Experimental assessment of aerodynamic and aeroacoustic interaction effects of wingtip-mounted propellers

• Autor(a) principal: Silva, Gabriel Pereira Gouveia da
• Data de Publicação: 2023
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
• Texto Completo: https://www.teses.usp.br/teses/disponiveis/18/18161/tde-08112023-174940/
• topic: aeroacoustics; aeroacústica; aerodinâmica; aerodynamics; distributed electric propulsion; hélice de ponta de asa; propulsão elétrica distribuída; túnel de vento; wind tunnel testing; wingtip-mounted propeller

The development of electric motors and batteries for aeronautical applications should soon allow the design of aircraft that benefit from better propulsion-airframe integration. These new aircraft must be able to take advantage of the synergistic effects of this integration that were previously not possible with heavy combustion engines. One of these new concepts made possible by electric motors is the so-called wingtip-mounted propellers. The advantage of this engine positioning is that the propeller\'s slipstream rotating in a direction opposed to the wingtip vortex allows the reduction of the induced drag, in addition to an increase in the propeller\'s efficiency due to the swirl recovery promoted by the wing. It is necessary to know how the design parameters affect these aircraft\'s aero-propulsive and aeroacoustic performance to allow a better exploration of these concepts in the early stages of aircraft design. In this context, the research presented in this thesis refers to the design and implementation of a test rig at the Department of Aeronautical Engineering at EESC-USP for aerodynamic and aeroacoustic tests of distributed electric propulsion (DEP) aircraft wings. In addition, the aerodynamic forces and the noise generated by different combinations of propeller installation positions about the leading edge and chordspan plane, flap, and aileron deflections were measured in wind tunnels. In general, the propellers installed below the wing chord line allowed a more significant reduction of the induced drag factor (up to 25.7% about the corresponding condition without the propeller). The wingtip-mounted propeller mounted also increased the effectiveness of the aileron by up to 57% (for negative aileron deflections) and up to 75% (for positive aileron deflections), practically keeping the effectiveness of the flap unchanged, which was outside of the propeller stream tube. Regarding the acoustic measurements, the results showed that broadband noise was practically independent of the installation position of the propeller, which was not observed for the tonal noise, whose intensity and directivity pattern was highly dependent on the propeller installation position.