• Journal of Wetlands Research
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• v.25 no.3
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• pp.176-183
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• 2023

The aim of this paper is to understand the blade number effect on vortex turbine performance in the cylindrical vortex chamber below the free water surface. Using the same blade profile, the performance of gravitational vortex turbine is tested each with 2, 3, 4, 5 and 6 blades installed at the relative vortex height (y/h_v) ranging from 0.065 to 0.417. The obtained results indicate that the rotation, voltage, current and power increase in the relative vortex height of 0.065 and 0.111 when increasing the number of blades at flow velocity of less than 0.7 m/s. The average power of the 5-blade turbine is more than others. The performance of the 4-blade turbine with a 130 mm diameter installed near the orifice is higher than that of the same number of blades with a 220 mm diameter in the vortex chamber.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.75-82
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• 2011

Marine current energy is one of the most interesting renewable and clean energy resources that have been less exploited. Especially, Korea has worldwide outstanding tidal current energy resources and it is highly required to develop tidal in-stream energy conversion system in coastal area. The objective of study is to investigate harnessing techniques of tidal current energy and to design the a 100 kW horizontal axis tidal turbine using blade element momentum theory with Prandtl's tip loss factor for optimal design procedures. In addition, Influence of Prandtl's tip loss factor at local blade positions as a function of tip speed ratio was studied, and the analysed results showed that power coefficient of designed rotor blade using NACA 63812 was 0.49 at rated tip speed ratio.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.442-450
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• 2011

A measurement system using stereo pattern recognition (SPR) method was configured to measure the rotor blade deformations and motions. An SPR-based measurement system was prepared using six stereo cameras. Through a series of experiments to evaluate the system measurement uncertainty, it was verified that the SPR system had less than 0.2mm standard uncertainty. The combined standard uncertainties for the lead-lag, flapping, and pitching motions were estimated as 0.296mm, 0.209mm, and $0.238^{\circ}$, respectively. The SPR system was installed at a general small-scaled rotor test system at Korea Aerospace Research Institute. The blade motions and elastic deformation were successfully measured under the conditions with rotating speeds of 360rpm or 589rpm, and collective pitch angles of $0^{\circ}$, $4^{\circ}$, or $6^{\circ}$. The advantages of the SPR system was analyzed in comparison with the measurement system used in Higher Harmonic Control Aeroacoustic Rotor Test -II.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.9-16
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• 2017

In this paper, the aerodynamic design process of wind turbine blades is established. The optimization design strategy is presented and the constraints that must be reviewed during the aerodynamic design process are summarized. Based on this, this study developed a BEMT-based aerodynamic optimal design program that can be applied easily to actual work, not only for research purposes, but also can be integrated from the initial concept design stage to the final 3D shape detail design stage. The developed program AeroDA consisted of a concept design module, basic design module, optimal TSR module, local shape optimization module, performance analysis module, design verification module, and 3D shape generation module. Using the developed program, an improved design of the 5MW blade by NREL was made, and it was confirmed that this program could be used for design optimization. In addition, a 10kW blade aerodynamic design and turbine detailed performance analysis were carried out, and it was verified by a comparison with the commercial program DNVGL Bladed.

• 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.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.1
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• pp.70-80
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• 2004

This study proposes a development result for the 1-kW class small wind turbine system, which is applicable to relatively low wind speed regions like Korea and has the variable pitch control mechanism. In the aerodynamic design of the wind turbine blade, parametric studies were carried out to determine an optimum aerodynamic configuration which is not only more efficient at low wind speed but whose diameter is not much larger than similar class other blades. A light composite structure, which can endure effectively various loads, was newly designed. In order to evaluate the structural design of the composite blade, the structural analysis was peformed by the finite element method. Moreover both structural safety and stability were verified through the full- scale structural test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.10
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• pp.884-890
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• 2007

The procedure for the aerodynamic design of the rotor blades for 10 kW-level HAWT (horizontal axis wind turbine) has been investigated to be practiced systematically. The approximately optimal shape was designed using an inverse method based on the momentum theory and the blade element method. The configuration was tested in the wind tunnel of the Korea Air Force Academy, and the data was compared with those obtained from the real system manufactured from the present design. From this research, the authors established the systematic technolo for wind turbine blades, and set up the technical procedure which can be extended for the future design of middle and large sized wind turbines.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.185-191
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• 2008

The aerodynamic losses so attributed to the endwall - usually termed secondary flow losses or secondary losses - can be as high as 30$\sim$50% of the total aerodynamic losses in a blade or stator row. Inlet guide vanes, with lower total turning and higher convergence ratios, will have smaller secondary losses, amounting to as much as 20% of total loss for an inlet stator row. These are important part for improving a turbine efficiency. The present study deals with a leading edge chamfer groove on a wing-body to investigate the vortex generation and characteristics of a horseshoe vortex with the installed height, and depth of the groove. The current study is investigated with $FLUENT^{TM}$.

• 기계와재료
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• v.23 no.4
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• pp.74-83
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• 2011

풍력발전기 동적 시뮬레이션 프로그램 개발을 위해 미국풍력기술연구센터(NWTC)의 프로그램군에 대해 분석하고 이를 소개하였다. 본 편에서는 에어포일 데이터를 생성하는 AirfoilPrep, IEC 61400-1 기준의 극한 조건에 해당하는 허브 높이의 바람 데이터를 생성하는 IECWind, 통계적인 방법에 의해 전 영역에 대한 난류 바람 데이터를 생성하는 TurbSim, 복합재료 블레이드의 구조적 특성치를 계산하는 PreComp, 블레이드와 타워의 모드 형상을 구하는 BModes와 같은 전처리기를 중심으로 설명하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.182.1-182.1
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• 2010

현재 전 세계적으로 가장 널리 개발하고 보급되어지고 있는 풍력산업의 시장 규모는 매년 확대되고 있다. 특히 소형 풍력발전 시스템은 낙도 등의 전력 공급이 어려운 지역에 경제성 있는 전력 보급을 가능하게 한다. 국내의 미전화 지역과 일반 가정에서 풍력 에너지 자원을 적극 활용 개발하기 위해서 보다 우수한 성능의 풍력발전기용 블레이드를 설계하고자, 공기역학적인 최적설계에 대해 연구함으로써 추후 보급형 풍력발전 시스템의 개발에 필요한 설계 기술을 확립하고자한다. 본 연구는 설계된 블레이드의 유동해석 및 성능예측을 위하여 경제적으로 많은 지원이 필요한 대규모 풍동실험이 아닌 상용 CFD를 사용하여 보다 효율적으로 우수한 성능을 가지는 풍력 터빈을 설계함에 있다. Reynolds Averaged Navier-Stokes 방정식에 기반을 둔 CFD의 경우 이론적으로 명확한 해석이 가능하고, 실제 터빈의 운전 환경과 동일한 다양한 물리적 변수를 입력 데이터로서 활용할 수 있는 장점이 있기 때문에 풍력 터빈의 설계 과정에서 반영된 미소한 블레이드 형상변화 및 운전 조건의 변화에 따른 유동장의 변화 및 풍력터빈 성능을 정확히 예측할 수 있는 장점을 가지고 있다.