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확대 모델을 이용한 루버 휜의 국부 열전달 특성변화에 관한 연구
김정국(Jungkuk Kim),小山繁(Shigeru Koyama),桑原憲(Ken Kuwahara),박병덕(Byung-Duck Park),김동휘(Dong-Hwi Kim),사용철(Yong-Cheol Sa) 대한설비공학회 2008 대한설비공학회 학술발표대회논문집 Vol.2008 No.2
The present study was investigated the local heat transfer characteristics and temperature distribution on the louver fin by using the expansion model. Heat transfer rate, frost mass and temperature distribution of the louver fin under frosting condition were experimentally investigated. Local heat transfer rate and heat flux on the louver were analyzed by the conduction heat transfer between top and lower part of the louver. The experimental key parameter was brine inlet temperature(-5, -10, -15℃). The heat transfer performance and frost mass at brine temperature of -15℃ were increased by maximum 3 time than the brine temperature of -5℃. At all experimental case, local heat transfer rate and heat flux of the louver were almost symmetry at the louver number of 6. Especially, local heat transfer rate and heat flux were maximum increased on the louver number of 4 and 8.
착상에 의한 휜관형 열교환기의 성능변화에 관한 실험적 연구
김정국(Jungkuk Kim),小山繁(Shigeru Koyama),桑原憲(Ken Kuwahara),박병덕(Byung-Duck Park),김동휘(Dong-Hwi Kim),사용철(Yang-Cheal Sa) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.2
The present study was investigates the effect of the parameters on the frost formation and heat transfer performance such as fin shape, air temperature and air velocity. Heat transfer rate and pressure drop by frost were experimentally investigated. Effect of the wet blub temperature and air velocity on the heat transfer performance has been also investigated. The heat transfer performance of the louver fin and tube type heat exchanger was higher by maximum of 0.85% than the corrugate fin type at the air temperature of 2.0/1.5℃. As the wet blub temperature of air were increased, the heat transfer rate, pressure drop and mass of frost of three test models were increased. Especially, the maximum heat transfer rate and maximum pressure drop were shown for the Type B louver fin heat exchanger. As an experimental result, the enhancement factor(EF) of louver fin and tube type heat exchanger was only 0.2 - 0.4 due to the high pressure drop.
김정국(Jung-Kuk Kim),桑原憲(Ken Kuwahara),小山繁(Shigeru Koyama),박병덕(Byung-Duck Park) 한국산업융합학회 2008 한국산업융합학회 논문집 Vol.11 No.4
The present study investigated the pressure drop and the total frost mass of the louvered fin type heat exchanger, which is widely used at the air-conditioning system. The pressure drop due to the frosting phenomenon and the total frost mass were investigated by changing the wet bulb temperature condition of the inlet air. Hence the brain of 55wt% was used as a cooling solution instead of a common refrigerant. The temperature difference between the brine and the tube outside wall at the outlet of heat exchanger was 10℃, at maximum, higher than that at the inlet of heat exchanger. As the wet bulb temperatures were increased, the pressure drop was linearly increased due to the increment of frost mass. And the increment of heat exchange rate was smaller than that of inlet air enthalpy due to the increment of frost mass. The pressure drop of air side was rapidly increased due to the progress of frosting phenomena. The run time that the pressure drop occurred rapidly was decreased by the growth of frost.