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Performance prediction of Darrieus vertical axis wind turbines using double multiple stream-tube model

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Horizontal and vertical axis wind turbines (HAWTs and VAWTs) are two main kinds of wind turbines, which are the most popular way to catch energy from the wind. By comparison, VAWTs have some advantages, but they also have the complexity in aerodynamics that needs a deep investigation. | TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 18, SOÁ K7- 2015 Performance prediction of Darrieus vertical axis wind turbines using double multiple stream-tube model Le Thi Hong Hieu Nguyen Chi Cong Luong Huu Trong Ho Chi Minh city University of Technology, VNU-HCM (Manuscript Received on July 08th, 2013, Manuscript Revised September 03rd, 2013) ABSTRACT Horizontal and vertical axis wind turbines (HAWTs and VAWTs) are two main kinds of wind turbines, which are the most popular way to catch energy from the wind. By comparison, VAWTs have some advantages, but they also have the complexity in aerodynamics that needs a deep investigation. A code is developed based on Double multiple stream-tube and corrections of the dynamic stall for Darrieus VAWTs. It is capable of estimating the output power versus different operating conditions defined by the tipspeed-ratio. The code is also validated with experimental data of many SANDIA Darrieus VAWT turbines. Key words: DMST, VAWT, HK-VAWT, Darrieus type, momentum theory, blade element method, Dynamic stall, SANDIA 17-m, SANDIA 5-m. Length of blades m Nomenclature | | = ∆ sin , Blade element’s area Abbreviations of a stream-tube HAWT Horizontal axis wind turbines Rotor rotational speed rad/s VAWT Vertical axis wind turbines Power coefficient DMST Double multiple stream-tube Lift force coefficient DS Dynamic stall Drag force coefficient TSR Tip speed ratio Normal force coefficient AOA Angle of attack Tangential force Symbol coefficient Power W Thrust force coefficient Tip speed ratio The thrust force acts on N Air density kg/m3 disk or a blade element Velocity of wind m/s Rotor torque Nm Relative velocity m/s Local radius m Mach number Maximum rotor radius or m Rotor swept area m2 radius at equator Thickness ratio / Local turbine height m Chord line m Height of rotor m Number of blades Trang 153 SCIENCE & TECHNOLOGY DEVELOPMENT, Vol 18, No.K7- 2015 = / , nondimentional rotor height = / , nondimentional rotor radius Azimuthal