Consideration of heat transfer enhancement mechanism using nano- and micro-scale porous layer

T. Kunugi, Y. Ueki, T. Naritomi, H. Son, Z. Kawara, S. Muko, S. Wakamori
{"title":"Consideration of heat transfer enhancement mechanism using nano- and micro-scale porous layer","authors":"T. Kunugi, Y. Ueki, T. Naritomi, H. Son, Z. Kawara, S. Muko, S. Wakamori","doi":"10.1109/THETA.2008.5167158","DOIUrl":null,"url":null,"abstract":"A convective heat transfer enhancement using nano- and micro-scale porous layer surface was discovered by Kunugi et al. The heat transfer experiments, analytical considerations, flow visualization near the porous layer, and the porous layer surface observation were performed to grasp the heat transfer characteristics and the heat transfer enhancement mechanism. The heat transfer experiments revealed the porous layers were capable to enhance heat transfer by 20-25% in net energy compared to the bare plate, independently of substrate materials. The heat transfer experiment changing the Reynolds number showed the Reynolds number dependency of heat transfer performance. One-dimensional unsteady heat conduction analysis showed the temperature recovery of the porous layer was incapable to catch up with the very fast temperature fluctuation, so that the porous layer might be a thermal-resistance when the main flow was strongly turbulent. The vestige visualized by the tracer-particles of around 0.85 mum in diameter showed a fluid behavior like \"squirt\" from the porous layer. From observation of the porous-layer surface, the porous layer has some micron-scale bubbles inside its own pore-connecting structure in spite of the good wetting feature. The expansion and contraction of the bubble-foam in the layer was observed and these behaviors may be considered as the main contribution to the mechanism of the heat transport.","PeriodicalId":414963,"journal":{"name":"2008 Second International Conference on Thermal Issues in Emerging Technologies","volume":"255 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2008-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2008 Second International Conference on Thermal Issues in Emerging Technologies","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/THETA.2008.5167158","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 3

Abstract

A convective heat transfer enhancement using nano- and micro-scale porous layer surface was discovered by Kunugi et al. The heat transfer experiments, analytical considerations, flow visualization near the porous layer, and the porous layer surface observation were performed to grasp the heat transfer characteristics and the heat transfer enhancement mechanism. The heat transfer experiments revealed the porous layers were capable to enhance heat transfer by 20-25% in net energy compared to the bare plate, independently of substrate materials. The heat transfer experiment changing the Reynolds number showed the Reynolds number dependency of heat transfer performance. One-dimensional unsteady heat conduction analysis showed the temperature recovery of the porous layer was incapable to catch up with the very fast temperature fluctuation, so that the porous layer might be a thermal-resistance when the main flow was strongly turbulent. The vestige visualized by the tracer-particles of around 0.85 mum in diameter showed a fluid behavior like "squirt" from the porous layer. From observation of the porous-layer surface, the porous layer has some micron-scale bubbles inside its own pore-connecting structure in spite of the good wetting feature. The expansion and contraction of the bubble-foam in the layer was observed and these behaviors may be considered as the main contribution to the mechanism of the heat transport.
查看原文
分享 分享
微信好友 朋友圈 QQ好友 复制链接
本刊更多论文
纳米和微尺度多孔层强化传热机理的探讨
Kunugi等人发现利用纳米和微尺度多孔层表面增强对流换热。通过传热实验、分析考虑、多孔层附近流动可视化、多孔层表面观察等方法,掌握了多孔层的传热特性和强化传热机理。传热实验表明,与基材材料无关,多孔层能够将净能量的传热提高20-25%。改变雷诺数的换热实验表明,雷诺数对换热性能有依赖性。一维非定常热传导分析表明,多孔层的温度恢复无法赶上非常快的温度波动,因此当主流是强湍流时,多孔层可能是一个热阻。直径约0.85 μ m的示踪颗粒显示出类似于从多孔层“喷射”的流体行为。从多孔层表面观察可知,多孔层虽然具有良好的润湿特性,但其自身的连孔结构内部存在一些微米尺度的气泡。观察到层内气泡的膨胀和收缩,这些行为可以认为是热传递机制的主要贡献。
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 去求助
来源期刊
自引率
0.00%
发文量
0
期刊最新文献
Microscale transprot in the thermal processing of new and emerging advanced materials Calculation of local heat transfer coefficient on axisymmetric geometries using different methods of fringe analysis EXperimental study of convective heat transfer and pressure loss of SiO2/water nanofluids Part 2: Imposed uniform heat flux - Energetic performance criterion Air flow regimes and IAQ modeling in air conditioned spaces Analytical simulation of rich hydrogen gas - Air Proton Exchange Membrane Fuel Cell system fueled by natural gas
×
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
现在去查看 取消
×
提示
确定
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
已复制链接
已复制链接
快去分享给好友吧!
我知道了
×
扫码分享
扫码分享
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 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 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1