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마상범,노민수,김광용 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.3
Discrete cavities with guide vanes were developed and optimized to improve the operating stability of a centrifugal compressor. Various combinations of search algorithms and surrogate models were tested to find the best optimization methods. Aerodynamic analysis was performed using three-dimensional Reynolds-averaged Navier–Stokes equations. The numerical results obtained for the total pressure ratio and adiabatic efficiency were validated with experimental data for the centrifugal compressor with a smooth casing. The yaw and pitch angles of the guide vanes and axial distance between cavities were selected as design variables. The stall margin was used as an objective function for the design optimization. Latin hypercube sampling was used to select 27 sample points in the design space. The best combination was found by testing four surrogate models (response surface approximation, Kriging, radial basis neural network, and deep neural network models) and three searching algorithms (a genetic algorithm, particle swarm optimization, and hybrid PSO-GA). Hybrid PSO-GA with the DNN model showed the best overall results. The optimum design showed increments of 13.36% and 3.78% in the stall margin compared to compressors with a smooth casing and the reference cavity design, respectively.
유체-구조 연성해석을 이용한 능동/수동 유동제어방식이 결합된 고하중 축류 팬의 성능특성 연구
마상범,김광용,최재호,이원석 한국수소및신에너지학회 2017 한국수소 및 신에너지학회논문집 Vol.28 No.1
An investigation on aerodynamic performance of a highly-loaded axial fan has been conducted to find the effects of tip injection and casing groove on aerodynamic performance in this study. Three-dimensional Reynolds-averaged Navier-Stokes equations with k-ε turbulence model were used to analyze the fluid flow in the fan with Fluid-Structure Interaction (FSI) analysis. The hexahedral grid was used to construct computational domain, and the grid dependency test drew the optimal grid system. FSI analysis was also carried out to predict the deformation of rotor and stator blades, and the effect of deformation on the aerodynamic performance of axial fan was analyzed compared to the performance predicted without FSI analysis.
2.5 kW 급 프로펠러형 마이크로 수차 매개변수 연구
마상범,김성,최영석,차동안,김진혁 한국수소및신에너지학회 2020 한국수소 및 신에너지학회논문집 Vol.31 No.4
A parametric study of a 2.5 kW class propeller type micro hydraulic turbine was performed. In order to analyze the internal flow characteristics in the hydraulic turbine, three dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model were used and the hexahedral grid system was used to construct computational domain. To secure the reliability of the numerical analysis, the grid dependency test was performed using the grid convergence index method based on the Richardson extrapolation, and the grid dependency was removed when about 1.7 million nodes were used. For the parametric study, the axial distance at shroud span (L) between the inlet guide vane and the runner, and the inlet and outlet blade angles (β1, β2) of the runner were selected as the geometric parameters. The inlet and outlet angles of the runner were defined in the 3 spans from the hub to tip, and a total of 7 geometric parameters were investigated. It was confirmed that the outlet angles of the runner had the most sensitive effect on the power and efficiency of the micro hydraulic turbine.
마상범,김성,최영석,차동안,김진혁 한국수소및신에너지학회 2020 한국수소 및 신에너지학회논문집 Vol.31 No.3
In this work, a preliminary design of an inlet guide vane and runner for developing a 2.5 kW hydraulic turbine was conducted by using computational fluid dynamic analysis. Three-dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model were used to analyze the fluid flow in the hydraulic turbine. The hexahedral grid system was used to construct computational domain, and the grid dependency test was performed to obtain the optimal grid system. Velocity triangle diagram considering the flow angles of the inlet guide vane and runner was analyzed to obtain a basic geometry of the inlet guide vane and runner. Through modification of the preliminary design, the hydraulic performances of the turbine have improved under overall drop conditions. Especially, the efficiency and power of the turbine increased by 0.95% and 1.45%, respectively, compared to those of the reference model.