masterThesis
Estudo numérico de um aerogerador projetado com a metodologia BEM e da utilização de um intensificador de potência
Fecha
2017-08-28Registro en:
BARROS, Aideé Amélia Torres Sampaio. Estudo numérico de um aerogerador projetado com a metodologia BEM e da utilização de um intensificador de potência. 2017. 132f. Dissertação (Mestrado em Engenharia Mecânica) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2017.
Autor
Barros, Aideé Amélia Torres Sampaio
Resumen
Concerns about the greenhouse effect and the ill-treatment of the environment due to nonrenewable
energy sources, such as fossil fuels, has aroused a special interest in the use of
renewable energy sources, such as wind energy. Wind energy has been standing out in Brazil’s
current energy scenario. The conversion of wind energy into electricity is accomplished with
wind turbines. Wind Turbines, which are responsible for the conversion of wind energy into
electricity, are intensively studied, since they are a powerful system for energy conversion, but
still have a low efficiency when compared to other systems. One way to increase efficiency is
using flanged diffusers in order to create a pressure gradient which would result in a larger flow
of air, in the rotor, at a higher speed. As the output power of a wind turbine is directly
proportional to the velocity, the power would increase. Therefore, the present work investigates
how the use of a flange diffuser coupled to a low power wind turbine can influence its power
output. In order to achieve this objective, the design and 3D modeling of the rotor of a wind
turbine with a conversion capacity of 300W was done using the Blade Element Momentum
(BEM). Transient numerical simulations of the turbulent flow using CFD software were
accoplished. Two different 3D models were considered, the first one was only the wind turbine
and the second was the wind turbine with an element to increase power, thus allowing a
comparison between the two configurations. As a secondary objective, comparisons of the
numerical results with the analytical results of the adopted design methodology (BEM) were
carried out to identify whether the data obtained through the design (axial induction factor,
angles, velocities triangle) are present in the numerical solution. The analysis allowed to verify
that the diffuser increases the velocity of the air, passing through the wind rotor, by
approximately 50%, causing an increase of 330% in the output power. Maximum differences
of about 10% were found between the analytical solution and the numerical solution. In
addition, it was observed that with the increase of the velocity of the mass of air, and without
the increase of the speed rotation, the velocities triangle ends up being modified which
generates the stall phenomenon. Finally, a new analysis was done, with the corrected speed
rotation, where it can be observed that the speed triangle stabilizes.