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단단 천음속 축류압축기 동익의 Stacking Line 설계 최적화
장춘만,김광용,Jang Choon-Man,Abdus Samad,Kim Kwang-Yong 한국유체기계학회 2006 한국유체기계학회 논문집 Vol.9 No.3
Shape optimization of a rotor blade in a single-stage transonic axial compressor has been performed using a response surface method and three-dimensional Navier-Stokes analysis. Two shape variables of the rotor blade, which are used to define a blade skew, are introduced to increase an adiabatic efficiency. Throughout the shape optimization of a rotor blade, the adiabatic efficiency is increased to about 2.2 percent compared to that of the reference shape of the stator. The increase in efficiency for the optimal shape of the rotor is due to the pressure enhancement, which is mainly caused by moving the separation position on the suction surface of rotor blade to the downstream direction.
Optimization of Rotor Blade Stacking Line Using Three Different Surrogate Models
장춘만,Abdus Samad,김광용 한국유체기계학회 2007 한국유체기계학회 논문집 Vol.10 No.2
This paper describes the shape optimization of rotor blade in a transonic axial compressor rotor. Three surrogate models, Kriging, radial basis neural network and response surface methods, are introduced to find optimum blade shape and to compare the characteristics of object function at each optimal design condition. Blade sweep, lean and skew are considered as design variables and adiabatic efficiency is selected as an objective function. Throughout the shape optimization of the compressor rotor, the predicted adiabatic efficiency has almost same value for three surrogate models. Among the three design variables, a blade sweep is the most sensitive on the object function. It is noted that the blade swept to backward and skewed to the blade pressure side is more effective to increase the adiabatic efficiency in the axial compressor. Flow characteristics of an optimum blade are also compared with the results of reference blade.1. Introduction*Fire & Eng. Services R. D., Korea Institute of Construction TechnologyE-mail : jangcm@kict.re.kr
장춘만,김광용 한국유체기계학회 2004 한국유체기계학회 논문집 Vol.7 No.1
Three-dimensional vortical flow and separated flow topology near the casing wall in an axial flow fan having two different tip clearances have been investigated by a Reynolds-averaged Navier-Stokes (RANS) flow simulation. The simulation shows that the tip leakage vortex formed close to the leading edge of the blade tip on suction side grows in the streamwise direction. On the casing wall, a separation line is formed upstream of the leakage vortex center due to the interference between the leakage vortex and main flow. The reverse flow is observed between the separation line and the attachment line generated downstream of the trailing edge, and increased with enlarging tip clearance. The patterns of a leakage velocity vector including a leakage flow rate are also analyzed according to two tip clearances. It is noted that the understanding of the distribution of a limiting streamline on the casing wall is very important to grasp the characteristics of the vortical flow in the axial flow fan.
Performance Enhancement of 20kW Regenerative Blower Using Design Parameters
장춘만,전현준 한국유체기계학회 2014 International journal of fluid machinery and syste Vol.7 No.3
This paper describes performance enhancement of a regenerative blower used for a 20 kW fuel cell system. Two design variables, bending angle of an impeller and blade thickness of an impeller tip, which are used to define an impeller shape, are introduced to enhance the blower performance. Internal flow of the regenerative blower has been analyzed with threedimensional Navier-Stokes equations to obtain the blower performance. General analysis code, CFX, is introduced in the present work. SST turbulence model is employed to estimate the eddy viscosity. Throughout the numerical analysis, it is found that the thickness of impeller tip is effective to increase the blower efficiency in the present blower. Pressure is successfully increased up to 2.8% compared to the reference blower at the design flow condition. And efficiency is also enhanced up to 2.98 % compared to the reference one. It is noted that low velocity region disturbs to make strong recirculation flow inside the blade passages, thus increases local pressure loss. Detailed flow field inside the regenerative blower is also analyzed and compared.
장춘만,이종성,전완호,임태균 한국수소및신에너지학회 2013 한국수소 및 신에너지학회논문집 Vol.24 No.6
This paper presents how to determine AEP(Annual Energy Production) by a small wind turbine in DuckjeokDo island. Evaluation of AEP is introduced to make a self-contained island including renewable energy sources of wind, solar, and tidal energy. To determine the AEP in DuckjeokDo island, a local wind data is analyzed using the annual wind data from Korea Institute of Energy Research firstly. After the wind data is separated in 12-direction, a mean wind speed at each direction is determined. And then, a small wind turbine power curve is selected by introducing the capacity of a small wind turbine and the energy production of the wind turbine according to each wind direction. Finally, total annual wind energy production for each small wind turbine can be evaluated using the local wind density and local energy production considering a mechanical energy loss. Throughout the analytic study, it is found that the AEP of DuckjeokDo island is about 2.02MWh/y and 3.47MWh/y per a 1kW small wind turbine installed at the altitude of 10 m and 21m, respectively.
장춘만,이상문,전완호,임태균 한국수소및신에너지학회 2014 한국수소 및 신에너지학회논문집 Vol.25 No.6
This paper presents annual energy production (AEP) by a 1.5kW wind turbine due to be installedin Deokjeok-Do island. Local wind data is determined by geometric shape of Deokjeok-Do island and annual winddata from Korea Institute of Energy Research at three places considered to be installed the wind turbine. Numericalsimulation using WindSim is performed to obtain flow pattern for the whole island. The length of each computationgrid is 40 m, and k-e turbulence model is imposed. AEP is determined by the power curve of the wind turbineand the local wind data obtained from numerical simulation. To capture the more detailed flow pattern at thespecific local region, Urumsil-maul inside the island, fine mesh having the grid length of 10m is evaluated. Itis noted that the input data for numerical simulation to the local region is used the wind data obtained by thenumerical results for the whole island. From the numerical analysis, it is found that a local AEP at the Urumsil-maulhas almost same value of 1.72 MWh regardless the grid resolutions used in the present calculation. It is notedthat relatively fine mesh used for local region is effective to understand the flow pattern clearly.