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히트파이프를 삽입한 수소저장물질의 열전달 특성에 관한 수치해석적 연구
박영학(Young Hark Park),부준홍(Joon Hong Boo) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
A numerical analysis was conducted to predict the effect of inserted heat pipes on the heat transfer characteristics of metal hydride(MH), which inherently has extremely low thermal conductivity. In order to increase the effective conductivity of MH material the most efficient insert configuration is to be identified. Less than two hours of transient time is of concern when decreasing or increasing the temperature for absorption and discharge of hydrogen gas. Commercial softwares were employed to predict the transient as well as steady-state temperature distribution of the MH material with inserted heat transfer enhancing tube or heat pipes. The numerical results were compared and analyzed from the view point of temperature uniformity and transient period.
상변화 물질을 조합한 히트파이프의 성능 특성에 관한 연구
박영학(Young Hark Park),정의국(Eui Guk Jung),부준홍(Joon Hong Boo) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
This study deals with performance characteristics of heat pipe combined with a solid-liquid phase change material(PCM). The outer diameter of the heat pipe was 9.5 ㎜ and the total length was 600 ㎜, where the evaporator, the adiabatic section and the condenser lengths were equally 200 ㎜. A paraffin wax having a melting point of 58.5℃ was used as PCM. The paraffin container was attached to the adiabatic section of the heat pipe. The paraffin container had outer diameter of 18 ㎜, wall thickness of 1.2 ㎜ and the total length of 100 ㎜. The heat pipe was tested with tilt angle of horizontal degree and favorite angle 10 degree, with evaporator lower position to provide stable operation of the heat pipe. Input thermal load was varied from 40 W, with increment of 40 W, to above 100 W until the maximum temperature of the heat pipe wall reached 200℃. Test results of the PCM heat pipe were presented in comparison with conventional heat pipe of the same basic dimensions. The performance was analyzed in terms of temperature distribution, thermal resistance and heat transport capability.
내부에 히트파이프를 삽입한 메탈 하이드라이드 반응기의 열전달 특성에 대한 수치해석 연구
박영학(Young Hark Park),부준홍(Joon Hong Boo) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
This study deals with heat pipes inserted into the metal hydride(MH) reactor to increase the effective thermal conductivity of the system and thus to enhance the thermal control characteristics. A numerical analysis was conducted to predict the effect of inserted heat pipes on the heat transfer characteristics of MH, which inherently has extremely low thermal conductivity. The numerical model was a cylindrical container of O.D. 76.3 ㎜ and length 1 m, which is partially filled with about 60% of MH material. The heat pipe was made of copper-water combination, which is suitable for operation temperature range between 10℃ and 80℃. Both inner -and outer- heat pipes were considered in the model. Less than two hours of transient time is of concern when decreasing or increasing the temperature for absorption and discharge of hydrogen gas. FLUENT, a commercial software, was employed to predict the transient as well as steady-state temperature distribution of the MH reactor system. The numerical results were compared and analyzed from the view point of temperature uniformity and transient time up to the specified maximum or minimum temperatures.
고온 히트파이프식 태양열 흡수기의 내부형상 변화에 따른 열전달 특성의 수치해석
박영학(Park, Young-Hark),부준홍(Boo, Joon-Hong),강용혁(Kang, Yong-Heack) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.05
A numerical analysis was conducted to predict the heat transfer characteristics of a solar receiver which is subject to very high heat fluxes and temperatures for solar thermal applications. The concentration ratio of the solar receiver ranges 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with a solar receiver according to internal geometry variation incorporating high-temperature heat pipe. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm and the angle of receiver end wall set 90?,;60?,;45?,;30?. And the diameter of the heat pipe was 12.7 mm, 48 axial channels of the same dimensions were attached to the outer wall of the receiver with even spacing in the circumferential direction. The channels are changed to high-temperature sodium heat pipes. Commercial softwares were employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels. The numerical results are compared and analyzed from the view point of high-temperature solar receiver.
고온 히트파이프를 사용한 태양열 흡수기의 열전달 특성에 관한 수치해석적 연구
박영학(Young Hark Park),정의국(Eui Guk Jung),부준홍(Joon Hong Boo) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
A numerical analysis was conducted to predict the heat transfer characteristics of a solar receiver which is subject to very high heat fluxes and temperatures for solar thermal applications. The concentration ratio of the solar receiver ranges from 200 to 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with a solar receiver incorporating high-temperature sodium heat pipe as well as a typical one that employs a molten-salt circulation loop. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 ㎜ and the length was 400 ㎜. For the molten-salt circulation type receiver, 48 axial channels of the same dimensions were attached to the outer wall of the receiver with even spacing in the circumferential direction. The molten salt are fed through the channels by forced convection using a special pump. For the heat pipe receiver, the channels are changed to high-temperature sodium heat pipes. Commercial softwares were employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels. The numerical results are compared and analyzed from the view point of high-temperature solar receiver.