气固两相圆柱绕流的直接数值模拟

本文运用谱元方法对气固两相圆柱绕流进行了直接数值模拟。在获得高精度计算流场信息基础上,进行颗粒扩散运动的研究。通过研究颗粒大小对颗粒扩散运动的影响来刻画气固两相圆柱绕流的物理特征。研究时发现,由于圆柱尾流独特的涡结构特征,颗粒在流场中心轴线附近区域的扩散机理主要是决定于吸力作用,该作用会驱使小颗粒卷吸进入圆柱尾部近壁区,甚至与圆柱后壁发生碰撞,这种扩散机理与混合层中颗粒扩散机理明显不同。

DIRECT NUMERICAL SIMULATION OF PARTICLE DISPERSION IN THE TEMPORAL WAKE OF A CIRCULAR CYLINDER

The primary purpose of the paper is to make a physical investigation of particles dispersion in the temporal cylinder wake. Based on accurate gas-field simulation, the associated dispersion pattern of particles with different Stokes numbers is examined. Particle Stokes number is considered to characterize the particle dispersion in the cylinder wake. It is first indicated that the mechanism of particle dispersion in the circular cylinder wake mainly depends on the repulsion process, The repulsion effect not only causes particles with small Stokes numbers (St = 0.01) to approach backward cylinder or even collide with its back face, but also makes particles burst out from the high concentration area developing a mushroom shaped distribution. Certainly, evident differences are established between particle dispersion in cylinder wake and that in mixing layers.