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Master's Dissertation
DOI
https://doi.org/10.11606/D.18.2020.tde-22102020-104551
Document
Author
Full name
Daniel Garcia Ribeiro
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2020
Supervisor
Committee
Muñoz, Hernan Dario Ceron (President)
Malatesta, Vinicius
Santana, Leandro Dantas de
Title in Portuguese
Análise paramétrica da geometria de winglets na eficiência aerodinâmica para uma pá de gerador eólico de eixo horizontal
Keywords in Portuguese
Winglets
Eficiência de turbinas eólicas de eixo horizontal (HAWT)
Fluidodinâmica computacional (CFD)
Vórtices de ponta de pá
Abstract in Portuguese
A conversão de energia cinética do vento em energia elétrica, numa turbina eólica de eixo horizontal, é limitada por diversas perdas e, dentre elas, existem as perdas aerodinâmicas que ocorrem na ponta da pá em razão dos vórtices criados nesta mesma região. Embora existam diversos estudos sobre aplicação de dispositivos de ponta para a redução de tais vórtices e o aumento da eficiência de turbinas eólicas, ainda se fazem necessários estudos sobre determinados parâmetros de winglets e como eles influenciam nos coeficientes de potência e empuxo. Assim, este trabalho objetiva analisar, no software CFD ANSYS CFX®, o efeito da utilização de winglets e da variação do seu afilamento e da corda de sua raiz nos coeficientes aerodinâmicos de uma turbina eólica de eixo horizontal. As equações RANS são resolvidas em regime permanente, utilizando o modelo de turbulência κ - ω SST e com a metodologia moving reference frame. As simulações são validadas e comparadas com os resultados experimentais de um consórcio internacional denominado "IEA Wind Task 29 Mexnext". Foram estabelecidas 12 configurações diferentes de winglets e os resultados mostram que quanto maior o afilamento e menor a corda da raiz, maior é o aumento no coeficiente de potência e menor o aumento no coeficiente de empuxo, com valores máximos de 2,98% e 4,87% respectivamente, além de que tais alterações dependem do regime de operação da turbina. Ademais, foi observado que essas alterações ocorrem em razão do enfraquecimento dos vórtices de ponta de pá.
Title in English
Parametric analysis of winglets geometry on aerodynamic efficiency of an horizontal axis aerogenerator blade
Keywords in English
Blade tip losses
Computational Fluid Dynamics (CFD)
Horizontal axis wind turbines performance
Winglets
Abstract in English
Converting kinetic energy into electrical energy is limited by many losses in a horizontal axis wind turbines. Some of these losses are the aerodynamic ones and they occur at blades tips due to vortex structures that are shed away from this region. Although there are many studies about the effects of blade tip devices on wind power augmentation, it is still necessary to study more about some specific winglet parameters and how they influence power and thrust coefficient. Therefore, this research aims to analyse the effects of using winglets and how its tapered ratio and root chord exert influence on a horizontal axis wing turbine aerodynamic coefficients. The RANS equations are numerically solved in steady state, with κ - ω SST turbulence model and moving reference frame methodology. The simulations are computed in CFD ANSYS CFX® software, validated and compared with experimental results from the "IEA Wind Task 29 Mexnext" international consortium. Twelve different configurations of winglets were designed and the results showed that the bigger the tapered ratio and the smaller the root chord are, the bigger the power coefficient increase becomes and the smaller the thrust coefficient becomes. Maximum obtained values were 2,98% and 4,87% respectively. Besides that, the changes in aerodynamic coefficients depends on the wind turbine operation condition. Furthermore, it was concluded that these changes occur due to the weakening of tip votices.
 
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Publishing Date
2021-06-01
 
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