wing embedded engines for large blended wing body aircraft
DESCRIPTION
Wing Embedded Engines For Large Blended Wing Body Aircraft. A Computational Investigation Michael Farrow MEng Aerospace Engineering. Introduction. Why? Embedded Engines Blended Wing Bodies Method CAD Meshing Solving Results Obtained Problems Encountered Conclusions Questions. - PowerPoint PPT PresentationTRANSCRIPT
22/05/2009 1
A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Wing Embedded EnginesFor
Large Blended Wing Body Aircraft
A Computational Investigation
Michael FarrowMEng Aerospace Engineering
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Introduction
• Why?– Embedded Engines– Blended Wing Bodies
• Method– CAD– Meshing– Solving
• Results Obtained• Problems Encountered• Conclusions• Questions
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
The First Jet Airliner
• The de Havilland DH-106 Comet 1• First Flew in 1949• Four Fully Embedded dH Ghost 50 Turbojets
[1]
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Embedded Engines
[2] [3] [4]
[5] [7][6]
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
The Embedded Argument
For• Reduction in Weight• Reduction in Viscous Drag• Potential Reduction in
Pressure Drag• Potential Noise Reduction
Against• Optimisation of Inlet
Efficiency is Difficult• Engine Failures/Fires are
More Dangerous• Maintenance and Upgrade
Hampered by Structure
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
The Embedded Argument
[8]
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
The Blended Wing Body
• Smoothly Sweeps Wings into Fuselage• Complete Lifting Body• Large Cargo Volume to Wingspan Ratio
[9][10]
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Construction of CAD Geometry
• Sampled from Public Domain Images• 3 Test Cases
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Drag Estimation
• Required for Engine Sizing• Skin Friction Drag
– Estimated Using Thin Plate Aerodynamics
• Pressure Drag– Function of the Projected Cross Sectional Area
• Induced Drag from the Lift Coefficient & Span Efficiency
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Construction of Mesh
• Unstructured Tetrahedral Mesh using ICEM CFD• Prism Layer Grown Outwards from Surfaces
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Results - Clean
Contours of Static Pressure (Pascals)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Results - Clean
Contours of Static Pressure (Pascals)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Results – Podded
Contours of Static Pressure (Pascals)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Results - Embedded
Contours of Static Pressure (Pascals)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Results - Embedded
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Problems Encountered
• Insufficient Mesh Quality• Underexpanded Jet Exhaust – Unphysical Results
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Conclusions
• Embedded Configuration Optimal - External Aerodynamics– Minimum Lift Loss– Less Viscous Drag than Podded– Less Pressure Drag than Podded AND Clean
• However:– Optimisation Required for Both Configurations– Serious Structural Questions Remain– Design & Investigation of Duct Flow Required
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Any Questions?
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
References1. http://bose.utmb.edu/tdpower/Comet.jpg2. http://www.palba.cz/forumfoto/albums/USA_Letectvo/normal_Yb-
49_01.jpg3. http://img.dailymail.co.uk/i/pix/2007/05_02/
Vulcan260507_468x308.jpg4. http://library.thinkquest.org/04oct/02032/poze/b2spirit_4.jpg5. http://www.abpic.co.uk/images/images/1080254M.jpg6. http://www.flightglobal.com/airspace/photos/apgphoto/images/
619/raf-nimrod-mra4.jpg7. http://plane-crazy.purplecloud.net/Aircraft/Jets/Valiant/Valiant-
B1.jpg8. http://media.nowpublic.net/images//
44/5/44546fb20c750216d0a98359a2280ab8.jpg9. http://www.flightglobal.com/blogs/aircraft-pictures/BWBlarge.jpg10. NASA Facts – July 1997 – The Blended Wing Body
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Additional Slides
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Pressure Profile
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Duct Flow
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Solution
• Spalart-Allmarus Scheme• Initial Incompressible Solution feeds Compressible• Boundary Conditions - Cruise Conditions for BWB
Aircraft– Pressure Far Field– 12,000m ISA– Mach 0.85
• Engine Inlet & Exhaust Conditions from Engine Model
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Comparison - Lift
3388.97
3370.57
3376.75
3360
3365
3370
3375
3380
3385
3390
3395
Clean Podded Embedded
Aircraft Configuration
Tota
l Lif
t Forc
e (
kN
)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Comparison – Viscous Drag
52.63
55.94
53.23
50
51
52
53
54
55
56
57
Clean Podded Embedded
Aircraft Configuration
Vis
cous
Dra
g F
orc
e (
kN
)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Comparison – Pressure Drag
73.08
77.73
66.65
60
62
64
66
68
70
72
74
76
78
80
Clean Podded Embedded
Aircraft Configuration
Est
imate
d P
ress
ure
Dra
g F
orc
e (
kN
)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Comparison – Fuel Consumption
3.00 2.92
0
1
1
2
2
3
3
4
Podded Embedded
Aircraft Configuration
Est
imate
d C
ruis
e F
uel F
low
Rate
(kg/s
)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Comparison – Installation Mass
0
2000
4000
6000
8000
10000
12000
14000
16000
Podded Engine Embedded Engine
Aircraft Configuration
Es
tim
ate
d I
ns
tall
ati
on
Ma
ss
(k
g)
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Engine Modelling
• GE90-115B Turbofan• Thermodynamic Mapping by Stage• Perfect Scaling Assumed
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Engine Placement
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Mesh
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Mesh – Prism Layer
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Span Loading
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Engine Options
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A Computational Investigation of Wing Embedded EnginesMichael FarrowMEng Aerospace Engineering
Jet Flow
Contours of Mach Number