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히트펌프 증발기의 착상 예측을 위한 핀-관 모델에서의 국부 서리 물성치와 서리성장에 관한 연구
곽동근(Dongkwen Kwak),이윤석(Yoonsuk Lee),조금남(Keumnam Cho),하야세 가쿠(Gaku Hayase) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5
The present study measured the frost characteristics on an array of fin-tube under the heat pump condition. The key parameters were air temperature from 2 to 7℃, absolute humidity of air from 2.98 to 3.92g/㎏DA, air velocity from 1 to 2m/s, and cooling surface temperature from -5 to -15℃. The coolant was 50% ethylene-glycol aqueous solution. Frost surface temperature was decreased and frost thickness was increased near the tube side of the fin-tube arrangement. Frost temperature profiles on the fin side were fully scanned. Heat transfer rate was increased up to 30 minutes and the decreased as the frost thickness was thickened as time passes.
곽동근(Dongkwen Kwak),김승연(Seungyoun Kim),조금남(Keumnam Cho),하야세 가쿠(Gaku Hayase) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
The present study investigated frost characteristics of fin-tube evaporator with multiple fins for the heat pump. Number of fin was ranged from one to five. Key test conditions were air temperature of 2℃, absolute humidity of air of 3.7g/㎏DA, air velocity of 0.5㎧, and surface temperature of the refrigerant of -10℃. The coolant was 50% ethylene-glycol aqueous solution. Local and average frost thicknesses were measured around the fin of the fin-tube. They were compared with the values predicted by the correlations obtained as the function of frost temperature for the flat plate and circular tube. Average frost mass was gradually increased as the number of fin increased even though frost characteristics for the case with multiple fin showed similar trend with the case with single fin through the test period. Similar frost pattern was observed at different gap between adjacent fins. The effect of number of fins on the frost characteristics was analyzed.
히트펌프 증발기의 착상 예측을 위한 핀-관 모델에서의 서리 물성치 예측
곽동근(Dongkwen Kwak),조금남(Keumnam Cho) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
The present study measured the frost characteristics on the adjacent fins of scale-up fin-tube model, and proposed experimental correlations under the heat pump condition. The key parameters were air temperature from 2 to 7℃, absolute humidity of air from 3.17 to 4.01 g/kgDA, air velocity from 0.5 to 2.5m/s, and cooling surface temperature from -5 to -15℃. The coolant was 50% ethylene-glycol aqueous solution. The fin-tube model has the tube diameter of 22mm and fin size 36 ? 60 mm. Frost surface temperature was decreased and frost thickness was increased near the tube side of the fin-tube arrangement. Frost temperature profiles on the fin side were fully scanned. And the correlations of local frost thickness and frost surface temperature were proposed as functions of the Reynolds number, Fourier number, absolute humidity, dimensionless temperature and measurement position. They agreed within 11%.