浓悬浮液中渗透性颗粒的扩散特性研究

摘要

本文利用浓悬浮液中渗透性颗粒的短时扩散动力学数值模拟的结论，并结合Cohen-de Schepper近似和Percus-Yevick近似，研究了不同粒径渗透性颗粒的有效扩散系数随体积分数和渗透率的变化关系。结果表明：对于浓悬浮液中一定粒径的渗透性颗粒，其扩散系数随渗透率的增加而增加，随体积分数的增加而减少；具有相同粒径与流体动力学屏蔽深度比值且波数较大的渗透性颗粒，其粒径对扩散的影响可以忽略。%We have studied the effective diffusion coefficient of permeable particles with different radii at different permeability and volume fractions by using the numerical simulation results of short-time diffusion dynamics of permeable particles in concentrated suspensions and the combination of Cohen-de Schepper and Percus-Yevick approximations. As a result, the diffusivity of particles having the same radius will increase monotonically with increasing permeability to a certain volume fraction, and decrease linearly with increasing volume fraction to a certain permeability. While the effect of particle radius on the measured effective diffusion coefficients for the permeable particles with larger wave-numbers at the same ratio of particle radius to the hydrodynamic penetration depth may be neglected.