多孔式鰭片對高功率LED散熱模組熱傳性能之研究

A Study of Perforate Heat-Sink on the Heat Transfer Performance of High-Power LED Modules

曾慶文(Qing-Wen Zeng)

指導教授 ： 蔡瑞益

中原大學/工學院/機械工程研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200661

摘要

當LED照明燈具並非完全封閉時，其內部流場並不會呈現完全的自然對流，而是會根據環境流體的速度呈現混和對流亦或是強制對流，而若散熱模組鰭片擺放方式與環境流體流入方向互相垂直時，可能造成流體無法順利進入散熱模組流道內造成溫度分佈不均或局部高溫等問題。為此本文提出一多孔鰭片(Perforate Fin)之設計，目的在於增加流體在散熱模組內的流動能力，降低流體受到鰭片阻擋時的影響，此外本設計亦有增加熱對流面積及抑制熱邊界層發展之效用。
本文使用CFD-RC計算流體力學軟體以模擬進行輔助驗證。在比較市售常見散熱模組幾何後得知放射狀散熱模組由於錐形流道設計而擁有最好散熱效率。在維持鰭片體積相同的情況下，散熱模組增加孔洞後由於面積增加，故對流熱傳能力也得以上升。其後以改變環境流體流速、熱源型式、熱源溫度以及散熱模組材料以得知多孔式幾何最適合之環境。結果顯示熱源溫度的降幅會隨流體流速提升而增加，但下降幅度則受熱源溫度高低及熱源形式影響。大面積陣列熱源當流速提升時溫度降幅最小，而溫度較高之單點式熱源對多孔幾何所帶來的效率則最好。此外，由於多孔式幾何的使用會伴隨散熱面積的增加，因此以輻射散熱做為主要熱傳機制的陶瓷性材料在此也有良好的發揮空間 。

關鍵字

陶瓷材料 ； 多孔式幾何 ； LED散熱模組

並列摘要

When the LED lamp is not in a completely closed environment the flow field in the lamp will not show complete natural convection but show mixed convection or forced convection which is divided by inlet fluid velocity, when LED heat sink fin’s arrangement is perpendicular to the direction of inlet fluid it may causes some thermal problems like non-uniform temperature distribution or hot point. To avoid those thermal problems the perforate fin had been investigated by numerical analysis.
The perforate fin will provide much better performance of fluid through the heat sink, furthermore it also provide not only increase the heat transfer area but also restrain the developing of thermal boundary layers at the same time. Simulation results show that perforate fin have better performance because of its lager heat transfer area. In order to chose the best environment for perforate geometry, the relation to the fluid velocity、heat source form、heat source temperature and heat sink material had been investigated respectively. Results show that the heat transfer performance is proportional to velocity, but the relation to the temperature gradient of heat source is influenced by other factors, the matrix heat source with large area has smallest temperature gradient when velocity increase, and high temperature point heat source under perforate form has best efficiency when velocity increase. Furthermore, it’s a good ideal to choose ceramic material because its high emissivity, it is appropriate material for perforate heat sink due to the larger heat transfer area of perforate type.

並列關鍵字

Ceramic material ； Perforate fin ； LED heat sink

參考文獻

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