| Summary: | 碩士 === 淡江大學 === 機械與機電工程學系碩士班 === 98 === This study aims to design and fabricate a visualization flat plat heat pipe, with 0.4mm, 0.7mm and 1.0mm thick sintered copper wick structure. Three different sintering thicknesses of wicks with a series of filling ratio of deionized water were tested at heat input of 20W, 40W and 60W. Through a high-speed camera, the experiment was conducted to observe the boiling phenomenon of the evaporator in heat pipe. Evaporation resistance was evaluated from the measured temperature to analyze the parameters impact on performance.
The experimental results showed that the flat plate heat pipe at the different heat input, with the different thicknesses of wicks and filling ratio, which would affect thermal performance of the module, such as temperature of heat source and evaporation resistance. At input power of 60W, the 0.4mm thick wick structure with 5% filling ratio has the lowest resistance of 0.119℃/W. Through visual observation, the liquid surface would descend when the heat flux increased, and the evaporation resistance could reach a minimum by increasing heat flux before drying out. We also found that the main reason for affecting the heat transfer mechanism is the height of working fluid inside the heat pipe. When the liquid surface is above the top of wicks, the mainly boiling mechanism is pool boiling with higher evaporation resistance, and a thin film boiling occurred with a lower resistance, when the surface is below the top of wicks.
|
|---|
