Computational modelling of Leidenfrost drops
Computational modelling of Leidenfrost drops
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DOI：
10.1017/jfm.2022.66
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发表时间：
2022-02
影响因子：
3.7
通讯作者：
I. Chakraborty;M. Chubynsky;J. Sprittles
中科院分区：
文献类型：
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作者：
I. Chakraborty;M. Chubynsky;J. Sprittles
摘要Leidenfrost效应是一个有效的计算模型，它捕获液滴内部的流动，模拟润滑框架中的蒸汽流动，并能够解决这个过程的动力学问题。最初的重点是准静态液滴和相关的几何形状的蒸汽膜下形成的下降，在那里我们能够与实验分析进行比较，并评估的有效性范围内的理论模型在Sobac等人。（物理评论E，第103卷，2021年，039901）。计算模型还允许我们探索参数空间，改变液滴大小和液体粘度，计算结果与高粘度液体的理论模型非常一致。有趣的是，对于大水滴，计算模型和实验之间的差异发生，并提供了这种观察的可能原因。我们的预测揭示的功能，包括一个政权的下降和最小的蒸汽层厚度作为一个功能的下降尺寸的一个无凹痕的底部表面。最后，模拟动力学的能力，揭示了预测和跟踪大滴的蒸汽“烟囱”不稳定性的计算。
Abstract The Leidenfrost effect, where a drop levitates on a vapour film above a hot solid, is simulated using an efficient computational model that captures the internal flow within the droplet, models the vapour flow in a lubrication framework and is capable of resolving the dynamics of the process. The initial focus is on quasi-static droplets and the associated geometry of the vapour film formed beneath the drop, where we are able to compare with experimental analyses and assess the range of validity of the theoretical model developed in Sobac et al. (Phys. Rev. E, vol. 103, 2021, 039901). The computational model also allows us to explore parameter space, varying both the drop size and viscosity of the liquid, with computational results in excellent agreement with the theoretical model for high-viscosity liquids. Interestingly, for large water drops, discrepancies between the computational model and experiments occur, and possible reasons for this observation are provided. Our predictions reveal features including a regime with a dimpleless bottom surface of the drop and a minimum in the vapour layer thickness as a function of the drop size. Finally, the capability to simulate dynamics is revealed by computations that predict and track the vapour ‘chimney’ instability for large drops.