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Projeto detalhado do sistema propulsivo para um veículo Aéreo Não Tripulado com capacidade de voo vertival e uma célula de combustível de hidrogénio
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Abstract(s)
A presente dissertação decorre de um projeto de desenvolvimento de um veículo aéreo nâo tripulado (VANT), com capacidade de descolagem e aterragem vertical e com célula de combustível de hidrogénio como fonte principal de energia. O projeto abrange diversas áreas de estudo sendo esta dissertação centrada no estudo do sistema propulsivo. Como ponto de partida são abordados conceitos relativos ao sistema propulsivo assim como fundamentos da metodologia computacional adotada.
Posteriormente são definidos e justificados os parâmetros inicias inerentes à fase conceptual, seguido da análise e selecão dos componentes do sistema propulsivo.
Na fase detalhada é efetuada a análise teórica Blade Element Theory referente às hélices de voo horizontal.
A metodologia é validada, apresentando resultados de thrust consistentes com os resultados experimentais, representando um bom método de comparação de hélices. A análise da dinâmica de fluidos computacional é efetuada com recurso ao software Ansys CFX utilizando o modelo de turbulência k_E adequado para escoamentos rotacionais e números de Reynolds analisados. Os ensaios em túnel de vento realizados apresentam um desvio padrão inferior a 1 N, pelo que se concluiu ser uma boa amostra recolhida.
Perante a comparação dos resultados práticos e experimentais, referentes às hélices de voo horizontal
e ao rotor vertical, obteve-se um erro inferior a 10 %, o que valida a modelação e a metodologia computacional adotadas. Por último, é demonstrado que o desempenho da hélice de voo horizontal e
rotor vertical selecionados cumpre com os requisitos do projeto.
This dissertation stems from a project to develop an unmanned aerial vehicle (UAV), with vertical take-off and landing capability and with a hydrogen fuel cell as the main source of energy. The project covers several areas of study with this dissertation’s main focus being the study of the propulsive system. As a starting point, basic concepts related to the propulsive system are discussed, together with the fundamentals of the computational methodology adopted. Subsequently, initial parameters, inherent to the conceptual phase, are defined and justified, followed by the analysis and selection of the components for the propulsive system. In the detailed phase, the Blade Element Theory theoretical analysis regarding the horizontal flight propellers is carried out. The methodology is validated, showing thrust values consistent with the experimental data, representing a good method for comparing propellers. The computational fluid dynamics analysis (CFD) is performed using the Ansys CFX software with the k_E turbulence model, suitable for rotational flows and the Reynolds number analyzed. The wind tunnel tests presented acceptable results, since the standard deviation was smaller than 1 N. When comparing the computational and experimental results, referring to the horizontal flight propellers and the vertical rotor, an error of less than 10 % was obtained, validating the adopted modelling and computational methodology. Finally, it is demonstrated that the performance of the selected horizontal flight propeller and vertical rotor meets the design requirements.
This dissertation stems from a project to develop an unmanned aerial vehicle (UAV), with vertical take-off and landing capability and with a hydrogen fuel cell as the main source of energy. The project covers several areas of study with this dissertation’s main focus being the study of the propulsive system. As a starting point, basic concepts related to the propulsive system are discussed, together with the fundamentals of the computational methodology adopted. Subsequently, initial parameters, inherent to the conceptual phase, are defined and justified, followed by the analysis and selection of the components for the propulsive system. In the detailed phase, the Blade Element Theory theoretical analysis regarding the horizontal flight propellers is carried out. The methodology is validated, showing thrust values consistent with the experimental data, representing a good method for comparing propellers. The computational fluid dynamics analysis (CFD) is performed using the Ansys CFX software with the k_E turbulence model, suitable for rotational flows and the Reynolds number analyzed. The wind tunnel tests presented acceptable results, since the standard deviation was smaller than 1 N. When comparing the computational and experimental results, referring to the horizontal flight propellers and the vertical rotor, an error of less than 10 % was obtained, validating the adopted modelling and computational methodology. Finally, it is demonstrated that the performance of the selected horizontal flight propeller and vertical rotor meets the design requirements.
Description
ALF/ENGAER 139426-G Pedro Afonso Aires Penso Machado e Silva.
Júri: Presidente: BGEN/EngEl 119923-E Rui Fernando da Costa Ferreira; Orientador: MAJ/EngAer 131603-G João Vítor Aguiar Vieira Caetano; Dr. Frederico José Prata Rente Reis Afonso
Vogal: Prof. Dr. Afzal Suleman.
Keywords
Célula de combustível Dinâmica de fluidos computacional Hélice Hidrogénio Sistema propulsivo VANT CFD Fuel cell Hydrogen Propeller Propulsive system UAV
Citation
Publisher
Academia da Força Aérea