http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 장승일(Seong-Il Jang) (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
장승일(Seong-Il Jang),최선묵(Sun-Muk Choi),김대희(Dae-Hui Kim),오후규(Hoo-kyu Oh) 한국마린엔지니어링학회 2005 한국마린엔지니어링학회 학술대회 논문집 Vol.2005 No.-
The experiments were conducted without oil in a closed refrigerant loop which was driven by a magnetic gear pump. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and evaporator(test section). The test section was made of a horizontal stainless steel tube with the inner diameter of 4.57 ㎜, and length of 4 m. The experiments were conducted at mass flux of 200 to 700 ㎏/㎡s, saturation temperature of 0℃ to 20℃, and heat flux of 10 to 30 ㎾/㎡. The test results showed the evaporation heat transfer of CO₂ has great effect on more nucleate boiling than convective boiling. The evaporation heat transfer coefficients of CO₂ are highly dependent on the vapor quality, heat flux and saturation temperature. In comparison with test results and existing correlations, correlations failed to predict the evaporation heat transfer coefficient of CO₂, therefore, it is necessary to develop reliable and accurate predictions determining the evaporation heat transfer coefficient of CO₂ in a horizontal tube.
-
이산화탄소용 열펌프시스템의 성능특성에 관한 실험적 연구
장승일(Seong-Il Jang),전민주(Min-Ju Jeon),유태근(Tae-Guen Yu),손창효(Chang-hyo Son),오후규(Hookyu-Oh) 한국마린엔지니어링학회 2006 한국마린엔지니어링학회 학술대회 논문집 Vol.2006 No.-
냉매 충전량과 이차유체의 입구조건은 CO₂용 열펌프시스템의 성능실험에서 중요한 제어변수이다. 따라서, 열펌프사이클의 적용과 난방성능 향상을 위해 제어변수의 특성을 조사하는 것이 필요하다. 본 논문에서, CO₂용 열펌프 사이클의 성능 실험은 여러 가지 냉매 충전량에서 이차유체 입구조건에 변화를 주어 수행 되었다. 실험결과, 난방COP는 냉매 충전량이 증가함에 따라 1158g의 냉매 충전량에서 최대가 되었다가 감소하는 경향이 나타나며, 이는 COP,가 최대가 되는 냉매충전량이 존재함을 나타낸다. 또한, 난방성능은 가스쿨러내 이차유체의 질량유량의 증가에 따라 증가하였다. 가스냉각기내 2차유체의 입구온도가 10℃에서 40℃로 증가하면, 난방용량, 압축일량, 토출압력은 각각 -8.57%, -35.78%, 32.78%로 변화했으며, 증발기 2차유체의 입구 온도가 감소하였을 때 난방 COP는 감소하는 경향을 보였다.
-
경사진 헬리컬 코일 열교환기의 열전달 특성에 관한 연구
손창효,전민주,장승일,오후규,Son, Chang-Hyo,Jeon, Min-Ju,Jang, Seong-Il,Oh, Hoo-Kyu 한국마린엔지니어링학회 2007 한국마린엔지니어링학회지 Vol.31 No.6
The heat transfer coefficient and Pressure drop during gas cooling process of $CO_2$ (R-744) in inclined helical coil copper tubes were investigated experimentally. The main components of the refrigerant loop are a receiver. a variable-speed pump. a mass flow meter, a pre-heater and a inclined helical coil type gas cooler (test section). The test section consists of a smooth copper tube of 2.45mm inner diameter. The refrigerant mass fluxes were varied from 200 to $600[kg/m^2s]$ and the inlet Pressures of gas cooler were 7.5 to 10.0 [MPa]. The heat transfer coefficients of $CO_2$ in the inclined helical coil tubes increases with the increase of mass flux and gas cooling pressure of $CO_2$. The pressure drop of $CO_2$ in the gas cooler shows a relatively good agreement with those Predicted by Ito's correlation developed for single-phase in a helical coil tube. The local heat transfer coefficient of $CO_2$ agrees well with the correlation by Pitla et al. However, at the region near pseudo-critical temperature. the experiments indicate higher values than the Pitla et al. correlation. Therefore. various experiments in the inclined helical coil tubes have to be conducted and it is necessary to develop the reliable and accurate prediction determining the heat transfer and pressure drop of $CO_2$ in the inclined helical coil tubes.
-
냉매 충전량에 따른 CO<sub>2</sub>용 수냉식 열펌프의 성능 특성에 관한 연구
손창효,유태근,장승일,오후규,Son, Chang-Hyo,Yu, Tae-Guen,Jang, Seong-Il,Oh, Hoo-Kyu 한국마린엔지니어링학회 2007 한국마린엔지니어링학회지 Vol.31 No.5
The performance characteristics of water-chilling heat pump using $CO_2$ with respect to variation of refrigerant charge amount was investigated experimentally. An experimental apparatus is consisted of a compressor, a gas cooler, an expansion valve, an evaporator and a liquid receiver. All heat exchangers used in the test rig are counter-flow-type heat exchangers with concentric dual tubes, which are made of copper. The gas cooler and the evaporator consist of 6 and 4 straight sections respectively arranged in parallel, each has 2400 mm length. The experimental results summarize as the followings : As the refrigerant charge ratio of $CO_2$ heat pump system increases, the discharge pressure and compressor ratio increases, but mass flow rate of refrigerant decreases. Also the compressor work increases with the increase of refrigerant charge ratio. However, the heating and cooling capacity of $CO_2$ heat pump decreases as the refrigerant charge ratio increases. The maximum heating COP of $CO_2$ heat pump system presented at 0.25 refrigerant charge ratio. It is possible to confirm the optimum charge ratio of $CO_2$ heat pump system by the viewpoint of heating COP.
ScienceON연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
