Abstract A non-equilibrium molecular dynamics (NEMD) simulation method has been developed to simulate mixing of a liquid with a vapor and identify the characteristics of the liquid-vapor interface in the mixing process. Our results show that for the case of subcritical mixing, local phase equilibrium is established, and saturated liquid and saturated vapor are formed on either side of the interface at the prevailing saturation temperature that is fixed by the pressure of the system independent of the temperature difference across the interface. For transcritical mixing, significant clustering of molecules is found at the “transitional diffuse” interface. We found that the local density and local temperature of the transcritical interface can be directly mapped to the near critical region of the Ar/Ar and Kr/Ar vapor-liquid phase diagram. Finally, for the case of supercritical mixing, our simulations show a gradual change of density consistent with diffusion-controlled fluid mixing.

中文翻译：

---

液气系统亚临界、超临界和跨临界混合的非平衡分子动力学研究

摘要 开发了一种非平衡分子动力学（NEMD）模拟方法来模拟液体与蒸汽的混合，并识别混合过程中液-汽界面的特征。我们的结果表明，在亚临界混合的情况下，建立了局部相平衡，在主要饱和温度下，在界面两侧形成饱和液体和饱和蒸汽，该温度由系统压力固定，与温差无关跨界面。对于跨临界混合，在“过渡扩散”界面处发现了显着的分子簇。我们发现跨临界界面的局部密度和局部温度可以直接映射到 Ar/Ar 和 Kr/Ar 汽液相图的近临界区域。最后，