碩士 / 國立勤益科技大學 / 冷凍空調系 / 97 / The fin and tube heat exchangers with staggered tube are investigated numerically in the study. The parameters studied include row number, fin type, slit fin division number and fin pitch. The inlet air velocity is increased from 0.25m/s to 6.5m/s to examine the parameter influences upon heat transfer and pressure drop under different air velocity. The effects of offset strip and tube in different row upon heat transfer are also analyzed through numerical simulation particularly to provide understanding of the heat transfer mechanism of an offset strip fin-and-tube heat exchangers.
To study the scale effect of heat exchanger, the tube diameter are scaled down proportionally to tube pitch from 9.88㎜ to 7.6㎜. The results show that the slit division numbers and tube row number will increase the heat transfer rate, but will also increase the pressure drop. The fin offset strip and tube row number have more distinctly heat transfer effect in the high air velocity and large fin pitch. The heat transfer enhancement of slit fin is dominantly through the fin, the primary tube surface has limiting effect on heat transfer despite of the fin type.
| Identifer | oai:union.ndltd.org:TW/097NCIT5703026 |
| Date | January 2009 |
| Creators | Jun-Jie, Lin, 林俊傑 |
| 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 | 73 |
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