الفهرس 
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Abstract
The applications of small scale wind turbines have significant growth in recent years, especially in remote areas or areas with a weak electricity grid. However small wind turbines exist on the market with different designs and different number of blades for instance, two, three and five. Also, in some applications the number of blades may increase above five blades.
This study presents experimental and numerical investigations for a small scale wind turbine with different blade number of two, three, five and six in order to recommend the best rotor configuration. An experimental measurements were performed in a commercial wind turbine ANEMOS 455 model for three, five and six rotor blades. While numerical calculation was performed as well for two, three, five and six blades number. This turbine is available on the market with five blades. The rotor diameter is 2 m and the rotational speed varied from 100 to 800 RPM. Measurements were carried out for different tip speed ratios in a closed-loop open test chamber wind tunnel of the University of Perugia (Italy) at inlet velocity of 6, 7, and 8 m/s. Numerical investigation was performed as well to extend the investigation above those measured experimentally. Numerical calculation was performed using a steady-RANS with the Shear Stress Transport SST k- turbulence model, adopting the multiple reference frame (MRF) strategy to reduce the computational effort.The effect of wind tunnel blockage, defined as the ratio of wind turbine swept area to the tunnel cross section area on the performance of wind turbine is also presented. It was found that:
i) The wind tunnel wall interference led to an increase of the measured power coefficient which approached the Betz limit for all measured velocities.
ii) Increasing number of blade (solidity) leads to produce a narrow power curve, than for low solidity wind turbines. Hence, the turbine with high solidity is very sensitive to tip speed ratio
iii) High solidity wind turbine has smaller cut in wind speed than low solidity wind turbine, which makes it suitable to work in low wind speed conditions
iv) The wind turbine with 3 blades configuration has the maximum power coefficient in respect to 5 and 6 blade turbines, higher by around 2 and 4 percent respectively. Numerical results showed reasonable agreements with experimental measurements.