碩士 / 國立勤益科技大學 / 冷凍空調系 / 95 / The effects of variation of fin material and tube pitch on the plate finned-tube heat exchanger are studied by numerical method. Five fin materials、two tube diameter、two fin pitches and three tube pitches are investigated. Three rating methods are used in the paper: the first method used the Schmidt approximation equation to iterate the fin efficiency, the second method used the Bessel analysis solution to iterate the fin efficiency, and the third method used the Bessel analysis fin efficiency with Schmidt iterated heat transfer coefficient. The results show that the heat exchanger capacity are not affected by the tube diameter and fin material under the low air velocity（0.51m/s）with small fin spacing and the results of the three heat exchanger capacity calculating method used in the study are all the same. Similar results are shown when the tube pitch is increased under the low air velocity.
The heat exchanger capacity calculated by the heat transfer coefficients of the aluminum fin would have much error when the air velocity is high. The discrepancy is caused by the decreased fin efficiency and the tube effect on the heat transfer. The results show that the second calculation method has better result when the fin conductivity is larger than the sample(Aluminum)。The first calculation method has better result when the fin conductivity is lower than the Aluminum.
The Bessel solution of the fin efficiency is recommended to be used with the sample heat transfer coefficient in the calculation of the increased tube pitch heat exchanger.
This study demonstrate the error of the heat exchanger capacity rated by empirical heat transfer coefficient may be caused by the excluding of the fin material and tube diameter in the calculation.
| Identifer | oai:union.ndltd.org:TW/095NCIT5703007 |
| Date | January 2007 |
| Creators | Wei-hsun, Lee, 李韋勳 |
| Contributors | Wen-Chien, Hsieh, 謝文健 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 79 |
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