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마이크로 진동형 히트 파이프 내 열역학적 상태에 관한 실험적 연구
전수환(Soohwan Jun),김성진(Sung Jin Kim) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
Experiments were performed to investigate thermodynamic states in micro pulsating heat pipes (MPHPs) in a horizontal orientation. The rectangular microchannel in the MPHPs with 10 and 15 turns was engraved on the silicon wafer with a thickness of 1 mm to form a closed-loop. The width and height of the channels were 1 mm and 0.5 mm, respectively. The pressure variations of vapor plugs were measured using the pressure transducers in the adiabatic section. Simultaneously, the temperature variations of vapor plugs and liquid slugs were obtained by micro-thermocouples. For the flow visualization, a Pyrex glass with a thickness of 0.7 mm was used as a cover. Ethanol was used as the working fluid. The MPHP with 10 turns exhibits a large-amplitude oscillation followed by a long-term stopover phenomenon repeatedly, while the MPHP with 15 turns shows a relatively stable oscillation with the large amplitude. In the stopover region, vapor plugs occupy the channels in the evaporator section, while liquid slugs occupy the channels in the condenser section. The amplitude is very small and the frequency is approximately 60 Hz. It results in a dryout in the evaporator section, and the vapor plugs are superheated. In addition, there exists very large temperature gradient in vapor plugs. On the other hand, in a stable operation region with the large amplitude, the two-phase mixture having a complex flow behavior oscillates from the evaporator to the condenser. During the large-amplitude oscillation, it is identified that vapor plugs are alternately saturated and locally superheated.
다양한 턴 수를 갖는 폐루프형 진동형 히트 파이프와 폐쇄형 진동형 히트 파이프에 관한 연구
전수환(Soohwan Jun),김성진(Sung Jin Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
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.
생명공학기술적 관점에서 질병중심 중개연구의 효율적 성과분석에 대한 실증연구
전수환(Su-Hwan Cheon),정성철(Sung-Chul Jung),제영태(Young-Tae Je),김기태(Gi-Tae Kim),김명환(Myung-Hwan Kim),박성호(Seong-Ho Park),전혜경(Hye-Kyoung Jeon),권준영(Jun-Young Kwon),김동일(Dong-Il Kim),김동석(Dong-Seok Kim),이경민(Kyung-M 한국생물공학회 2012 KSBB Journal Vol.27 No.1
Recently, translational research (TR) in health technology (HT) has been considered as an emerging alternative research system for the improvement of human health. TR from bench to bedside involves a strong bidirectional relationship between basic science discovery and clinical practice. To support R&D planning and policy in HT effectively, the performance of TR programs was analyzed and evaluated in a R&D project on health and medical technology. TR programs were classified into three parts: unilateral TR, bilateral TR and multilateral TR. Bibliometrics and citation analysis were performed to assess research papers and gather information for the performance analysis of TR programs. In addition, both quantitative and qualitative analysis were successfully carried out using ISI Web of Science, Google Scholar Citations, SCOPUS and Knowledgematrix. In conclusion, the performance analysis of TR programs could significantly improve the efficiency of R&D plans, R&D management and evaluation for a safe and healthy life.