Convective Thermal Transport at Superhydrophobic Surfaces

超疏水表面的对流热传输

• 批准号: 1235881
• 负责人: R Daniel Maynes
• 金额: $ 32.48万
• 依托单位: Brigham Young University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1235881&HistoricalAwards=false
• 关键词: Convective; Thermal; Transport; Superhydrophobic; Surfaces

CBET-1235881MaynesSuperhydrophobic surfaces are highly water repellent surfaces and are generated by combining microscale structuring and a hydrophobic coating such that liquids will only be in contact with a fraction of the solid surface. Their use in engineering devices occurs anywhere non-wetting surfaces are desired, although future uses are likely to be more expansive. The decrease in surface contact area between the liquid and solid phases, and thus increase in contact with a trapped gas, leads to distinct alterations of the thermal boundary conditions at the plane of the surface. Consequently, the fundamental convection physics for liquid flow over these surfaces differs drastically from classical behavior. A comprehensive understanding of the local thermal transport physics is necessary to utilize such surfaces in emerging technologies and is the primary goal of this research project. In general, it is expected that convective heat transfer coefficients will be reduced, droplets will change phase slower, and the boiling curve will be significantly altered for liquid in contact with such surfaces. The objectives of this research project are to characterize the departure from classical transport behavior due to the superhydrophobic nature of a surface. Specifically convective heat transfer is explored for: 1) Heat transfer to static liquid droplets resting on superhydrophobic surfaces, 2) Mini- and microchannel, developing and developed transport in channels with SH walls, 3) Influence on free convection dynamics for vertical SH surfaces adjacent to a liquid layer, and 4) Alteration of the classical boiling curve for liquids on SH surfaces. The research is conducted using complementary laboratory based experimental and analytical approaches to explore these topics for a range of typical superhydrophobic surface topologies. The results will be a knowledge base allowing prediction of convective heat transfer coefficients for the scenarios explored and as a function of the superhydrophobic surface topologies.This project will explore the influence of superhydrophobicity on convective heat transfer at liquid-solid surface interfaces. Uses of superhydrophobic surfaces include self-cleaning surfaces, drag reducing surfaces, non-wetting surfaces in condensers, microfluidic manipulators in lab-on-a-chip concepts, microscale heat exchangers, and many more. For many of these, and a wide range of other potential applications, the issue of thermal transport at superhydrophobic surfaces is of fundamental importance for their implementation into high performance thermal systems. This project will advance basic knowledge related to heat transfer at superhydrophobic surfaces and provide increased understanding for implementation of such surfaces into optimized engineering devices.

CBET-1235881Maynes超疏水表面是高度防水的表面，是通过将微型结构和疏水涂层相结合而产生的，这样液体只会与固体表面的一小部分接触。它们在工程设备中的应用出现在任何需要非润湿表面的地方，尽管未来的用途可能会更加广泛。液相和固相之间的表面接触面积减少，从而增加与截留气体的接触，导致表面平面处热边界条件的明显改变。因此，这些表面上液体流动的基本对流物理学与经典行为有很大不同。全面了解局部热传输物理对于在新兴技术中利用此类表面是必要的，也是该研究项目的主要目标。一般来说，预计对流传热系数将降低，液滴相变速度将变慢，并且对于与此类表面接触的液体，沸腾曲线将显着改变。该研究项目的目标是表征由于表面的超疏水性质而导致的与经典传输行为的偏离。具体对流传热的探索包括：1）向静止在超疏水表面上的静态液滴传热，2）微型和微通道，在具有SH壁的通道中发展和发展传输，3）对邻近液体层的垂直SH表面的自由对流动力学的影响，以及4）SH表面上液体的经典沸腾曲线的改变。该研究是使用基于互补实验室的实验和分析方法进行的，以探索一系列典型超疏水表面拓扑的这些主题。结果将成为一个知识库，允许预测所探索的场景的对流换热系数，并将其作为超疏水表面拓扑的函数。该项目将探讨超疏水性对液-固表面界面对流换热的影响。超疏水表面的用途包括自清洁表面、减阻表面、冷凝器中的非润湿表面、芯片实验室概念中的微流体操纵器、微型热交换器等等。对于其中许多以及广泛的其他潜在应用来说，超疏水表面的热传输问题对于将其实施到高性能热系统中至关重要。该项目将推进与超疏水表面传热相关的基础知识，并加深对将此类表面应用到优化工程设备中的理解。