| Summary: | 碩士 === 國立高雄第一科技大學 === 機械與自動化工程研究所 === 100 === This study aims at improving the thermal efficiency of rotary kilns. Rotary kilns are often used for processing materials that need to be dried such as tobacco, sludge, ores, and food products. The size of the kilns depends on the amount and types of material need to be dried. The fuel includes natural gas, coal, and oil. In this time of global warming where energy efficiency and carbon reduction are popular issues, our study purpose is to enhance the heat transfer rate of devices that emit large amounts of carbon dioxide.
Our initial investigation indicated that this device had poor thermal efficiency that caused the loss of most heat energy. Hence, some baffles were added on lifts to retain more heat energy in drums, increase the possibility of turbulent flow in the hot gas stream, and improve heat transfer efficiency. We utilized computational fluid dynamics simulation software (FLUENT), to simulate temperature inside rotary kilns and flow field characteristics. Meanwhile, we investigated multiple factors including the dimension of the baffle, amount, and density of baffle arrangement. The Taguchi method was used to achieve optimal design.
The results showed that the two models for drums are able to improve heat transfer efficiency and reduce costs. The first structure maintains the original size of drum double heat transfer efficiency. The second structure maintains identical conditions for heat transfer efficiency, shortened 42% of the drum length.
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