碩士 / 國立成功大學 / 機械工程學系碩博士班 / 98 / The finite difference method in conjunction with the least-squares scheme and experimental temperature data is proposed to predict the average overall heat transfer coefficient, heat transfer rate on a vertical annular circular fin of annular-finned tube heat exchangers for two kinds fins and various fin spacings. The overall heat transfer coefficient on this annular circular fin is assumed to be non-uniform. Thus, the whole plate fin is divided into several sub-fin regions in order to predict the average overall heat transfer coefficient. heat transfer rate from the knowledge of the measured experimental temperatures. The unknown heat transfer coefficient on each sub-fin region can be assumed to be constant. The results show that the average heat transfer coefficient and the fin efficiency decrease with increasing the fin height and increase with increasing the fin spacing. The average heat transfer coefficient and fin efficiency can approach their corresponding asymptotical value obtained from fin for the fin spacing above a certain value. The heat transfer rate also increases with increasing the fin spacing. The average heat transfer coefficient increases with the air speed for various fin spacing in force convection. The average heat transfer coefficient increases with the fin spacing and it can approach its corresponding asymptotical value obtained from a single annular circular fin for various air speed above a certain value. The present estimates of the heat transfer coefficient under the isothermal condition in natural and force convection agrees with those were obtained from textbooks. In order to evidence the accuracy and reliability of the present inverse scheme, A comparison between the present results estimated and previous results will be made.
| Identifer | oai:union.ndltd.org:TW/098NCKU5490133 |
| Date | January 2010 |
| Creators | Huan-TingLin, 林煥庭 |
| Contributors | Chen-Han Taw, 陳寒濤 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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