• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1303-1308
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• 2008

This paper presents effects of impeller geometrical parameters on the performance of a centrifugal pump impeller. The effects of meridional parameters and vane plane development parameters on the performance of the impeller were numerically studied using a commercial CFD code and DOE(design of experiments) software. Geometrical parameters in a method of meridional view and vane plane development were selected and defined to generate the 3D impeller shape. The response variables are defined in a total head and efficiency curve with flow rate. The influences of selected design variables on the various objective functions were examined as a result of the calculation using 2k factorial.

• Journal of the korean society of oceanography
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• v.38 no.1
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• pp.11-16
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• 2003

The three dimensional structure of thermohaline circulation in a D-plane is investigated using a conceptual two layer model and a scaling argument. In this simple model, the water mass formation region is excluded. The upper layer represents the oceans above the main thermocline. The lower layer represents the deep ocean below the thermocline and is much thicker than the upper layer. In each layer, geostrophy and the linear vorticity balance are assumed. The cross interfacial velocity that compensates for the deep water mass formation balances downward heat diffusion from the top. From the above relations, we can determine the thickness of the upper layer, which is the same as thermocline depth. The results we get is basically the same as that we get for an f-plane ocean or the classical thermocline theory. Mass budget using the velocity scales from the scaling argument shows that western boundary and interior transports are much larger than the net meridional transport. Therefore in the thermohaline circulation, horizontal circulation is much stronger than the vertical circulation occuring on a meridional plane.

• The KSFM Journal of Fluid Machinery
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• v.6 no.1 s.18
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• pp.30-36
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• 2003

This paper presents the analysis of flows through three different types of radial compressor impeller by using quasi-three-dimensional analysis method. The method obtains two-dimensional solution for velocity distribution on meridional plane, and then calculates approximately the static pressure distributions on blade surfaces. Finite difference method is used for the solutions of governing equations. The compressors have low level compression-ratio and 12 straight radial blades with no backsweep. The results are compared with experimental data and the results of three-dimensional inviscid analysis with those by finite element method. It is found that the agreements with experimental data are good for the cases where viscous effects are not dominant.

• The KSFM Journal of Fluid Machinery
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• v.12 no.3
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• pp.7-12
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• 2009

In this paper, shape optimization based on three-dimensional flow analysis has been performed for impeller design of centrifugal compressor. To evaluate the objective function of an isentropic efficiency, Reynolds-averaged Navier-Stokes equations are solved with SST (Shear Stress Transport) turbulence model. The governing equations are discretized by finite volume approximations. The optimization techniques based on the radial basis neural network method are used for the optimization. Latin hypercube sampling as design of experiments is used to generate thirty design points within design space. Sequential quadratic programming is used to search the optimal point based on the radial basis neural network model. Four geometrical variables concerning impeller shape are selected as design variables. The results show that the isentropic efficiency is enhanced effectively from the shape optimization by the radial basis neural network method.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.106-112
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• 2001

This paper presents analysis of the flows through three different types of radial compressor impeller by using quasi-three-dimensional analysis method. The method obtains two-dimensional solution for velocity distribution on meridional plane, and then calculates approximately the static pressure distributions on blade surfaces. Finite difference method is used for the solutions of governing equations. The compressors have low level compression-ratio and 12 straight radial blades with no sweepback. The results are compared with experimental data and the results of inviscid analysis with finite element method. It can be concluded that the agreement is good for the cases where viscous effects are not dominant.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.628-633
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• 2001

This paper presents analysis of the flows through three different types of radial compressor by using quasi-three-dimensional analysis method. The method obtains two-dimensional solution for velocity distribution on meridional plane, and then calculates approximately the static pressure distributions on blade surfaces. Finite difference method is used for the solutions of governing equations. The compressors have low level compression-ratio and 12 straight radial blades with no sweepback. The results are compared with experimental data and the results of inviscid analysis with finite element method. It can be concluded that the agreement is good for the cases where viscous effects are not dominant.

• International Journal of Fluid Machinery and Systems
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• v.2 no.2
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• pp.172-178
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• 2009

This paper reports on an investigation (using RSM with commercial CFD software) of the performance characteristics of the impeller in a centrifugal pump. Geometric parameters of vane plane development were defined with the meridional shape and frontal view of the impeller. The parameters are focused on the blade-angle distributions through the impeller in a fixed meridional geometry. For screening, a $2^k$ factorial design has been used to identify the important design parameters. The objective functions are defined as the total head rise and the total efficiency at the design flow-rate. From the $2^k$ factorial design results, it is found that the incidence angles and the exit blade angle are the most important parameters influencing the performance of the pump.

• The KSFM Journal of Fluid Machinery
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• v.15 no.6
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• pp.58-63
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• 2012

This paper presents a numerical study on the performance improvement of axial-flow pump with guide vanes. Design optimization for guide vanes in an axial-flow pump has been studied through the implementation of a commercial CFD code and DOE (design of experiments). We also discussed how to improve the performance of the axial-flow pump by designing the guide vanes. Geometric design variables were defined by the meridional plane and vane plane development of guide vanes. The effect of hub tip ratio analyzed the meridional plane of guide vanes. The importance of the geometric design variables was analyzed using $2^k$ factorial designs. The objective functions for guide vane geometric variables were defined as the total efficiency and the total head at the design flow rate. From the $2^k$ factorial design results, the important design variables were found and the performance was increased in comparison with the base design model.

• Journal of the Korean earth science society
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• v.41 no.4
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• pp.344-355
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• 2020

Tropical cyclone scale vortices and associated Rossby waves were investigated numerically using high-resolution barotropic models on the global domain. The equations of the barotropic model were discretized using the spectral transform method with the spherical harmonics function as orthogonal basis. The initial condition of the vortex was specified as an axisymmetric flow in the gradient wind balance, and four types of basic zonal states were employed. Vortex tracks showed similar patterns as those on the beta-plane but exhibited more eastward displacement as they moved northward. The zonal-mean flow appeared to control not only the west-east translation but also the meridional translation of the vortex. Such a meridional influence was revealed to be associated with the beta gyre and the Rossby wave, which are formed around the vortex due to the beta effect. In the case of the basic zonal state of climatological mean, the meridional translation speed reached the maximum value when the vortex underwent recurving.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.14-24
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• 2011

In this paper, design optimization for mixed-flow pump impellers and diffusers has been studied using a commercial computational fluid dynamics (CFD) code and DOE (design of experiments). We also discussed how to improve the performance of the mixed-flow pump by designing the impeller and diffuser. Geometric design variables were defined by the vane plane development, which indicates the blade-angle distributions and length of the impeller and diffusers. The vane plane development was controlled using the blade-angle in a fixed meridional shape. First, the design optimization of the defined impeller geometric variables was achieved, and then the flow characteristics were analyzed in the point of incidence angle at the diffuser leading edge for the optimized impeller. Next, design optimizations of the defined diffuser shape variables were performed. The importance of the geometric design variables was analyzed using $2^k$ factorial designs, and the design optimization of the geometric variables was determined using the response surface method (RSM). The objective functions were defined as the total head and the total efficiency at the design flow rate. Based on the comparison of CFD results between the optimized pump and base design models, the reason for the performance improvement was discussed.