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김성윤(SㆍYㆍKim),김유택(YㆍTㆍKim),남청도(CㆍDㆍNam),이영호(YㆍHㆍLee),강호근(HㆍKㆍKang),김성동(SㆍDㆍKim) 한국마린엔지니어링학회 2005 한국마린엔지니어링학회 학술대회 논문집 Vol.2005 No.-
The effect of break down of centrifugal pump due to entrained air has not been clarified yet. Thus, air-water two-phase flow experimental apparatus was installed to clarify the effect of break down. The performance results of a single-phase flow satisfied reappearance. Also, the heads coincided well impeller types.
퓐이 나선형으로 부착된 원주의 후류에 관한 실험적 연구
남청도(C. D. Nam),안윤수(Y. S. Ahn) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.4
The characteristics of two dimensional turbulent wake flow past a circular cylinder with helical fin was investigated by using X type hot wire anemometer for the experiment. As a result it is cleared that Karman vortex sheds from the cylinder with helical fin as the same as a circular cylinder or a rectangular cylinder. Turbulent characteristics such as the distribution of the mean velocity, turbulent kinetic energy, autocorrelation coefficient and its spectrum of them are suggested. It is also found that the width of the wake flow become larger as the pitch of the fin increased, and the frequency of vortex shedding is on the decrease.
퓐이 나선형으로 부착된 원주희 후류에 관한 실험적 연구
남청도(C.D.Nam),민경용(K.Y.Min) 한국해양대학교 해사산업연구소 2001 海事産業硏究所論文集 Vol.11 No.-
The characteristics of two dimensional turbulent wake flow past a circular cylinder with helical fin was investigated by using X type hot wire anemometer for the experiment. As a result it is cleared that Karman vortex sheds from the cylinder with helical fin as the same as a circular cylinder or a rectangular cylinder. Turbulent characteristics such as the distribution of the mean velocity, turbulent kinetic energy, autocorrelation coefficient and its spectrum of them are suggested. It is also found that the width of the wake flow become larger as the pitch of the fin increased, and the frequency of vortex shedding is on the decrease.
수평축 풍력발전용 터빈의 유동 해석을 위한 상용 CFD 코드의 적용성 평가에 관한 연구
김범석(B. S. Kim),김정환(J. H. Kim),남청도(C. D. Nam),이영호(Y. H. Lee) 한국유체기계학회 2002 유체기계 연구개발 발표회 논문집 Vol.- No.-
The purpose of this 3-D numerical simulation is evaluate the application of a commercial CFD code to predict 3-D flow characteristics of wind turbine. The experimental approach, which has been main method of investigation, appears to be its limits, the cost increasing disproportionally with the size of the wind turbines, and is hence mostly limited to observing the phenomena. Hence, the use of Computational Fluid Dynamics (CFD) techniques and Navier-Stokes solvers are considered a very serious contender. The flow solver CFX-TASCflow is employed in all computations presented in this paper. The 3-D flow separation and the wake distribution of 2 bladed Horizontal Axis Wind Turbines (HAWTs) are compared to Heuristic model and visualized result by NREL(National Renewable Energy Laboratory). Simulated 3-D flow separation structure on the rotor blade is very similar to Heuristic model and the wake structure of the wind turbine is good agree with visualized results.
모장오(J. O. Mo),남구만(G. M. Nam),강신정(S. J. Kang),남청도(C. D. Nam),이영호(Y. H. Lee) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.10
A commercial CFD code is applied to analyze the 3-D viscous flow field within vertical multi-stage centrifugal pump including impeller of centrifugal pump with 6 blades and guide vane with 11 blades. The numerical analysis of vertical multi-stage centrifugal pump is performed by changing flow rate from 10 to 26 ㎥/h at the constant 3500rpm. The characteristics such as total pressure coefficient, total head shaft horse power, power efficiency, discharge coefficient are represented according to flow rate changing. the Vertical multi - stage pump consist of the impeller, guide vane, and cylinder. the grid of numerical analysis used in the Vertical multi - stage pump is 18000, 450000 and 100000 cells in case of impeller, guide vane, cylinder each other, and total grid is 730000 cells In the future, we will need to perform flow calculation of vertical multi-stage centrifugal pump by considering meridional shape of guide vane.
