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@PHDTHESIS{Weintraub:1004558,
author = {Weintraub, Daniel},
othercontributors = {Jeschke, Peter and Broichhausen, Klaus-Dieter},
title = {{M}antelpropellerantriebe für {K}leinflugzeuge},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2025-01495},
pages = {1 Online-Ressource : Illustrationen},
year = {2024},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University 2025; Dissertation, Rheinisch-Westfälische
Technische Hochschule Aachen, 2024},
abstract = {A design procedure for ducted fan propulsion systems is
presented in this thesis, which is used to evaluate their
operating behavior, noise and drag. Based on an exemplary
propulsion system design for a small aircraft with 1000 kg
take-off mass and a hybrid electric power train, the design
trade-offs of ducted propeller propulsion systems as well as
their advantages and disadvantages compared to the free
propeller are discussed.A combination of mean line flow
analysis and engine performance calculation methods is used
to model the ducted fan performance. Losses, noise and drag
are accounted for using partly analytical and partly
empirical models from literature. The motor operating
behavior is evaluated based on performance maps. Design
studies show that the fan and nozzle cross-sectional areas
are by far the most important parameters influencing
performance. Noise emissions also strongly depend on the
blade and vane numbers. The influences of pitch, chord
length and blade angles on performance and noise emissions
are also evaluated; they are significantly lower in most
cases. Performance follows steady trends as design
parameters or operating points change. Noise emissions, by
contrast, often change abruptly and strongly, driven by the
complex generation mechanisms of rotor-stator-interaction
noise. The exemplary propulsion design deals with a hybrid
electric ducted fan propulsion system powered by an internal
combustion engine with intermittent support from an electric
motor. For ducted fans without variable pitch blades, adding
the electric motor partially offsets some operational
limitations and makes significantly more thrust available
throughout parts of the flight mission, e.g., at take-off.
Moreover, ducted fans allow for a much quieter take-off than
required by current small aircraft certification standards
that have been developed for free propellers. For the
exemplary application, the calculated noise is more than 20
dB below the noise limit. Further noise reduction can be
achieved with a hybrid electric propulsion system. The
additional thrust enables a steeper climb on take-off, which
halves the time required to reach cruising altitude and
thereby significantly reduces noise on the ground. Overall,
ducted fans are promising low-noise propulsion systems and
their performance is improved when adding an electric motor,
thereby creating a hybrid powertrain. Due to the complex
relationship between performance and noise,
multidisciplinary methods are required for the predesign of
these propulsion systems, such as those presented in this
work.},
cin = {413510},
ddc = {620},
cid = {$I:(DE-82)413510_20180101$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2025-01495},
url = {https://publications.rwth-aachen.de/record/1004558},
}
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