Lavino Alessio D, Smith Edward, Magnini Mirco, Matar Omar K
Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, U.K.
Department of Mechanical and Aerospace Engineering, Brunel University London, Uxbridge, Middlesex UB8 3PH, U.K.
Langmuir. 2021 May 11;37(18):5731-5744. doi: 10.1021/acs.langmuir.1c00779. Epub 2021 Apr 29.
In this work, we investigate nucleate pool boiling via non-equilibrium molecular dynamics simulations. The effect of nano-structured surface topography on nucleation and transition to a film-like boiling regime is studied at the molecular scale, by varying the cavity aspect ratio, wall superheat, and wettability through a systematic parametric analysis conducted on a Lennard-Jones (LJ) system. The interplay of the aforementioned factors is rationalized by means of a classical nucleation theory-based model. The solid surface is heated uniformly from the bottom in order to induce the nanobubble nucleation. Insight into the cavity behavior in heat transfer problems is achieved by looking at temperature and heat flux profiles inside the cavity itself, as well as at the time of nucleation, for different operating conditions. The role of the cavity size in controlling the vapor embryo formation is highlighted, and its dependence on the other investigated parameters is summarized in a phase diagram. Our results show that heterogeneity at the nanoscale plays a key role in determining pool boiling heat transfer performance, suggesting a promising approach to optimize nanostructured surfaces for energy and thermal management applications.
在这项工作中，我们通过非平衡分子动力学模拟研究了池内核态沸腾。通过在 Lennard-Jones（LJ）系统上进行系统的参数分析，改变腔体的纵横比、壁面过热度和润湿性，在分子尺度上研究了纳米结构表面形貌对成核以及向膜状沸腾 regime 转变的影响。借助基于经典成核理论的模型，对上述因素之间的相互作用进行了合理化分析。固体表面从底部均匀加热以诱导纳米气泡成核。通过观察不同操作条件下腔体内部的温度和热流分布以及成核时刻，深入了解了传热问题中的腔体行为。强调了腔体尺寸在控制蒸汽胚胎形成中的作用，并在相图中总结了其对其他研究参数的依赖性。我们的结果表明，纳米尺度的异质性在决定池沸腾传热性能方面起着关键作用，这为优化用于能源和热管理应用的纳米结构表面提供了一种有前景的方法。
