Transforming pool boiling into a pumpless self-sustained flow boiling system for efficient cooling at high heat fluxes

将池沸腾转变为无泵自持流动沸腾系统，以在高热通量下进行高效冷却

• 批准号: 2022614
• 负责人: Satish Kandlikar
• 金额: $ 32.26万
• 依托单位: Rochester Institute of Tech
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2022614&HistoricalAwards=false
• 关键词: Transforming; pool; boiling; into; pumpless

Current trend of electronics miniaturization introduces higher heat generation rates while substantially reducing surface area for heat dissipation. Phase change cooling with pool boiling is an attractive cooling method. Flow boiling is more efficient but requires a pump, which makes it more complex. This project presents an innovative concept that transforms pool boiling into a self-sustained pumpless flow boiling system and dramatically improves cooling performance. It utilizes a tapered gap in which a bubble expands in a preferential direction of increasing flow area and creates a self-sustained flow over the heater surface. The proposed work will provide thorough understanding of the underlying physics and enable optimal designs with different fluids for dramatically improving heat dissipation. It will offer educational opportunities to undergraduate and graduate students, while creating a new outreach activity "TinkerEngLab" with hands-on experience to minority and women students. The team will participate in an outreach activity called Beyond 9.8 for middle school students from underprivileged schools.The goal of the project is to develop a fundamental understanding of the fluid flow and heat transfer mechanisms that drive the self-sustained flow as a bubble grows and expands in a tapered gap. It will be accomplished through – 1) analytical work to establish the link between heat transfer around a growing bubble, pressure recovery and pressure drop in the tapered microgap, 2) numerical work to provide insight into bubble growth and instantaneous pressure field, and 3) experimental work for validation and practical data. Fundamental information on microlayer formation under a bubble and pressure distribution at the wall at various stages of bubble growth will be obtained. The numerical simulation of squeezing bubble will utilize advanced code developed in the lab to predict pressure field in the tapered microgap under dynamic conditions, and these will be experimentally validated by pressure mapping using micro-electromechanical sensors and high-speed visualization. The findings from the numerical study will be incorporated in developing a theoretical bubble squeezing model for flow dynamics and heat transfer. The knowledge and the model will provide design theories for developing highly efficient cooling systems with different fluids under different operating conditions. The work is expected to introduce a paradigm shift as pool boiling will no longer be limited by a stagnant pool of liquid, but will incorporate flow for achieving unprecedented cooling performance without requiring a pump. Its main application includes electronics cooling, but the work will open up new avenues in industrial and commercial applications as well.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.

当前电子设备小型化的趋势带来了更高的发热率，同时大大减少了散热表面积。流动沸腾冷却方法更有效，但需要泵，这使其更加复杂。一种创新概念，将池沸腾转变为自持式无泵流动沸腾系统，并显着提高冷却性能。它利用锥形间隙，其中气泡沿增加流动面积的优先方向膨胀，并形成自持式。拟议的工作将提供对底层物理的透彻理解，并实现不同流体的优化设计，从而显着改善散热效果，同时创建新的推广活动“TinkerEngLab”。该团队将参加一项针对贫困学校中学生的名为 Beyond 9.8 的外展活动。该项目的目标是加深对流体流动和传热机制的基本了解。驾驶气泡在锥形间隙中生长和膨胀时的自持流动将通过以下方式完成：1) 分析工作，建立生长气泡周围的传热、压力恢复和锥形微间隙中的压降之间的联系，2) 数值分析。致力于提供对气泡生长和瞬时压力场的深入了解，以及3）验证和实际数据的实验工作将获得气泡生长各个阶段的壁上压力分布和微层的基本信息。挤压的bubble 将利用实验室开发的先进代码来预测动态条件下锥形微间隙中的压力场，并且这些将通过使用微机电传感器和高速可视化的压力映射进行实验验证。数值研究的结果将被纳入其中。该知识和模型将为在不同操作条件下开发不同流体的高度冷却系统提供设计理论，因为有效的池沸腾将带来范式转变。不再被限制它的主要应用包括电子冷却，但这项工作也将为工业和商业应用开辟新的途径。该奖项反映了 NSF 的法定使命和使命。通过使用基金会的智力优点和更广泛的影响审查标准进行评估，该项目被认为值得支持。