PRESSURE-DRIVEN FLOW OF SUSPENSIONS - SIMULATION AND THEORY
PRESSURE-DRIVEN FLOW OF SUSPENSIONS - SIMULATION AND THEORY
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DOI：
10.1017/s0022112094002326
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发表时间：
1994-09-25
影响因子：
3.7
通讯作者：
BRADY, JF
中科院分区：
文献类型：
--
作者：
NOTT, PR;BRADY, JF
采用Stokesian动力学方法对零雷诺数下非布朗悬架通道内压力驱动流动进行了动力学模拟。模拟是针对相同颗粒的单层，作为无因次通道宽度和散装颗粒浓度的函数。从均匀分散开始，颗粒逐渐向通道中心迁移，导致浓度分布均匀，颗粒速度分布变钝。达到稳态的时间尺度为（H/a）(3)a/，其中H为通道宽度，a为颗粒半径，通道内平均悬浮速度。模拟所得的浓度和速度分布与实验结果定性一致。提出了一种悬浮液流动模型，该模型同时建立和求解宏观质量、动量和能量平衡。结果表明，垂直于平均运动方向的悬浮压力恒定的要求导致了非均匀流动中颗粒的迁移和浓度的变化。为了提供悬浮行为的非局部描述，引入了悬浮“温度”的概念——粒子速度波动的度量。该模型对河道流动的模拟结果与模拟结果吻合较好。
Dynamic simulations of the pressure-driven flow in a channel of a non-Brownian suspension at zero Reynolds number were conducted using Stokesian Dynamics. The simulations are for a monolayer of identical particles as a function of the dimensionless channel width and the bulk particle concentration. Starting from a homogeneous dispersion, the particles gradually migrate towards the centre of the channel, resulting in an homogeneous concentration profile and a blunting of the particle velocity profile. The time for achieving steady state scales as (H/a)(3)a/, where H is the channel width, a the radii of the particles, and the average suspension velocity in the channel. The concentration and velocity profiles determined from the simulations are in qualitative agreement with experiment.A model for suspension flow has been proposed in which macroscopic mass, momentum and energy balances are constructed and solved simultaneously. It is shown that the requirement that the suspension pressure be constant in directions perpendicular to the mean motion leads to particle migration and concentration variations in inhomogeneous flow. The concept of the suspension 'temperature'-a measure of the particle velocity fluctuations-is introduced in order to provide a nonlocal description of suspension behaviour. The results of this model for channel flow are in good agreement with the simulations.