Chemical-potential multiphase lattice Boltzmann method with superlarge density ratios
Chemical-potential multiphase lattice Boltzmann method with superlarge density ratios
复制标题
超大密度比化学势多相晶格玻尔兹曼法
DOI：
10.1103/physreve.102.013303
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发表时间：
2020
影响因子：
2.4
通讯作者：
Shan Xiaowen
中科院分区：
文献类型：
--
作者：
Wen Binghai;Zhao Liang;Qiu Wen;Ye Yong;Shan Xiaowen
液气密度比是模拟真实流体系统的多相流方法的关键属性。在这里，构建了化学势多相晶格玻尔兹曼方法来实现极大的密度比。模拟表明，该方法达到了非常低的温度，在该温度下液气密度比超过，而热力学一致性仍然保持。通过比例系数将网格空间与动量空间解耦，较小的网格步长提供更密集的晶格节点来精确描述过渡区域，并且所得的尺寸变换不会损失精度。采用紧凑的有限差分方法以高阶精度计算网格空间中的离散导数。这些增强了非理想力的计算精度，并将寄生电流抑制到非常低的水平，即使密度比高达数万。液滴飞溅的模拟验证了该模型对于动态流场是伽利略不变量的。化学势的上限用于减少非物理因素的影响，提高稳定性。
The liquid-gas density ratio is a key property of multiphase flow methods to model real fluid systems. Here, a chemical-potential multiphase lattice Boltzmann method is constructed to realize extremely large density ratios. The simulations show that the method reaches very low temperatures, at which the liquid-gas density ratio is more than, while the thermodynamic consistency is still preserved. Decoupling the mesh space from the momentum space through a proportional coefficient, a smaller mesh step provides denser lattice nodes to exactly describe the transition region and the resulting dimensional transformation has no loss of accuracy. A compact finite-difference method is applied to calculate the discrete derivatives in the mesh space with high-order accuracy. These enhance the computational accuracy of the nonideal force and suppress the spurious currents to a very low level, even if the density ratio is up to tens of thousands. The simulation of drop splashing verifies that the present model is Galilean invariant for the dynamic flow field. An upper limit of the chemical potential is used to reduce the influence of nonphysical factors and improve the stability.