Alternative design for variable-geometry rotor of vertical axis wind turbine

• Main Author: Jungao, Erwin A.
• Format: text
• Language: English
• Published: Animo Repository 2005
• Subjects: Engineering design; Wind turbines; Rotors; Manufacturing; Mechanical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/3333; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=10171&context=etd_masteral
• Institution: De La Salle University

The Philippine Energy Plan 1999-2008 projected a wind energy contribution of 410 MW. This action is a part of its commitment to United Nations Framework Convention on Climate Change (UNFCCC) and to utilize the countrys wind resource potential. However, the country is situated in a typhoon-belt. Wind gust over 250 km/h during typhoon is one of the key problems that may hinder the wind turbine development in the country. In the search for an alternative solution, a variable-geometry vertical-axis wind turbine (VGVAWT) rotor (Æ0.6m) as a test model with straight and symmetrical air-foil blades was designed. The rotor was designed so that the blades can be reefed to reduce the size of its projected area to limit both power and blade loads by self-acting control. The reduction in load was estimated based on blade element-theory; and used in the calculation of stress reduction using CATIA V5 design software. In the experiment, the test model is subjected by air velocities generated by an industrial fan. Rotor torques for corresponding rotational speeds were calculated by inertia-acceleration method. An omni-directional cup anemometer and a non-contact speed meter were used in wind speed and rotors rotational speed measurements, respectively. A maximum power of 2.5 watts (1.4% Cp) was generated by the rotor at 10.7 m/s free-air velocity and 70 rotor rpm with blades not reefed. At maximum reef of 60º with a relative rotor area of 41%, the torque load reduces up to 86%. The data can be used as a guide in the design of a Æ3-m prototype rotor.