碩士 / 雲林科技大學 / 機械工程系碩士班 / 97 / The thesis to discussed the heat transfer performance and pressure drop of compact heat exchangers in forced convection flow. In the previous investigations, when the fin pitch of heat sink with vortex generator was 1mm, the performance of heat transfer and pressure drop was not improved because the vortex generator was unable to result eddy flow. As the fin surface had fully distributed with dimples, its performance was degraded. However, after reduced quantity of dimple and rearrangesd the position of dimples, the performance of heat transfer and pressure drop was better than before. Therefore, the purpose of this study is to optimize the number of dimples and their positions on the fin for better performance. Firstly, a EFD software (Engineering Fluid Dynamics) is utilized to simulate the pressure drop and the temperature distribution for fins with the variation of dimple number and location for comparing their performance. From the simulated results, the best performance is selected for making test samples with the same dimple number and declined angle but with different gap. The test results of the three samples with the data generated from other fins with different arrangement of dimples are compared with the EFD predictions. The performance of fins is measured by the pressure differential instrumentation and thermal couples. Also, an infrared rays camera is used to take temperature distribution images on fins for analyzing the heat transfer performance for each fin.
The results indicates that pressure drop for the selected oblique dimple fin is similar to the plate fin. Using the VG-1 and FG-3 principles for thermal evaluation, the oblique dimple fin with the 6 -12 mm gap can reduce 9~13 % heat transfer area and 17.5~20 %, respectively, as compared to the plate fin at wind speed about 3~5 m/s.
| Identifer | oai:union.ndltd.org:TW/097YUNT5489007 |
| Date | January 2009 |
| Creators | Kuo-Liang Wun, 溫國良 |
| Contributors | none, 陳英洋 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 91 |
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