DEVELOPMENT OF OPTIMUM DESIGN CONFIGURATION AND PERFORMANCE FOR VERTICAL AXIS WIND TURBINE
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Publication Number: CEC-500-2005-084
Abstract:
A general aerodynamic optimization method was used to improve the torque characteristics of a Split-Savonius type vertical axis wind turbine. NASA INS2D software was used to compute the aerodynamic performances required to evaluate the torque characteristics. A decomposition, deformation, and reassembly method was developed to accommodate the variable geometry of the blade during the optimization process. The deformation of the grid was accomplished by a modified version of the Transfinite Interpolation (TFI) method. The method is first applied to a single blade of the turbine and yields a 27% improvement in overall torque. Further analyses were performed on a single blade with a spanwise slot and two-blade configuration with and without the slots and results indicated more than 10% further improvement in the overall torque with the slots in place. Two small scale prototype double-blades turbines with and without the spanwise slots were built and tested in the Boeing/CSULB low speed wind tunnel at three free stream mean velocities of 6.8, 8, and 9.75 m/sec which correspond to Reynolds numbers based on cord length of 12.25x104, 14.4x104, 17.6x104 respectively. The experiments were performed for blades at zero and 48% overlap conditions. Results show that at the free stream mean velocity of 6.8 m/sec, for the zero overlap condition, the peak power coefficients for the optimized blade with and without the slots are respectively 17% and 40% higher than the corresponding value for the high efficiency Benesh airfoil. The continuous increase in the power coefficients for the optimized blades extend to a tip speed ratio of 1.6, much higher than the range observed for the Benesh airfoil. Key Words: (vertical axis wind turbine, wind energy, thin airfoil optimization, aerodynamic optimization, wind turbine rotor optimization)
Author(s): William Kopko Commission Division: Technology Systems Division - R&D, PIER (500)
Office/Program: Energy Innovations Small Grant Pgm
PIER Program Area: Energy Innovations Small Grant (EISG)
Date Published: May 2005
Date On Line:
05/02/2005
Acrobat PDF File Size: 42 pages,
2,313 kilobytes**
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