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설원실,권오경,문춘근,윤정인,Seol, Won-Sil,Kwon, Oh-Kyung,Moon, Choon-Geun,Yoon, Jung-In 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.8
This research was concerned with the enhancement of heat transfer by surfactant added to the aqueous solution of LiBr. Different horizontal tubes were tested with and without an additive of normal octyl alcohol. The test tubes were a bare tube, floral tube and hydrophilic tube. The additive mass concentration was about 0.05${\sim}$5.5%. The heat transfer coefficient was measured as a function of solution flow rate for the range of 0.01${\sim}$0.034 kg/ms. The experimental results were compared with cases without surfactant. The enhancement of heat transfer by Marangoni convection effect generated by the addition of the surfactant is observed in each test tube. The increase of heat transfer coefficient by surfactant addition is about 35${\sim}$90% for bare tube, 40${\sim}$70% for the floral tube, 30${\sim}$50% for the hydrophilic tube and was higher for the cases with smaller a little solution flow rates.
이중관형 열교환기의 증발 열전달 특성에 관한 실험적 연구
이권재(Kwon Jae Lee),권오경(Oh Kyeong Kwon),김용찬(Yong Chan Kim),설원실(Won Sil Seol) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
An experimental investigation was carried out to examine the evaporative heat transfer characteristics in the double pipe heat exchanger using R-410a. The double pipe heat exchanger was helical coil type. The inner tube of double pipe heat exchanger was two types, spiral and circle. The experimental runs were carried out at a saturation temperature of refrigerant ranging between 5℃ and 15℃, and mass fluxes are 103.3~258.2 ㎏/㎡s. The inlet temperature of the water in the test section were 9℃, 12℃, 19℃ and 22℃. Heat transfer coefficient of refrigerant side of spiral type and circle type were 3.36~4.66 ㎾/㎡℃ and 2.64~3.86 ㎾/㎡℃. The pressure drop of refrigerant side for circle type was higher than that of spiral type at same mass flux. The effectiveness of spiral type and circle type were 0.34~0.66 and 0.19~0.57.
유체의 유입위치와 회전길이에 따른 이중관 열교환기의 유동특성
차동안(Dong An Cha),이승하(Seung Ha Lee),권오경(Oh Kyung Kwon),설원실(Won Sil Seol) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
The length and position of the inlet port on the double tube heat exchanger is analyzed by CFX ver.11 for studying the characteristic of its flow uniformity. When the boundary conditions of the inlet temperature and mass flow rate were each 20 ℃ and 10 ~ 50 ㎏/min, 3 models that are based on the distance between the inlet port and the center of the heat exchanger(0, 5.025, 10.05 ㎜) were analyzed to find the uniformity of the flow rate. Based on the flow rate, 4 rotating lengths (23.723, 33.890, 44.057, 57.274 ㎜) were used to study the flow distribution according to Reynolds Number. The results show that, when the distance from the inlet to the position of the center of the heat exchanger is 10.05 ㎜ and the rotating length is 57.274 ㎜, the flow uniformity is the most unified.
세라믹 볼을 이용한 판형열교환기 세정에 관한 실험적 연구
차동안(Dong-An Cha),권오경(Oh-Kyung Kwon),채희만(Hee-Man Chae),권정태(Jeong-Tae Kwon),설원실(Won-Sil Seol) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
To maintain efficiency of heat exchanger, fouling of heat transfer surface is important to remove. This study was to investigate cleaning result of plate heat exchanger using ceramic ball. The fouling is created in heat transfer surface of plate heat exchanger using CaCO₃ as the fouling subject. The fouling concentration varied from 10 mol/m³ to 20 mol/m³. The overall heat transfer coefficient recovered 97.9% for 10mol/m³ case, and 94.3% for 20 mol/m³ case in comparison with initial state. It can be concluded that the cleaning of ceramic ball contribute significantly to the of performance recovery for overall heat transfer coefficient and fouling resistance after cleaning experiment.