• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.493-493
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• 2009

Recently, small vertical axis wind turbine attracts attention because of its clean, renewable and abundant energy resources to develop. Therefore, a cross-flow type wind turbine is proposed for small wind turbine development in this study because the turbine has relatively simple structure and high possibility of applying to small wind turbine. The purpose of this study is to investigate the effect of the turbine‘s structural configuration on the performance and internal flow characteristics of the cross-flow turbine model using CFD analysis. The results show that guide nozzle should be adopted to improve the performance of the turbine. Optimization of the nozzle shape will be key-importance for the high performance of the turbine.

• International Journal of Fluid Machinery and Systems
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• 제9권2호
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• pp.169-174
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• 2016

A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio. Therefore, it is a good candidate for use as a self-starting turbine. Furthermore, it has low noise and excellent stability; therefore, it has attracted attention from the viewpoint of applications as a small wind turbine for an urban district. However, its maximum power coefficient is extremely low (10 %) as compared to that of other small wind turbines. In order to improve the performance and flow condition of the cross-flow rotor, the symmetrical casing with a nozzle and a diffuser are proposed and the experimental research with the symmetrical casing is conducted. The maximum power coefficient is obtained as $C_{pmax}=0.17$ in the case with the casing and $C_{pmax}=0.098$ in the case without the casing. In the present study, the power characteristics of the cross-flow rotor and those of the symmetrical casing with the nozzle and diffuser are investigated. Then, the performance and internal flow patterns of the cross-flow wind turbine with the symmetrical casings are clarified. After that, the effect of the side boards set on the symmetrical casing is discussed on the basis of the analysis results.

• Journal of Advanced Marine Engineering and Technology
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• 제37권2호
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• pp.163-169
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• 2013

In order to make the vertical-axis cross flow wind turbine commercially feasible, a guide vane is adopted and the effect of the guide vane shape is examined in order to improve the wind turbine performance. CFD analysis on the performance and internal flow of the turbine is carried out for the wind turbine model. The result shows that when the guide nozzle is installed, almost over two times of power coefficient are achieved in comparison with the case of no guide nozzle installation. The guide nozzle acts as a role of suppressing the flow resistance at the blade passage, which is found when the guide nozzle is installed. Moreover, in this study, two kinds of the guide vane with a straight type and a curved type are adopted and compared. The curved guide vane nozzle produces higher power coefficient in comparison with that of straight guide vane nozzle.

• 설비공학논문집
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• 제22권8호
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• pp.562-566
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• 2010

Wind energy is one of the most general natural resources in the world. However, as of today, generating electricity out of wind energy is only available from big wind generator, Furthermore, an axial-flow turbine is the only way to produce electricity in the big wind generator. This paper is for the guidance of drawing impact fact about power turbine using cross-flow type transferring wind energy to electricity energy. It will find the ideal value which enables to make cross-flow power turbine(CPT) using computational fluid dynamics(CFD) code. This study tries to analyze the "Solidity" characteristics. We can find out turbine-blade number through CFD. CFD is using "Fluent_ver 6.3.16", and the data from its result will judge fan-blade performance through specific torque and specific power from each "Solidity" model. Based upon the above, we will make cross-flow power turbine of multi-blade centrifugal fan instead of axial-flow type.

• 설비공학논문집
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• 제23권8호
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• pp.543-548
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• 2011

New concept of wind energy conversion system is proposed to increase the energy density at a given working space. The quality of wind for wind power generation is depend on its direction and speed. However, the quality is not good on land because wind direction is changeable all the time and the speed as well. The most popularly operated wind turbine system is an axial-flow free turbine. But its conversion efficiency is less than 30% and even less than 20% considering the operating time. In this research, a cross-flow type wind turbine system is proposed with a convergent-divergent duct system to accelerate the low speed wind at the inlet of the wind turbine. Inlet guide vane is also introduced to the wind turbine system to have continuous power generation under the change of wind direction. In here, the availability of wind energy generation is evaluated with the change of the size of the inlet guide vane and the optimum geometry of the turbine impeller blade was found for the innovative wind power generation system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3050-3055
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• 2007

