Heat transfer enhancement accompanying Leidenfrost state suppression at ultrahigh temperatures.
Heat transfer enhancement accompanying Leidenfrost state suppression at ultrahigh temperatures.
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DOI：
10.1021/la502456d
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发表时间：
2014-10
期刊：
影响因子：
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通讯作者：
A. Shahriari;J. Wurz;V. Bahadur
中科院分区：
文献类型：
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作者：
A. Shahriari;J. Wurz;V. Bahadur
众所周知的莱顿弗罗斯特效应是在液体和下面的热表面之间形成蒸汽层。这种绝缘蒸汽层严重降低了热传递，并导致表面干燥。我们测量的传热增强和干燥预防的好处，伴随着静电抑制莱顿弗罗斯特状态。蒸汽层中的界面电场可以将液体吸引到表面并促进润湿。这一原理甚至可以在超过500 °C的温度下抑制干燥，这是Leidenfrost温度的8倍以上。鲁棒的莱顿弗罗斯特状态抑制观察到各种液体，从低电导率的有机溶剂导电盐溶液。蒸汽层的消除使散热能力增加了1个数量级以上。测得的排热能力超过500 W/cm（2），这是水在普通工程表面上的临界热通量（CHF）的5倍。此外，热传递速率可以通过所施加的电压来电控制。基本的科学解释通过多物理场分析模型，捕捉耦合的静电-流体-热输运现象的基础静电莱顿弗罗斯特状态抑制。总的来说，这项工作揭示了干燥预防的物理基础，并展示了超低功耗的电可调沸腾传热。
The well-known Leidenfrost effect is the formation of a vapor layer between a liquid and an underlying hot surface. This insulating vapor layer severely degrades heat transfer and results in surface dryout. We measure the heat transfer enhancement and dryout prevention benefits accompanying electrostatic suppression of the Leidenfrost state. Interfacial electric fields in the vapor layer can attract liquid toward the surface and promote wetting. This principle can suppress dryout even at ultrahigh temperatures exceeding 500 °C, which is more than 8 times the Leidenfrost superheat for organic solvents. Robust Leidenfrost state suppression is observed for a variety of liquids, ranging from low electrical conductivity organic solvents to electrically conducting salt solutions. Elimination of the vapor layer increases heat dissipation capacity by more than 1 order of magnitude. Heat removal capacities exceeding 500 W/cm(2) are measured, which is 5 times the critical heat flux (CHF) of water on common engineering surfaces. Furthermore, the heat transfer rate can be electrically controlled by the applied voltage. The underlying science is explained via a multiphysics analytical model which captures the coupled electrostatic-fluid-thermal transport phenomena underlying electrostatic Leidenfrost state suppression. Overall, this work uncovers the physics underlying dryout prevention and demonstrates electrically tunable boiling heat transfer with ultralow power consumption.