壓電磁力連動風扇應用於微型投影機內之散熱研究

Study of the Multiple Piezoelectric Magnetic Fans System Applied to a Pico Projector

林柏廷(Bo-Ting Lin)

指導教授 ： 馬小康

國立臺灣大學/工學院/機械工程學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201601233

摘要

隨著科技發達，電子設備之效能愈來愈好，然而其體積卻是愈來愈小，且電子和照明設備的溫度將明顯影響其效率以及壽命。因此，如何將設備溫度控制在特定範圍內將非常重要。壓電磁力連動風扇為本實驗室發展出之獨特散熱技術，利用單片壓電片搭配永久磁鐵即可達到同時驅動多片被動扇葉進行振動，顯著提升散熱能力，在節省成本的同時保持其低功耗，低噪音的效果。
本實驗針對微型投影機內之有限可運用空間設計了五組不同尺寸組合之壓電磁力連動風扇，搭配熱管模組的設計，將熱由發熱源傳輸到風扇前端的散熱鰭片後，藉由風扇的擺動進行散熱。藉由實驗找出擁有最佳散熱能力之風扇後，再針對此風扇設置於不同擺放方向以及和不同散熱模組搭配進行研究。
實驗結果顯示擁有35 mm長之碳纖維片和5 mm長之麥拉片之扇葉風扇具有最佳之散熱效能，其搭配熱管模組且熱源輸入功率為8 W時，熱阻值達到4.13 K/W，而對流熱傳係數和Ri值分別為158.09 Wm^(-2) K^(-1)和0.018，顯示出風扇產生之強制對流主導了對流熱傳。
將此組風扇進行不同擺放方向之散熱實驗，結果顯示當上下顛倒擺放時，對於散熱能力將有不良影響，此時對流熱傳係數由158.09 Wm^(-2) K^(-1)降至115.00 Wm^(-2) K^(-1)。
將此組風扇與另一鋁板模組和均溫板模組搭配後進行散熱實驗，結果顯示在熱源輸入功率為8 W時，與鋁板和均溫板模組搭配時之熱阻值分別為4.93 K/W和3.09 K/W，指出均溫板模組於此三種散熱模組中為與壓電磁力連動風扇之最佳搭配選擇，而原始旋轉風扇之熱阻值為3.77 K/W。

關鍵字

壓電磁力連動風扇 ； 壓電風扇 ； 微型投影機 ； 熱效能 ； 散熱

並列摘要

In this study, five different multiple piezoelectric magnetic fans (MPMF) were developed to be applied in a pico projector. The MPMF with the optimal thermal performance can be discovered through the experiment. The thermal performances of this MPMF under different orientations and with different two other cooling modules were further investigated.
The result shows that the MPMF with the combination of a 35-mm long carbon fiber plate and a 5-mm long Mylar plate for passive fans (Model D) possesses the optimal thermal performance, and its thermal resistance under 8-W heater power was 4.13 K/W and meanwhile the convective heat transfer coefficient and the Richardson number were 158.09 Wm^(-2) K^(-1) and 0.018, respectively.
The result also indicates that the upside down orientation has an undesirable effect on thermal performance, the convective heat transfer coefficient dropped from 158.09 Wm^(-2) K^(-1) to 115.00 Wm^(-2) K^(-1) under 8-W heater power, and the thermal resistance rose from 4.13 K/W to 4.95 K/W.
Comparing the heat pipe module, vapor chamber module, and the aluminum plate module, the result demonstrates that the MPMF with the vapor chamber module provides the best cooling ability. The thermal resistance of the model D with the vapor chamber under 8-W heater power was merely 3.09 k/W which was even lower than 3.77 K/W of the rotary fan.

並列關鍵字

MPMF ； piezoelectric fan ； pico projector ； thermal performance ； heat dissipation

參考文獻

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