| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 103 === The present study applies the inverse method and computational fluid dynamics commercial software in conjunction with the experimental method to predict the heat transfer and fluid flow characteristics of plate-finned tube heat exchangers. The effects of parameters such as air velocity, fin spacing and tube diameter are examined. Due to the heat transfer coefficient on the fin is non uniform, the fin is divided into several sub-regions. Later, the inverse method applies finite difference method in conjunction with the least-squares scheme and the experimental data to estimate the heat transfer coefficient on the fins. More accurate results can be obtained if the heat transfer coefficient is close to the inverse results and matches the existing correlations. The results obtained using the RNG k-ε turbulence flow model for the tube diameter being 27 mm and the laminar model for the tube diameter being 2 mm is more accurate. It means the importance of flow model is negligible, and the number of grid points may also need to change with the air velocity. Therefore, the present study applies different flow models with appropriate grid points to obtain the fin temperature, heat transfer coefficient, air velocity and pressure distribution. Furthermore, the heat transfer coefficient, friction factor and the pressure drop of the big tube diameter is larger than the small tube diameter. The increases friction factor is about 153％ to 277％.
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