Probing interfacial phase-change transport events in flow boiling on micro- and nanotextured surfaces

探测微米和纳米纹理表面上流动沸腾中的界面相变传输事件

• 批准号: 1403657
• 负责人: Saeed Moghaddam
• 金额: $ 30.6万
• 依托单位: University of Florida
• 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 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1403657&HistoricalAwards=false
• 关键词: Probing; interfacial; phase; change; transport

CBET-1403657The ever-increasing generation of heat has become an impediment to advancements and the efficient operation of many electronics and energy applications, such as power and RF electronics, high-performance computers, solid-state lasers, and concentrated solar cells. The liquid-cooling process has been considered a remedy for the thermal management of these applications. The phase-change liquid-cooling process in microchannels, in particular, has received significant attention. A main focus of the scientific community for nearly two decades has been to enhance the boiling heat-transfer coefficient in microchannel heat sinks. However, a major obstacle has been the relatively limited understanding of transport characteristics, which is caused by difficulties related to diagnosing interfacial behavior in microchannels. Such knowledge is essential to advancing the science and technology of compact and high performance two-phase flow heat sinks. The objective of this study is to use a new measurement approach to understand the physics of different microscale heat transfer mechanisms involved in flow boiling in microchannels.The objective of this research is to utilize a new measurement approach to understand the physics of different microscale heat transfer mechanisms involved in flow boiling in microchannels and to measure their relative contributions to the overall surface heat transfer. Advancing both scientific understanding and engineering practice in this field requires experimental capabilities for characterization of the underlying interfacial processes. Furthermore, transformative improvements in the control of phase change heat transfer may come from the development of new mechanistic models, with inspiration and validation from experimental techniques that can probe temperature and heat flux with sufficient sensitivity over the relevant length and time scales. The proposed approach involves a high-resolution measurement of the thermal field (temperature and heat flux) at the fluid-solid interface in microchannels. The unique aspect of the proposed measurement approach is the implementation of a composite wall with embedded micro-sensors that allow the surface heat flux to be determined. The thermal field measurements are synchronized with the high-speed imaging of bubbles as well as the thickness of the liquid film formed between the vapor and solid phases. The laser interferometry method is utilized in measuring the liquid film thickness. Experimental studies will be conducted to explain the mechanisms of heat transfer in flow boiling in microchannels, evaluate the accuracy of prominent mechanistic two-phase microchannel models, and understand the role of surface micro- and nanostructures on the interfacial transport events and flow boiling characteristics.

不断增加的热量产生已经成为许多电子和能源应用的进步和高效运行的障碍，例如功率和射频电子，高性能计算机，固态激光器和聚光太阳能电池。液体冷却过程被认为是这些应用的热管理的补救措施。微通道中的相变液冷过程尤其受到了广泛的关注。近二十年来，提高微通道散热器的沸腾传热系数一直是科学界关注的焦点。然而，一个主要的障碍是对传输特性的理解相对有限，这是由于诊断微通道中界面行为的困难造成的。这样的知识是必不可少的，以推进科学技术的紧凑和高性能的两相流散热器。本研究的目的是利用一种新的测量方法来了解微通道中流动沸腾的不同微尺度传热机制的物理特性。本研究的目的是利用一种新的测量方法来了解微通道中流动沸腾中不同微尺度传热机制的物理特性，并测量它们对整体表面传热的相对贡献。推进这一领域的科学理解和工程实践需要实验能力来表征潜在的界面过程。此外，相变传热控制的变革性改进可能来自于新机制模型的发展，这些模型的灵感和验证来自于实验技术，这些实验技术可以在相关的长度和时间尺度上以足够的灵敏度探测温度和热通量。所提出的方法涉及微通道中流固界面的热场（温度和热流密度）的高分辨率测量。所提出的测量方法的独特之处在于实现了带有嵌入式微传感器的复合壁，可以确定表面热通量。热场测量与气泡的高速成像以及气相和固相之间形成的液膜厚度同步。采用激光干涉法测量液膜厚度。实验研究将解释微通道中流动沸腾的传热机制，评估两相微通道模型的准确性，并了解表面微纳米结构对界面传递事件和流动沸腾特性的作用。

项目成果

Role of bubble growth dynamics on microscale heat transfer events in microchannel flow boiling process

• DOI: 10.1063/1.4937568
• 发表时间: 2015-12-14
• 期刊: APPLIED PHYSICS LETTERS
• 影响因子: 4
• 作者: Bigham, Sajjad;Moghaddam, Saeed
• 通讯作者: Moghaddam, Saeed

Physics of the Microchannel Flow Boiling Process and Comparison With the Existing Theories

微通道流动沸腾过程的物理原理及其与现有理论的比较

• DOI: 10.1115/1.4036655
• 发表时间: 2017
• 期刊: Journal of Heat Transfer
• 作者: Bigham, Sajjad;Moghaddam, Saeed
• 通讯作者: Moghaddam, Saeed

Microscale study of mechanisms of heat transfer during flow boiling in a microchannel

微通道流动沸腾传热机理的微观研究

• DOI: 10.1016/j.ijheatmasstransfer.2015.04.034
• 发表时间: 2015
• 期刊: International Journal of Heat and Mass Transfer
• 影响因子: 5.2
• 作者: Bigham, Sajjad;Moghaddam, Saeed
• 通讯作者: Moghaddam, Saeed