CAREER:Multi-Scale Meniscus Thin-Film Evaporation Enhancement using Hierarchical Tri-Porous Media

题目：使用分层三孔介质的多尺度半月板薄膜蒸发增强api: Chanwoo ParkInstitution: University of Nevada， renoe电子和能源系统的进步需要更高效的冷却来有效地管理高热流和大散热。由于其优越的冷却能力和低热阻，相变传热是在等温条件下消除这种苛刻的热负荷以避免热致损伤的首选方法。半月板薄膜蒸发是池沸腾中的气泡生长和离开、流动沸腾中的段塞流和环空流、毛细孔结构中的芯沸腾、降膜蒸发等相变过程中常见的基本现象。延伸的半月板（希腊语为新月形）是靠近三相（气-液-固）接触线的弯曲液体区域，其液膜厚度发生剧烈变化。从纳米到微观再到宏观。扩展半月板分为三个不同的区域：(i)吸附层[厚度为O（10 nm）的液体和固体分子之间的分子间结合力区域]，（ii）薄膜蒸发区[厚度为O（100 nm）的分离压力主导区域]，其中蒸发主要是由于薄液体膜的小热阻而发生的（iii）本征半月板[厚度为O（100 μ m）的毛细管压力主导区域]。对于半月板薄膜蒸发增强，相互作用的多尺度移动半月板和固体表面形态的基本理解是必要的。本项目将研究多层尺度（纳米、微观和宏观）多孔介质对半月板薄膜蒸发的增强作用。(i)宏观尺度表面调制（ii）微观尺度多孔结构（例如，相互连接的颗粒或电线）与（iii）纳米和微观尺度表面形态（例如，第二层表面），并专门研究微观尺度半月板拓扑结构和微观尺度毛细管间隙中的动力学，以及宏观尺度液体分布和运输辅助的中尺度半月板薄膜蒸发。这种分层的多尺度方法在自然界中很常见，但在工程中很少见，它将为深入研究三长度尺度的系统设计和制造提供独特的机会，将复杂界面和相变过程的纳米、中观和宏观尺度分析结合起来。从这项研究中获得的见解将推动各种新兴应用的发展，如使用膜蒸馏的太阳能便携式水脱盐器、用于烧灼肿瘤的热疗植入物的生物传热、芯片实验室、纳米流体、功能表面、微推力卫星的微型冷却系统和纳米热？二极管依赖于多尺度和多物理过程的吸附/解吸/扩散、扩散、润湿、相变和界面不稳定性

CBET-1351274Title: Multi-Scale Meniscus Thin-Film Evaporation Enhancement using Hierarchical Tri-Porous MediaPI: Chanwoo ParkInstitution: University of Nevada, RenoAdvances in electronic, and energy systems require more efficient cooling to effectively manage high heat fluxes and large heat dissipation. Because of its superior cooling capabilities with low thermal resistances, phase change heat transfer is the preferred method to remove such demanding heat loads at isothermal conditions to avoid thermally induced damage. Meniscus thin-film evaporation is a fundamental phenomenon commonly found in phase change processes such as bubble growth and departure in pool boiling, slug and annular flows in flow boiling, wick boiling in capillary porous structures, and falling-film evaporation. The extended meniscus (Greek for crescent) is a curved liquid region near a three-phase (gas-liquid-solid) contact line which undergoes a drastic change in its liquid film thickness?from nano to micro to macro-scales. The extended meniscus is divided into three distinctive regions: (i) the adsorbed layer [region of intermolecular-bonding forces between liquid and solid molecules of a thickness O(10 nm)], (ii) the thin-film evaporating region [disjoining-pressure-dominant region of a thickness O(100 nm)] where evaporation predominantly occurs due to the small thermal resistance of the thin liquid film and (iii) the intrinsic meniscus [capillary-pressure-dominant region of a thickness O(100 µm)]. For meniscus thin-film evaporation enhancement, a fundamental understanding of interplaying multi-scale moving meniscus and solid surface morphology is warranted. This project will study the meniscus thin-film evaporation enhancement using hierarchical multi-scale tri (nano, micro and macro) porous media ? (i) macro-scale surface modulation of (ii) micro-scale porous structures (e.g., interconnected particles or wires) with (iii) nano- and micro-scale surface morphology (e.g., second-tier surfaces) and specifically investigate micro-scale meniscus topology and dynamics in micro-scale capillary gaps, and meso-scale meniscus thin-film evaporation assisted by macro-scale liquid distribution and transport.This hierarchical multi-scale approach, common in nature but rare in engineering, will provide a unique opportunity to delve into three-length-scale system designs and fabrication, combining nano-, meso- and macro-scale analyses for complex interfacial and phase-change processes. The insight gained from this research will advance a variety of emerging applications such as solar-powered point-of-use portable water desalinators using membrane distillation, bio-heat transfer from hyperthermia implants for cauterizing tumors, lab-on-a-chip, nano-fluidics, functional surfaces, miniature cooling systems of microthrust-powered satellites, and nano thermal?diode which rely on multi-scale and multi-physics processes of adsorption/desorption/diffusion, spreading, wetting, phase change and interfacial instability