• 전기의세계
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• v.41 no.10
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• pp.3-9
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• 1992

동해안의 6개 예정입지 지점의 다년간 기상데이터를 분석한 결과 3개지점 정도의 유수한 후보지를 발견하였다. 특히 장기갑의 평균풍속은 제주도 월항지역 보다 더 우수한 결과를 얻었다. 이 지역에 설치할 수 있는 풍력터빈의 형식으로 수직축 Darrieus Type을 검토한 결과 무리가 없음을 알 수 있었다. 수직축 터빈은 풍속 6m/s이상이면 정격의 발전모드에 진입하니, 3개 지역의 분석결과 년4000시간 이상의 발전은 가능하리라 사료된다. 단위 풍력발전 용량은 향후 상세설계가 뒤따라야 하겠지만, 대략 150-200KW로 산정되며 년간 단위 기계에서 600-800Mwh의 전력을 얻을 수 있으리라 예상된다.

• Journal of Ocean Engineering and Technology
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• v.27 no.3
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• pp.67-72
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• 2013

In this study, numerical analyses that considered the dynamic interaction effects between the flow and a turbine were carried out to investigate the power output performance of an H-type Darrieus turbine rotor, which is one of the representative lifting-type vertical-axis tidal-current turbines. For this purpose, a commercial CFD code, Star-CCM+, was utilized for an example three-bladed turbine with a rotor diameter of 3.5 m, a solidity of 0.13, and the blade shape of an NACA0020 airfoil, and the optimal tip speed ratio (TSR) and corresponding maximum power coefficient were evaluated through exhaustive simulations with different sets of flow speed and external torque conditions. The optimal TSR and maximum power coefficient were found to be approximately 1.84 and 48%, respectively. The torque and angular velocity pulsations were also investigated, and it was found that the pulsation ratios for the torque and angular velocity were gradually increased and decreased with an increase in TSR, respectively.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.241-248
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• 2010

This paper deals with the performance analysis and design of the Darrieus-type vertical axis turbine to evaluate the effect of key design parameters such as number of blade, blade chord, pitch and camber. The commercial CFD software FLUENT was employed as an unsteady Reynolds-Averaged Navier-Stokes (RANS) solver with k-e turbulent model. Grid system was modelled by GAMBIT. Basic numerical methodology of the present study is appeared in Jung et al. (2009). Two-dimensional analysis was mostly adopted to avoid the barrier of massive calculation required for parametric study. It was found that the highly efficient turbine model could be designed through the optimization of design parametrrs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.677-681
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• 2011

Characteristics of vertical and horizontal axis wind turbines are explained. The speed and direction of wind on the blade of the Darrieus type turbine changes very severely. Therefore dynamic stall happens periodically and the wake from the front blade deteriorates the performance of rear blades. Blade element momentum theory(BEMT) is widely utilized for aerodynamic design and performace prediction of horizontal axis wind turbine(HAWT). Computation analysis and wind tunnel test are also performed for the performance prediction.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.183.2-183.2
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• 2010

본 개발에서의 해상용 풍력발전기는 크게 허브와 블레이드를 합한 상부 구조물, 전기 발전기와 연결 조인트의 중간구조물, 각종 제어 장치가 들어있는 제어박스로 나누어진다. 상부 구조물은 Circular Hub 타입의 Darrieus 형상으로 양력(lift)을 이용한 회전력이 발생하며, Circular Hub 타입은 기존의 허브와 블레이드를 연결하여주는 암(arm)에 의해 유발되는 항력토크를 최소화 하기 위한 신개념 형상설계가 이루어 졌으며, 저속에서 우수한 회전특성을 가진다. 이는 바람을 받아 기계적 에너지로 전환 하는 역할을 하며, 풍력발전기의 성능에 직접적인 영향을 미친다. 중간구조물의 전기발전기는, 상부에서 발생된 기계적 에너지를 이용하여 전기적 에너지로 전환 하는 역할을 수행한다. 이렇게 전환된 전기적 에너지는 하부의 제어박스를 거쳐서 해상용 부이(buoy)의 하단에 위치한 베터리 뱅크로 전달, 저장되어 부이에서 쓰이는 전력을 충당하게 된다. 한편 본 개발은 풍력발전기의 공력하중 해석과 로터블레이드의 설계, 풍력발전기의 구조, 진동해석, MPPT 제어컨트롤러와 Breaking controller, 풍동 및 차량시험을 통한 성능평가 및 분석 등의 순으로 개발을 수행하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.1
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• pp.151-159
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• 2020

