Aerodynamics and CFD at Volvo Car Corporation agenda

Aerodynamics and CFD at Volvo Car Corporation agenda

Aerodynamics and CFD at
Volvo Car Corporation
KTH April 2012
Johan Ljungberg
Volvo Car Corporation
Page 1
agenda
Page 2
background
…..
CFD group, Organization, Basic
aerodynamics definitions
Influence of aerodynamics
…..
Why is aerodynamics important? Review,
Challenges facing Aerodynamics
Development process
…..
Process overview
Drive project
…..
Aerodynamics development of C30 DRIVe
facilities
…..
Test techniques and methods
Graduated from KTH 2005
Scania AB 2005-2006
Volvo Cars 2006-
Present at the CFD group: 19 employees
Page 3
VCC Environmental & Fluid Dynamics Centre
Product Development
Complete Vehicle
Environmental and
Fluid Dynamics Centre
Fuel Economy
Page 4
Weight/MOC
Thermo
Aero/Contamination
CFD
Aerodynamics definitions
D = ½ x ρ x v2 x Cd x A
D is the force of drag, which is by defention the force component in the
direction of the flow velocity
ρ is the mass density of the fluid
v is the velocity of the object relative to the fluid
A is the frontal area
Cd is the dimensionless drag coefficient, related to the object´s shape
Page 5
Influence of Aerodynamics
Drag (fuel consumption, top speed, acceleration)
High-speed stability (lift)
Cross-wind stability (side force and yawing moment)
Passenger comfort (cabriolets)
Cooling Performance
Dirt deposition (visibility)
Aero acoustics (limiting the strength of sources)
Body deformation (Door frames etc)
Page 6
Influence of Aerodynamics
Sources of drag on a modern car
45%
30%
25%
Page 7
Influence of Aerodynamics
Aerodynamics part of total fuel consumption
Electrical
systems
Transmission
losses
8%
16%
Lost kinematic energy
during braking
Drag
26%
”EU Combined cycle” NEDC
(Note! Average speed ≈33km/h)
29%
Rolling
resistance
21%
Page 8
Influence of Aerodynamics
Aerodynamics part of total fuel consumption
Electrical Transmission
losses
systems
9%
8%
Rolling
resistance
30%
Drag
53%
Constant speed 90 km/h
Page 9
Influence of Aerodynamics
Year
Cd
PV 544
1955
Amazon
1960
0,50
0,48
P1800
1963
0,48
P1800ES
1968
0,61
240
1974
0,47
245
1975
0,45
343
1979
0,42
760
1982
0,44
765
1985
0,40
960
1990
0,40
854
1992
0,35
855
1993
0,34
S80
1998
0,31
V70
2000
0,33
XC90
2002
0,40
V50
2004
0,35
S40N
2003
0,34
460
1986
0,39
480ES
1985
0,38
S40
1995
0,34
V40
1995
0,36
Page 10
Cd v Year
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
1950
1960
1970
1980
1990
2000
2010
2020
Influence of Aerodynamics
Year
Cd
PV 544
1955
Amazon
1960
0,50
0,48
P1800
1963
0,48
P1800ES
1968
0,61
240
1974
0,47
245
1975
0,45
343
1979
0,42
760
1982
0,44
765
1985
0,40
960
1990
0,40
854
1992
0,35
855
1993
0,34
S80
1998
0,31
V70
2000
0,33
XC90
2002
0,40
V50
2004
0,35
S40N
2003
0,34
460
1986
0,39
480ES
1985
0,38
S40
1995
0,34
V40
1995
0,36
CdxA v Year
1,20
1,10
1,00
0,90
0,80
0,70
0,60
1950
1960
1970
1980
1990
2000
2010
Page 11
Influence of Aerodynamics
Year
Cd
PV 544
1955
Amazon
1960
0,50
0,48
P1800
1963
0,48
P1800ES
1968
0,61
240
1974
0,47
245
1975
0,45
343
1979
0,42
760
1982
0,44
765
1985
