臺灣博碩士論文加值系統

本研究是提出一個氣冷式電子散熱的新方向，改善一般風扇散熱的缺點，透過高壓靜電產生的靜電吸附力，讓彈性金屬片產生類似於壓電風扇的機械振動，同時運用其導電性質，當作高壓電的導電電極，使高壓電極與接地的鋁質散熱片中間的空氣解離，產生複合型的振動離子風來增強熱傳效率。實驗設計以7.5 W功率加熱，在0~20 kV電壓範圍內，調整高壓電極葉片和鋁質散熱片之間的電極間距 Dv = 5 mm~20 mm，局部熱傳係數可提昇為7.23~24.91 (W/m2K)，因施加負高壓和正高壓不同極性時，會改變電暈放電的電流值，實驗在-14 kV操作電壓，電極間距Dv = 10 mm的條件下，最佳熱傳係數可達27.08 (W/m2K)，最後比較振動式散熱、離子風散熱與複合式振動離子風散熱的散熱效能，散熱效能表現最好的是EHD式離子風散熱，在7.5W的供應熱源下，下降溫度達44.9 □C，平均電流為71.33 □A, 消秏功率 713 mW, 而靜電式振動離子風的複合式散熱效應，下降溫度43 □C，電流只有21.27 □A，為212.7 mW，秏用功率不到離子風散熱的三分之一，靜電式振動離子風散熱是整體效能中最節能的，加上振動的效應擴大散熱範圍，在低功率下達到接近於離子風的散熱效能，另外有量測振動頻率和振幅與操作電壓的關係，並評估其運用在電子散熱上的可行性。



關鍵字：電液動力學(EHD)、離子風、靜電致動器、壓電風扇

This study is to propose a novel concept to augment natural convection in association with electronic cooling. It can be used as a supplement to general fan cooling. The mechanical vibrations through the high-voltage make use the electrostatic adsorption force will vibrate the metal blade to act as the piezoelectric fan. With the use of the metal blade along with the high–voltage electrode will generate ionic wind between the electrode and the ground- aluminum heat sink. As a result, the local heat transfer coefficient can be obtained in the range of 7.23~24.91 (W/m2K) for an electrode-spacing Dv = 5 mm~20 mm when operated at the voltages of 1~20 kV. Different polarity of the voltage will change the current value of the corona discharge. The local heat transfer coefficient = 27.08 (W/m2K) can be obtained at an operating voltage of -14 kV at an electrode-spacing Dv of 10 mm. We also compare the performance of vibrating cooling, EHD cooling and Electrostatic ion wind vibration cooling . For a 7.5W heat source, the best performance can be achieved via electrostatic ion wind vibration cooling with power consumption being less than one-third of EHD cooling. And the decreased temperature of Electrostatic ion wind vibration cooling is 43 □C which is almost identical to 44.9 □C of EHD cooling. These enhancements are due to the effect of the vibration of metal blade. Besides, the vibration frequency and the amplitude of the operating voltage are also reported in this study.

Keywords: Electro-hydraulic dynamics (EHD), Ion wind, Electrostatic actuator, piezoelectric fan.

中文提要 …………………………………………………… i
英文提要 …………………………………………………… ii
誌謝 ………………………………………………………… iv
目錄 ………………………………………………………… v
表目錄 ……………………………………………………… ix
圖目錄 ……………………………………………………… x
符號說明 …………………………………………………… xv
一、 導論…………………………………………………… 1
1.1研究背景與動機………………………………………… 1
1.2文獻回顧………………………………………………… 3
1.2.1離子風………………………………………………… 3
1.2.2壓電風扇……………………………………………… 4
1.2.3 靜電致動器薄膜材料之楊氏模數的檢測技術…… 6
1.3 本文大綱……………………………………………… 8

二、 低功率靜電式振動離子風的相關理論與實驗原型… 11
2.1靜電感應的現象………………………………………… 13
2.2微致動器發展現況……………………………………… 15
2.3靜電式致動器原理……………………………………… 16
2.4電液動力學原理………………………………………… 17
2.5電液動力學基本公式…………………………………… 20
2.6電液動力學應用於熱傳增強…………………………… 21
2.6.1電壓和電極距離……………………………………… 21
2.6.2電極極性……………………………………………… 23
2.6.3電極形狀……………………………………………… 23
2.7壓電風扇………………………………………………… 24

三、 靜電式離子風垂直振動致動器的設計……………… 27
3.1針狀離子風效應………………………………………… 27
3.2靜電式吸附力裝罝產生垂直類壓電式風扇振動……… 29
3.3靜電式離子風垂直振動散熱扇實驗裝置設計………… 31
3.4振動金屬葉片材質選擇………………………………… 32

四、 靜電式懸臂樑測試結構之方程式推導……………… 33
4.1懸臂樑簡介與理論……………………………………… 33
4.2樑的撓度………………………………………………… 33
4.3K. E. Petersen 的懸臂樑受靜電負載變形方程式… 36
4.4懸臂樑受靜電負載變形方程式之數值分析模擬……… 38

五、 高壓靜電式振動離子風實驗設備與量測方法………… 42
5.1熱電偶校正之基礎測量與誤差傳遞分析………………… 42
5.1.1熱電偶校正實驗目的…………………………………… 42
5.1.2熱電偶校正實驗設備…………………………………… 42
5.1.3熱電偶校正實驗原理…………………………………… 46
5.1.4熱電偶校正實驗結果…………………………………… 47
5.2靜電振動式離子風散熱的熱傳實驗設備………………… 48
5.2.1HVPS高電壓與電流量測的誤差校正與分析設備……… 55
5.3靜電振動式電極與散熱板的振動致風散熱實驗設計…… 57
5.4正高壓離子風與電極間距調整的散熱測試實驗設計…… 60
5.5振幅與頻率量測實驗設計………………………………… 63
5.6振動現象之高速攝影取樣實拍…………………………… 65
5.7負高壓電極離子風與電極距離的散熱測試實驗設計…… 66
5.8施加不同熱功率對熱傳係數的實驗……………………… 69
5.9 振動葉片不同的電極形狀和尺寸……………………… 70
5.10靜電式振動離子風複合式散熱實驗設計……………… 72
5.11實驗溫度量測與計算資料簡化………………………… 73

六、 實驗結果與討論………………………………………… 78
6.1靜電振動式電極振動致風的散熱結果………………… 78
6.2正高壓離子風散熱效應之實驗結果…………………… 80
6.3振幅與頻率量測實驗結果……………………………… 82
6.3.1振動模態量測說明…………………………………… 82
6.3.2振幅與操作電壓之間的關係………………………… 85
6.3.3靜電式振動與自由振動量測結果…………………… 96
6.3.4振動頻率與操作電壓之間的關係…………………… 108
6.4負高壓與正高壓離子風散熱效應之比較……………… 109
6.5振動現象之高速攝影…………………………………… 111
6.6施加不同熱功率對熱傳係數的影響…………………… 113
6.7振動葉片不同電極形狀和尺寸的實驗結果…………… 115
6.8靜電式振動與高電壓離子風散熱實驗結果…………… 117

七、 結論與未來展望……………………………………… 119
參考文獻……………………………………………… 122

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