CAREER: Bridging Length Scales to Unlock the Mechanistic Interdependence of Phase Interface Dynamics and Heat Transfer in Pool Boiling Processes

在一个死水池中，从浸没在水中的加热元件中沸腾液体的过程，被称为“池沸”，在发电厂、制冷系统、制造业、食品生产和许多其他对人类生活的维持和质量至关重要的事业的成功运行中起着至关重要的作用。在池沸腾过程中实现更高效率的一个主要科学障碍是对与单个蒸汽泡产生相关的小长度和时间尺度的传热机制的有限理解。在这个项目中，一个创新的方法池沸腾实验将提供温度，热流密度和液-气相界面信息从单个蒸汽泡下。该项目将提供对潜在物理过程的更好理解，可用于改进更大规模的池沸腾过程。与实验室的工作相协调，该项目还支持与热能基础相关的K-12和本科生的战略体验式学习和推广活动，特别强调测量这些活动如何影响学生的理解。通过这些举措，教育工作者将获得宝贵的见解，了解来自不同背景的学生如何最好地学习热科学，从而提高学生的成功，并在传统和代表性不足的群体中增加对科学、技术、工程和数学（STEM）学科的参与。该项目的总体科学目标是深入了解单个和合并气泡条件下与气泡成核、生长和离开相关的各种传热模式的时间和相对重要性。这是通过一系列微制造测试设备实现的，这些测试设备具有以一个或多个人工形成的成核位点为中心的热界面和相位界面传感功能，传感器输出暂时耦合到高速成像系统。这提供了一种方法来解开在池沸腾过程中液体，蒸汽和固体之间复杂的相互作用的关键见解，包括关于移动接触线，微尺度接触角和微层行为在核沸腾传热中的行为和作用的长期争论的问题。该方法的通用性使其能够用于研究各种沸腾现象、制度、条件和多尺度表面改性剂，从而形成一套有价值的新能力，可以提供高水平的生产力，并为更大的科学界带来好处。该合同由美国工程局化学、生物工程、环境和运输系统部门和综合活动办公室促进竞争性研究的既定计划共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The process of boiling a liquid from a submerged heating element in a stagnant pool, known as "pool boiling", plays a critical role in the successful operation of power plants, refrigeration systems, manufacturing, food production, and many other endeavors that are vital to the sustenance and quality of human life. A major scientific barrier to achieving greater efficiencies in pool boiling processes is the limited understanding of the heat transfer mechanisms at the small length and time scales associated with the generation of individual vapor bubbles. In this project, an innovative approach to pool boiling experimentation will provide temperature, heat flux, and liquid-vapor phase interface information from beneath individual vapor bubbles. This project will provide better understanding of the underlying physical processes which can be used to improve pool boiling processes at larger scales. In coordination with efforts in the laboratory, this project also supports strategic experiential learning and outreach initiatives for K-12 and undergraduate students related to the fundamentals of thermal energy, with special emphasis on measuring how these activities affect student understanding. Through these initiatives, educators will gain valuable insight into how students from different backgrounds best learn about the thermal sciences, thereby improving student success and increasing participation in science, technology, engineering, and math (STEM) disciplines within both traditional and underrepresented groups.The overall scientific objective of this project is to obtain a deep understanding of the timing and relative importance of the various modes of heat transfer associated with bubble nucleation, growth, and departure for both single and coalesced bubble conditions. This is achieved via a family of microfabricated test devices with thermal- and phase interface-sensing features centered on one or more artificially created nucleation sites, with sensor outputs temporally coupled to a high-speed imaging system. This provides a means of unlocking key insights into the complex interplay between liquid, vapor, and solid during pool boiling processes including long-debated questions regarding the behavior and roles of the moving contact line, microscale contact angles, and microlayer behavior in nucleate boiling heat transfer. The versatility of this method allows it to be employed to study a wide range of boiling phenomena, regimes, conditions, and multiscale surface modifiers, thereby making for a valuable new set of capabilities that can provide a high level of productivity and benefit to the greater scientific community. This award is jointly funded by the Division of Chemical, Bioengineering, Environmental, and Transport Systems in the Directorate of Engineering and the Established Program to Stimulate Competitive Research in the Office of Integrative Activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.