Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011, USA.
Phys Rev E. 2017 Sep;96(3-1):033309. doi: 10.1103/PhysRevE.96.033309. Epub 2017 Sep 14.
The smoothed particle hydrodynamics (SPH) method has been increasingly used for simulating fluid flows; however, its ability to simulate evaporating flow requires significant improvements. This paper proposes an SPH method for evaporating multiphase flows. The present SPH method can simulate the heat and mass transfers across the liquid-gas interfaces. The conservation equations of mass, momentum, and energy were reformulated based on SPH, then were used to govern the fluid flow and heat transfer in both the liquid and gas phases. The continuity equation of the vapor species was employed to simulate the vapor mass fraction in the gas phase. The vapor mass fraction at the interface was predicted by the Clausius-Clapeyron correlation. An evaporation rate was derived to predict the mass transfer from the liquid phase to the gas phase at the interface. Because of the mass transfer across the liquid-gas interface, the mass of an SPH particle was allowed to change. Alternative particle splitting and merging techniques were developed to avoid large mass difference between SPH particles of the same phase. The proposed method was tested by simulating three problems, including the Stefan problem, evaporation of a static drop, and evaporation of a drop impacting a hot surface. For the Stefan problem, the SPH results of the evaporation rate at the interface agreed well with the analytical solution. For drop evaporation, the SPH result was compared with the result predicted by a level-set method from the literature. In the case of drop impact on a hot surface, the evolution of the shape of the drop, temperature, and vapor mass fraction were predicted.
光滑粒子流体动力学（SPH）方法已越来越多地用于模拟流体流动；然而，其模拟蒸发流动的能力需要显著提高。本文提出了一种用于蒸发多相流的 SPH 方法。本 SPH 方法可以模拟液-气界面处的热质传递。基于 SPH 对质量、动量和能量守恒方程进行了重新制定，然后用于控制液体和气体两相中的流体流动和传热。蒸气种类的连续方程用于模拟气相中的蒸气质量分数。通过克劳修斯-克拉佩龙（Clausius-Clapeyron）相关关系预测界面处的蒸气质量分数。通过蒸发速率来预测界面处从液相到气相的质量传递。由于液-气界面处的质量传递，允许 SPH 颗粒的质量发生变化。开发了替代的粒子分裂和合并技术，以避免同一相的 SPH 粒子之间存在较大的质量差异。通过模拟三个问题来测试所提出的方法，包括 Stefan 问题、静态液滴的蒸发以及液滴冲击热表面的蒸发。对于 Stefan 问题，界面处蒸发速率的 SPH 结果与解析解吻合良好。对于液滴蒸发，将 SPH 结果与文献中基于水平集方法预测的结果进行了比较。在液滴冲击热表面的情况下，预测了液滴形状、温度和蒸气质量分数的演变。
