| Summary: | 碩士 === 國立清華大學 === 動力機械工程學系 === 93 === Pulsating heat pipe (PHP) is a newly developed two-phase-flow heat transfer device, which can transfer heat very efficiently in both sensible and latent forms. Due to the simple structure and the bent characteristics, PHP becomes a prosperous heat transfer machine. The purpose of this study is to build several closed-loop PHPs made by copper tube (outer diameter 1/8”, inner diameter 2mm) or glass tube (outer diameter 3mm, inner diameter 2mm), which is partially filled with a working fluid such as water. Based on the above developed PHP, the experiments were conducted as follows: (1) to observe visualization of flow pattern inside the PHP tube, (2) to measure the thermal transport performance of PHPs, and (3) to compare the performance of PHP and traditional heat pipe (THP). The experimental results show that (1) the type of flow pattern inside the PHP tube depends on the input heat loading. It was found that the flow pattern changes from the oscillating to transiting and then to stable period with increasing input heat loading; (2) the thermal resistance of PHP decreases with increasing heat loading. In addition, when the filling ratio is equal to 30%, it reaches the best heat transfer efficiency. When the angle of inclination changes, main parameter that effects efficiency of PHP, will be different; and (3) in case that both heat loading and area of heat transfer surface are equal, PHP may have the better heat transfer efficiency than THP at the vertical operating condition.
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