The Boxprop is a novel, double-bladed, tip-joined propeller for high-speed flight. The concept draws inspiration from the box wing concept and could potentially decrease tip vortex strength compared with conventional propeller blades. Early Boxprop designs experienced significant amounts of blade interference. By performing a wake analysis and quantifying the various losses of the flow, it could be seen that these Boxprop designs produced 45% more swirl than a conventional reference blade. The reason for this was the proximity of the Boxprop blade halves to each other, which prevented the Boxprop from achieving the required aerodynamic loading on the outer parts of the blade. This paper presents an aerodynamic optimization of a 6-bladed Boxprop aiming at maximizing efficiency and thrust at cruise. A geometric parametrization has been adopted which decreases interference by allowing the blade halves to be swept in opposite directions. Compared with an earlier equal-thrust Boxprop design, the optimized design features a 7% percentage point increase in propeller efficiency and a lower amount of swirl and entropy generation. A vortex-like structure has also appeared downstream of the optimized Boxprop, but with two key differences relative to conventional propellers. (1) Its formation differs from a traditional tip vortex and (2) it is 46% weaker than the tip vortex of an optimized 12-bladed conventional propeller.

References

References
1.
Larsson
,
L.
,
Grönstedt
,
T.
, and
Kyprianidis
,
K. G.
,
2011
, “
Conceptual Design and Mission Analysis for a Geared Turbofan and an Open Rotor Configuration
,”
ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition
,
Vancouver, Canada
,
June 6–10
, pp.
359
370
.
2.
Patrao
,
A. C.
,
Avellán
,
R.
,
Lundbladh
,
A.
, and
Grönstedt
,
T.
,
2016
, “
Wake and Loss Analysis for a Double Bladed Swept Propeller
,”
ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition
,
Seoul, South Korea
,
June 13–17
, pp.
V001T01A013
.
3.
Patrao
,
A. C.
,
Grönstedt
,
T.
,
Avellán
,
R.
, and
Lundbladh
,
A.
,
2018
, “
Wake Energy Analysis Method Applied to the Boxprop Propeller Concept
,”
Aerosp. Sci. Technol.
,
79
, pp.
689
700
.
4.
Adkins
,
C. N.
, and
Liebeck
,
R. H.
,
1994
, “
Design of Optimum Propellers
,”
J. Propul. Power
,
10
(
5
), pp.
676
682
.
5.
Drela
,
M.
,
2006
,
QPROP Formulation
,
Massachusetts Inst. of Technology Aeronautics and Astronautics
,
Cambridge, MA
.
6.
Negulescu
,
C. A.
,
2013
, “
Airbus AI-PX7 CROR Design Features and Aerodynamics
,”
SAE Int. J. Aerosp.
,
6
(
2
), pp.
626
642
.
7.
Avellán
,
R.
,
Patrao
,
A. C.
,
Lundbladh
,
A.
, and
Grönstedt
,
T.
,
2015
, “
Preparing for Proof-of-Concept of a Novel Propeller for Open Rotor Engines
,”
The 22nd International Symposium on Air Breathing Engines
,
Phoenix, Arizona
,
Oct. 25–30
, ISABE Paper No. ISABE-2015-20097.
8.
Ellbrant
,
L.
,
Eriksson
,
L.-E.
, and
Mårtensson
,
H.
,
2012
, “
Design of Compressor Blades Considering Efficiency and Stability Using CFD Based Optimization
,”
ASME Turbo Expo 2012: Turbine Technical Conference and Exposition
,
Copenhagen, Denmark
,
June 11–15
, pp.
371
382
.
9.
Ellbrant
,
L.
,
Eriksson
,
L.-E.
, and
Mårtensson
,
H.
,
2012
, “
CFD Optimization of a Transonic Compressor Using Multiobjective GA and Metamodels
,”
Proceedings of the 28th International Congress of the Aeronautical Sciences
,
Brisbane, Australia
,
Sept. 23–28
, pp.
2698
2712
.
10.
Lejon
,
M.
,
Andersson
,
N.
,
Grönstedt
,
T.
,
Ellbrant
,
L.
, and
Mårtensson
,
H.
,
2016
, “
Optimization of Robust Transonic Compressor Blades
,”
ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition
,
Seoul, South Korea
,
June 13–17
, pp.
V02CT45A022
.
11.
Schnell
,
R.
,
Yin
,
J.
,
Voss
,
C.
, and
Nicke
,
E.
