Hydro-electric power is a method of generating electricity from the rotational force of turbine blades by using the potential energy of a river or reservoir water. Recently, the necessity of small hydropower development is expanding due to the development and support of renewable energy, and because of the difficulty and environmental problems of huge dams. The purpose of this paper is to deal with a method of increasing the efficiency of small water turbine that can be adopt in low head condition. In order to improve the turbine efficiency, channel shape is optimized in order to minimize head loss using computational fluid dynamics. The angle values for the contraction and enlargement part of the channel where the turbine is located are found from the analyses. Additionally, three-dimensional analysis is applied to the optimized channel shape in order to confirm the optimized pipe.

This paper presents the flow analysis of flow over a cylindrical helical-blade turbine to investigate its optimum performance by varying design parameters. For numerical investigations, shear stress transport (SST) turbulence model is used. This simulation is carried out using commercial code CFX by ANSYS Inc. In this paper, the shape optimization was of turbine blades with NACA0021 performed for the vertical-axis turbine having the cylindrical shape. The influences of blade angle of attack, helical angle, and solidity on each shape are grasped. From of the flow analysis, power coefficient decreased when the helical angle was 20 degrees or more, and no electricity is produced when the solidity of 0.1. As a result of the shape optimization, the cylindrical turbine showed the highest power coefficient of 0.2733 at 3° of the blade angle of attack, 10° of the helical angle, and 0.2 of the solidity at the tip speed ratio of 1.

This is to develop a micro water turbine which makes some power from just a fluid velocity in the water pipe. While power is produced from impulsive force which generated by a high head in the case of existing water turbine, this is to produce a power from rotating force of helical turbine which rotated by fluid velocity in the water pipe. Some results of analysis fluid pattern at turbine blade for design shows that bubble is generated from turbulence surrounding blade and pulsatory motion generated as fluid being blocked and opened by blade due to turbine structure. This two phenomena cause to lower power production efficiency and shorten turbine durability. So this is studied to minimize bubble generation and pulsation for optimizing design of turbine blade. Therefore it is determined that the number of blade is three, geometric form of blade is NACA 4420 and angle of blade is 30 degree. An experiment equipment of water turbine is manufactured on the base of these factors(NACA 4420, angle 30。). It is obtained that power production of turbine increases in proportion to velocity which is changed from 1.7 m/sec to 3.5 m/sec. When fluid velocity is 1.7m/sec the power production of turbine is 355W. Power production increase continuously as increasing the fluid velocity and power is 2kW on 3m/sec of fluid velocity.

The performance of helical hydro turbine in water pipe line depends on the sectional shape of turbine blade, pitch angle of turbine blade, solidity and number of turbine blades, To investigate the effects of these design factors on the performance of helical hydro turbine, flow analysis was carried out by using commercial code ANSYS CFX version 14..5. From CFD analysis we obtained the optimum design factors which were the asymmetric blade shape of NACA4420, the pitch angle of 15 degrees and the solidity of 0.3. These results can be used for the actual design of sphere-shaped helical turbine in water pipe line.

In this study, the capability of an existing analysis method for the fluid-structure-soil interaction of an offshore wind turbine is expanded to account for the geometric nonlinearity and sea water drag force. The geometric stiffness is derived to take care of the large displacement due to the deformation of the tower structure and the rotation of the footing foundation utilizing linearized stability analysis theory. Linearizing the term in Morison’s equation concerning the drag force, its effects are considered. The developed analysis method is applied to the earthquake response analysis of a 5 MW offshore wind turbine. Parameters which can influence dynamic behaviors of the system are identified and their significance are examined.