基于格子Boltzmann方法颗粒团聚物曳力系数的数值模拟及应用研究

应用气固两相流动的格子Boltzmann-离散颗粒运动模型,气体流动采用格子Boltzmann方法的D2Q9模型,固体颗粒运动采用牛顿第二运动定律计算,壁面采用具有二阶计算精度的半步长反弹边界条件,数值模拟了循环流化床提升管内颗粒团聚物的运动过程。模拟结果表明,颗粒团聚物的气固相间曳力系数随颗粒团聚物的空隙率和雷诺数的增大而减小;拟合得到基于格子Boltzmann方法的气固相间曳力模型;采用基于格子Boltzmann方法的气固相间曳力模型的欧拉-欧拉双流体模型模拟循环流化床提升管内颗粒相密度和颗粒质量流量径向分布,模拟结果与实验结果很接近。

Numerical Simulation and Application of Drag Coefficient of Particle Clusters in a Riser Based on Lattice-Boltzmann Method

The flow process of particle clusters in a circulating fluidized bed riser was numerically simulated by using gas-solid two-phase flow Lattice Boltzmann-Discrete particle model,in which D2Q9 model,Newton’s second law and half-way rebound boundary condition with second-order calculation accuracy were adopted to calculate gas flow,solid flow track and wall surface,respectively.The results indicated that the drag coefficient of the particle clusters reduces with the increase of their Reynolds number and porosity.The particle density and particle mass flow rate radial distribution in the riser were simulated by Euler-Euler two-fluid model based on the drag force model of Lattice Boltzmann method,the results coincided with the experimental results.