Molecular-Scale Solutal Electrokinetics and Micro-Scale Control of Interfacial Phenomena in Ebullient Heat Transfer

沸腾传热中界面现象的分子尺度溶液动电学和微尺度控制

• 批准号: 0755720
• 负责人: Raj Manglik
• 金额: $ 30万
• 依托单位: University of Cincinnati Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0755720&HistoricalAwards=false
• 关键词: Molecular; Scale; Solutal; Electrokinetics; Micro

CBET-0755720, ManglikThis research is a fundamental multi-scale study of the molecular electrokinetics of surface-active agents (organic/synthetic monomers, micelles and/or biomolecules), and their modulation of interfacial phenomena (surface wetting and interfacial tension) for the control of nucleate boiling and associated ebullience in aqueous solutions. At the molecular-scale, the additive molecular dynamics at the liquid-vapor interface, and its physisorption and electrokinetics at the liquid-solid interface are to be investigated. These processes in turn affect micro-scale changes in liquid-vapor interfacial tension and solid-liquid wetting (where the two usually complimentary forces can now be decoupled due to the reagent electrokinetics and molecular mobility). The consequent changes in transient transport mechanisms during pool boiling with its characteristic embryonic vapor nucleation and subsequent bubble growth will be investigated. Also, the macro-scale ebullient heat transport, governed by macro-layer interfacial heat transfer, bubble growth and its dynamics (coalescence, collapse, and translation) will be studied and modeled, so as to identify and correlate boiling control (enhancement or suppression) parameters. In essence, the principal hypothesis that liquid-vapor interfacial tension and solid-liquid surface wetting (primary determinants of micro-scale nucleation and macro-scale ebullience, and hence boiling control predictors) can be decoupled and controlled by the molecular adsorption-physisorption, micellar dynamics, and electrokinetics of reagents in aqueous solutions would be established, and predictive correlations developed. Intellectual Merit: The findings of this study will (i) advance the fundamental science of interfacial phenomena and its manipulation by the molecular dynamics of surface-active agents in aqueous solutions, (ii) be insightful in establishing the micro-scale mechanisms at liquid-solid and liquid-vapor interfaces that characterize nucleate phase-change, and (iii) lead to the advancement of the fundamental science and engineering for an effective passive control technique, using ?designed? reagents (nano-sized micelle-chains and surfactant-like protein-based biomolecules), for nucleate phase-change ebullience and heat transfer. Broader Impact: This project will significantly enhance the training of students in cross-stream and inter-disciplinary engineering science, provide an experience in advanced experimentation (state-of-the-art instrumentation) and mathematical/simulation analysis, and help produce highly motivated engineers and researchers who have the depth and breadth of knowledge, and skills for advanced research and education careers. The integration of research with education, particularly involving women and minority engineering students, would further address the national need of training a more diverse engineering work force. Also, outreach with industrial and national laboratory partners will lend to long-term technology transfer. In a broader transformative essence, the reagent molecular dynamics/electrokinetics-modulated ebullient phase-change discovered in this work, is a new frontier in developing not only novel chemical and biological sensors, micro-fluidic or lab-on-chip devices, micro-scale heat exchangers, and effective thermal management of space-based systems, but also novel surface-active biomolecules and micellar polymers that may have a wider range of inter-disciplinary applications.

这项研究是对表面活性剂（有机/合成单体，胶束和/或生物分子）的分子动力学及其对界面现象（表面润湿和界面张力）的调节的基础多尺度研究，以控制水溶液中的核沸腾和相关的沸腾。在分子尺度上，研究了添加剂在液-气界面上的分子动力学及其在液-固界面上的物理吸附和电动力学。这些过程反过来影响了液-汽界面张力和固-液润湿的微观变化（由于试剂电动力学和分子迁移率，这两种通常互补的力现在可以解耦）。池沸腾过程中瞬态输运机制的变化及其特征的胚胎蒸汽成核和随后的气泡生长将被研究。此外，宏观尺度的沸腾热传输，由宏观层界面传热，气泡生长及其动力学（合并，崩溃和平移）控制，将被研究和建模，以确定和关联沸腾控制（增强或抑制）参数。从本质上讲，液-汽界面张力和固-液表面润湿（微尺度成核和宏观尺度沸腾的主要决定因素，因此是沸腾控制预测因素）可以通过分子吸附-物理吸附、胶束动力学和水溶液中试剂的电动力学解耦和控制的主要假设将被建立，并建立预测相关性。智力优势：本研究的发现将(i)推进界面现象的基础科学及其通过水溶液中表面活性剂的分子动力学来操纵的基础科学，（ii）在建立表征成核相变的液-固和液-气界面的微观尺度机制方面具有洞察力，以及（iii）导致基础科学和工程的进步，有效的被动控制技术，使用？试剂（纳米胶束链和表面活性剂样蛋白基生物分子），用于核相变沸腾和传热。更广泛的影响：该项目将显著加强学生在跨流程和跨学科工程科学方面的培训，提供先进实验（最先进的仪器）和数学/模拟分析方面的经验，并帮助培养具有深度和广度知识的高度积极性的工程师和研究人员，以及从事高级研究和教育事业的技能。将研究与教育结合起来，特别是让妇女和少数民族工程学生参与，将进一步满足国家培养更多样化的工程工作队伍的需要。此外，与工业和国家实验室伙伴的联系将有助于长期的技术转让。在更广泛的变革本质上，在这项工作中发现的试剂分子动力学/电动力学调制沸腾相变，不仅是开发新型化学和生物传感器，微流体或芯片实验室设备，微尺度热交换器和空间系统的有效热管理的新前沿，而且是新型表面活性生物分子和胶束聚合物，可能具有更广泛的跨学科应用。