Creating Tunable Adaptive Boiling Heat Transfer Surfaces with Electrowetting

CBET-1236606PI：刘栋：热能传输是涉及发电和能量传输的众多工业过程中的一个关键方面。核态沸腾作为一种有效的传递大量热能的手段，已经被应用了几十年。因此，如果核态沸腾换热能够得到更好的控制和强化，这些过程的能效将会显著提高。核态沸腾强化换热技术有两个主要目标：1)最大限度地提高受热表面的单位温升换热；2)提高核态沸腾换热的上限，也就是所谓的临界热流密度，在临界热流密度下，表面被干蒸汽覆盖，可能发生灾难性的烧毁。目前流行的强化方法是基于沸腾表面的化学或形貌结构。然而，这种表面结构的主要缺点是它们的静态性质，这阻碍了对时空动态沸腾过程的主动控制。因此，核态沸腾的有效热性能远远低于其巨大的潜力。该项目将探索一种新的场所，通过利用电润湿创建可调节的自适应沸腾表面来增强核沸腾换热。它利用疏水性和亲水性在核沸腾过程中的互补作用，并利用电润湿能力来可逆地和稳健地改变表面润湿性。这项研究将阐明电润湿调制可逆表面润湿对核态沸腾的影响，并展示这种可调自适应沸腾换热表面的高效和低成本制造。通过利用电润湿，这项工作将为主动控制和优化关键的晶核沸腾过程提供一个以前从未探索过的强大工具。强化核态沸腾换热将提高各种能源系统的效率，降低系统的体积和成本。该项目将为克服核态沸腾换热技术中的性能限制障碍提供一种变革性的方法。因此，它将对依赖核态沸腾作为主要传热手段的行业产生深远的影响。这项工作开发的设计和制造技术将为经济地大规模生产用于沸腾换热应用的功能表面奠定基础。休斯顿大学将建立一个综合的研究和教育项目，这是美国种族最多元化的研究型大学之一。该方案将通过积极招聘合格的少数族裔和女性学生作为本科生/研究生研究助理，为代表性不足的群体创造新的职业机会。教育外展活动将为K-12教师和学生提供科学培训和实验室经验。

CBET-1236606PI: Dong LiuThermal energy transport is a critical aspect in a myriad of industrial processes involving power generation and energy transmission. Nucleate boiling has been employed for decades as an effective means of transferring large amount of thermal energy. Thus, if nucleate boiling heat transfer can be better controlled and enhanced, energy efficiency of these processes will be improved significantly. There are two primary goals of nucleate boiling heat transfer enhancement technologies: 1) to maximize heat transfer per unit temperature rise in the heated surface, and 2) to increase the upper limit of nucleate boiling heat transfer, also known as the critical heat flux, at which the surface is blanketed with dry vapor and catastrophic burnout may occur. The prevailing enhancement methods are based on chemically or topographically structuring the boiling surface. However, the main disadvantage of such surface structures is their static nature, which prevents active control of the spatiotemporally dynamic boiling process. Consequently, the available thermal performance of nucleate boiling is far below its enormous potentials. This project will explore a new venue to enhance nucleate boiling heat transfer by creating tunable adaptive boiling surfaces with the aid of electrowetting. It capitalizes on the complimentary roles of hydrophobicity and hydrophilicity played in nucleate boiling, and takes advantage of the ability of electrowetting to alter the surface wettability reversibly and robustly. This research will elucidate the effects of electrowetting-modulated reversible surface wetting on nucleate boiling as well as demonstrate the efficient and low-cost manufacturing of such tunable adaptive boiling heat transfer surfaces. By exploiting electrowetting, this work will provide a previously unexplored and powerful tool to actively control and optimize the key nucleate boiling processes. Enhancing nucleate boiling heat transfer will improve the efficiency and reduce the size and cost of various energy systems. This project will provide a transformative approach to conquer the performance-limiting obstacles in nucleate boiling heat transfer technologies. Thus, it will have far-reaching impacts on industries that rely on nucleate boiling as the primary means of heat transfer. The design and fabrication techniques developed in this work will lay the foundation toward economical large-scale production of functional surfaces for boiling heat transfer applications. An integrated research and education program will be established at University of Houston, which is one of the most ethnically diverse research universities in the nation. The program will create new career opportunities for underrepresented groups by actively recruiting qualified minority and female students as undergraduate/graduate research assistants. The educational outreach activities will provide scientific training and laboratory experiences to K-12 teachers and students.