0,40
960
1990
0,40
854
1992
0,35
855
1993
0,34
S80
1998
0,31
V70
2000
0,33
XC90
2002
0,40
V50
2004
0,35
S40N
2003
0,34
460
1986
0,39
480ES
1985
0,38
S40
1995
0,34
V40
1995
0,36
Page 12
Frontal Area v Year
2,90
2,70
2,50
2,30
2,10
1,90
1,70
1,50
1950
1970
1990
2010
2020
Influence of Aerodynamics
Challenges facing Aerodynamicists
Styling
Manufacturing
- Parts
- Assembly
Packaging
Visbility
Other attributes (Thermo, dirt, handling, etc)
”Carry-over” content
Cost
Page 13
Drive project
Aerodynamics on the C30 DRIVe
Page 14
Drive project
C30 DRIVe Aerodynamic parts
Cooling air intake
Front undershield
Front wheel deflectors
Page 15
Drive project
C30 DRIVe Aerodynamic parts
Cover plate
Roof wing
Diffusor panel
Rear bumper
Page 16
Floor panels
Drive project
C30 DRIVe Drag reduction
∆Cd -0.002
∆Cd -0.012
∆Cd -0.002
Page 17
Drive project
C30 DRIVe Aerodynamic parts
Special wheels - Libra
∆Cd -0.005 (compared to steel rims)
Lowered chassis
∆Cd -0.005
Page 18
Aerodynamic drag reduced more than 10% compared to standard car
Fuel consumption reduced by:
• 0,12 l/100km or 3g CO2/km (EU Combined)
- (this corresponds to an equivalent weight reduction of approx. 80kg)
• 0,3 l/100km @ constant 90km/h
Page 19
facilities
In-house testing in three wind tunnels, Gothenburg
PVT
Test section 27m2
(6.6mx4.1m , length 15.8m)
Max speed 250 kph
Temp. +20 to 60° C
Chassi dyn. load 150 kW
Sun sim. max 1200 W/m2
Page 20
MWT
1:5 scale of PVT
Test section 1.1m2
Max. speed 200 kph
Climatic
Test section/nozzle 11.2m2
Max. speed 200 kph
Temp range -40 to +50° C
Chassi dyn. load 280 kW
Sun sim. max 1200 W/m2
facilities
Balance measurements
Effect of configuration changes on aero coefficients
Sensitivity to flow angle, vehicle attitude and wind speed
Turn table
Wheel
Drive Units
Centre belt
Supporting
struts
Measuring
frame
Page 21
facilities
Why Moving Ground is Neccessary
Provides correct relative movement
between the car body and tunnel floor
Provides correct relative movement
between the car body and wheels
Page 22
Influences flow under
and around the car
facilities
Stationary Floor and Wheels
Wind
Page 23
facilities
Moving ground and rotating wheels
Wind
Road/Floor
Page 24
facilities
Optimasation affected
Roof and boot
Wheel Design
Front-end and deflectors
Underbody design
Page 25
facilities
Increase the knowledge gained from aerodynamic testing
Flow visualization (smoke, surface paint, tufts)
Page 26
facilities
Increase the knowledge gained from aerodynamic testing
Preasure measurements
Page 27
facilities
Increase the knowledge gained from aerodynamic testing
Wake measurements
Seven-hole probe rake
Page 28
D=
∫∫ ( P + ρ U
1
2
1
− P2 − ρ U 22 ) dydz
Floor traverse
facilities
Increase the knowledge gained from aerodynamic testing
Wake measurements 100 mm downstream base
Total pressure
Microdrag
Identify regions that can be improved
Page 29
Thank you for your attention!
Page 30
Want to jumpstart your career?
Apply to the
Volvo Cars Global
Graduate Programme 2013
start August 2013, application fall 2012
www.volvocars.com/graduate
Page 31