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

事业：使用分层三孔介质进行多尺度弯月面薄膜蒸发增强

• 批准号: 1464504
• 负责人: Chanwoo Park
• 金额: $ 40万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1464504&HistoricalAwards=false
• 关键词: CAREER; Multi; Scale; Meniscus; Thin

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

CBET-1351274标题：使用分层三多孔介质的多尺度弯月形薄膜蒸发增强PI：Chanwoo Park机构：内华达州大学，里诺电子和能源系统的进步需要更有效的冷却，以有效地管理高热通量和大的散热。由于其具有低热阻的上级冷却能力，相变传热是在等温条件下去除这种苛刻的热负荷以避免热致损坏的优选方法。弯月面薄膜蒸发是相变过程中常见的基本现象，如池沸腾中的气泡生长和脱离、流动沸腾中的段塞流和环状流、毛细多孔结构中的芯吸沸腾以及降膜蒸发。扩展弯月面（希腊文为新月形）是一个弯曲的液体区域附近的三相（气-液-固）接触线，经历了急剧变化的液膜厚度？从纳米到微米再到宏观。延伸的弯月面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键合力区域]，（ii）薄膜蒸发区域[厚度为O（100 nm）的分离压力主导区域]，其中由于薄液膜的小热阻而主要发生蒸发，以及（iii）内在弯月面[厚度为O（100 µm）的毛细压力主导区域]。对于弯月面薄膜蒸发强化，有必要对多尺度运动弯月面和固体表面形貌的相互作用有一个基本的了解。本计画将研究使用分级多尺度三层（奈米、微米与巨观）多孔介质强化弯月面薄膜蒸发。(i)宏观尺度表面调制（ii）微观尺度多孔结构（例如，互连的颗粒或线）与（iii）纳米和微米尺度的表面形态（例如，第二层表面），并专门研究微尺度毛细间隙中的微尺度弯月面拓扑结构和动力学，以及宏观尺度液体分布和传输辅助的中尺度弯月面薄膜蒸发。这种分层多尺度方法在自然界中很常见，但在工程中很少见，将提供一个独特的机会来深入研究三长度尺度系统设计和制造，结合纳米、复杂界面和相变过程的中、宏观分析。从这项研究中获得的见解将推动各种新兴的应用，如太阳能供电的使用点便携式水淡化器使用膜蒸馏，生物热传递从高温植入物烧灼肿瘤，实验室芯片，纳米流体，功能表面，微型冷却系统的微推力驱动的卫星，和纳米热？它依赖于吸附/脱附/扩散、铺展、润湿、相变和界面不稳定性等多尺度和多物理过程