風扇對切換電源供應器內部之流場分析

Flow Field Analysis inside Switching Power Supply Affected by the Fan

羅迪彥(Di-Yen Lo)

指導教授 ： 郭鴻森 ； 李基禎

大同大學/工程學院/機械工程學系所/碩士(2011年)

摘要

本文主要以模擬分析，探討以改變風扇風速及其流向，對伺服器的切換電源供應器( SPS：Switching Power Supply )內部散熱性能之研究。本文主要以計算流體力學套裝軟體PHOENICS來作數值模擬分析，探討切換電源供應器內部系統之流場變化以及晶片表面的溫度變化。
本模擬模型的內部結構並非對稱圖形，再加上內部結構繁雜，因此不同風扇的風速與流向，所產生的流場也會不同，其系統之最高溫度也會不一樣。
經過整體系統的數值模擬分析，發現抽風時局部的最高溫度比吹風時還來得低，其原因為抽風時，遇到障礙物會產生繞過流的狀況較明顯，而使後方晶片能受到對流作用而能有效地散熱。
吹風式與抽風式之間最高溫度之溫差會隨著風扇風速之提升而有所提高。當風扇的風速分別為2m/s、3m/s、4m/s、5m/s時，其最高溫度之溫差分別約為1.8℃、3.2℃、3.6℃、3.7℃。而最高溫度之溫差之間的差異性反而隨風扇風速的提升，而逐漸變小。換言之，抽風效果雖然比吹風佳，不過隨著風扇風速的提高，最後會使吹風與抽風所能降低的溫度趨緩。

關鍵字

非均勻流場 ； 強制對流 ； 散熱模組 ； 切換電源供應器 ； 風扇

並列摘要

The aim of this study is to simulate the thermal performance of the SPS ( Switching Power Supply ). Through changing the flow velocity and direction of the fan flow. The variation of flow field around the SPS and the temperature distribution of chips are studied inside a computer. The software of PHOENICS was used to analyze its effect in this research.
This study presents that the complex structure of the model around the SPS is not a symmetrical pattern. Due to the difference of the flow velocity and flow direction, the flow field and the highest temperature inside SPS will be varied.
After numerical analysis for the whole system, it is found that the highest local temperature of air for suction type is lower than that of air blowing type. It will become obvious that bypass flow resulting from the barrier will make the chips behind the barrier difficult to dissipate heat by convection effectively.
The highest temperature difference between the type of blowing and suction will increase by the fan velocity raising. In different fan velocities with 2m/s, 3m/s, 4m/s, and 5m/s, the highest temperature differences are about 1.8℃, 3.2℃, 3.6℃ and 3.7℃. The distinctions between the highest temperature differences will become small by raising the fan velocity. In other words, the effect in suction is greater than in blowing. However, the effect on reducing temperature will approach to its limit by the fan velocity raising.

並列關鍵字

Forced convection ； Thermal dissipation module ； Switching power supply ； Non-uniform flow field

參考文獻

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