Abstract
The research work depicts the study of the comparison of a 1kW Fixed Pitch Vertical Axis Wind Turbine (VAWT) and a Variable Pitch VAWT via analytical, numerical and experimental results. Being an emerging technology, wind turbine is becoming a source of attraction for the researchers. The VAWT in comparison to the Horizontal Axis Wind Turbine (HAWT), has shown numerous benefits. The fundamental purpose of this work is to maximize the output power and output torque of the wind turbine. For achieving an improved output, a novel and unique mechanism, termed as pitching mechanism, is employed that follows the variable pitch concept. The mathematical modelling was done for the straight blade variable pitch VAWT as well as for the fixed rotor. The four bar mechanism was developed, to execute the variable pitch mechanism, and implemented in the form of the CAD model. A scaled down 3D Model of the rotor was manufactured using 3D printing technique. The aerodynamic forces such as lift and drag were measured upon the rotor as per the testing on the rotor in the wind tunnel. CFD simulations were run for the fixed pitch as well as the variable pitch rotor. The transient analysis was performed for the azimuthal angle ranging from 0 to 360 degrees and for a pitch angle varying from +25 to-25 degrees in ANSYS software. The comparative study was undertaken, keeping in view the analytical, simulation and experimental results. A worthy agreement was observed between analytical, software and experimental results and a promising increase in power and torque was observed due the introduction of the variable pitch mechanism. The power produced by the variable pitch design showed a significant increase in the power production as compared to the fixed pitch design. The numerical and experimental values of cp for the variable pitch design were quite comparable.
Estimation of blade loads for a variable pitch vertical axis wind turbine from particle image velocimetry
