• Journal of Advanced Marine Engineering and Technology
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• v.37 no.3
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• pp.274-281
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• 2013

The variable demand on the energy market requires a great flexibility in operating hydro turbines. However, Francis turbine operated at off-design conditions poses technical challenges related to large unsteady forces given by residual swirl and angular momentum. In order to improve the performance of a Francis turbine, the paper presents a numerical investigation of the 3D flow in the turbine at off-design conditions and discusses the influence of variable guide vane openings on the internal flow of a Francis turbine with the help of computational fluid dynamics. First, the internal flow characteristics of Francis turbine operated by varied guide vane angle at off design condition are computed and the optimal guide vane angle is obtained. Secondly, the Francis turbine is operated with guide vane number varies at the optimal guide vane angle. Finally, pressure contours and velocity distributions in the distributor are discussed and compared.

• International Journal of Fluid Machinery and Systems
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• v.10 no.1
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• pp.86-98
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• 2017

In order to obtain high efficiency and low resistance droplet separation apparatus, axial vane type gas-liquid separators with different guide vanes were designed, and the RNG $k-{\varepsilon}$ model as well as discrete phase model (DPM) were used to investigate the flow pattern inside the separators. It was shown that the tangential velocity distribution under different guide vanes have Rankine vortex characteristics, pressure distribution exhibits a high similarity which value becomes big as the increase of the blade outlet angle and the decrease of the guide vane numbers. The increase of the guide vane numbers and the decrease of the blade outlet angle could make separation improve significantly. The separation efficiency is almost 100% when the droplet diameter is bigger than $40{\mu}m$.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.79-85
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• 2007

The performance of in-line duct fan depends on the design parameters of impeller and guide vane such as sweep back angle of impeller hub, guide vane angle etc. In this study four kinds of impellers having different sweep back angles, $0^{\circ}$, $17.5^{\circ}$, $35^{\circ}$, $52.5^{\circ}$ with 8 guide vanes, and different guide vane angles, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$ were selected and their performance measured to investigate the effects of design parameters. The results show that both sweep back angle of impeller hub and the guide vane angle have large effect on the efficiency. Especially, it was found that the mixed flow impellers having sweep back angle between $17.5^{\circ}$ and $35^{\circ}$ gave good performances for in-line duct fan.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.373-377
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• 2005

The Performance of in-line duct fan depends on the design parameters of impeller and guide vane. such as sweep back angle of impeller, the number of blades, outlet blade angle, guide vane angle etc. In this experimental study total four kinds of impellers having different sweep back angles, $90^{\circ},\;72.5^{\circ},\;55^{\circ},\;37.5^{\circ}$ with 8 guide vanes, different the number of blades, 6ea, 8ea, 10ea, 12ea, different kinds of outlet blade angles, $30^{\circ},\;45^{\circ}.\;60^{\circ}$ and different kinds of guide vane angles, $15^{\circ},\;30^{\circ},\;45^{\circ}$ were selected and their performance measured to investigate the effects of them. The results were non-dimensionalized to compare their performance.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.35-43
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• 2019

In this study, a guide vane with varying positions and incidence angles was adopted to a pin-fin channel to analyze the change in thermal performance and pressure loss characteristics. A numerical analysis was conducted to investigate the effect of incidence angles and positions on heat transfer and flow characteristics at Re =1400. The results of it were compared those of a pin-fin channel without a guide vane. In case 1 when the incidence angle is $0^{\circ}$, the heat transfer performance is maximized and improved by approximately 5% when compared to the pin-fin channel without the guide vane. In case 2 when the incidence angle is $10^{\circ}$, the pressure loss is minimized and decreased by approximately 1.9% when compared to the pin-fin channel without the guide vane.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.402-407
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• 2002

A commercial CFD code is applied to analyze the 3-D viscous flow field within vertical multi-stage centrifugal pimp including impeller with 6 blades and guide vane with 11 blades and is performed by changing flow rate from 10 to $26\;m^3/h$ at the constant 3500rpm. The purpose of this 3-D numerical simulation is to confirm how much the effect of blade inlet angle of guide vane has an influence on the performance of vertical multi-stage centrifugal pimp. these results performed by $20^{\circ},\;30^{\circ}$ inlet angle of guide vane are compared with grundfos performance data. The vertical multi-stage pump consist of the impeller, guide vane, and cylinder. The characteristics such as total pressure coefficient total heat shaft horse power, power efficiency, discharge coefficient are represented according to flow rate changing.

• International Journal of Fluid Machinery and Systems
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• v.8 no.3
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• pp.132-141
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• 2015

This paper presents a CFD-based methodology for the prediction of guide vane torque in hydraulic turbine distributor for aligned and misaligned configurations. A misaligned or desynchronized configuration occurs when the opening angle of one guide vane differs from the opening angle of all other guide vanes, which may lead to a torque increase on neighbouring guide vanes. A fully automated numerical procedure is presented, that automates computations for a complete range of operation of a 2D or 3D distributor. Results are validated against laboratory measurements.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.8
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• pp.580-588
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• 2009

This paper summarizes the experimentally-measured performance of small-scale, vertical-axis wind turbine for the purpose of improving the aerodynamic efficiency and its controllability. The turbine is designed to have a Savonius-Type rotor with an inlet guide-vane and an side guide-vane so that it achieves a higher efficiency than any lift- or drag-based turbines. The main design factors for this high-efficient, vertical wind turbine are the number of blades (Z), and the aspect ratio of Height/Diameter (H/D) among many. The basic model has the diameter of 580mm, the height of 464mm, and the blade number of 10. The maximum power coefficient of 0.50 was experimentally measured for the above-mentioned specifications. The inlet-guide vane ensures the maximum efficiency when the angle of attack to the rotor blade lies between $15^{\circ}$ and $20^{\circ}$. This experimental results for the vertical-axis wind turbine can be applied to the preliminary design of turbine output curve based on the wind characteristics at the proposed site by controlling its aerodynamic performance given as a priori.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.385-389
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• 2003

Three-dimensional experimental analysis was conducted in the pulverizer simplified isothermal model. The experiment model was constructed on a 1/3.5 scale of 500MW pulverizer. The purpose of this study is to investigate the effect of design parameters on the pulverized coal separator efficiency. Where used pulverized coal separator design parameters are guide vane angle, static classifier angle, dynamic classifier rpm. Taguchi method was used to find the effective design parameters related to pulverized coal separator efficiency. The results of the experiment showed that guide vane angle and dynamic classifier rpm were the design key parameters. In addition to the total number of experiment cases were reduced by Taguchi method.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.10b
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• pp.171-175
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• 1996

thermal diode is a device which allows heat to be transferred in one direction by convection due to difference of density of fluid. Vertical plate for heat collection and radiation are of utility for design of thermal diode. It was considered the transient process of air filled thermal diode with guide vane which combined rectangular and parallelogrammic shape enclosures. Gr was kept constantly on 1.60$\times$1010 and error range was $\pm$2% during the experiment. Nu was examined when inclined angle are 15$^{\circ}$and 45$^{\circ}$and, also the experiments was carried out with and without guide vane as well. Specially, The effect of guide vane was sensitive. Developed region inclined angle, which is characteristic of system.