Monteferrante Michele, Melchionna Simone, Marconi Umberto Marini Bettolo
Consiglio Nazionale delle Ricerche, Istituto di Chimica del Riconoscimento Molecolare (ICRM-CNR), Via Mario Bianco, 20131 Milan, Italy.
Istituto Processi Chimico-Fisici, Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Università La Sapienza, P.le A. Moro 2, 00185, Rome, Italy.
J Chem Phys. 2014 Jul 7;141(1):014102. doi: 10.1063/1.4885719.
When simulating multicomponent mixtures via the Lattice Boltzmann Method, it is desirable to control the mutual diffusivity between species while maintaining the viscosity of the solution fixed. This goal is herein achieved by a modification of the multicomponent Bhatnagar-Gross-Krook evolution equations by introducing two different timescales for mass and momentum diffusion. Diffusivity is thus controlled by an effective drag force acting between species. Numerical simulations confirm the accuracy of the method for neutral binary and charged ternary mixtures in bulk conditions. The simulation of a charged mixture in a charged slit channel show that the conductivity and electro-osmotic mobility exhibit a departure from the Helmholtz-Smoluchowski prediction at high diffusivity.
当通过格子玻尔兹曼方法模拟多组分混合物时，希望在保持溶液粘度不变的同时控制组分之间的互扩散率。本文通过修改多组分Bhatnagar-Gross-Krook演化方程实现了这一目标，即引入了两个不同的质量和动量扩散时间尺度。因此，扩散率由作用于组分之间的有效阻力控制。数值模拟证实了该方法对于本体条件下中性二元混合物和带电三元混合物的准确性。对带电狭缝通道中带电混合物的模拟表明，在高扩散率下，电导率和电渗迁移率偏离了亥姆霍兹-斯莫卢霍夫斯基预测。
