Chalmers University of Technology HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005 Valeri I. Golovitchev POSSIBLE ”ROAD” MAP OF SOLVING NEW SPRAY COMBUSTION PROBLEMS IN COMPRESSION IGNITED ENGINE MODELING Chalmers University of Technology Gothenburg, Sweden HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
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Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Valeri I. Golovitchev
POSSIBLE ”ROAD” MAP OF SOLVING NEW SPRAY COMBUSTION PROBLEMS IN COMPRESSION IGNITED ENGINE MODELING
Chalmers University of TechnologyGothenburg, Sweden
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Valeri I. Golovitchev
POSSIBLE ”ROAD” MAP OF SOLVING NEW SPRAY COMBUSTION PROBLEMS IN COMPRESSION IGNITED ENGINE MODELING
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
With contribution of:Mr. J. GustavssonDr. N. Nordin
Dr. Y. Murata (Waseda University, Japan)
Dr. L. Montorsi (University of Modena and Reggio Emilia)
Miss A. Häggström (SCANIA AB)
Miss M. Bergman
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Spray atomization models
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
‘breakup’
parcel
droplet rp0
parent
child
new parent−
= −p p c
b
dr r rdt t Λ
= Λ
0 KH
c RT
Br
2
τ
Λ Ω= Ω
1 p0
KH KHb
RT
3.726 B r
tC
Λ Ω
Λ ΩKH KH
RT RT
,
,
ΛKHΛ0 KH2B
ΛRT
ΛRT
ρ=ρ
lb b 0
g
L C d
Hybrid Kelvin-Helmholtz/ Rayleigh-Taylor droplet breakup model
*
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Droplet drag model
ρ= ρ = ⋅
uuru
ur
ur
rup d
2gp
l d f
Udv Um V A
dt 2 Ua C
+
23d
d
24 11 Re
Re 6=d,sphereC
0.424
≤dRe 1000
>dRe 1000
= +d,sphered C (1 2.C 632 y)
Taylor Analogy Model
ρ σ µ= − −
ρ ρ ρ&& &
2g l
2 3 2l l l
U2 8 5y y y
3 r r r
Droplet’s equation of motion
Modified Stokes’ low
= ⋅ + ⋅r r rr
t pg jg a j
nozzle
uuuuuurpv
uuurg
uurj
uuuuuurpx
the direction of travel
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Improved 3-D spray model
850.0 K, 4.03 MPa, 16.0 kg/m3
Dis
tanc
e fr
om th
e no
zzle
m
m
0
60
20
40
80
Pen
etra
tion
mm
Time ms
Injection duration
Am
ount
of e
vapo
rate
d fu
el m
g
Time ms
Injection quantity
( Wall )
Droplet diameter mm
Fuel vapor g/cm3
0.0 0.13 0.26
0.0 0.023 0.0045
0
20
40
60
80
0 0.3 0.6 0.9 1.2 1.5
0
4
8
12
16
0 0.5 1 1.5 2 2.5
KH-RT model
KH model
KH-RT model
KH model
KH model
Liquid Vapor
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Validation of 3-D spray modelD
sita
nce
from
the
nozz
le
mm
0
60
20
40
80
Pen
etra
tion
mm
Time ms
KH-RT modelExp.
850.0 K, 4.03 MPa, 16.0 kg/m3
KH-RT model
Exp.
( Wall )Droplet diameter mm
Fuel vapor g/cm3
0.0 0.13 0.26
0.0 0.023 0.0045
0
20
40
60
80
0 0.2 0.4 0.6 0.8 1 1.2
KH-RT model can predict the measured maximum penetration of the liquid phase under high pressure and temperature conditions
KH-RT model
Exp.
