CO₂-Hydrate와 CO₂ 가스 혼합물의 전달물성과 관내측 열전달계수 및 압력강하 예측

윤린,Yun, Rin 대한설비공학회 2013 설비공학 논문집 Vol.25 No.5

The Thermophysical properties of thermal conductivity, viscosity, and heat capacity for $CO_2$ slurry ($CO_2$ gas and $CO_2$-hydrate mixture) having a high gas phase volume fraction were predicted using the conventional mixture models and the TRAPP model under hydrate formation conditions. Based on the calculated thermophysical properties, the heat transfer coefficient and pressure drop of the $CO_2$ slurry in the tube were predicted. The thermal conductivity of $CO_2$ slurry ranged from 0.02 to 0.2 W/m-K, and the mixture viscosity was larger than that of pure $CO_2$ by 1.9~2.7 times. The heat capacity of $CO_2$ slurry ranged from 63 to 68% of that for pure $CO_2$. The predicted heat transfer coefficient of $CO_2$ slurry was 6 times higher than that of pure $CO_2$. In the separate model, the estimated pressure drop increased with an increase of $CO_2$-hydrate mole fraction, and was 60% of that of pure $CO_2$.

마이크로채널과 핀 튜브 열교환기를 적용한 가정용 에어컨디셔너의 성능 평가

윤린 대한설비공학회 2007 설비공학 논문집 Vol.19 No.1

In this study the seasonal performance of a residential air conditioning system having either a fin-and-tube condenser or a microchannel condenser is experimentally investigated. A commercially available 7kW capacity residential air conditioning system having a fin-and-tube condenser served as the base system. The test results show that the system with a microchannel heat exchanger has a reduced refrigerant charge amount of 10%, the coefficient of performance is increased by 6% to 10%, and the SEER is increased by 7% as compared with those of the base system. Moreover, the condensing pressure of the system is decreased by 100kPa and the pressure drop across the condenser is decreased by 84%. The microchannel heat exchanger enhances the SEER of the residential air conditioning system by providing better heat transfers at reduced pressure drops.

나선형 핀튜브 열교환기의 열전달 특성에 관한 실험적 연구

윤린,김용찬,김슬우,최종민 대한설비공학회 2005 설비공학 논문집 Vol.17 No.6

This study experimentally examines the air-side performance of spiral finned tube heat exchangers. The effects of fin spacing, fin height, and tube alignment were investigated. Reduction of fin spacing decreased the Colburn j factor. However, the effect of fin height on the Colburn j factor was negligible. An increase of tube row decreased the Nusselt number for both staggered and in-line tube alignments. However, the decrease of the Nusselt number for the in-line tube alignment was much more significant than that of the staggered tube alignment. The average Nusselt number of the staggered tube alignment was larger than that of the in-line tube alignment by 10% when the Reynolds number ranged from 300 to 1700. An empirical correlation of the Nusselt number was developed by using geometric parameters of heat exchanger and correction factors. The correction factor considered the effects of tube alignment and number of tube rows on the heat transfer. The proposed correlation yielded a mean deviation of 4% from the present data.

임계점 부근에서의 R1234ze(E)와 R134a의 응축열전달계수 연구

윤린 대한설비공학회 2023 설비저널 Vol.52 No.12

초임계조건에서 CO2-오일 혼합물의 물성예측을 통한 냉각 열전달특성 연구

윤린 대한설비공학회 2011 설비저널 Vol.40 No.12

INFLOW CONDENSATION HEAT TRANSFER CHARACTERISTICS OF CO2 IN MICROCHANNEL

윤린,황윤호 대한설비공학회 2014 International Journal Of Air-Conditioning and Refr Vol.22 No.2

