EHD Enhanced Heat Transfer by Inserting Needle Electrodes into Heat Sink / 鰭片底面裝置針狀電極之EHD增強散熱技術研究

碩士 / 國立清華大學 / 動力機械工程學系 / 95 / It is not suitable for the rate of heat transfer under natural convection in some situations which can not utilize active cooling technology, so heat transfer enhanced by electrohydrodynamics (EHD) is experimentally investigated in this work. The system of inserting needle electrodes into heat sink can effectively increase the rate of heat transfer due to the corona wind generated by EHD. The polarity of electric field, distance of electrode to pin-fin, height of pin-fin, configuration of pin-fin, spread of pin-fin and position of electrode will be taken into account. The results reveal that both the spark voltage and heat transfer rate for negative corona are better than those for positive one. In pin-fin design, EHD technology belongs to force convection for reducing thermal resistance of convection with increasing area of cooling. When height of pin-fin is one centimeter, EHD can distort flow field reduced thermal resistance of convection. The maximum heat transfer coefficient with EHD is greater than that without EHD by three and half times. The minimum thermal resistance of convection with EHD is lower than that without EHD by half times. In addition to, inserting needle electrodes into heat sink is not only reduced power consumption but also improved efficiency.

Identiferoai:union.ndltd.org:TW/095NTHU5311068
Date January 2007
CreatorsChang,Chao-Chiu, 張兆秋
Contributors許文震
Source SetsNational Digital Library of Theses and Dissertations in Taiwan
Languagezh-TW
Detected LanguageEnglish
Type學位論文 ; thesis
Format73

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