Parametric study and flow characteristics of a new duct for ducted wind turbines system using analytical hierarchy process: numerical & experimental study

This paper aims to study aerodynamic modeling and optimization of the ducts to increase the power efficiency of ducted wind turbines. We design ducted wind turbines based on the features used to determine the sizes and indices of wind tunnels. Many researchers used analytical and numerical methods to select the optimized duct. This study evaluates the effect of design parameters, such as nozzle length, contraction ratio, and outlet diameter, on multiple responses. By applying the analytical hierarchy process (AHP), we find the best design of a duct optimizing the multi-criteria responses. A duct prototype is fabricated to validate the optimal design, and experimental analyses are conducted based on the fabricated duct. A measurement system estimates the pressure distribution in the inlet contraction section; then, a hot-wire sensor investigates wind speed and the flow turbulence in the throat section. A good correlation between calculated data and measured values was found during the estimation of pressure distribution along the inlet contraction wall. Investigation of flow turbulence in the throat section indicates velocity in the duct throat can increase from 2.6 to 2.9 times related to the free flow velocity at different working speeds. Spectral analysis of the flow signal inside the duct shows two peaks in a frequency lower than 32 Hz related to wind tunnel vibration and Gartler vortex. Then, the flow disturbances will not significantly impact the performance of the wind turbine placed inside the duct throat.