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arXiv 0904.2882cond-mat.softcond-mat.mtrl-sci
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用格子玻尔兹曼方法模拟剪切作用下的液-汽相分离

Simulating liquid-vapor phase separation under shear with lattice Boltzmann method

Ce Wang, Aiguo Xu, Guangcai Zhang, Yingjun Li

摘要:

利用Shan-Chen格子Boltzmann模型研究了剪切作用下的汽液两相分离。除了流变特性外,我们还分析了由于界面两侧流体的切向速度差而引起的Kelvin-Helmholtz(K-H)不稳定性。我们还讨论了液滴的生长行为。靠近壁的区域是层状有序的,其中流体动力学效应占主导地位。在大部分的系统的图案是近各向同性的,其中畴生长的结果主要来自扩散机制。界面张力和K-H不稳定性使近壁处的液带易于破裂。当剪切速率增大时,由于上游蒸发与下游凝结的不等价性以及表面张力的作用,液滴斜向伸长。较强的对流使材料颗粒的转移更容易,从而使液滴变得更大。

英文摘要:

We study liquid-vapor phase separation under shear via the Shan-Chen lattice Boltzmann model. Besides the rheological characteristics, we analyze the Kelvin-Helmholtz(K-H) instability resulting from the tangential velocity difference of the fluids on two sides of the interface. We discuss also the growth behavior of droplets. The domains being close to the walls are lamellar-ordered, where the hydrodynamic effects dominate. The patterns in the bulk of the system are nearly isotropic, where the domain growth results mainly from the diffusion mechanism. Both the interfacial tension and the K-H instability make the liquid-bands near the walls tend to rupture. When the shear rate increases, the inequivalence of evaporation in the upstream and coagulation in the downstream of the flow as well as the role of surface tension makes the droplets elongate obliquely. Stronger convection makes easier the transferring of material particles so that droplets become larger.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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