| Summary: | 碩士 === 遠東技術學院 === 機械研究所 === 93 === The numerical simulation is used to analyze the heat transfer and fluid flow characteristic of staggered fin-and-tube heat exchangers in this study. The circular tubes and elliptic tubes are adopted to be the heat transfer tube, combined with the wavy-types vortex generators, which are used to enhance the heat transfer rate of the heat exchangers. The results show that the circular tube heat exchangers with wavy type vortex generator has the best performances than that of others, which increase the heat transfer rate about 24% higher than that of plate heat exchanger, but the penalty is the pressure drop also increase 34%, the average area reduction is 18%. The performances of the elliptic tube heat exchanger with vortex generator increased average 16% heat transfer rate, and decreased 20% ~ 40% pressure drop, which indicated 16.8% area reduction. The winglet type of vortex generators used in elliptic tube exhibit the best performances of area reduction rate at higher velocity applications.
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