筆記型電腦散熱系統之主動式熱沉最佳化設計

Abstract

近年來，由於CPU頻率上升及元件密集度提高，使得筆記型電腦內所產生的熱量愈來愈高，因此散熱問題是筆記型電腦內設計上的一大挑戰，而其中主動式熱沉是筆記型電腦內最重要的散熱元件，因此，基於散熱、成本及設計空間的考量下，主動式熱沈的最佳化設計是筆記型電腦的散熱系統設計中極重要的問題。 散熱片是主動式熱沈最重要的散熱元件。因此本研究主要在討論散熱片的最佳化設計。利用STAR-CD套裝軟體模擬平行板散熱片流場及熱傳的共軛問題，模擬結果顯示出不同片數條件下散熱片表面的局部、平均對流熱傳係數和根部至頂部溫度分布。 其次，基於散熱片體積、成本、散熱量之考量，以發熱量各別為13、17、21、25瓦的設計條件，來尋找不同熱傳性能要求之下最佳化設計，以達到降低CPU的溫度之要求，並做為設計筆記型電腦散熱系統之依據。

Recently, with the continuing increase of CPU’s frequency and system power dissipation in notebook personal computers, high performance thermal solutions such as heat pipe, heat sink, thermal spreader, and fans have witnessed an increasing number of applications in the notebook personal computers. Among them, active heat sinks are main elements in heat transfer system of a notebook PC. Therefore, based on the consideration of heat transfer, cost and space in notebook PC, the optimum design of active heat sinks is a very important subject. The objective of this research is to study notebook personal computer CPU heat sinks by STAR-CD software. The numerical simulation is performed by considering a conjugate problem which solved both flow and heat transfer in air stream and heat conduction in the fins of heat sinks. Simulation results showed local, average heat transfer coefficients of the fin and distribute temperature from bottom to top of fin. Secondly, based on the consideration of volume, cost, and dissipation of heat sinks, an optimum design, under various demands of heat–transferred amount of 13,17,21,25watts power of CPU individually, is explored by theoretical analysis to decrease the temperature generated from CPU. The results offered better references in designing heat transfer system in notebook PC.