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Multi-Stage Fuel Injection - II
(Pilot and Post Injection in Spray Combustion Modeling)
Series of smaller injections must be optimized to achieve design goals
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Fuel compositions studied
Fuel A-D• Different three-component mixtures• Large spread in volatility
Fuel E• Blend of n-heptane and toluene• Used as fuel vapour representation in
the Diesel surrogate model (Chalmers)• Species with similar volatility
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Fuel mixtures in the study
0.30----0.70Fuel E (mole)
-0.600.300.10--Fuel D (mass)
-0.330.330.33--Fuel C (mass)
-0.100.300.60--Fuel B (mass)
-0.33--0.330.33Fuel A (mass)
tolueneC7H8
n-hexadecaneC16H34
n-dodecaneC12H26
iso-octaneC8H18
n-decaneC10H22
n-heptaneC7H16
• Myong, K., Suzuki, H., Senda, J., Fujimoto, H., Spray Structure of Multi-Component Fuels on Evaporating Transient Diesel Sprays, Thiesel Conference, Valencia (2004).
• Myong, K., Arai, M., Suzuki, H., Senda, J., Fujimoto, H., Vaporization Characteristics and Liquid-Phase Penetration for Multi-Component Fuels, SAE 2004-01-0529 (2004).
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Large volatility differences (A)
0
1
0 0,0001 0,0002t (s)
d2 /d02 (
-)
Cold-start
Idle
• No notable sequential evaporation.
• Volatility differences are reduced at high temperatures and pressures.
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Large volatility differences (A)
Idle
0
1
0 0,0001t (s)
Mas
s fr
actio
ns (
-)
n-heptanen-decanen-hexadecane But…
Mass fractions in dropletchanges during evaporation.
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Large volatility differences (B-D)Cold-start
0
1
0 0,0001 0,0002t (s)
d2 /d0
2 (-)
Fuel BFuel CFuel D
Idle
0
1
0 0,0001t (s)
d2 /d02 (
-)
Fuel BFuel CFuel D
• No notable sequential evaporation.• Evaporation rates are similar.• Heat-up times differ.
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Large volatility differences (B-D)
Idle, Fuel C
0
1
0 0,0001t (s)
Mas
s fr
actio
ns
iso-octanen-dodecanen-hexadecane
• Mass fractions in droplet changes during evaporation process.
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Similar volatility (E)
Idle
0
1
0 0,00005t (s)
d2 /d02 (
-)
Pure n-heptanePure tolueneFuel E
Evaporation rates ofpure species andthe mixture are similar.
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Idle
0
1
0 0,00005t (s)
d2 /d02 (
-)
Pure n-heptanePure tolueneFuel E
Evaporation rates ofpure species andthe mixture are similar.
Similar volatility (E)
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Droplet Spray Collision Model: New Approach
Binary collision schematics in relative motion
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
30 deg. 60 deg. 90 deg.
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Regime diagram for turbulent combustion
* Borghi(1995), Peters(1999), Poinsot(1991)
Laminar plane flame fronts
Well-stirred combustion
Da<<1
Da=1
Wrinkled flame fronts
Corrugated flamelets
Distributed combustion
Peters criterion (Ka=100)
Klimov -Williams criterion (Ka=1)
Thin reaction zone
10-1 100 101 102 103 104
10-1
100
101
102
103
104
lI/δL
u rms/S
L
Ka>1
Torn flame fronts
Island formation
Ka~1
Ka<1
Da>>1
Ret =1
Laminar plane flame fronts
Well-stirred combustion
Da<<1
Da=1
Wrinkled flame fronts
Corrugated flamelets
Distributed combustion
Peters criterion (Ka=100)
Klimov -Williams criterion (Ka=1)
Thin reaction zone
10-1 100 101 102 103 104
10-1
100
101
102
103
104
lI/δL
u rms/S
L
Ka>1
Torn flame fronts
Island formation
Ka~1
Ka<1
Da>>1
Ret =1
Ret=urmslI/νTurbulent Reynolds number
Damkohler number
Karlovitz number
Da=τI/τchem
Ka=τchem/τη
dominated by chemical kinetics
dominated by turbulent mixing
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Chalmers University of Technology
HTCES – High Tech Cars and Engines – Modena, Italy – May, 26-27 2005
Reactive volume = computational cell
Averaged concentrations at the beginning of the integration step: [X] i
0 Averaged concentrations at the end of the integration step: [X]i1