CFD에 의한 1㎿ 수평축 풍력발전용 로터 설계 및 해석에 관한 연구
김범석(B. S. Kim),김유택(Y. T. Kim),남청도(C. D. NAM),김진구(J. G. Kim),이영호(Y. H. Lee) 한국유체기계학회 2004 유체기계 연구개발 발표회 논문집 Vol.- No.-
In this paper, a 1㎿ HAWT(FIL-1000) rotor blade has been designed by BEMT(Blade Element Momentum Theory) with Prandtl's tip loss. Also, a 3-D flow and performance analysis on the FIL-1000 rotor blade has been carried out by using the 3-D Navier-Stokes commercial solver (CFX-5.7) to provide more efficient design techniques to the large-scale HAWT engineers. The rated power and itsapproaching wind velocity at design point (TSR=7.5) are 1㎿ and 9.99m/s respectively. The rotor diameter is 54.5m and the rotating speed is 26.28rpm. Airfoils such as FFA W-301 , DU91-W-250, DU93-W-210, NACA 63418, NACA 63415 consist of the rotor blade from hub to tip. Recent CFX version, 5.7 was adopted to simulate 3-D flow field and to analyze the performance characteristics of the rotor blade. Entire mesh node number is about 730,000 and it is generated by ICEM-CFD to achieve better mesh quality. The predicted maximum power occurringat the design tip speed ratio is 931.45㎾. Approaching to the root, the inflow angle becomes large, which causesthe blade to be stalled in the region. Therefore, k-ω SST turbulence model was used to predict the quantitative flow information more accurately. Application of commercial CFD code to optimum blade design and performance analysis was proved to be more effective environment to HAWT blade designers.
김성윤(S-Y Kim),김범석(B-S Kim),김정환(J-H Kim),남청도(C-D Nam),이영호(Y-H Lee) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.4
The purpose of this paper is to present the optimum flap heights and deflection angles on NACA 63₂-215 airfoil. In this numerical investigation, the angle of attack is fixed at 8° and the heights of the flaps are 0.5%, 1.0%, 1.5% and 2.0% of the airfoil chord length. Reynolds number is 2.4×10?. A Navier-Stokes code, FLUENT, was used to calculate the aerodynamic characteristics of NACA 63₂-215 airfoil. We carried out a benchmark calculation with FLUENT code on NACA 4412 airfoil to examine a reliability of the code. Prediction of local pressure coefficients are found to be in good agreement wi th the results of Wadcock's. The effects of difference deflection angles of the flap are compared and the flap heights ranging from 0.5% to 2% of the airfoil chord are also compared. The results indicate that all investigated flaps could increase lift and drag coefficient. The airfoil with 90° flap shows a excellent aerodynamics characteristics compared with other angles trailing edge flaps. It is concluded that this study gives a promise for the future development of wind turbine optimum design.
김정환(J.H.Kim),김범석(B.S.Kim),김유택(Y.T.Kim),남청도(C.D.Nam),이영호(Y.H.Lee) 한국마린엔지니어링학회 2003 한국마린엔지니어링학회 학술대회 논문집 Vol.2003 No.-
The wind turbine blade is the equipment converted wind into electric energy. The effect of the blade has influence of the output power and efficiency of wind turbine. The design of blade is considered of lift-to-drag ratio, structure, a condition of process of manufacture and stable maximum lift coefficient, etc. This study is used the simplified method for design of the aerodynamic blade and aerodynamic analysis used blade element method. This process is programed by delphi-language. The program has any i!1put values such as tip speed ratio, blade length, hub length, a section of shape and max lift-to-drag ratio. The program displays chord length and twist angle by input value and analyzes performance of the blade.
김성윤(S.Y.Kim),김정환(J.H.Kim),강호근(H.K.Kang),김유택(Y.T.Kim),남청도(C.D.Nam),이영호(Y.H.Lee) 한국마린엔지니어링학회 2004 한국마린엔지니어링학회 학술대회 논문집 Vol.2004 No.-
A numerical investigation was performed to determine the effect of airfoil on the optimum flap height and tip clearance using NACA00l5 Wells turbine. A Navier-Stokes code, FLUENT and CFX-TASCflow were used to calculate the flow field of the Wells turbine. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used in definining the 3-D numerical grid is based upon that of an experimental test rig. This paper tries to analyze the optimum double flaps and tip clearances of Wells turbine with the numerical analysis.