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.
| Identifer | oai:union.ndltd.org:TW/095NTHU5311068 |
| Date | January 2007 |
| Creators | Chang,Chao-Chiu, 張兆秋 |
| Contributors | 許文震 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 73 |
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