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평관형 및 나선 그루브형 열사이폰의 응축열전달 성능 향상에 관한 연구
박종운(J. U. Park),한규일(K. I. Han),조동현(D. H. Cho) 한국동력기계공학회 2005 한국동력기계공학회 학술대회 논문집 Vol.- No.-
This study concerns the performance of condensation heat transfer in plain and grooved thermosyphons. Distilled water, methanol, ethanol have been used as the working fluids. In the present work, a copper tube of the length of 1200㎜ and 14.28㎜ of inside diameter is used as the container of the thermosyphon. Each of the evaporator and the condenser section has a length of 550㎜, while the remaining part of the thermosyphon tube is adiabatic section. A study was carried out with the characteristics of heat transfer of the thermosyphon 50, 60, 70, 80, 90 helical grooves in which boiling and condensation occur. The liquid filling as the ratio of working fluid volume to total volume of thermosyphon, the kinds of working fluid, the inclination angle, grooves and operating temperature have been used as the experimental parameters. The experimental results show that the number of grooves, the amount of the working fluid, the kind of working fluid, angle of inclination angle are very important factors for the operation of thermosyphon. The maximum heat transfer was obtained when the liquid fill was about 20 to 25% of the thermosyphon volume. The relatively high rates of heat transfer have been achieved in the thermosyphon with grooves. The helical grooved thermosyphon having 70 to 80 grooves in water, 60 to 70 grooves in methanol and 70 to 80 grooves in ethanol shows the best heat transfer coefficient in both condensation.
고열유속 전자장치에서의 비등열전달 향상을 위한 마이크로 핀 제작
임태우(T. W. Lim),유삼상(S. S. You),정석권(S. K. Jeong),박종운(J. U. Park),김준효(J. H. Kim) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-
Microengineering using MEMS refers to the technologies and practice of making three dimensional structures and devices with dimensions in the order of micrometers. Eight kinds of micro fins with the dimensions of 50×60, 50×150, 100×200, 100×250, 100×300, 150×375. 200×500, 200×600 ㎛² (thickness×pitch) were fabricated on the surface of a square silicon chip with the dimensions of 20×20×0.5 ㎣ by using the wet etching technique. In cooling small devices generating high heat flux and ultra high heat flux, micro fin and micro channel heat sinks are considered an effective method. We investigate the processes fabricating micro fin which can cool the large amount of heat generated from high density devices.
평관형 및 나선 그루브형 열사이폰 내부 작동유체의 포화온도와 단열부의 표면온도에 관한 연구
한규일(K. I. Han),조동현(D. H. Cho),박종운(J. U. Park),이상진(S. J. Lee) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4
This study is focused on the comparison between the internal saturation temperature of the working fluid and the surface temperature of adiabatic zone of two-phase closed thermosyphons with various helical grooves. Distilled water, methanol and ethanol have been used as the working fluid. In the present work, a copper tube of the length of 1200㎜ and 14.28㎜ of inside diameter is used as the container of the thermosyphon.. Each of the evaporator and the condenser section has a length of 550㎜, while the remaining part of the thermosyphon tube is adiabatic section. A experimental study was carried out for analyzing the performances of having 50, 60, 70, 80, 90 helical grooves. A plain thermosyphon having the same inner and outer diameter as the grooved thermosyphons is also tested for the comparison. The results show that the numbers of grooves and the type of working fluids are very important factors for the operation of thermosyphons. A good agreement between the internal saturation temperature of working fluid and the surface temperature of adiabatic zone of two-phase closed thermosyphons with various helical grooves is obtained.
나선 그루브형 열사이폰의 작동유체의 변화에 대한 응축열전달 성능에 관한 연구
한규일(K.I.Han),조동혁(D.H.Cho),박종운(J.U. Park),이상진(S.J.Lee) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
This study concerns tile performance of condensing heat transfer in two-phase closed thenl1osyphons with various helical grooves. Distilled water, methanol, ethanol have been used as the working fluid. In the present work, a copper tube of the length of 1200mm and 14.28nml of inside diameter is lISed as the container of the thermosyphon. Each of the evaporator and the condenser section has a lengtl1 of 55Orrun, wltile the remaining part of the thelmosyphon tube is adiabatic section. A experimental study was canied out for analyzing tIle pe:1iormances of having 50, 50, 70, 80, 90 helical grooves. A plrtin thennosyphon having tile same inner and outer diameter as ilie grooved iliennosyphons is also tested for the comparison. The type of working fluid and the numbers of grooves of the tllennosyphons with vmious helical grooves have been used as the expelirnental parameters. The expelimental results have been assessed and cornpm'ed with existing theories. The results show tlmt tJle type of working fluids are very imporumt factors for tlle operation of tl1ennosyphons. And the maximum enhancement (i.e. the ratio of the heat transfer coefficients tJle helical tlu~nnosyphons to plain tl1ermosyphons) is 1.5- 2 for condensation.
단파를 이용한 Clonic Facial Spasm 치험 1예
도종웅,박종운,김상철,정상섭,이규창,이헌재 대한신경외과학회 1975 Journal of Korean neurosurgical society Vol.4 No.2
Clonic facial spasm had attracted for attention of neurosurgeons for a long time. However the optimal way of treatment is not established yet. In this report, we are describing a case of clonic facial spasm treated by making a lesion on the facial nerve at stylomastoid foramen with radiofrequency lesion generator which has been applied for percutaneous cordotmy or percutaneous gasserian ganglionotomy.