Fluctuating hydrodynamics of reactive liquid mixtures
Fluctuating hydrodynamics of reactive liquid mixtures
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DOI：
10.1063/1.5043428
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发表时间：
2018-08-28
影响因子：
4.4
通讯作者：
Donev, Aleksandar
中科院分区：
文献类型：
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作者：
Kim, Changho;Nonaka, Andy;Donev, Aleksandar
波动流体动力学(FHD)提供了一个框架，用于以与统计力学和非平衡热力学一致的方式模拟微观波动。本文给出了具有随机化学的等温反应性不可压缩液体混合物的FHD公式。脉动多组分质量扩散采用Maxwell-Stefan描述，不假定稀溶液，动量动力学由流体速度的随机Navier-Stokes方程描述。我们考虑非稀相混合物的质量作用定律的热力学一致性推广，并将其用于化学主方程(CME)中，将反应模型化为泊松过程。与传统的反应扩散主方程方法相比，当反应分子数目较多时，FHD方法具有显著的计算效率，而且即使在每个流体动力电池中只有10个反应分子时，也能保持精度。我们提出了一种数值算法来求解耦合的FHD和CME方程，并在平衡和非平衡问题上进行了验证。我们模拟了在存在酸碱中和反应的情况下，从一个完全平坦的界面开始的扩散驱动的引力不稳定性。我们证明了速度和浓度涨落之间的耦合主导了不稳定性的初始增长。由AIP出版公司出版。
Fluctuating hydrodynamics (FHD) provides a framework for modeling microscopic fluctuations in a manner consistent with statistical mechanics and nonequilibrium thermodynamics. This paper presents an FHD formulation for isothermal reactive incompressible liquid mixtures with stochastic chemistry. Fluctuating multispecies mass diffusion is formulated using a Maxwell-Stefan description without assuming a dilute solution, and momentum dynamics is described by a stochastic Navier-Stokes equation for the fluid velocity. We consider a thermodynamically consistent generalization for the law of mass action for non-dilute mixtures and use it in the chemical master equation (CME) to model reactions as a Poisson process. The FHD approach provides remarkable computational efficiency over traditional reaction-diffusion master equation methods when the number of reactive molecules is large, while also retaining accuracy even when there are as few as ten reactive molecules per hydrodynamic cell. We present a numerical algorithm to solve the coupled FHD and CME equations and validate it on both equilibrium and nonequilibrium problems. We simulate a diffusively driven gravitational instability in the presence of an acid-base neutralization reaction, starting from a perfectly flat interface. We demonstrate that the coupling between velocity and concentration fluctuations dominates the initial growth of the instability. Published by AIP Publishing.