碩士 / 國立中央大學 / 機械工程研究所 / 99 / Heat transfer of vertical oriented flat plate and straight fin enhanced by electrohydrodynamics (EHD) is experimental investigated in this work. Heat transfer of four types of fin having the same frontal area are discussed under natural convection and EHD enhancement, including flat plate, straight fin with different height, and offset strip fin.
Heat transfer coefficient of flat plate is the highest among other fins under both natural convection and EHD enhancement, but the heat transfer rate of flat plate is the lowest due to the smallest heat transfer area. The major reason affecting heat transfer of straight fin is the boundary layer development between fins. Under natural convection, heat transfer coefficient of straight fin - H29 and straight fin - H15 are almost the same due to boundary layer between fins becomes fully development early. Under EHD enhancement, heat transfer coefficient of straight fin - H15 is higher than straight fin - H29 by 10 ~ 15 %. Boundary layer is thinner under corona wind and becoming fully development at late of the fin length. Cold air can enter the channel of straight fin with lower fin height easier than higher fin height. Thus the heat transfer is higher with straight fin - H15 than straight fin - H29. Heat transfer of offset strip fin has no improvement due to the effect of increased flow resistant and boundary layer fully developed.
| Identifer | oai:union.ndltd.org:TW/099NCU05489020 |
| Date | January 2011 |
| Creators | Tai-chang Lu, 盧泰昌 |
| Contributors | Chien-yuh Yang, 楊建裕 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 149 |
Page generated in 0.0015 seconds