• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.252-256
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• 1999

In this research, the performance predictions of the submersible mixer were investigated. The variation of the performance characteristics by changing the impeller design parameters were discussed through the flow calculation results by using a commercial program, FLUENT. The performance of the submersible mixers is related to the velocity diffusion profiles downstream of the impeller and also the required input motor power to mix the fluid. In this study, the various design parameters such as the number of blade, the hub and tip diameters, the impeller blade profiles and revolution speed of the blades were taken for the fixed values. The blade sweep direction, the chord length distribution along with the radius of the blade and the inlet blade angle were changed to make different testing models. The flow calculation results show the effect of the changed design parameters on the performance of the submersible mixers and also give some helpful information for designing more efficient submersible mixers.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.33-39
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• 2004

Viscous flows around a cooling tower fan with sweep are numerically investigated. The Navier-Stokes equations and the continuity equation are solved in the flow domain. The Reynolds stresses are modelled using the $\kappa-{\varepsilon}$ turbulence model. The governing equations are discretized with the Finite Volume Method. The pressure and the velocity are linked with the SIMPLE algorithme. Flow and pressure characteristics around the fan are investigated. The pressure sharply increases through the fan. Pressure variations on the pressure and suction sides of the fan are well represened in the calculations. The flow streamlines in the blade passage are nearly parallel to the blade.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.36-43
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• 2011

The present study deals with numerical flow analysis to investigate the effect of sweep and lean on the performance characteristics of a partial admission supersonic turbine. The flow analysis was performed for three different angles. The angles of sweep and lean are $5^{\circ}$, $10^{\circ}$, $15^{\circ}$. The results of the flow analysis showed that the efficiency is improved as the sweep angle is increased. However, a sweep angle of $5^{\circ}$ was less effective in comparison with the baseline model. The total pressure loss was reduced as the lean angle is increased, but the total to static efficiency was decreased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.786-792
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• 2010

The present study deals with numerical flow analysis to investigate the effect of sweep and lean on the performance characteristics of a partial admission supersonic turbine. The flow analysis was performed for three different angles. The angles of sweep and lean are $5^{\circ}$, $10^{\circ}$, $15^{\circ}$. The results of the flow analysis showed that the efficiency is improved as the sweep angle is increased. However, a sweep angle of $5^{\circ}$ was less effective in comparison with the baseline model. The total pressure loss was reduced as the lean angle is increased, but the total to static efficiency was decreased.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.74-79
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• 2005

Computational studies on the hydrodynamic behavior of the forward-sweep inducers for the rocket-engine turbopump are presented in comparison with the conventional backward- sweep inducers. In the present study, two kinds of forward-sweep inducers are designed and numerically investigated. Forward-sweep inducers have bigger tip solidity compared to backward-sweep inducers even with shorter axial length due to their forward-sweep leading edge profiles. It is shown that back flows at the inlet decreases dramatically for forward- sweep inducers. And the low pressure region at the back flow are also decreased, which is assumed to promote the suction performance of the inducers. It seems that the hub located upstream of the tip at the leading edge induces pre whirl at the inlet blade tip for the backward sweep inducer. And this pre whirl leads to the big back flow.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1017-1024
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• 2012

The aerodynamic design and analysis on advanced propeller with blade sweep was performed for recent turboprop aircraft. HS1 airfoil series are selected as a advanced propeller blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. Propeller geometry is generated by varying chord length and pitch angle at design point of target aircraft. Advanced propeller is designed by apply the modified chord length, the tip sweep which is based on the geometry of conventional propeller. The aerodynamic characteristics of the designed Advanced propeller were verified by CFD(Computational Fluid Dynamic) and evaluated to be properly designed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.365-370
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• 2000

A computational study on the effect of sweep angle of axial fan on its noise is performed in the present paper. The forward swept axial fan was designed by numerical optimization method incorporated with three dimensional flow analysis. The objective function was defined by the ratio of generation rate of turbulent kinetic energy to pressure head. And, two variables related with sweep angle distribution are used for design variables. The swept fan has better performance characteristics and noise level. The experimental result shows that spectrums of no-sweet and swept fans have differences in the blade passage frequency, especially in the broadband. And the overall noise level of swept fan is lower 10dB(A) than that of no-sweep fan. For the comparison of flow fields between no-sweep fan and swept fan, CFX-TASCflow computational fluid dynamics software is used. Standard k-${\varepsilon}$ model is used for the turbulence model. Distributions of pressure and turbulent kinetic energy distributions are compared in order to find what happen in the low-noise swept fan.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.543-544
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• 2006

Shape optimization of a transonic axial compressor rotor operating at the design flow condition has been performed using three-dimensional Navier-Stokes analysis and three different surrogate models: i.e.., Response Surface Method(RSM), Kriging Method, and Radial Basis Function(RBF). Three design variables of blade sweep, lean and skew are introduced to optimize the three-dimensional stacking line of the rotor blade. The object function of the shape optimization is selected as an adiabatic efficiency. Throughout the shape optimization of the rotor blade, the adiabatic efficiency is increased for the three different surrogate models. Detailed flow characteristics at the optimal blade shape obtained by different optimization method are drawn and discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.7 s.250
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• pp.603-611
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• 2006

This paper presents the response surface optimization method using three-dimensional Wavier-Stokes analysis to optimize the blade shape of an axial flow fan. Reynolds-averaged Wavier-Stokes equations with $k-{\epsilon}$ turbulence model are discretized with finite volume approximations using the unstructured grid. Regression analysis is used for generating response surface, and it is validated by ANOVA and t-statistics. Four geometric variables, i.e., sweep and lean angles at mean and tip respectively were employed to improve the efficiency. The computational results are compared with experimental data and the comparisons show generally good agreements. As a main result of the optimization, the total efficiency was successfully improved. Also, detailed effects of sweep and lean on the axial flow fan are discussed.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.4
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• pp.307-313
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• 2003

A technique for the design of cooling tower fans with sweep is presented. This technique is developed using the equations for the one dimensional inviscid flow through the fan blade, the empirical equations, and the experimental correlations. A parabolic function is used to generate a sweep of the fan. Design data for the fan and the balde can be obtained for a given flow rate and a pressure rise. Also, the present method is used to construct the three dimensional model for the designed fan. Design data and the model show general characteristics of the axial propeller fan.