• Journal of Advanced Research in Ocean Engineering
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• v.1 no.2
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• pp.73-84
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• 2015

The turbine is one of the most important components in the tidal current power device which can convert current flow to rotational energy. Generally, a tidal turbine has two or three blades that are subjected to hydrodynamic loads. The blades are continuously deformed by various incoming flow velocities. Depending on the velocities, blade size, and material, the deformation rates would be different that could affect the power production rate as well as turbine performance. Surely deformed blades would decrease the performance of the turbine. However, most studies of turbine performance have been carried out without considerations on the blade deformation. The power estimation and analysis should consider the deformed blade shape for accurate output power. This paper describes a fluid-structure interaction (FSI) analysis conducted using computational fluid dynamics (CFD) and the finite element method (FEM) to estimate practical turbine performance. The loss of turbine efficiency was calculated for a deformed blade that decreased by 2.2% with maximum deformation of 216mm at the blade tip. As a result of the study, principal causes of power loss induced by blade deformation were analysed and summarised in this paper.

• Journal of the Korean Solar Energy Society
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• v.36 no.1
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• pp.75-81
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• 2016

The west and south coastal regions of Korea are known to be of strong tidal current speed. With the increasing demand for renewable energies, the resource assessment has been a crucial issue which should be conducted before any detail planning and development of the potential sites for tidal current farm. Although there are several results of resource assessment of tidal current energy in Korea, the resource assessment method is not officially announced. This undefined methodology makes the results unreliable and useless. Recently new renewable energy potential definition has been announced by KIER (Korea Institute of Energy Research). This categorizes energy potential as four steps; theoretical, geographical, technical and market potentials. This paper describes the resource assessment of tidal current power in Korea based on API (Averaged Power Intercepted). The results show that the Incheon-Gyeonggi and Jeollanam-do are very promising areas for tidal current power in Korea.

• International Journal of Ocean System Engineering
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• v.1 no.3
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• pp.144-147
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• 2011

The rotor that initially converts the flow energy into rotational energy is a very important component that affects the efficiency of the entire tidal current power system. Rotor performance is determined by various design variables. Power generation is strongly dependent on the incoming flow velocity and the size of the rotor. To extract a large quantity of power, a tidal current farm is necessary with a multi-arrangement of devices in the ocean. However, the interactions between devices also contribute significantly to the total power capacity. Therefore, rotor performance, considering the interaction problems, needs to be investigated to maximize the power generation in a limited available area. The downstream rotor efficiency is affected by the wake produced from the upstream rotor. This paper introduces the performance of a downstream rotor affected by wakes from an upstream rotor, demonstrating the interference affecting various gabs between devices.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.160.2-160.2
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• 2011

바다를 가로막는 방벽이나 방조제의 배수갑문 또는 조력발전소의 수문과 같이 인공 해양구조물을 통하여 흐르는 고속 해류를 이용하여 발전하는 해류발전 방식에 있어서, 고속 해류에 적합한 수차터빈과 발전기의 특성을 알아보았다. 조석간만의 차가 큰 지역에 설치되는 인공 해양구조물을 지나는 해류는 인공 해양구조물 전후에 발생하는 해수의 위치에너지 차이가 운동에너지로 바뀌면서 조석간만의 자연현상에 의해 발생되는 조류의 속도보다 훨씬 더 빠르게 흐른다. 이론적으로 우리나라의 서해안의 조석간만의 범위 3~8m로부터 7.5~12m/s 정도의 고속 해류가 가능하다. 이러한 경우에 적합한 해류발전기는 수차터빈 날개지름의 크기가 5m에서부터 12m 이하이면서, 증속기어박스와 발전기, 유압시스템 및 냉각시스템 그리고 전력변환장치를 포함하는 발전시설들을 해수면 위에 설치하는 것이 바람직하다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.67-73
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• 2006

Uldolmok waterway is famous for its strong tidal current with maximum current of about 12knots, which is located between the Chindo island off the southwestern tip of Korean peninsula and mainland. A serious of field observations, along with numerical modeling, have been carried out over the last several years, in order to understand the tidal dynamics and to examine the related variables according to the tidal current power plant (TCPP) operation.

• Journal of the Korean Solar Energy Society
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• v.26 no.4
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• pp.47-54
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• 2006

The current power generation is very suitable renewable energy for the application to Korean western and south coastal regions where characterized as having high current speed. Being different from tidal power generation that needs tremendous dam structure to preserve water, the current power generation utilizes the ocean current flow without damaging to estuary area and its environment. There are still many areas to understand the characteristics of current power generation for the actual field installation. As designing muti module with several rotors, the interaction between rotors will occur that would affect the efficiency and RPM of each rotor. In this study, the interactions caused by gaps between rotors in multi module are studied.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.99-104
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• 2006

There are several advantages to make use of a bridge pier for the tidal power generation. Current velocity increases near the pier, therefore the tidal power generation becomes more efficient because the power is proportional to the cubic of the current velocity. The pier is convenient for access and maintenance of the hydraulic turbine and the power unit. The project is now underway at the Ikitsuki Bridge in Tatsuno-Seto Strait of Nasasaki Prefecture, where the tidal current was measured by the bottom mount ADCP for almost one year. Model experiments for a Darrieus water turbine with two and three straight blades were carried out in the circulating water channel, in which the power coefficients of the turbine were obtained as a function of blade section and the attaching angle of a blade to the rotor. Those experimental results are discussed to obtain an optimum Darrieus turbine for tidal power generation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.16 no.1
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• pp.43-47
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• 1980

The author designed and tested the high sensitive three-phase power factor meter and relay circuit, and dealt with the circuit to detect the phase of the current and the voltage. An operational amplifier comparator circuit and two single-phase transformers are used to control and detect the phase angle between the current and the voltage. The results obtained are as follows: 1. Converting the sine wave input current into the constant amplitude rectangular wave form by using a transistor chopper circuit, the power factor can be measured precisely over the load current of 0.08 A. 2. Using the moving coil type current meter, the power factor meter can be read in uniform . scale all over the range. 3. Using the three-phase power factor meter, the power factor relay which works at any power factor can be made.

• Journal of Ocean Engineering and Technology
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• v.27 no.3
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• pp.73-78
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• 2013

CFD (computational fluid dynamics) analyses that considered the dynamic interaction effects between the flow and a turbine were performed to evaluate the power output characteristics of two representative vertical-axis tidal-current turbines: an H-type Darrieus turbine and Gorlov helical turbine (GHT). For this purpose, a commercial CFD code, Star-CCM+, was utilized, and the power output characteristic were investigated in relation to the scale ratio using the relation between the Reynolds number and the lift-to-drag ratio. It was found that the power coefficients were significantly reduced when the scaled model turbine was used, especially when the Reynolds number was lower than $10^5$. The power output characteristics of GHT in relation to the twisting angle were also investigated using a three-dimensional CFD analysis, and it was found that the power coefficient was maximized for the case of a Darrieus turbine, i.e., a twisting angle of $0^{\circ}$, and the torque pulsation ratio was minimized when the blade covered $360^{\circ}$ for the case of a turbine with a twisting angle of $120^{\circ}$.

• Journal of Energy Engineering
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• v.22 no.4
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• pp.386-393
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• 2013

An feasibility analysis is performed for the tidal current power generation with the examination of the sea water speed distribution at Pungdo. In this analysis, the water speed distribution which is the key issue was obtained from the actual speed distribution data and results in "the annual current tidal power". Due to the lack of cost information, we applied EPRI data from the internet site instead of the actual information. The result could be used as a base data for the construction of current tidal power plant in the near future. And it is expected to provides good data for the Energy policy.