In this study, we investigated two-phase flow patterns and effects of oil concentration on the heattransfer coefficient and pressure drop of CO2 undergoing condensation process in a microchannel,and from the data collected, we developed a prediction model of CO2 condensation heat transfer coefficient in smooth tube and microchannels. The narrow single rectangular channel was utilizedto observe flow patterns of CO2 under the condensation process. Experimental results show thatthe transition of vapor quality from intermittent flow to annular flow advances with increase ofmass flux and with decrease of condensation temperature. The heat transfer coefficient decreased by 50% as compared to that of the pure CO2 when the oil concentration was increased from 0.7 to1.2 wt.% for the mass flux of 600 kg m2 s1. The pressure drop slightly decreased with oilconcentration as compared to that of pure CO2. We developed the prediction model for the heattransfer coefficient of CO2 undergoing condensation process in microchannel by considering the effects of the liquid film thickness and of the interface shape between liquid and vapor phases onthe heat transfer coefficient. The present prediction model estimated the experimental data within18.9% of mean deviation. For the pressure drop in microchannel tubes, the existing modelsdeveloped by Mishima and Hibiki, and Garimella showed the marginal predictability.

수평원관 내 CO₂ R-22 및 R-134a의 증발열전달 특성에 관한 실험적 연구

윤린,황준현,최영돈,김용찬,Yun, Rin,Hwang, Jun-Hyeon,Choi, Young-Don,Kim, Yong-Chan 대한기계학회 2002 大韓機械學會論文集B Vol.26 No.7

Evaporation heat transfer coefficients of carbon dioxide($CO_2$), R-22, and R-134a in a horizontal smooth tube were measured and analyzed as a function of heat flux, mass flux, and evaporating temperature. The experiments were carried out by varying heat flux from 10 to 20 $kW/m^2$, mass flux from 170 to 340 $kg/m^2s$, and saturation temperatures of 5 and $10^{\circ}C$. It was found that the heat transfer coefficient of $CO_2$ decreased with a rise of quality due to an earlier liquid-film dryout as compared to R-22 and R-134a. Averaged heat transfer coefficients of $CO_2$ were 22-63% higher than those of R-22 and R-134a at all test conditions. The effects of mass flux and heat flux on averaged heat transfer coefficients were much greater in $CO_2$ than in R-22 and R-134a. When comparing $CO_2$ test results with the correlations in the literature, the existing models yielded large deviations at medium and high qualities. Therefore, a generalized correlation for $CO_2$evaporation heat transfer needs to be developed by including the effects of dryout phenomenon.

이산화탄소 냉동 시스템 내 CO₂와 PAG오일의 혼합비에 대한 실시간 측정 센서개발

윤린 한밭대학교 2006 한밭대학교 논문집 Vol.23 No.-

The relation between the capacitance of OCR sensor at suction side of the CO2 cycle was obtained. The solubility of coz used in calculating the actual OCR amount was obtained from the measured mixture density. The capacitance of the OCR sensor decreased with the increase of the mixture density under the present test conditions. The capacitance of the OCR sensor depends on the mixture density and the uniformity of the oil distributed inside the OCR sensor, The distribution of the OCR sensor is strongly affected by the density ratio between the oil and CO2. It can be concluded from the present results that the oil droplet distribution across the plates inside the sensor is the dominant factor in deciding the capacitance under the present test conditions.

설비공학논문집의 SCOPES 등재를 위한 3가지 전략

윤린 대한설비공학회 2024 설비저널 Vol.53 No.4

공학교육 입문설계의 운영사례 연구 (한밭대학교 중심으로)

윤린 한국공학교육학회 2016 공학교육연구 Vol.19 No.4

In this paper, we surveyed from students and professors of Hanbat National University to examine the current state of running the introductory engineering design and to derive the direction of future improvements of the subject. A total of 783 students from nine departments and 12 professors who are in charge of the introductory engineering design participated in the present questionnaire evaluation. Outcome categories of the interest in their major and the learning of design theory appears relatively lower than other learning outcomes of the introductory engineering design course. Accordingly, it is determined that the theoretical aspects of designing should be emphasized in performing a team project. The design process, writing and presentation ability, teamwork theory are dealt in more than 70% of the departments, but engineering ethics, patent, visualization education had not been addressed in a number of departments due to their department characteristics. While a lesson outcome of the creativity resulted in the largest for the students, most of the professor feel difficult in increasing the creativity. It is urgent to develope of teaching methods in order to promote the creativity in the introductory engineering design course.