Aerosol particle deposition in numerically simulated channel flow
Aerosol particle deposition in numerically simulated channel flow
复制标题
DOI：
10.1063/1.857344
复制
发表时间：
1989-07
影响因子：
4.6
通讯作者：
J. McLaughlin
中科院分区：
文献类型：
--
作者：
J. McLaughlin
本文用拟谱法计算了刚性球形颗粒在槽道湍流中的运动轨迹，模拟了三维时变流场。假设通道是垂直的，使得重力不能直接导致颗粒在壁上的沉积。颗粒被假定为足够小和广泛的分离，使其对流体速度场的影响可以忽略不计。结果发现，当颗粒被分配到随机的初始位置与初始速度是等于当地的流体速度，颗粒往往积累在粘性子层。在粘性子层的边缘处，存款在壁上的颗粒通常具有速度的法向分量，该法向分量的大小与通道的核心中的速度的法向分量的强度相当（即，摩擦速度的数量级）。具有由Saffman推导的层流形式的剪切诱导升力被发现对颗粒轨迹几乎没有影响，除了在粘性子层内，它在颗粒的惯性沉积和捕获颗粒的积累中起着重要作用。存款的颗粒的雷诺数与1相比并不小。
The trajectories of rigid spherical particles in a turbulent channel flow are computed using a pseudospectral computer program to simulate the three‐dimensional, time‐dependent flow field. It is assumed that the channel is vertical so that gravity cannot directly cause the deposition of particles on the walls. The particles are assumed to be sufficiently small and widely separated so that their influence on the fluid velocity field can be ignored. It is found that when the particles are assigned random initial locations with initial velocities that are equal to the local fluid velocity, the particles tend to accumulate in the viscous sublayer. At the edge of the viscous sublayer, the particles that deposit on the wall typically possess normal components of velocity that are comparable in magnitude to the intensity of the normal component of the velocity in the core of the channel (i.e., of the order of magnitude of the friction velocity). A shear‐induced lift force having the form derived by Saffman for laminar flow is found to have virtually no effect on particle trajectories, except within the viscous sublayer where it plays a significant role both in the inertial deposition of particles and in the accumulation of trapped particles. The Reynolds number of the particles that deposit does not remain small compared with unity.