Lattice Boltzmann methods for binary mixtures with different molecular weights.
Lattice Boltzmann methods for binary mixtures with different molecular weights.
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DOI：
10.1103/physreve.71.046704
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发表时间：
2005-04
期刊：
影响因子：
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通讯作者：
M. McCracken;J. Abraham
中科院分区：
文献类型：
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作者：
M. McCracken;J. Abraham
以前的作者提出了二元混合物的格子玻尔兹曼方法。然而，这些方法仅限于具有几乎相同分子量的流体。在这项工作中，提出了两种改进的方法来模拟不同分子量的流体。第一种方法是基于物理原理，即在相同温度下，具有不同分子量的颗粒以不同的晶格速度（DLS）移动。因此，对于具有不同分子量的物质采用不同的流动距离。第二种方法是通过选择平衡分布函数中的常数来开发的，以这种方式可以调整每个物种的声速。在这种方法中，物种具有相同的晶格速度（SLS）。使用多尺度展开，该方法重现适当的物种连续性方程的宏观极限。通过对二元扩散问题的研究，对方法的精度进行了评价。的DLS方法被证明是能够模拟在流体中的扩散与较大的比的分子量相对于SLS方法。
Previous authors have suggested lattice Boltzmann methods for binary mixtures. However, these methods are limited to fluids with nearly the same molecular weight. In this work, two modified methods are proposed for simulating fluids with different molecular weights. The first method is based upon the physical principle that particles with different molecular weights move at different lattice speeds (DLS) when at the same temperature. Therefore, different streaming distances are employed for species with different molecular weights. A second method is developed by selecting constants in the equilibrium distribution function in such a way that the speed of sound can be adjusted for each species. In this approach, the species have the same lattice speed (SLS). Using multiscale expansions, the methods are shown to reproduce the appropriate species continuity equation in the macroscopic limit. The accuracy of the methods is evaluated by studying binary diffusion problems. The DLS method is shown to be able to simulate diffusion in fluids with larger ratios of molecular weights relative to the SLS method.