다양한 턴 수를 갖는 폐루프형 진동형 히트 파이프와 폐쇄형 진동형 히트 파이프에 관한 연구

Closed-loop micro pulsating heat pipes (CLMPHPs) and closed-end micro pulsating heat pipes (CEMPHPs) were compared experimentally to determine which type of a MPHP performs better. The MPHPs have a meandering rectangular channel, and the width and height of the channel are 1mm and 0.5 mm, respectively. For flow visualization in MPHPs, the Pyrex glass was used as a cover. Ethanol was used as a working fluid, and filling ratio of the working fluid was fixed at 50%. A series of experiments were performed at various input powers and inclination angles for the MPHPs with 5, 10, 15, and 20 turns. Experimental results show that the CLMPHP requires as many as 20 turns for an orientation-independent performance while only 10 turns is enough for the CEMPHP to have orientation-independent performance. The CEMPHP has higher effective thermal conductivity up to 1.3 times in a vertical mode and 2.5 times in a horizontal mode than the CLMPHP. Finally, it is recommended to use the CEMPHP which has more than 10 turns for an orientation-independent performance.