考虑热对流的椭圆颗粒沉降规律的研究

A Numerical Study on the Sedimentation of an Elliptical Particle With Thermal Convection

基于双分布格子波尔兹曼模型研究了包含热对流的二维椭圆颗粒在竖直管道内的沉降问题,分析了热对流对沉降规律的影响。根据椭圆颗粒运动行为的不同,划分了四个格拉晓夫数区间,即沿管道中心线做周期性振荡、偏离管道中心线稳定沉降、沿管道中心线做不规则周期性振荡和偏离管道中心线做周期性振荡。在颗粒沉降过程中,强制对流、自然对流和壁面效应三者相互竞争,共同决定颗粒的运动行为。

Sedimentation of an elliptical particle in a vertical channel with thermal convection is investigated with the double-population lattice Boltzmann method, and the effect of thermal convection on the particle behavior is analyzed. According to the particle behavior, four regimes in terms of Grashof number are identified, i.e., periodic oscillation along the channel centerline, steady settling off the centerline, irregular periodic oscillation along the centerline and periodic oscillation off the centerline. During the sedimentation process, the forced convection, natural convection and wall effect compete with each other, which determine the particle behavior.