,
2012
, “
Assessment and Optimization of the Aerodynamic and Acoustic Characteristics of a Counter Rotating Open Rotor
,”
ASME J. Turbomach.
,
134
(
6
), p.
061016
.
12.
Lepot
,
I.
,
Leborgne
,
M.
,
Schnell
,
R.
,
Yin
,
J.
,
Delattre
,
G.
,
Falissard
,
F.
, and
Talbotec
,
J.
,
2011
, “
Aero-Mechanical Optimization of a Contra-Rotating Open Rotor and Assessment of its Aerodynamic and Acoustic Characteristics
,”
Proc. Inst. Mech. Eng., Part A
,
225
(
7
), pp.
850
863
.
13.
Capitao Patrao
,
A.
,
Montero Villar
,
G.
,
Takachi Tomita
,
J.
,
Bringhenti
,
C.
,
Avellan
,
R.
,
Lundbladh
,
A.
, and
Grönstedt
,
T.
,
2016
, “
An Optimization Platform for High Speed Propellers
,”
Aerospace Technology Congress 2016
,
Stockholm
,
Oct. 11–12
.
14.
Saravanamuttoo
,
H. I. H.
,
2001
,
Gordon Frederick Crichton Rogers, and Henry Cohen. Gas Turbine Theory
,
Pearson Education
,
Harlow, Essex
.
15.
Sullivan
,
W. E.
,
Turnberg
,
J. E.
, and
Violette
,
J. A.
,
1984
,
Large-Scale Advanced Prop-Fan (LAP) Blade Design
,
Hamilton Standard Division, United Technologies
,
Hamilton Standard; Windsor Locks, CT
.
16.
ANSYS Inc.
,
2012
, ANSYS CFX-Solver Modelling Guide, version 14.5.
17.
Deb
,
K.
,
Pratap
,
A.
,
Agarwal
,
S.
, and
Meyarivan
,
T. A. M. T.
,
2002
, “
A Fast and Elitist Multiobjective Genetic Algorithm: NSGA-II
,”
IEEE Trans. Evol. Comput.
,
6
(
2
), pp.
182
197
.
18.
Hall
,
C.
,
Zachariadis
,
A.
,
Brandvik
,
T.
, and
Sohoni
,
N.
,
2014
, “
How to Improve Open Rotor Aerodynamics at Cruise and Take-Off
,”
Aeronaut. J.
,
118
(
1208
), pp.
1103
1123
.
19.
Denton
,
J. D.
,
1993
, “
Loss Mechanisms in Turbomachines
,”
ASME 1993 International Gas Turbine and Aeroengine Congress and Exposition
,
Cincinatti, OH
,
May 24–27
, pp.
V002T14A001
.
20.
Dixon
,
S. L.
, and
Hall
,
C.
,
2010
,
Fluid Mechanics and Thermodynamics of Turbomachinery
,
Butterworth-Heinemann
,
London
.
21.
Miller
,
R. J.
, and
Denton
,
J. D.
,
2012
,
Loss Mechanisms in Turbomachines
,
Cambridge Turbomachinery Course, University of Cambridge
,
Cambridge, UK
, pp.
79
116
.
22.
Andersson
,
J.
,
Eslamdoost
,
A.
,
Patrao
,
A. C.
,
Hyensjö
,
M.
, and
Bensow
,
R. E.
,
2018
, “
Energy Balance Analysis of a Propeller in Open Water
,”
Ocean Eng.
,
158
(
2018
), pp.
162
170
.
23.
Brandvik
,
T.
,
Hall
,
C.
, and
Parry
,
A. B.
,
2012
, “
Angle-of-Attack Effects on Counter-Rotating Propellers at Take-Off
,”
ASME Turbo Expo 2012: Turbine Technical Conference and Exposition
,
Copenhagen, Denmark
,
June 11–15
, pp.
523
534
.
24.
Van Zante
,
D. E.
,
Collier
,
F.
,
Orton
,
A.
,
Arif Khalid
,
S.
,
Wojno
,
J. P.
, and
Wood
,
T. H.
,
2014
, “
Progress in Open Rotor Propulsors: The FAA/GE/NASA Open Rotor Test Campaign
,”
Aeronaut. J.
,
118
(
1208
), pp.
1181
1213
.
25.
Capitao Patrao
,
A.
,
2017
,
Implementation of Blade Element Momentum/Vortex Methods for the Design of Aero Engine Propellers
,
Chalmers University of Technology
,
Gothenburg
.
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