Department of Mechanical Engineering & Texas Materials Institute, The University of Texas at Austin , Austin, Texas 78712, United States.
Langmuir. 2017 Nov 21;33(46):13207-13213. doi: 10.1021/acs.langmuir.7b02878. Epub 2017 Nov 8.
An applied electric field can fundamentally eliminate the Leidenfrost effect (formation of a vapor layer at the solid-liquid interface at high temperatures). This study analyzes electrostatic suppression of the Leidenfrost state on liquid substrates. Electrostatic suppression on silicone oil and Wood's metal (liquid alloy) is studied via experimentation, high-speed imaging, and analyses. It is seen that the nature of electrostatic suppression can be drastically different from that on a solid substrate. First, the Leidenfrost droplet completely penetrates into the silicone oil substrate and converts to a thin film under an electric field. This is due to the existence of an electric field inside the substrate and the deformability of the silicone oil interface. A completely different type of suppression is observed for Wood's metal and solid substrates, which have low deformability and lack an electric field in the substrate. Second, the minimum voltage to trigger suppression is significantly lower on silicone oil when compared to Wood's metal and solid substrates. Fundamental differences between these transitions are analyzed, and a multiphysics analytical model is developed to predict the vapor layer thickness on deformable liquids. Overall, this study lays the foundation for further studies on electrostatic manipulation of the Leidenfrost state on liquids.
外加电场可以从根本上消除莱顿弗罗斯特效应（即在高温下固液界面形成蒸汽层）。本研究分析了静电对液体基底莱顿弗罗斯特状态的抑制作用。通过实验、高速成像和分析研究了硅油和伍德合金（液态合金）上的静电抑制作用。结果表明，静电抑制的性质可能与固体基底上的性质有很大的不同。首先，莱顿弗罗斯特液滴在电场作用下完全渗透到硅油基底中，并转化为薄膜。这是由于基底内部存在电场以及硅油界面的可变形性。而对于变形性低且基底内不存在电场的伍德合金和固体基底，则观察到完全不同类型的抑制作用。其次，与伍德合金和固体基底相比，硅油上触发抑制所需的最小电压要低得多。分析了这些转变之间的基本差异，并开发了一个多物理分析模型来预测可变形液体上的蒸汽层厚度。总的来说，本研究为进一步研究液体上莱顿弗罗斯特状态的静电控制奠定了基础。
