碩士 / 國立成功大學 / 機械工程學系碩博士班 / 101 / The present study applies the experimental and numerical inverse methods to predict the average heat transfer coefficient and heat transfer coefficient under the isothermal situation on a vertical square fin of the four-tube plate finned-tube heat exchangers for staggered arrangements and various tube pitch, fin spacings and air velocities, and also investigate the effect on heat transfer characteristics by using another fan behind the fins. These tubes may not have the same temperature in the present study. Due to the non-uniform distribution of the heat transfer coefficient, the whole plate fin is divided into several sub-fin regions before performing the inverse scheme, and the average heat transfer coefficient on each sub-fin region is assumed to be unknown. Later, the inverse scheme of the finite difference method in conjunction with the Least squares scheme and experimental measured temperatures is applied to determine the present results. Results show that and in nature convection increase with increasing the tube pitch and fin spacing S. However, and in force convection increase with increasing the , S and air velocity, under both conditions, Due to the increasing tube pitch caused by the increased amplitude becomes smaller with increasing distance between tube. So present study shows the larger tube pitch the better heat dissipation we have. Other findings are that the average heat transfer coefficients in the upstream and wake fin regions of the 2nd row may be generally lower than these on other sub-fin regions, so we use the outlet fan to improve this problem. In order to validate the accuracy and reliability of the present results, the values are compared with those obtained from the existing correlations or computational fluid dynamics commercial code. Besides, the present study also applies the commercial software, Fluent, in conjunction with the present experimental data to obtain the inter-fin flow field of the plate finned-tube heat exchanger and temperature measurements at various measurement locations of the fin.
| Identifer | oai:union.ndltd.org:TW/101NCKU5490044 |
| Date | January 2013 |
| Creators | Chih-HanLu, 呂致翰 |
| Contributors | Han-Taw Chen, 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 | 100 |
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