具有雙向斜型肋結構的微流道對水冷散熱器熱傳性能之影響

Effect of microchannel with bidirectional slant rib structure on the heat transfer performance of a water cooler

劉信廷(Hsin Ting Liu)

指導教授 ： 翁輝竹

中原大學/工學院/機械工程學系/碩士(2022年)

https://doi.org/10.6840/cycu202201410

摘要

在增強微流道的熱傳策略中，增加肋結構與腔體造型是許多研究所探討的，然而過去文獻中鮮少對於雙向的斜型肋對於熱傳效應的分析，因此，本研究遂針對此結構的微流道進行數值模擬，並解析對於熱傳的提升與壓力的影響。

與傳統的無肋結構的微流道相較，具備雙向斜型肋結構的微流道可以讓流體產生雙向渦流的現象，並藉此產生熱邊界的中斷、傳熱面積的增加以及混沌移流的產生。藉由流道肋結構的幫助，使液冷散熱器的效益大幅提升。因雙向斜型肋傳熱面積較大，且可更有效地產生邊界層的中斷效應，熱傳效應明顯較單排肋更佳。 本 論 文 使用Ansys Fluent 2019 R1 版的模擬軟體，模擬微流道中雙向斜型肋結構於不同攻角與間距的綜合比較。除了觀察攻角對流體流動路徑的影響外，並探討雙向斜型肋結構之間隔距離，與同一排肋結構的間距差異對熱流傳導的影響。當肋結構間距、攻角與流體速度不同時，會顯著影響流道的流動特性及熱傳性能。

研究發現當肋攻角為45°且雷諾數大於500，雙向斜型肋間隔相等時流體的流動所呈現週期性的雙向渦流效應可以產生較佳的熱傳效應，同時也產生較強的壓降與摩擦係數，這樣的流道結構可以在不用增加泵浦功率的情況下，大幅增加熱傳效率。透過增加簡易幾何造型的肋結構，可以顯著提升整體的微流道熱傳效率，這對於強化微流道液冷散熱的效率具有重大的意義。在工業的應用上，對於許多的電子通訊設備或是電動車電池模組的散熱具備高價值的參考依據。使用模擬軟體先行驗證，可以節省實際開模製作樣品的時程與成本，也可以預先調整出較佳的能耗需求，在提高熱傳效率的同時也節省運作成本。

關鍵字

雙向斜型肋結構 ； 微流道 ； 熱傳效率 ； 雙向渦流 ； 攻角 ； 肋間距 ； 混沌平流

並列摘要

When discussing strategies to enhance heat trans fer in microchannel , adding rib structures and cavity shapes has been discussed in many studies. However, in the past,there are few studies on the heat transfer effect of bidirectional slant ribs in the literature. Therefore, in this study, numerical simu lations were carried out for the micro channel with this structure, and the influences on the heat transfer enhancement and pressure were analyzed.

It was found that compared with the traditional microchannel, the microchannel
with bidirectional slant rib s tructure can generate bidirectional eddy currents in the fluid, resulting in the interruption of thermal boundary, the increase of heat transfer area, and the chaotic advection With the rib structure of the channel, the efficiency of the liquid cooling ra diator is greatly improved. Because the heat transfer area of bidirectional slant rib is larger, and the interruption effect of boundary layer can be generated more effectively, the heat transfer effect is obviously better than that of single row rib.

This paper uses Ansys Fluent 2019 R1 simulation software to simulate the
comprehensive comparison of bidirectional slant rib structures in microchannels at different attack angles and spacing In addition to observing the effect of attack angles on the fluid f low path, the effect of the spacing distance between bidirectional slant rib structures and the spacing difference of the same row of rib structures on heat flow conduction is also discussed. When the rib structure spacing, attack angle and fluid velocity are different, the flow characteristics and heat transfer performance of the flow channel will be significantly affected. The study found that when the attack angle of the rib is 45 degrees and the bidirectional slant rib interval is equal, the flow of the fluid can exhibit a periodic bidirectional vortex effect. Such a flow channel structure can greatly increase the heat transfer efficiency without increasing the pump power. By adding a rib structure with a simple geometric shape, the overall heat transfer efficiency of the microchannel can be significantly improved, which is great significance for enhancing the efficiency of liquid cooling and heat dissipation in the microchannel. In industrial applications, it is a valuable reference for the heat dissipat ion of many electronic communication equipment or battery modules of electric vehicles. Using simulation software to verify in advance can save the time and cost of mold samples, and can also adjust the optimal energy consumption in advance, which can impr ove heat transfer efficiency and save operating costs.

並列關鍵字

bidirectional slant rib structure ； microchannel ； efficiency of heat transfer transfer ； bidirectional eddy currents currents ； attack angles ； rib spacing ； chaotic advection

參考文獻

Alfellag, M. A., Ahmed, H. E., and, Kherbeetb, A. S., 2020, “Numerical simulation of hydrothermal performance of minichannel heat sink using inclined slotted plate-fins and triangular pins,” Applied Thermal Engineering, 164, 114509.

Aref, H, 1984, “Stirring by chaotic advection,” Journal of Fluid Mechanics, 143, 1–21.

Chai, L., Xia, G. D., and Wang, H. S., 2016, “Numerical study of laminar flow and heat transfer in microchannel heat sink with offset ribs on sidewalls,” Applied Thermal Engineering, 92, 32–41.

Chai, L., Xia, G., Zhou, M., Li, L., and Qi, J., 2013, “Optimum thermal design of interrupted microchannel heat sink with rectangular ribs in the transverse microchambers,” Applied Thermal Engineering, 51,880–889.

Chang, H. C., Sen, M., 1994, “Application of chaotic advection to heat transfer,” Chaos, Solitons & Fractals, 4, 955–975.