The Effect of Fin Array Height and Spacing on Heat Transfer Performance during Pool Boiling from Extended Surfaces

Maureen Winter, J. Weibel
{"title":"The Effect of Fin Array Height and Spacing on Heat Transfer Performance during Pool Boiling from Extended Surfaces","authors":"Maureen Winter, J. Weibel","doi":"10.1109/iTherm54085.2022.9899575","DOIUrl":null,"url":null,"abstract":"The use of heat sinks is a promising approach to extend the range of immersion cooling in dielectric fluids to higher heat fluxes for thermal management of next-generation electronics. However, the effects of extended surface area enhancement on the heat transfer performance under pool boiling conditions are not well understood, even in the simple case of straight fins. Further investigation of the heat-flux-dependent variation of boiling modes that can manifest along the fin height is required. Although approaches exist to predict the extended surface pool boiling heat transfer coefficient, they have been developed from single fins. As a result, when applied to fin arrays, they are rarely accurate across the full operating range up to the critical heat flux, particularly if height or spacing varies drastically. To better understand the effects of fin arrays on heat transfer, pool boiling experiments are performed using copper fins in water, varying fin height and spacing. These variations span a range from much larger to less than half of the scale of the capillary length scale, Lb. The pool boiling data, complemented with high-speed visualization of the boiling regimes and bubble dynamics, strongly support a hypothesis that Lb is the key length scale. Heat transfer from fin array heat sinks with heights and spacings above Lb are shown to be accurately predicted using existing fin analysis approaches from the literature. However, spacings smaller than Lb affect the nucleate boiling superheat while heights shorter than Lb are unable to support multiple boiling regimes along the fin sidewall, both leading to disagreement between the experiments and predictions. These aspects, coupled with observation of vapor entrapment between closely spaced fins, indicate that new predictive methods must be developed. The valuable insights offered into the effects of fin array height and spacing on pool boiling provide a pathway toward heat sink design optimization for immersion cooling applications.","PeriodicalId":351706,"journal":{"name":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","volume":"60 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2022 21st IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (iTherm)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/iTherm54085.2022.9899575","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 1

Abstract

The use of heat sinks is a promising approach to extend the range of immersion cooling in dielectric fluids to higher heat fluxes for thermal management of next-generation electronics. However, the effects of extended surface area enhancement on the heat transfer performance under pool boiling conditions are not well understood, even in the simple case of straight fins. Further investigation of the heat-flux-dependent variation of boiling modes that can manifest along the fin height is required. Although approaches exist to predict the extended surface pool boiling heat transfer coefficient, they have been developed from single fins. As a result, when applied to fin arrays, they are rarely accurate across the full operating range up to the critical heat flux, particularly if height or spacing varies drastically. To better understand the effects of fin arrays on heat transfer, pool boiling experiments are performed using copper fins in water, varying fin height and spacing. These variations span a range from much larger to less than half of the scale of the capillary length scale, Lb. The pool boiling data, complemented with high-speed visualization of the boiling regimes and bubble dynamics, strongly support a hypothesis that Lb is the key length scale. Heat transfer from fin array heat sinks with heights and spacings above Lb are shown to be accurately predicted using existing fin analysis approaches from the literature. However, spacings smaller than Lb affect the nucleate boiling superheat while heights shorter than Lb are unable to support multiple boiling regimes along the fin sidewall, both leading to disagreement between the experiments and predictions. These aspects, coupled with observation of vapor entrapment between closely spaced fins, indicate that new predictive methods must be developed. The valuable insights offered into the effects of fin array height and spacing on pool boiling provide a pathway toward heat sink design optimization for immersion cooling applications.
翅片阵列高度和间距对扩展表面池沸腾传热性能的影响
散热片的使用是一种很有前途的方法,可以将介电流体的浸没冷却范围扩展到下一代电子产品的热管理的更高热通量。然而,在池沸腾条件下,即使是在简单的直翅片情况下,扩展表面积增强对传热性能的影响也不是很清楚。需要进一步研究沸腾模式随热通量的变化,这种变化可以沿翅片高度表现出来。虽然已有方法预测扩展表面池沸腾换热系数,但它们都是从单翅片开始发展起来的。因此,当应用于鳍阵列时,它们很少在整个工作范围内精确到临界热通量,特别是如果高度或间距变化很大。为了更好地了解翅片阵列对换热的影响,采用不同高度和间距的铜翅片在水中进行了池沸实验。这些变化范围从比毛细管长度尺度大得多的范围到比毛细管长度尺度小一半的范围,Lb。池沸腾数据,加上沸腾状态和气泡动力学的高速可视化,有力地支持了Lb是关键长度尺度的假设。利用文献中现有的翅片分析方法,可以准确地预测高度和间距高于Lb的翅片阵列散热器的传热。然而,小于Lb的间距会影响核沸腾过热度,而小于Lb的高度不能支持沿翅片侧壁的多种沸腾状态,这两者都导致实验与预测之间的不一致。这些方面,再加上对紧密间隔翅片间水汽夹持的观察,表明必须发展新的预测方法。对翅片阵列高度和间距对池沸腾的影响提供了有价值的见解,为浸入式冷却应用的散热器设计优化提供了途径。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
自引率
0.00%
发文量
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:604180095
Book学术官方微信