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1
Scientific
coordination: Dr. Arvind G. Rao
AHEAD : Advanced Hybrid Engines for
Aircraft Development
1-
284636)
Level 1: Start 1/10/2011, duration 3 years
2
Main Challenges in Civil Aviation
3
Future Aviation Fuel
The long term availability of
fossil fuels cannot be
guaranteed.
As fossil fuel become scarce,
the price will increase and
alternative fuels may be used.
In the medium term biofuels
offer an attractive option.
In the long term, Hydrogen or
Liquid Natural Gas seems the
most attractive option.
Kerosene
Synthetic fuel / GTL/CTL/Biofuels
LNG/ Hydrogen
Aircraft Primary Energy Source
Electric
Kerosene
Synthetic fuel / GTL/CTL/Biofuels
LNG/ Hydrogen
LNG/ Hydrogen
Aircraft Primary Energy Source
Electric
4
Cryogenic Fuels (LNG & LH2)
The mass energy density of
Hydrogen is much higher than
of kerosene, so less fuel is
needed. But the volume is
much higher as well and the
liquid has to be cooled.
LNG mass density is slightly
better than kerosene but it
also requires special storage
tanks.
5
Storage of Cryogenic Fuels
Storage of LNG and Hydrogen
requires large low temperature
tanks.
Initial configuration studies
proved to be unattractive as
drag would be increased, thus
increasing the fuel burn.
New configurations are
needed.
6
Storage of Cryogenic fuels in a Multi fuel BWB
LH2/LNG tanks
Kerosene/ Biofuels
BWB has inherently has extra volume which can be used to
accommodate the cylindrical fuel tanks
This novel idea of multi fuel BWB is unique which optimizes
the usage of space in a BWB
7
LNG/ LH2 Main Combustor
Kerosene/ Biofuel Secondary Flameless
Combustor
Bleed cooling by LH2
Counter rotating shrouded fans
Higher Specific Thrust
Low Installation Penalty
Next generation hybrid engine
8
Overview of the workpackage structure
Conceptual Configuration
WP2: Dual Hybrid combustion
system
Environmental
Assessment and Integration
Dissemination
: Management
Technical
Solutions
Assessment
and Final
Configuration
Outreach
9
Multi Fuel Blended Wing Body Design
The main task in this WP is to do the conceptual
design of the multi-
fuel blended wing body aircraft
10
Optimization procedure
Modules
Preliminary design
11
Novel Configuration
Multi fuel Blended Wing Body
TU Delft proposes a Blended
Wing Body configuration
combined with a slender wing
for a very efficient new aircraft
that would replace the Boeing
777 or Airbus 340.
It incorporates 3 fuel tanks
without substantial drag
penalty.
12
Preliminary design
= 24.2
= 0.305
= 0.0018
ref
= 900 m
2
Aerodynamics
L
D
13
Preliminary design
Materials: Carbon Fiber Reinforced
Polymer
Main structure
Elliptical frames
Ribs
Bulkheads
Structures (1)
14
Preliminary design
Stability:
Canards
Winglets
Control:
Variable camber canard
Elevons
Winglet rudders
Stability and Control
15
Preliminary design
New-BWB
242,800 kg
MTOW
237,970
122,220 kg
265.04
(T/W)
0.21
527,810 N
cruise
98,195 N
Weight breakdown
16
The Bleed Cooling system
The main task of this task is to design a cooling
system to cool the bleed air with the cryogenic
17
17
Van Dijk, I.P.,Rao, G.A
and
Buijtenen, J.P, “A
Novel Technique of Using LH2 in Gas Turbine
Engines”,
ISABE 2009
, Sept 7-11, Montreal, ISABE 2009-
Use of Cryogenic fuel as a heat sink
Using the cryogenic fuel to cool the bleed air is the best way of
improving the thermal efficiency of a turbofan engine
Stator coolingHeat exchanger in
duct
Colder turbine cooling
bleed
Airco system link
Reduction in fuel consumption
Increase in Specific Thrust
Performance overview for all studied cycle
18
Aim and objectives
The specific objectives of this work package are to:
To study and analyze suitable techniques /
methodology that could be used for cooling
the
bleed
Preliminary design of the heat exchange system
between the bleed air and LH2
To perform the sizing of the various components within the
hybrid engine
in order to
obtain the approximate
dimensions of the hybrid engine.
To estimate the overall weight of the hybrid engine
19
D project based on
baseline
engine
LH2 Storage
Designed
Heat Exchanger
LH2 FMM
H2 Combustor
Inter Turbine Flameless
Combustor
Design of the cryogenic fuel to air heat exchanger
20
Project development tree
:
Basic model
Rejected due to
high stress between
compartments
Rejected due to
Rejected due to
21
The hydrogen combustion chamber
The aim of this task is to design the primary
combustor for the hybrid engine using hydrogen as
22
Axial injection
controlled by mass flow meter
Impact of axial injection:
Increases axial velocity at outlet
Downstream shift of central recirculation zone
Increasing axial injection
( in % )
0
7.5
Axial Injection - PIV in Water Tunnel
desired flow field
tot
VV

23
Combustion Test Rig
Gas-fired tests with 100% hydrogen with axial injection on the
TUB combustion test trig
24
Moveable Block (MB)
burner:
Large mixing length
Lm=170mm
Pressure loss � 10%
New burner:
Reduced mixing length
Long = 100mm
Short = 80mm
Pressure loss 3-
=170mm
=80mm
Air
Air
Fuel
Fuel
Reduced Dimensions
Approaching an Applicable Design
25
Atmospheric conditions: new burner exhibits wide operational
range without any flashback occurance
Fired Tests:
Stability Map
0
0,2
0,4
0,6
0,8
1
1,2
0
100
200
300
400
500
Equivalence Ratio
T
preheat

