旁通概念應用在熱沉平板鰭片之熱傳性能分析與探討

Abstract

為改善在強制對流下平板鰭片熱沉之鰭片性能，本研究將針對現有平板鰭片熱沉之改良，並導入旁通(partial bypass)的概念進行新的熱沉鰭片設計，使得部分強制氣流流經鰭片時不會流經前排鰭片而直接流往後排鰭片。儘管如此設計會減少鰭片散熱面積進而降低其散熱量，但卻會大大減少強制對流下的壓降，進而減少強制對流機械之耗能，抑或是在相同耗能情況下可增加流體流量，進而增加整體熱傳量，達到增加熱傳性能的效果。為評估各種不同設計之性能，本研究藉由模擬各種設計模型，比較在不同幾何參數設計下之鰭片所產生之壓降與熱傳現象，分析其熱傳性能與差異性，並藉由實驗來驗證各種設計，以作為新一代熱沉鰭片設計之參考。

In order to enhance the heat transfer rate of heat sink plate fin, this study made a brand new design to existing heat sink plate fin by introducing the concept of “partial bypass”. The basic idea is to introduce bypass cold stream which bypasses the front part of the plate fin and mixes with the hot stream across the front part of the plate fin, and the mixed stream flows through the rear part of the plate fin. Through this concept, plate fin area is reduced but lowered the pressure drop of forced convection. The concept can be implemented with either maintaining the same total flowrate, heat transfer rate but accompanies with a much lower pressure drop or it can be applied with the same pumping power but accompanies with a much higher heat transfer rate.