流体扩张和收缩流中沉降的格子Boltzmann模拟分析

对于Oldroyd-B型黏弹性流体，本文应用格子Boltzmann方法(LBM)，实现了流体在二维1:3扩张流道及3:1收缩流道中流动的数值模拟，获得了黏弹性流体在扩张和收缩流道中的流场分布．结合颗粒的受力和运动规则，基于点源颗粒模型，数值分析了颗粒在扩张流和收缩流中的沉降过程和特征，讨论了颗粒相对质量和起始位置以及雷诺数Re和威森伯格数Wi对颗粒沉降特征的影响．结果表明，颗粒相对质量和起始位置以及Re对颗粒沉降轨迹和落点影响较大，而Wi的影响则较小．

Simulation Analysis of the Particle Settlement Motion in Viscoelastic Fluid Expansion and Contraction Flows Using the Lattice Boltzmann Method

In this paper, based on the lattice Boltzmann method (LBM) and the Oldroyd-B model, the plane 1:3 and 3:1 sudden expansion and contraction flow of viscoelastic fluid was studied numerically. The streamline patterns for sudden expansion and contraction flow of viscoelastic fluid with different Reynolds numbers Re and Weissenberg numbers Wi were obtained. Then, using the point source of particles method about the lattice Boltzmann equation (LBE), and combined with the force and movement rules of particles, the settlement motion of particle in the viscoelastic expansion and contraction flows was numerically analyzed. The influences of the relative mass of particle, starting position of particle, Reynolds number Re and Weissenberg number Wi on the settlement characteristics of particle were discussed. The results indicate that the relative mass and the initial position and Re have a great influence on the particle settling trajectory and falling point, while Wi has a little influence on these.