Spectral Analyses of an Optimized Ducted Wind Turbine using Hot-Wire Anemometry

The use of ducted wind turbines is developing and various scientists in their studies investigate the performance, economic analysis, and energy production by these types of turbines at a lower cost. In this paper, the ratio of wind speed increment related to free stream wind speed and turbulence rate in a pre-designed duct used for a horizontal three-blade wind turbine was evaluated using a hot-wire anemometer sensor and data analysis methods. The duct installed in the University of Tehran Aerospace Faculty wind tunnel and flow characterization was performed by using CTA apparatus to measure and evaluate the wind flow turbulency in the throat section of the duct, where the wind turbine was installed. Wind speed analysis was done at different speed of the wind tunnel test section and shown that in the throat section of the duct the wind speed increased with a constant slope and in more analysis, it was found the wind speed in the duct throat can be increased to 2.5 up to 3 times of free stream flow speed at a different wind speed of wind tunnel test section. Fast Fourier transform was used to evaluate the frequency content of measured signals and it is shown that frequency level decreased by any decrease in wind flow speed and its energy level. From spectral analysis, it was found that only a few peaks are included in the extracted frequency that shown low turbulence inside the duct it can be concluded that the flow disturbances will not have a significant impact on the performance of the wind turbine placed inside the duct throat.