碩士 / 逢甲大學 / 機械工程學所 / 96 / The inverse heat transfer method was adopted in this research to study the optimal three-dimensional fin shape profile of a finned-tube heat exchanger. A modified conjugate gradient method was developed in this research, the method could succeed in obtaining the optimal three-dimensional fin shape profile. The effects of different fin materials and flow velocities were studied with dimensional form;and the effects of different Biot number distributions were also studied with dimensionless form in this research. It is observed by the numerical results that the fin thickness of the optimal fin shape varies with the position on the fin; and the top view profile of the optimal fin shape is not a circularity. It has a sharp fin thickness gradient in the radius direction and in the angle direction on the rear part of the circular tube as well. Regarding the effects of fin materials, the optimal steel fin shape has notch area on the rear part of the circular tube and extended fin surface area on the both sides of the circular tube; but this phenomenon is not observed for aluminum or cooper fins. The fin thickness gradient for the steel fin is the greatest; and which is the least for the cooper fin.The cooper fin has the largest surface area of the optimal fin shape ;and the area for the steel fin is the smallest among the three materials. Regarding the effect of the flow velocity, it is observed that the fin thickness gradient increases and the fin surface area decreases as the flow velocity increases. Especially for steel fin,it has distinct notch area on the rear part of the circular tube, and extended fin surface area on the both sides of the circular tube for higher flow velocity. No matter how Biot number is distributed, the optimal fin thickness is the thickest at the tube surface, thickness decrease gradually along radius direction. As the Biot number increases, the optimal fin thickness at tube increases, the fin thickness gradient is much greater.
| Identifer | oai:union.ndltd.org:TW/096FCU05489002 |
| Date | January 2008 |
| Creators | Chun-Jen Wang, 王俊仁 |
| Contributors | Wen-Jeng Chang, 張文政 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 97 |
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