| Summary: | 碩士 === 聖約翰科技大學 === 自動化及機電整合研究所 === 100 === An effective heat pipe will be affected by its length, the sort of the working fluid, and the capillary structure. In this dissertation, silver nano-fluid (5ppm, 30ppm and 50ppm) and DI water were separately filled in different length heat pipes which diameter is 6 mm. And then, to observe differences of performance that different working fluid in three lengths of the heat pipe (180mm, 200mm, and 220mm). Besides, the effects of different angles on heat pipe are conducted the same diameter and silver nanoparticles（30nm） but different concentration. To measure efficiency of grooved heat pipe, sintering heat pipe and composite heat pipe that set in different conditions including different inclined angles, operating power and concentration of working fluid filling through the experiment. Finally, with the measurement of thermal resistance, I finished the benefit analysis of heat pipe.
To compare the difference that groove, sintering and composite wick structure in different conditions, the result of experiment shows the best concentration of silver nano-fluid that is 5ppm to compare DI water and silver nano-fluid. In grooved heat pipe with every kind of fluid and concentration, dry out happens when its inclined angle is up to 10° or more; in sintering heat pipe, it can withstand over 60°inclined angle, so that is larger than grooved heat pipe; in composite heat pipe, its maximum of heat conducting value will vary with its length. When length is 180mm, the transmission efficiency of every working medium is about 60W; when length is 200mm, the transmission efficiency of every working medium is about 50W; when length is 220mm, the transmission efficiency of every working medium is about 40W. In the end, whether the working fluid is DI water or nano-fluid, the best transmission efficiency of heat pipe all occurs at the positive inclined angle 75° of groove, sintering and composite wick structure.
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