圆管内粗糙壁面处微细颗粒沉积规律研究  

Investigation of mechanism of micro-particle deposition on rough surfaces inside a tube

作　　者：靳少永 徐明海[1] 孙宪航 李会明 王政 

机构地区：[1]中国石油大学(华东)储运与建筑工程学院能源与动力工程系,青岛266580

出　　处：《应用力学学报》2017年第4期735-741,共7页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51276199)

摘　　要：针对固体颗粒在圆管中的沉积问题,本文采用DEM(Discrete-Element Method)描述颗粒与壁面的碰撞特征,采用湍流雷诺应力模型结合拉格朗日随机轨道模型对0.01μm^50μm的微细颗粒在壁面的沉积特性进行了研究。考查了颗粒粒径、重力、壁面位置、雷诺数Re、有效表面能、弹性模量对沉积速率的影响。结果表明:下壁面的沉积速率最大,上壁面的最小;颗粒在下壁面的沉积速率随量纲为一的弛豫时间呈V型曲线变化;当空气平均流速为0.5m/s时,颗粒小于1μm时即可忽略重力的影响,并且随着空气流速的增大,需要考虑颗粒重力的临界直径会逐渐增大;颗粒的粘附/反弹特征对沉积有很大影响,有效表面能越大,沉积速率越大;有效弹性模量越大,沉积速率越小;当颗粒小于10μm时,沉积速率随雷诺数Re的增大而增大;当颗粒大于等于10μm时,沉积速率随雷诺数Re的增大而减小。For the particle deposition in tubes, the deposition characteristics of micro-particle from 0.01 μm to 50 μm are numerically investigated by using Reynolds stress model coupling Lagrangian-based discrete random walk on rough surfaces inside a tube. A Discrete-Element Method(DEM) is employed to describe collisions between particles and wall. The computations are performed for different parameters including particle diameters, gravity, wall positions, Reynolds numbers, effective surface energy and elastic moduli. The results show that the particle deposition velocity on bottom wall is higher than those on side and top wall and presents a V-shape curve with particle dimensionless relaxation time. On the basis of the mean air velocity of 0.5 m/s, influence of gravity can be neglected when the particle is less than 1 μm, and the particle critical diameter increases with the increase of air velocity. Besides, the adhesion/rebound characteristics of particles have great influence on the particle deposition velocity.

关 键 词：DEM 颗粒沉积 粗糙壁面 气固两相流 

分 类 号：O359[理学—流体力学]