Browsing by Issue Date, starting with "2022-03-11"
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- Estudo do Confinamento da Hélice para o Sistema Propulsivo do Avião do Air Cargo Challenge 2021/2022Publication . Leite, Edson Lopes Barbosa; Silvestre, Miguel Ângelo RodriguesNo âmbito da participação da equipa AERO@UBI no Air Cargo Challenge (ACC) 2021/2022, foi realizado um estudo de viabilidade da utilização de uma hélice em ducto de forma a maximizar a tração da aeronave. Este ducto é projetado com base num estudo numérico realizado no Ducted Fan Design Code (DFDC). O estudo numérico serve de base para o desenho e fabrico, com tecnologias de impressão 3D por deposição de filamento fundido, de um protótipo utilizado em testes de validação da solução em ensaios no túnel de vento. Nestes ensaios, concluiuse que os resultados numéricos obtidos eram otimistas e o desempenho do conjunto propulsivo em túnel de vento mostrouse inferior ao da hélice não confinada para velocidades superiores a 10 m/s. Portanto a utilização de um ducto não seria viável para a aeronave ACC 2021/2022.
- Development of a Propeller Blade for a Variable Pitch MechanismPublication . Rodrigues, André Filipe Gomes; Silvestre, Miguel Ângelo RodriguesConsidering the evolution of the urban air mobility concept and the increasing number of vertical takeoff and landing aircraft in development, the use of the correct propeller for this kind of aircraft is paramount. This dissertation’s purpose is to develop a propeller blade with a propulsive efficiency as good as possible when used in a variable pitch mechanism. A blade propeller geometry was developed to be used in the different stages of flight. Therefore, during take-off, climbing and hover conditions the propeller can be used with low pitch to increase the performance in thrust per unit power. On the other hand, during cruise flight condition the propeller can be used with a coarse pitch to operate with greater propulsive efficiency. A proper propeller blade geometry was achieved. The respective CAD model with additional features was developed to build a prototype of the propeller using a FDM 3D printer. Specific printing settings and different finishing processes were applied to obtain the most accurate results possible. Comparing numerical and experimental results small divergences were realized. Considering the similarity between the results and the similar divergences that also occurred in the analysis of different propellers tested in identical conditions are indicators that it is possible to use 3D printing as a low cost way of rapid prototyping low Reynolds number propellers geometries that can be submitted to experimental performance tests.