Aeroacoustic analysis of aerodynamically optimized joined-blade propeller for future electric aircraft at cruise and take-off
Journal article, 2020

A novel propeller with the blade tips joined in pairs, named Boxprop, is designed and optimized for a conceptual electric aircraft using an efficient optimization platform. According to the thrust requirement of the electric aircraft at cruise, the Boxprop with optimal efficiency is down-selected from the Pareto front of thrust coefficient and propeller efficiency. Furthermore, the blade pitch angle is adjusted to meet the thrust requirement at take-off. It is found that the Boxprop is capable of suppressing tip vortices and inducing a wider wake behind blade tip in comparison to a conventional propeller usually shedding a concentrated tip vortex, which could potentially improve the propulsive efficiency. Afterwards, the aeroacoustic analysis performed by the hybrid integral method of Reynolds-Averaged Navier Stokes equations (RANS) and convected Ffowcs Williams and Hawkings (FW-H) equation shows that the tonal noise from the Boxprop with three joined blades operating at cruise is similar to a conventional three-bladed propeller, though being stronger than a conventional six-bladed propeller. Although the tip vortices have been suppressed by the joined-blade tips of the Boxprop, the corresponding tonal noise reduction is not prominent. Next, the Boxprop noise at take-off is studied. Unsteady RANS is used to resolve varying flow structures that become dominant under the take-off condition. Angle of attack (AOA) is found as an important factor influencing the noise generation. The radiated noise upstream and downstream of the propeller significantly intensifies due to increasing AOA. The AOA effects of the Boxprop follow a similar trend to a conventional propeller. The findings for the Boxprop aeroacoustics have enhanced the understanding of tip-vortex suppression techniques in connection with the tonal noise generation, which will be greatly helpful to the aeroacoustic design of Boxprop applied to electric aircraft in the future.

Aeroacoustics

Boxprop

Aerodynamic optimization

Electric aircraft

Author

Zhongjie Huang

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Huadong Yao

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Oliver Sjögren

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Anders Lundbladh

Chalmers, Mechanics and Maritime Sciences

GKN Aerospace Sweden

Lars Davidson

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Aerospace Science and Technology

1270-9638 (ISSN)

Vol. 107 106336

Reduction of Propeller Noise for Future Electrical Aircrafts

Chalmers, 2019-04-01 -- 2021-03-31.

Areas of Advance

Transport

Subject Categories

Subatomic Physics

Aerospace Engineering

Vehicle Engineering

DOI

10.1016/j.ast.2020.106336

More information

Latest update

1/7/2021 1