應用兩相熱傳於電子散熱模組之性能研究

The Investigation of Thermal Performance of Two-Phase Thermal Module

王榮昌(Jung-Chang Wang)

指導教授 ： 陳希立

國立臺灣大學/工學院/機械工程學研究所/博士(2007年)

https://doi.org/10.6342/NTU.2007.00542

摘要

本文主要是針對兩相熱傳元件應用於電子散熱模組的性能作探討。利用性能實驗配合熱阻分析模式的方法，建立嵌入式熱管熱沉散熱模組的理論模式，並以此開發一套視窗軟體EHPHSC V1.0程式，使散熱模組業界對於設計分析此類散熱模組的熱性能有一套合適的軟體工具可應用。程式計算所得的理論值與實驗值誤差在12％以內，且運算時間迅速，已達業界使用的要求。結果顯示，嵌入式熱管熱沉散熱模組的總熱阻值會受到熱管性能影響，兩根嵌入式熱管熱沉散熱模組在加熱功率為140W時，具有最低總熱阻值為0.27℃/W，四根嵌入式熱管熱沉散熱模組在加熱功率為40~240W時，總熱阻值皆為0.24℃/W，不會有太大的變動。理論上，若使用具有熱阻值接近於零的U型熱管替代本文中的U型熱管，則熱管所帶走的熱量比例會最大，兩根及四根嵌入式熱管熱沉散熱模組分別為46％及63％。
對於分析兩相封閉迴路式熱虹吸管散熱模組的熱性能，本文主要是藉由量測冷凝器外管壁的五個溫度點分佈，探討散熱模組整個系統內部工作流體，因為位於左右兩側蒸發段與冷凝段內部蒸氣壓力及截面積的不同，造成左右兩側水位高度的差異。本文以池核沸騰及薄膜冷凝理論為基礎，推導出兩相封閉迴路式熱虹吸管散熱模組內部水位高度差的計算式。結果顯示，冷凝器外管壁溫度分佈，在一位於接近冷凝器出口的驟降溫度點之後，皆已經等於周圍環境的溫度，研判工作流體已經滲入到冷凝器內部，表示本文所使用的冷凝器管長，在不改變任何條件下，可以從14.28cm減少尺寸到10.14cm。

關鍵字

U型熱管 ； 兩相熱傳 ； 嵌入式熱管熱沉散熱模組 ； 熱阻 ； 兩相封閉迴路式熱虹吸管散熱模組

並列摘要

This paper investigates mainly two-phase heat transfer devices applied to electronic cooling modules. By using experimentation with a thermal resistance analysis model, we construct a theoretical model for embedded heat pipe heat sink coolers. To this end we developed a Windows-based application called EHPHSC v1.0, giving the industry a suitable tool for analyzing the thermal performance of this type of cooler. The theoretical values computed by the program fall within a 12% error of the experimental values, meeting industry requirements for use. The results show that the total thermal resistance value of the embedded heat pipe heat sink cooler is affected by the function of the embedded heat pipes. When a heat sink cooler with two embedded heat pipes is at a heating power of 140W, the total thermal resistance is at its minimum of 0.27°C/W. When a heat sink cooler with four embedded heat pipes is at a heating power of between 40W and 240W, the total thermal resistance is 0.24°C /W, which is not much of a change. If we replace the heat pipes used in this study with an ideal U-shaped heat pipe, then the heat capacity ratios of the two-pipe and four-pipe heat sink coolers are 46% and 63%, respectively.
Regarding the thermal performance of a two-phase closed loop thermosyphon cooling module, this paper looks at the working fluid within the entire cooling system mainly by measuring the temperature distribution in the walls of the condenser pipes. The differences in vapor pressure and cross sectional area between the evaporation end and condensation end result in a great difference in fluid level. According to the nucleate pool boiling theory and film condensation theory, we derive a method for calculating the internal fluid level differences between two-phase closed loop thermosyphon cooling modules. The results show that the temperature at the exit of the condenser is equal to the ambient temperature; the working fluid will permeate into the condenser. In this study we find conclude that the length of the condenser may be reduced from 14.28cm to 10.14cm without losing effectiveness.

並列關鍵字

U-Shaped Heat Pipe ； Two-Phase Heat Transfer ； Embedded Heat Pipe Heat Sink Cooler ； Thermal Resistance ； Two-Phase Closed Loop Thermosyphon Cooling Module

參考文獻

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