垂直軸風車専用に特化した勾玉形風車ブレードの性能検討

抄録

　　　A new wind turbine blade which has Magatama-type cross section is investigated. This blade is exclusively developed for vertical axis wind turbine (VAWT). It is expected that VAWT with this Magatama-type blade is able to operate in low wind speed condition. Numerical simulation is first attempted as a preliminary test to determine the configuration of the cross section of the Magatama blade. Intensive wind tunnel tests are then executed to investigate detailed other conditions to operate as a VAWT. Performance of VAWT with Magatama blades and that with conventional NACA0018 blades are compared by wind tunnel experiments. Results show the VAWT with Magatama blades effectively works and generates power in low tip speed ratio condition as compared with the VAWT with conventional NACA0018 blades. Angle of blades is usually set at drag-type or lift-type position on its rotor in conventional VAWT rotor case. On the other hand, VAWT with new Magatama blade generates maximum power when the Magatama blades are set at angle between conventional lift- and drag- type position. Pressure and velocity distributions around the blade on rotating rotor indicate this is caused by effective lift force generated by Magatama blade in backward side of azimuth position in low tip speed ratio condition.