【作者】 张云； 葛蔚； 王小伟； 杨朝合；

【Author】 Yun Zhang~(1,2),Wei Ge~(*2),Xiaowei Wang~2,Chaohe Yang~1 1.State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Qingdao 266555,China;2.State Key Laboratory of Multi-phase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China

【机构】 中国石油大学重质油加工国家重点实验室； 中国科学院过程工程研究所多相复杂系统国家重点实验室；

【摘要】 本文采用格子Boltzmann方法(LBM)在图形处理器(GPU)上计算了由静止圆柱阵列组成的团聚物最小周期单元内的不可压缩流体流动,流固交界面处采用直接反弹以实现无滑移边界,每个圆柱上的曳力通过统计动量交换直接求得。根据LBM求得的流体速度,对于团聚物中的单圆柱按能量最小多尺度(EMMS)模型计算平均曳力系数,并与假设颗粒均匀分布的相应曳力系数对比。将这两种曳力系数随密相空隙率变化曲线的交点作为均相与非均相的分界点,对颗粒雷诺数Re_p在0～10之间的6种固相份额的计算表明:当固相份额恒定时,该分界点随着Re_p的增加而降低;当Re_p恒定时,该点随着固相份额的增加而降低。更多还原

【Abstract】 In this presentation,the incompressible fluid flowing through a periodic domain with a cluster formed by arrays of cylinders was simulated by the lattice Boltzmann method(LBM) performed on graphics processing units(GPUs).The bounce-back scheme was adopted on the fluid-solid interfaces,which insures the no-slip boundary condition.The drag force on each cylinder was calculated by the momentum exchange method directly.Based on the flow field thus obtained,the average drag coefficient of each cylinder inside particle cluster is calculated by the Energy-Minimization Multi-Scale(EMMS) model,and compared with the drag coefficient based on the assumption of homogenous distribution of particles.The solid fraction in the cluster which gives equal values for these two kinds of drag coefficients is considered as the dividing line between homogenous and heterogeneous distribution.Six average solid fractions were studied for particle Reynolds number Re ranging from 0 to 10,indicating that this dividing line is subject not only to Re_p but also to average solid fraction:it decreases with the increase of Re_p at constant average solid fraction or increases with average solid fraction at constant Re_p.更多还原