http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
조영두,한창섭,유성연,Cho, Y.D.,Han, C.S.,Yoo, S.Y. 대한설비공학회 1999 설비공학 논문집 Vol.11 No.1
The present work presents condensation heat transfer and pressure drop data for the flow of R-12 in flat extruded aluminum tubes with small hydraulic diameters. The tube outside dimensions are $18mm(width){\times}1.7mm(height)$. Three types of internal geometry with the same outside dimensions are tested : sample 1 (7 tube holes), sample 2 (13 tube holes) and sample 3 (7 tube holes, micro-fin). The overall heat transfer coefficient is obtained for air-to-refrigerant heat transfer, and the Wilson plot method is used to determine the heat transfer coefficient for refrigerant flow. The sample 2 and sample 3 show significantly higher performance than sample 1. The heat transfer rates for the sample 2 and sample 3 are 9% and 12% higher, respectively, than sample 1. The friction factors for the sample 2 and sample 3 are 11.9% and 2.4% higher, respectively, than sample 1.
자동차용 열전지에서 유로배열 효과 예측을 위한 열유동 수치묘사
이관수(K. S. Lee),권재웅(J. W. Kwon),백창인(C. I. Baek),송영길(Y. K. Song),한창섭(C. S. Han),김동진(D. J. Kim) 한국자동차공학회 1995 한국 자동차공학회논문집 Vol.3 No.5
A numerical simulation of heat and fluid flow for predicting the effect of passage arrangement in automotive heat battery has been performed. The system is assumed to be a two-dimensional laminar flow and isothermal boundary is applied to the surface of the latent heat storage vessel. In the case of ideal heat battery the flow rate into each flow passage is evenly distributed. The various models are considered in the view of pressure drop and bulk temperature. The effects on the efficiency of the heat battery are examined by varying geometrical factors such as flow passage clearance, length of a inlet and outlet tank and the length of a latent heat storage vessel. The flow clearance is a very important -factor on the efficiency of a heat battery. As the flow passage clearance becomes narrow, the flow distribution becomes uniform and the bulk temperature increases, however the pressure drop is large. Therefore, optimal flow passage clearance has to be chosen. The present work can be used in optimizing heat battery efficiency.
상변화물질을 이용한 자동차용 열저장 시스템의 성능을 위한 수치 해석
이관수(K. S. Lee),김혁제(H. J. Kim),백창인(C. I. Baek),송영길(Y. K. Song),한창섭(C. S. Han),김동진(D. J. Kim) 한국자동차공학회 1996 한국 자동차공학회논문집 Vol.4 No.3
In this study, the performance of an automobile heat storage system using PCM is numerically simulated. For the analysis of system performance, The phase-change of the PCM and the tran-sient forced convective heat transfer for the HTF are considered simultaneously as a conjugate problem. The phase-change behavior is effectively analyzed using a concept of thermal resistance. From the correlations of phase change rate and heat transfer due to the variations of flow rate of HTF around PCM, the automobile heat storage system performance is predicted. The present results may be used as the fundamental information for the design of automobile heat storage system.<br/>
Chiller용 냉매 CFC-11과 대체냉매 HCFC-123의 전기장을 사용한 핵비등 열전달 촉진에 관한 연구
곽태희,김주형,정동수,김종보,차태우,한창섭,Kwak, T.H.,Kim, J.H.,Jung, D.S.,Kim, C.B.,Cha, T.W.,Han, C.S. 대한설비공학회 1994 설비공학 논문집 Vol.6 No.4
Pool boiling experiments were carried out to study the effect of electric field on nucleate boiling heat transfer. CFC-11 and its alternative HCFC-123 were used as working fluids. Boiling on both single tube and a bundle of five tubes was investigated. Heat flux varied from 5 to $25kW/m^2$ while the applied voltage changed from 0 to 1kV. The results showed that at low heat flux where boiling was not present or very weak, electric field-induced forced convection helped increase the heat transfer coefficients of CFC-11 and HCFC-123 significantly(4-15 times increase). However, at higher heat flux, nucleate boiling of CFC-11 which is a highly dielectric fluid, was not affected significantly by the application of electric field. In contrast to CFC-11, even at high heat flux, nucleate boiling of CFC-11 which has a relatively larger electric conductivity than CFC-11, was vigorously increased up to 2-4 times. The additional power required to apply the electric field was 1-2% of the total power consumption by the heater. The increase in overall heat transfer coefficient of evaporators with HCFC -123 was about 40%, suggesting a considerable reduction in evaporator size with EHD technique.
자동차용 에어컨의 고밀도 응축기 (SCC) 에서 배플의 위치 변화에 따른 성능향상에 관한 연구
이명재(M. J. Lee),박복춘(B. C. Pak),백병준(B. J. Back),염동석(D. S. Yeom),한창섭(C. S. Han) 한국자동차공학회 1997 한국 자동차공학회논문집 Vol.5 No.6
A new super compact condenser(SCC), which has been developed recently is especially suitable for an alternative refrigerant HFC-134a due to its high performance and compactness. The see is composed of two pipe headers, baffles, narrow multi-rectangular channels, and louvered fin arrays. Alternating inlet and outlet by the inserted baffles in pipe headers guide refrigerant to and from the narrow multi-rectangular channels. Since the flow rate and its length are changed depending on the number and location of baffles, the corresponding pressure drop and heat transfer rate are changed. The present study aims to theoretically and experimentally investigate the effects of baf-flr location and its number on the pressure drop and thermal performance of the see with 40 multi -rectangular channels.<br/> The results show that the present method provides an acceptable prediction of pressure drop and heat transfe rate for a 4 pass sec. However, the model significantly underpredicts the performance of a 3 pass see, which may be attributed to the phase separation of refrigerant flowing through header pipes. Pressure drop is more significantly influenced than heat transfer rate by the baffle lo-cation.<br/>