Análise integral de rotores eólicos verticais através da modelagem por tubos de corrente

Abstract

This work presents an integral analysis through the stream tube modeling applied to small vertical axis wind turbines with simple blade geometry (with a non-variable rotor radius) as well for a more complex geometry with variable rotor radius. By using the stream tube modeling, the induced velocities that actuates over the rotor blades are determined, being presented an analysis of the different stream-tube models available. An physical modeling of the problem is presented to make it possible to identify the equations related to the velocities and forces presents in the blade of an wind turbine, as well as the definition of the lift and drag coefficients for an NACA0012 airfoil. Through the equations that describes the physical phenomenon of the problem, an algorithm was developed in Python to solve and obtain the results and graphics to allow the analysis of interest. The analysis were conducted for two different turbine models, being one simpler, based on the Giromill, which results were compared with those results found in other papers and also, with an similar commercial generator. Another analysis were executed for an variable radius rotor with the Double V format by using an partitioning technique, in which the blade were cut in various same height elements, the results obtained through this method were compared with the previous results.