http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Modeling for the Performance Analysis of a Tubular SOFC/MGT Hybrid Power System
T. W. Song(송태원),J. L. Sohn(손정락),J. H. Kim(김재환),T. S. Kim(김동섭),S. T. Ro(노승탁),K. Suzuki 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.4
Performance of a solid oxide fuel cell (SOFC) can be enhanced by converting thermal energy of its high temperature exhaust gas to mechanical power using a micro gas turbine (MGT). A MGT plays also an important role to pressurize and warm up inlet gas streams of the SOFC. In this study, the influence of performance characteristics of the tubular SOFC on the hybrid power system is discussed. For this purpose, detailed heat and mass transfer with reforming and electrochemical reactions in the SOFC are mathematically modeled, and their results are reflected to the performance analysis. The analysis target is 220kWe SOFC/MGT hybrid system based on the tubular SOFC developed by Siemens-Westinghouse. Special attention is paid to the ohmic losses in the tubular SOFC counting not only current flow in radial direction, but also current flow in circumferential direction through the anode and cathode.
비정상 자연대류에 의한 온도성층화의 동특성에 관한 연구
강보선,이준식,이택식,노승탁,Kang, B.S.,Lee, J.S.,Lee, T.S.,Ro, S.T. 대한설비공학회 1988 설비저널 Vol.17 No.4
Dynamic characteristics of thermally-forced stratification process in a square enclosure with a linear temperature profile at the side walls have been investigated through flow visualization experiment and numerical analysis. The experiment was performed on air with the Rayleigh numbers of order $10^5$. A particle tracer method is used for the flow visualization and to obtain a sudden linear temperature profile at the side walls copper blocks which already have a linear temperature profile are come into contact with the thin copper plates of the test section. Immediately a meridional circulation is developed and heat transfer takes place from the wall to the interior region by circulation of fluid and finally a thermal stratification is achieved. In the numerical study, QUICK scheme for convective terms, SIMPLE algorithm for pressure correction, and the implicit method for the time marching are adopted for the integration of conservation equations. Comparison of flow visualization and numerical results shows that the developing flow patterns are very similar in dynamic nature even though there is a time lag due to the inevitable time delay in setting up a linear temperature profile. For high Rayleigh numbers, the oscillatory motion is likely to take place and stratified region is extended. However, initial temperature adjustment process is much slower than that for low Rayleigh numbers.
김민수,김동섭,원성필,노승탁,Kim, M.S.,Kim, T.S.,Won, S.P.,Ro, S.T. 대한설비공학회 1990 설비공학 논문집 Vol.2 No.3
Studies on the performance of a heat pump using non-azeotropic refrigerant mixtures are done. In order to estimate the thermodynamic properties for the selected non-azeotropic refrigerant mixtures including R22/R152a, R22/R142b, R22/R114 and R13B1/R152a, Peng-Robinson equation of state is adopted. The pressure-enthalpy diagram and the temperature-entropy diagram are plotted for each refrigerant mixture. Considerations on the capacity modulation for the heat pump system using refrigerant mixtures are taken into. Results show that when the heating load varies, the possibility for the capacity modulation is found in the heat pump system using a compressor with constant volume flow rate. Under a constant heating capacity condition in the heat pump system, the coefficient of performance increases when the refrigerant mixtures are used. The volume flow rate decreases as the mass fraction of lower boiler increases in this case.
원성필,김민수,김동섭,노승탁,Won, S.P.,Kim, M.S.,Kim, T.S.,Ro, S.T. 대한설비공학회 1990 설비공학 논문집 Vol.2 No.2
A theoretical cycle analysis has been performed for a basic heat pump, charged with non-azeotropic refrigerant mixtures, R22/R114 and R13B1/R152a. At first, a procedure is introduced to calculate thermodynamic properties simply and correctly, and the advantages of using refrigerant mixtures are discussed through the cycle analysis. It is shown that by using refrigerant mixtures in the heat pump, several improvements can be made. In comparison with conventional pure refrigerants, the application of refrigerant mixtures results in high reliabilities caused by the extension of the application limit, energetic improvements, and a continuous capacity control. From generalizing various results, the optimum compositions in refrigerant mixtures are also determined. The 30%/70% and 40%/60% compositions are selected for R22/R114 and R13B1/R152a, respectively.
태양열에 의한 냉방 및 난방시스템의 성능향상 (III) - 성층화계수의 예측을 위한 1차원 해석모델의 개발 -
유재경,노승탁,이준식,정석호,Yoo, J.K.,Ro, S.T.,Lee, J.S.,Chung, S.H. 대한설비공학회 1989 설비공학 논문집 Vol.1 No.1
A one dimensional analytic model for the prediction of the stratification coefficient of a liquid-based solar heating system is developed. The stratification coefficient, $K_s$, is defined as the ratio of the actual useful energy gain to the energy gain that would be achieved if there were no thermal stratification in the storage tank. Previous studies incorporated only collector-side effects, but in this study both the collector and load-side effects are included for the overall performance evaluation.
HFC 순수냉매 및 혼합냉매의 모세관내에서 마찰에 의한 압력강하
장세동,노승탁,Chang, S.D.,Ro, S.T. 대한설비공학회 1995 설비공학 논문집 Vol.7 No.4
The frictional pressure drop of a capillary tube flow is experimentally investigated for pure refrigerants such as R32, R125, and R134a and refrigerant mixtures such as R32/R134a(30/70 by mass percent), R32/R125(60/40), R125/R134a(30/70), and R32/R125/R134a(23/25/52). The binary interaction parameters for the calculation of viscosities of refrigerant mixtures are found based upon the data in the open literature. Several homogeneous flow models predicting the viscosity of two-phase region are compared to select the best model. Cicchitti's equation is known to be the most adequate for the prediction of the viscosity for refrigerant mixtures, which is used in the analysis of adiabatic capillary flows. A model for the prediction of the frictional pressure drop of single and two-phase flow is developed for refrigerant mixtures in this study. This model may be used to design and analyze the performance of a capillary tube in the refrigerating system.