• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.188.1-188.1
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• 2010

This paper describes the effort for the development of an actual wind simulation method on the wind turbine performance evaluation. It should be emphasized that the deep knowledge on real wind field is a key factor for both the design of a wind turbine and the performance evaluation. With this reason, there had been several simulation attempts to accurately match with the actual wind data. With an existing wind generation algorithm is under consideration, this study introduces several more new concepts including Van der Hoven spectrum being implemented in different methodology. Also this paper will compare the result from the wind simulations by using the basic formula with that by using MATLAB and SIMULINK previously developed. In addition, like the existing wind generation algorithm, random process for actual wind field simulation and white noise are incorporated to closely produce the actual wind field models.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.24-29
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• 2011

Conceptual study of an open-circuit type low-speed wind tunnel for performance test of wind turbine blade and airfoil is conducted. The tunnel is constituted of a settling chamber, a contraction, closed test section, a diffuser, two corners, a cross leg and a fan and motor. For the performance test, the closed test section width of 1.8 m, height of 1.8 m and length of 5.25 m is selected. The contraction ratio is 9 to 1 and maximum speed in the test section is 67 m/sec. Input power in the tunnel is about 238 kW and its energy ratio is 3.6. The wind tunnel designed in present study will be an effective tool in research and development of wind turbine and airfoil.

• International Journal of Fluid Machinery and Systems
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• v.7 no.4
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• pp.151-159
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• 2014

Low head hydropower is one of realistic renewable energies. The Darrieus-type hydro turbine with an inlet nozzle is available for such low head conditions because of its simple structure with easy maintenance. Experimental and numerical studies are carried out in order to examine the effects of gap distances between the runner pitch circle and two edges of inlet nozzle on turbine performances. By selecting narrower gaps of left and right edges, the performance could be improved. From the results of two dimensional numerical simulations, the relation between the performance and flow behaviors around the Darrieus blade are discussed to obtain the guideline of appropriate inlet nozzle design.

• International Journal of Fluid Machinery and Systems
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• v.1 no.1
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• pp.76-85
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• 2008

In order to extract micro hydropower in the very low specific speed range, a Positive Displacement Turbine (PDT) was proposed and steady performance was determined experimentally. However, the suppression of large pressure pulsation is inevitable for practical application of PDT. The objective of the present study is to reveal the mechanism and the characteristics of pressure pulsation in PDT by use of CFD and to suppress the pressure pulsation. Unsteady CFD analysis has revealed that large pressure pulsation is caused by large variation of rotational speed of the following rotor, while the driving rotor, which is output rotor, keeps constant speed. Here is newly proposed a 4-lobe helical type rotor which can reduce the pressure pulsation drastically and the performance prediction of new PDT is determined.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.316-319
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• 2008

A computational analysis has been conducted on the compressible flow in the turbine exhaust nozzle of the gas generator cycle liquid rocket engine. The commercial CFD code Fluent has been used. Four nozzle designs have been compared to select the turbine exhaust nozzle concept. Three candidates with single nozzle have comparable performance. The model with bifurcated nozzles shows significant performance loss. However it will be better in the view of balanced thrust distribution because of its symmetric geometry.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.606-609
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• 2009

Development of renewable energy is very important because of environmental problems caused by greenhouse effect. This is due to the use of fossil fuels which has serious consequences. Therefore, development of small hydropower can be a good countermeasure for the problems. The small hydropower is clean energy because the small hydropower generates few $CO_2$. Moreover, as the energy density by the small hydropower is high, it is economical for a society which wants to introduce the system. The purpose of this study is to improve the turbine performance. This study is about tubular-type hydro turbine among renewable energy that is based using the different water pressure level in pipe lines. The analysis was performed using the commercial CFD code ANSYS-CFX.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.492-492
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• 2009

Nowadays in Republic of Korea, there is no distinct reference for the related design technology of rotor blade of wind turbine. Therefore the optimum design and evaluation of performance is carried out with foreign commercial code softwares. This paper shows in-house code software that evaluates the aerodynamic design of wind turbine rotor blade using blade element-momentum theory (BEMT) and processes that is applied through various aerodynamics theories such as momentum theory, blade element theory, prandtl's tip loss theory and strip theory. This paper presents the results of the numerical analysis such as distribution of aerodynamic properties and performance curves using in-house code POSEIDON.

• KIEE International Transactions on Power Engineering
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• v.4A no.2
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• pp.51-57
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• 2004

This paper describes the dynamic performance of a variable speed wind turbine system responding to a wide variety of wind variations. Modeling of the wind generation using power electronics interface is proposed for dynamic simulation analysis. Component models and equations are addressed and their incorporations into a transient analysis program, PSCAD/EMTDC are provided. A wind model of four components is described, which enables observing dynamic behaviors of the wind turbine resulting from wind variations. Controllable power inverter strategies are intended for capturing the maximum power under variable speed operation and maintaining reactive power generation at a pre-determined level for constant power factor control or voltage regulation control. The components and control schemes are modeled by user-defined functions. Simulation case studies provide variable speed wind generator dynamic performance for changes in wind speed

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.160-163
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• 2010

We performed three-dimensional CFD analysis to investigate the effect of the nozzle-rotor axial gap of a partial admission supersonic turbine on the stage performance and the flow field. The computations are conducted for five axial gaps using flow analysis program, $FLUENT^{TM}$. The results show that the axial gap between nozzle and rotor give the effect on the mass flow rates of tip leakage and the flow angle at the rotor outlet.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.2
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• pp.209-214
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• 2009

The simulation software for predicting the performance of a wind turbine generator system (WTGS) is validated using the field measured data obtained from the idling test run of a dual rotor wind turbine recently developed and installed in Korea. Both steady-state and transient responses at low and high wind conditions are compared with the theoretically predicted ones from the simulation software WINSIM.