A wind turbine is one of the most popular energy conversion systems to generate electricity from the natural renewable energy source and an axial-flow type wind turbine is the most popular system for the electricity generation in the wind farm nowadays. In this study, a cross-flow type turbine has been studied for the application of wind turbine for electricity generation. The target capacity of electric power generation of the model wind turbine developing on the project is 12 volts, 130A/H (about 1.56kW). The important design parameters of the model turbine impeller are the inlet and exit angle of the turbine blade, number of blade, hub/tip ratio and the exit flow angle of the casing. In this study, the radial equilibrium theorem was used to decide the inlet and exit angle of the impller blade and CFD technique was used to have the performance analysis of the designed model power turbine to find out the optimum geometry of the CPT impeller and casing. The designed CPT with 24 impeller blades at ${\alpha}=82^{\circ}$, ${\beta}=40^{\circ}$ of turbine blade angle was estimated to generate 284.6 N.m of indicated torque and 2.14kW of indicated power.

• 한국산학기술학회논문지
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• 제15권3호
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• pp.1272-1278
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• 2014

본 최근 성장하고 있는 해상 풍력의 실험연구에서 풍동시험이 수직형 횡류 풍력발전시스템의 성능을 조사하기 위해 실시되었다. 풍동의 시험 부분은 제한된 크기로 인해 실제 풍력 발전의 입구 안내 베인을 약 1/5로 축소시켰고, 터빈 임펠러의 지름을 모형 임펠러의 1/2로 감소시켰다. 임펠러 블레이드 갯수는 풍력 발전 시스템의 출력에 대한 또 다른 중요한 변수이기 때문에 8개와 16개로 변경하여 시험하였다. 실험 분석 결과, 모형 풍력 터빈의 출력 제동력은 정격 풍속 12m/s에서 블레이드 갯수가 8개 보다 16개일 때 82% 출력이 증가된 278와트로 측정되었고, 정격 제동력은 정격 작동 조건에서 3.9kW로 계산되었다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.230-231
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• 2003

Two and three-dimensional flows around a cross-flow wind turbine are investigated by the numerical simulation. The turbine studied in this paper has cylindrical shape with many small blades along its periphery. Incompressible Navier-Stokes equation is used for this simulation. A rotating coordinate system, which rotates at the same speed of the turbine, is used in order to simplify the boundary conditions on the blades of the turbine. Additionally, a boundary fitted coordinate system is employed in order to express the shape of the blades precisely. A third order upwind scheme is chosen for the approximation of the non-linear terms. When the number of blades is about 10, the highest torque is obtained.

• 한국지열·수열에너지학회논문집
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• 제12권3호
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• pp.9-16
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• 2016

This study had the purpose on feasibility judgment through performance forecast of wind power generation system using the cross flow vertical type wind power turbine for the situation of domestic small size wind power technology development. Wind power generation system uses the principle of venturi tube that gathers the wind through the first guide vane, and second guide vein changes the angle of the wind simultaneously by playing the role of venturi tube. After this, wind got out from the second guide vane spins the wind power turbine and has the meaning of judging on the aspect of numerical interpretation the feasibility for the small size wind power generation through wind power generation system that comes out from the back.

• Ocean Systems Engineering
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• 제11권1호
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• pp.43-58
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• 2021

In the present work, a 3D numerical model is proposed to study local scouring around single vertical piers with different cross-section shapes under steady-current flow. The model solves the flow field and sediment transport processes using a coupled approach. The flow field is obtained by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations in combination with the k-ω SST turbulence closure model and the sediment transport is considered using both bedload and suspended load models. The proposed model is validated against the empirical measurements of local scour around single vertical piers with circular, square, and diamond cross-section shapes obtained from the literature. The measurement of scour depth in equilibrium condition for the simulations reveal the differences of 4.6%, 6.7% and 13.1% from the experimental measurements for the circular, square, and diamond pier cases, respectively. The model displayed a remarkable performance in the prediction of scour around circular and square piers where horseshoe vortices (HSVs) have a leading impact on scour progression. On the other hand, the maximum deviation was found in the case of the diamond pier where HSVs are weak and have minimum impact on the formation of local scour. Overall, the results confirm that the prediction capability of the present model is almost independent of the strength of the formed HSVs and pier cross-section shapes.