碩士 / 國立成功大學 / 系統及船舶機電工程學系碩博士班 / 97 / There are many physical values that can not be obtained through direct measurement or calculation in real engineering problems. However they can be estimated by using inverse design method based on measuring data. These problems are called inverse problems.
Inverse problems are also called optimum design problems. In many complex engineering problems this technique can be used to handle optimum design problems. In this thesis it is applied to forecast the optimum shapes of the fully wet fins.
In this study, a fully wet fin design problem is examined which means fin temperature distribution is lower than dew point temperature on the fin surface. Under this condition relative humidity of surrounding air, specific humidity of fully wet fin and dew point temperature become important in calculating the fin temperature. When the above three physical values are changed, latent heats of condensation of moisture are also changed and so is fin efficiency. Different fin volume and shape will result in different fin temperature distribution and different fin efficiency. The purpose of this work is to estimate the optimum shape of fin based on the desired fin volume and desired efficiency. The optimum shapes for the spine and longitudinal fully wet fins are estimated in the present inverse design problem by using the conjugate gradient method and finite different method based on the desired fin efficiency and fin volume.
In chapter two, the optimum shapes of the spine and longitudinal fully wet fins are estimated by using the conjugate gradient method as the thermal conductivity and Biot number are both assumed constants. The fin temperature distribution and fin efficiency by numerical method are compared with analytical solution to proof the accuracy of the present numerical solution. The optimum shape and efficiency are estimated by varying relative humidity of surrounding air, the fin desired volume, and Biot number.
In many complex engineering problems the thermal conductivity and Biot number are function of temperature, for this reason it is assumed that they are function of temperature in chapter 3 and the inverse problem becomes nonlinear. In this chapter we examine the effects of the temperature dependent Biot number and thermal conductivity on the final optimum fin shape.
| Identifer | oai:union.ndltd.org:TW/097NCKU5345007 |
| Date | January 2009 |
| Creators | Yun-lung Chung, 鍾昀龍 |
| Contributors | Cheng-hung Huang, 黃正弘 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 157 |
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