LES原PBM 模拟后台阶流动中颗粒的团聚

采用大涡模拟（Large Eddy Simulation，LES） 耦合颗粒群平衡模型（Population Balance Model，PBM） 的方法进行了对气固两相流在后台阶突扩模型的模拟计算，流场的涡结构演化与实验结果吻合较好. 在此计算结果的基础上，研究不同位置处、不同Stokes 数下，以及不同体积分数（Vc） 等条件下涡结构的变化对颗粒扩散和颗粒团聚效果的影响，结果表明涡结构的变化对颗粒的团聚有较大影响. 颗粒的Stokes 数较小，颗粒对涡结构的跟随性较强，但也对涡结构产生了破坏作用，使得流场开始部分颗粒的团聚效果较好，之后的破坏作用又逐渐地削弱了颗粒间的团聚. 颗粒的体积分数越大对涡结构的破坏越强，导致颗粒的团聚逐渐减弱
The large eddy simulation (LES) coupled Population Balance Model (PBM) was used to simulate the gas-solid two -phase flow through backward-facing step. The vortex structures in flow field were in good agreement with the experimental results. Based on this, it is found that the vortex structureshave effect on particle diffusion and particle aggregation under different sections and Stokes number and volume fraction (Vc). When the Stokes of the particles is smaller, they followthe vortex structure tightly, and alsodestroys the vortex structure.This has lead to abetter agglomeration among particles at the beginning of the flow field, while the destruction of the vortex structure has gradually weakened the aggregation among particles. The greater volume fraction of particles has caused greater damage to the vortex structure，hencethe agglomeration effection has been gradually weakened in flow.