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@PHDTHESIS{Hofmann:1016159,
author = {Hofmann, Jan-Philipp},
othercontributors = {Jeschke, Peter and Stumpf, Eike},
title = {{G}ondelauslegung für {M}antelpropellerantriebe},
school = {Rheinisch-Westfälische Technische Hochschule Aachen},
type = {Dissertation},
address = {Aachen},
publisher = {RWTH Aachen University},
reportid = {RWTH-2025-06777},
pages = {1 Online-Ressource : Illustrationen},
year = {2025},
note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
University; Dissertation, Rheinisch-Westfälische Technische
Hochschule Aachen, 2025},
abstract = {A design and evaluation method for the aerodynamic nacelle
design of ducted fans is presented in this thesis. Based on
an exemplary nacelle design for an ultralight aircraft
powered by two electric ducted fan propulsion systems, the
method is demonstrated and validated by experimental
investigations under different inflow conditions on a
prototype. Finally, important correlations for the
aerodynamic nacelle design are presented. The design and
evaluation method for the aerodynamic nacelle design is
based on a design procedure for ducted fan propulsion
systems which was developed at the Institute of Jet
Propulsion and Turbomachinery. Different nacelle geometries
are investigated for various operating points using
numerical solutions of the Reynolds-averaged Navier-Stokes
equations. For this purpose, the blading is represented by
an actuator disk model which is set up uniquely for the
blading and takes into account the local inflow velocity and
the angle of attack. The operating performance and other
parameters such as the total inlet pressure loss are
evaluated. The method is validated by experimental studies
on a reference geometry. Under axial flow conditions, the
thrust increases with increasing power and decreases at
higher flow velocity. The numerically calculated thrust
values are, as expected, slightly higher than the measured
data, and the calculated stagnation point positions
correspond with the experimentally determined ones over the
entire operating range. For increasing angle of attack, the
calcultated thrust values enhance at constant flow velocity
and constant propulsion power. This is confirmed by the
experimental data, but at large angles of attack of about
40° the measured thrust is up to 10 $\%$ below the
numerically calculated one. The quantification of important
correlations for the aerodynamic nacelle design is based on
three representative operating points, the take-off run, the
cruise flight and a take-off run under crosswind influence.
The variation of the inlet and the outer nacelle diameter
shows that a slimmer nacelle geometry requires up to 4 $\%$
less cruise power compared to the basic geometry while the
take-off performance remains almost constant and there are
no disadvantages under crosswind conditions. At the same
time, the slim nacelle geometry enables a significant
shortening of the nacelle. Shortening the inlet length by 20
$\%$ of the rotor radius reduces the required propulsion
power by around1 $\%$ both during take-off and cruise
flight, whereas shortening the nozzle length by the same
amount is negligible. In summary, the design and evaluation
method is suitable for evaluating different nacelle designs
and reproduces both operating performance and nacelle
aerodynamics of ducted fan propulsion systems very
accurately.},
cin = {413510},
ddc = {620},
cid = {$I:(DE-82)413510_20180101$},
typ = {PUB:(DE-HGF)11},
doi = {10.18154/RWTH-2025-06777},
url = {https://publications.rwth-aachen.de/record/1016159},
}
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