已知鰭片數目、深度與體積時的縱長型散熱器之最佳化分析

Optimum Thermal Analysis of Longitudinal Rectangular Heat Sink with the Prescribed Fin Number, Depth and Volume

王瑞麟(Rui-Lin Wang)

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(2009年)

摘要

摘 要
如何在有限空間的情況下，協助工程師設計出有效率的散熱器，使散熱器發揮最大的散熱功效，處理更高的熱量，同時又能考量到材料成本與重量，便是本研究的目的。
這個研究是針對縱長型的散熱器在已知體積與鰭片數目以及一邊的深度，求長方形鰭片的長度與寬度與橫截面積。利用最大散熱量的方程式，將散熱器上的鰭片面積利用累加的計算方式，將單一鰭片表面的熱傳量與鰭片間之底面的熱傳量加總起來，求得整個散熱片的總散熱量。並透過無因次化參數的輸入，經由數學推導出最佳化的公式，再利用程式求解此非線性的超越方程式，得到最佳化的值，然後利用最佳的值來求出最大的效率，並求得另一邊的長度與鰭片高度及鰭片的厚度，並且計算散熱器的熱阻值並闡明其散熱效益。
在計算過程中，考慮鰭片頂端的熱對流效應，與鰭片的厚度為此研究的主要變異條件，整體計算結果顯示，在不考慮熱對流效應時，周長可以被簡化，因為對整個熱傳效能影響在1%以下的誤差。但是考慮熱對流效應時，周長的計算就要被考慮進去，不然可能達到10%以上的誤差。根據計算結果顯示，有最大的散熱量的出現，是在鰭片的總體積與散熱器體積的比約在0.27~ 0.33之間。此數據可作為散熱器設計時，鰭片數目與鰭片厚度的參考。

關鍵字

散熱器 ； 最佳化 ； 散熱座

並列摘要

ABSTRACT
The goal of this thesis is try to assist engineer to design an effective Heat Sink, which intent to have the most effectiveness in handling maximum heat dissipation is presented , under limited space. And, the material cost and weight are also under consideration in this study.
The purpose of this study is focusing on the Longitudinal Rectangular Heat Sink, which the volume and fin number as well as one side depth have already known, for the length, width, and cross section area. Using the equation of maximum heat dissipating, accumulates the radiator fin on the fin area, add up the surface heat of a single fin and the bottom heat between fins for the total heat dissipating capacity of the Heat Sink. Through the dimensionless parameter input, formula simplification, then the method for the optimized value. Then use the Optimum for the maximum efficiency, the length of the other side, the height and thickness of thin, and the thermal resistance value. And clarify the radiation benefit.
In the process of computation, we have to consider Fin Tip Convection of the fin peak and fin peak thickness in this research. The whole result of the computation demonstrated that the fin peak heat convection and fin peak thickness do not have any influence to the entire radiation efficiency. So, it may be ignored during the computation. According to the computed result, the maximum heat dissipating capacity appear in, compares approximately, between 0.27~0.33 in the fin volume density. This data may work as the reference for the fin piece number in designing the radiator.

並列關鍵字

Heat sink ； Optimum

參考文獻

1.Morrioson,A.T., “Optimization of Heat Sink Fin Geometries for Heat Sink in Natural Convection,” Thermal Phenomena in Electronic Systems, 1992. I-THERM III, Intersociety Conference on Vol.5 , Issue 8 ,pp.145-148, 1992.

2.Azar,K., and Carlo D. Mandrone,“Effect of Pin Fin Density of the Thermal Performance of Unshrouded Pin Fin Heat Sinks,” J. Electron. Packag. Vol. 116, Issue 4, pp.306-309,1994.

4.R.H. Yeh, M. Chang, “Optimum Longitudinal Convective Fin Arrays”Int. Comm. Heat Mass Transfer 22 (3) pp.445-460, 1995.

5.Seri Lee, “Optimum Design and Selection of Heat Sinks”IEEE Transactions on Componements,Packaging and Manufacturing Technology Part A, Vol. 18,No.4,pp.812-817,1995.

9.H.S. Kou, J.J. Lee, C.Y. Lai, “Thermal Analysis and Optimum Fin Length of a Heat Sink” Heat Transfer Engineering 24 (2)pp.18-29, 2003.