摘要
以湍流剪切层中大尺度旋涡结构与颗粒群的相互作用及运动规律为研究对象,提出了一种基于离散涡方法与颗粒碰撞模型相耦合的双拉格朗日气固两相流模型.用次循环调整颗粒运动计算的时间步长,将两相计算耦合在一起,从而解决了离散涡方法求解单相流场与颗粒运动方程的时间相容性问题.首先用颗粒在兰金涡中的运动验证了所提的算法,随后将该方法应用于高雷诺数湍流旋涡结构中的颗粒水平输运过程研究,模拟了圆柱尾迹中颗粒的沉降过程及其被旋涡卷吸、扬起和团聚的过程,说明在有大尺度旋涡存在的流场中颗粒更容易被流体向下游输运.当来流速度与重力方向一致时,颗粒分布特性受颗粒Stokes数(St)影响.当St小于1时,颗粒响应流场变化的时间短,随St增加颗粒对流场变化的响应变得迟钝,重力所起的作用更加明显;当St远远大于1时,颗粒的分布几乎不受旋涡的影响,而与自由沉降的分布十分接近.
A new and effective Lagrangian-Lagrangian model based on the coupling of discrete vortex method （DVM） and the particle collision model was proposed to study the interaction between large eddies and particle cloud in turbulent flow across circular cylinders. To achieve the compatibility in the discrete vortex method, sub time-step was used to adjust the calculation time step of the particle motion to couple the two-phase simulation in our model. The present method was validated by the particle trajectory in Rankine vortex and was applied to simulate the horizontal particle transport process in high Reynolds number turbulent flow across circular cylinders for the particle sedimentation, entrainment and concentration process. The particle distributions were investigated with different Stokes number when the mean velocity was in the direction of gravity. For vertical gas-solid two phase flow, when the Stokes number is smaller than 1, particles are entrapped easily by vortex and finally is concentrated near the outer edges of vortex structure due to their quick response to the flow field. With the increase of Stokes number, particles respond more and more slowly to the flow field, and thus the influence of gravity is stronger. As Stokes number is far larger than 1, vortex structure has little influence on the particle distribution, which is similar to the distribution of free sedimentation.
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2009年第1期77-80,共4页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(50676079)
教育部新世纪优秀人才计划资助项目(NCET-07-0661)
教育部科学技术研究重点资助项目(107101)
关键词
圆柱绕流
颗粒碰撞
离散涡方法
气固两相流
双拉格朗日模型
flow across cylinder
particle collision
discrete vortex method
gas-solid two phase flow
Lagrangian-Lagrangian model
作者简介
王聪（1982-），男，硕士；
陈斌（联系人），男，教授．