Operability range of new burner

(u
0
=35
-
120 m/s)

HP,
m=130kg/h,
S=0.9, 8.8mm,
longMT
HP LBO,
m=130kg/h,
S=0.9, 8.8mm,
longMT
No flashback
Not tested
Lean blow out
26
emissions increase with inlet temperature Tin
Below 20
for all Tin at design equivalence ratio of φ≈0.4
-0.55
NOx
T
in
S=0.9 and
27
The Inter Turbine Flameless
Combustion Chamber
The main aim of this task is to design and validate
the secondary inter-
turbine flameless combustion
chamber for the AHEAD hybrid engine
28
Different Combustion Regimes
Flameless combustion

CHARACTERISTICS
Recirculation
combustion products
high
temperature
Reduced oxygen concentration
the
reactants
Highly transparent flame with low acoustic
oscillation
Distributed combustion zone
Uniform temperature distribution
Reduced temperature peaks
Low adiabatic flame temperature
High concentration
2 & H2O
Lower Damköhler number
and
emission
Comparison between a conventional
combustion and Flameless Combustion
(Wünning and
Wünning, 2003
)
29
Evaluated combustor configurations for the Inter
Turbine Flameless combustion Chamber
30
recirculated ultra lean combustor version #2
31
CFD for liquid fuel injection
Left picture shows
more significant
evaporation
process
32
Climate Impact Assessment of the
Multi-Fuel BWB Aircraft
The primary aim of this task is to analyse the effect
of changing aircraft emissions on the global climate
due to the use of multi-fuel BWB with hybrid
33
0.031
0.074
Climate impact of current air traffic (2005)
34
Global climate impact of contrail cirrus
Change in climate impact
contrail
cirrus
Change in formation
conditions (aircraft
related)
Change in soot emissions

Change in coverage and microphysical properties
contrail cirrus
Change in flight
level
35
Change in formation conditions II
Implications for contrail formation (2)
AHEAD BWBs will produce contrails in a deeper
atmospheric layer than conventional aircraft because the
threshold temperatures are higher (i.e. formation starts at
lower altitude).
36
upward shift - base case
downward shift - base case
Changes in contrail cirrus RF due to changes in flight level
- decrease of RF in mid latitudes,
- increase in tropics/subtropics,
- globally +4
2
(~9%)
-
increase of RF in mid latitudes,
-decrease in tropics/subtropics,
- globally -
37
Change in
contrail cirrus radiative
due
to a
replacement of
conventional planes
2 planes
level
(LH
conventional
forcing
increased
contrail
radiative
level
planes
2000
LH
Contrail
radiative
nearly
everywhere
decreased
version
AHEAD aircraft
Contrail cirrus radiative forcing - change in formation
+ shift of flight level by ~ 2000m
38
Change in contrail cirrus radiative
due to
a
replacement of
conventional planes by LNG planes
an
increase in
flight level by
2000m
(LNGup3
--
conventional).
cirrus
forcing increased (factor
particularly south of 45
N
relative to conventional air traffic.
ncreases smaller
than
for LH2
planes.
in contrail cirrus radiative
due
a shift in flight level
LNG
planes by
~
2000m (LNGup3
LNG)
Contrail cirrus radiative
reduced in
places.
LNG version of
AHEAD aircraft:
Contrail
-
formation
conditions + shift of flight level by ~ 2000m
39
Hybrid Engine Performance
40
Model
The model was
validated with GSP
Ambient
Condition
Nozzle
Cooling
Inter burner
LP Turbine
Inlet
Fan & Booster
Cp, gamma, R
Composition
Gas Properties
Pt, Tt
Fraction
Air Properties
Air Properties
Cp, gamma, R
Cp, gamma, R
Composition
Gas Properties
Composition
Gas Properties
Fraction
Cp, gamma, R
Cp, gamma, R
Composition
Gas Properties
Cp, gamma, R
Pt, Tt
Composition
Gas Properties
Cp, gamma,
Fraction
Engine
Performance
bypass
41
The
Engine Model in GSP
Inter-stage
Turbine Burner
Main Combustion
Chamber
42
Comparison of hybrid engine with GE
SFC
SFC
SEC
43
Comparison of hybrid engine with PW4056
SFC
SEC
44
Conclusion
Comparison with B777-200ER (1)
45
Comparison with B777-200ER (2)
46
Emission
range

14000

km

Aircraft

Reduction
(%)

KgCO2/(km*k
g)

Payload (kg)

Passengers

kgCO2/(Pas
senger*km)

B777

65.41

0.0014189

22478

186

0.172

A330

89.267

0.0045728

5737.1

48

0.554

B787

42.913

0.00085974

28985

239

0.104

BWB

0

0.0004908

36400

300

0.059

47
The AHEAD Aircraft
48
Advanced Hybrid Engines for Aircraft
Development
Delft University of Technology
WSK PZL-Rzeszow S.A
Technical University of Berlin
DLR, IPA
Israel Institute of Technology-
Technion
Cuenta b.v.
49
Dr. Arvind
Rao

Delft University of Technology
Flight Performance and Propulsion
T: +31 (0)15 27 83833
E: [email protected]
Kluyverweg 1
Delft
The Netherlands
www.ahead-
euproject.eu
This project receives funding from the European Union's Seventh Framework Programme
under grant agreement nr 284636

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