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Showing 2 results for Straight Blade
H. Seifi Davary, Sh. Kouravand, I. Khatami,
Volume 20, Issue 1 (1-2020)
Abstract
The important factor in turbine efficiency is turbine rotation. The higher the rotor time at different speeds, especially at low speeds, increases the turbine power. In this regard, first, the airfoil NACA0015 was selected and the K-ω SST turbulence method was used for numerical analysis. The validation was performed using experimental results. The wind turbine was designed and fabricated by CATIA software. The aluminum sheet used by a series alloy is used to make smooth, porous leaves from simple cards and diamond-shaped leaves, in a porous form with 0.3 mm thick. The instrument used in measurement, testing and fabrication have been calibrated to compute more precisely and to generate wind flow from the four-fan blower. The results show that the darriues vertical axis wind turbine with porous and flat blades has begun to rotation at the speed of 2.3 and 3.9 m/s. At the speed of 2.5 and 3 m/s, the rotation of wind turbine porous blade doubled and at the speed of 4 m/s, its rotation speed was 3 times higher than the speed of straight blade turbine. The rotation of wind turbine porous blade in speeds of 4.5, 5, 5.5, 6, 6.5 and 7 m/s were 56.25 %, 20 %, 22 %, 15 %, 7.5 %, and 12% higher than the straight blade turbine and in speed of 8-10 m/s the rotation of the straight blade turbine and porous blade turbine is almost equal.
Sh. Shams, M. Ramezani, A. Molaei,
Volume 20, Issue 5 (5-2020)
Abstract
The aerodynamic of Vertical Axis Wind Turbine (VAWT) is more complex than a horizontal axis wind turbine. In the present research, the combination of the Wagner unsteady aerodynamic model, static stall and Double Multiple Stream Tube (DMST) aerodynamic model have been used to investigate the aeroelastic behavior of VAWT. For this purpose, the DMST aerodynamic model, which is related to the vertical axis wind turbine aerodynamics model, has been used to obtain two parameters of the angle of attack and relative velocity. Then these two parameters have been applied to the Wagner nonlinear aerodynamics, which considers the effect of the static stall. This flexible nonlinear presented model based on DMST is called NFDMST aerodynamic model. One-degree of freedom of typical section and two-degree of freedom model have been investigated for static aeroelasticity and dynamic aeroelastic behavior, respectively. The VAWT blade experiences a variety of attack angles and relative velocity in a spin, so the goal is to obtain the instability velocity in a different position and consider the effect of aerodynamic and structure nonlinearity. The results show that the nonlinear aerodynamic model has accurate results and the aeroelastic design condition associated with -90degree azimuth angle, in which the minimum instability velocity is 45.2m/s. In addition, the change of instability speed of rotating airfoil in a spin is about 6%.