This study aimed to investigate the performance characteristics of vertical axis turbine of tidal energy convertor. Three-dimensional Reynolds-averaged Navier-Stokes equation with shear stress transport turbulence model has been solved to analyze the fluid flow of the vertical axis turbine. The hexahedral grids have been used to construct the computational domain and the grid dependency test has been performed to find the optimum grid system. Four steps have been carried out to design the vertical axis turbine of the 100 kW class tidal energy convertor.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.78.1-78.1
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• 2014

An ionization front (IF) surrounding an H II region is a sharp interface through which a cold neutral gas makes transition to a warm ionized phase by absorbing UV photons from central massive stars. We investigate the structure and instability of a plane-parallel D-type IF threaded by magnetic fields parallel to the front. We find that magnetic fields increase the maximum propagation speed of the IFs, while reducing the expansion factor, defined as the density ratio of neutral to ionized phases. IFs become unstable to distortional perturbations due to gas expansion across the fronts, exactly analogous to the Darrieus-Landau instability of ablation fronts in terrestrial flames. The growth rate of the IF instability is proportional linearly to the perturbation wavenumber as well as the upstream flow speed. The IF instability is stabilized by gas compressibility and becomes completely quenched when the front is D-critical. The instability is also stabilized by magnetic pressure when the perturbations propagate in the direction perpendicular to the fields. When the perturbations propagate in the direction parallel to the fields, on the other hand, it is magnetic tension that reduces the growth rate, completely suppressing the instability when ${\beta}$ < 1.5, with ${\beta}$ denoting the square of the ratio of the sound speed to the Alfven speed in the pre-IF region. When the front experiences an acceleration, the IF instability cooperates with the Rayleigh-Taylor instability to make the front more unstable. We discuss potential effects of IF instability on the evolution and dynamics of IFs in the interstellar medium.

• Wind and Structures
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• v.17 no.6
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• pp.647-670
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• 2013

The paper presents a numerical approach to study of fluid flow characteristics and to predict performance of wind turbines. The numerical model is based on Finite-volume method (FVM) discretization of unsteady Reynolds-averaged Navier-Stokes (URANS) equations. The movement of turbine blades is modeled using moving mesh technique. The turbulence is modeled using commonly used turbulence models: Renormalization Group (RNG) k-${\varepsilon}$ turbulence model and the standard k-${\varepsilon}$ and k-${\omega}$ turbulence models. The model is validated with the experimental data over a large range of tip-speed to wind ratio (TSR) and blade pitch angles. In order to demonstrate the use of numerical method as a tool for designing wind turbines, two dimensional (2-D) and three-dimensional (3-D) simulations are carried out to study the flow through a small scale Darrieus type H-rotor Vertical Axis Wind Turbine (VAWT). The flows predictions are used to determine the performance of the turbine. The turbine consists of 3-symmetrical NACA0022 blades. A number of simulations are performed for a range of approaching angles and wind speeds. This numerical study highlights the concerns with the self-starting capabilities of the present VAWT turbine. However results also indicate that self-starting capabilities of the turbine can be increased when the mounted angle of attack of the blades is increased. The 2-D simulations using the presented model can successfully be used at preliminary stage of turbine design to compare performance of the turbine for different design and operating parameters, whereas 3-D studies are preferred for the final design.