Low-Noise Propeller Design for Future Electric Aircraft
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Typ
Examensarbete på kandidatnivå
Program
Publicerad
2020
Författare
Haidari, Mohamed Hadi
Hövik, Felix
Lago, Caspian
Lindé, Fredrik Nyström
Sjöberg, Jacob
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Right now electric aircraft are being developed as an alternative to make the aviation
industry more sustainable. The electric airplanes available today are using
propellers connected to an electric engine as the main propulsion system, and thus
the propeller is a critical part of the airplane. This numerical study aims to give a
better understanding on how to create propellers optimized for electric aircraft with
minimum energy loss and noise emissions.
An existing propeller design methodology, implemented in the MATLAB environment
as OptoProp, is applied to design a propeller with optimum efficiency. A
documented case is then used to verify the applied program. Afterwards, the program
is utilised to conduct a parameter study where one or multiple parameters at
a given thrust are alternated, and also studying the usage of multiple propellers.
Then, the calculated data is used as input for the noise simulations. The results
from the parameter study indicates that increasing an individual parameter leads
to an improved aerodynamic performance. When testing multiple parameters the
positive results from increasing each parameter value continues to a certain point
after which the propeller performance decreases. When studying multiple propellers
it was found that optimal efficiency is achieved with a four propeller setup.
During this project tools used to simulate propeller noise have been developed in
a MATLAB environment. The programs are verified by comparing the results to
previously documented cases and then used to study sound emissions of single propellers
with varying parameters. The results from this study show the impact each
parameter has on the noise levels and their correlation with the tip Mach number
should be considered. Lastly, sound emissions of multiple propellers and different
propeller distributions are studied. This study indicates that the impact on noise
far away from the propellers is almost insignificant whereas the noise close to the
propellers generally decreases with an increasing number of propellers.
Since the conclusions from the two studies differ, compromises had to be made
in order to propose guidelines, taking the results from both studies into account.
The guidelines contain recommendations for an optimal propeller design, balancing
the choice between high efficiency and reduced noise pollution.
Beskrivning
Ämne/nyckelord
low-noise propeller , electric aircraft , propeller design , acoustic studies