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박동호(DongHo Park),서응렬(Eung Ryeol Seo),박용종(YongJong Park) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
A numerical study on the heat transfer enhancement and pressure drop has been performed. Results are presented as plots of heat flux, pressure drop, j-factor and f-factor. CFD analysis has been carried out on conventional fin type as a reference case to derive the parameters for heat transfer enhancement. The basic concept for the heat transfer enhancement has been focused on the hybrid type of slit and louver combined. Out of the studied cases, best case has been selected for further DOE study with parameter of slit shape. CFD results show agreement with experimental data with 7.5% of error. Using the result of the study, the fin pitch has been increased from 1.5mm to 1.7mm resulting in cost saving in heat exchanger for same performance.
노즐 각도에 따른 충돌 유동의 난류 에너지 및 열전달 분석
모도윤(Do Yoon Moh),장동규(Dong Kyu Jang),서응렬(Eung Ryeol Seo),권명근(Myoung Keun Kwon),이상진(Sang Jin Lee),이정학(Jung Hak Lee),고한서(Han Seo Ko) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
Generation of turbulent kinetic energy and application of heat transfer by impinging flow according to nozzle angle inside a sealed space were analyzed in this study. Flow pattern and thermal efficiency caused by the impinging flow from the nozzle were investigated. The turbulent kinetic energy was observed by reconstructing the velocity field using a PIV (Particle Image Velocimetry) visualization technique. Simultaneously, numerical simulation was also performed so as to verify the results with those of the PIV experiment. The turbulent modeling which described the flow characteristics was established by the developed numerical program. Then, the correlation between Reynolds number and Nusselt number was derived to express the thermal flow mechanism. It was confirmed that this study could be applied for an oven with the forced convection, and the thermal efficiency of 15 % was enhanced.
가정용 냉장고의 도어 개폐 시 외부 고온/고습 공기의 유입에 대한 실험적 연구
허광수(Kwang Su Heo),이상진(Sang Jin Lee),김현주(Hyun Joo Kim),서응렬(Eung Ryeol Seo) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
The purpose of this study is to establish quantitatively the influence of intake air flow with high temperature and high humidity during door opening process. The humidity inflow of freezer compartment is increased by relatively high humidity air from outside of refrigerator and is decreased and eventually stabilized while the intake humidity is turned as frost mainly on the surface of evaporator and secondly on the surface of interior parts. In this study the temperature and humidity variation have been measured with the parameters such as internal setting temperature and outside temperature. The humidity has been measured for the air passing through the evaporator as a reference without door opening. As a measurement result, external air inflow is affected by the temperature difference between inside and outside and moisture inflow is dominantly influenced by dew point difference. Inflow rate of external air is increased in proportion to the temperature difference and humidity inflow rate is inversely proportional to the dew point difference. The humidity changes in the evaporator, is not related to the inlet air and evaporator temperature. The relative humidity of evaporator outlet only affects the relative humidity of the inlet air.