Presentation Title(Arial Bold 30pt)
Author, Co-author Name, Organization (Arial 23pt)
Company Logo
INDIA
Theme: Disruptive Technology for Affordable and Sustainable Mobility
2-5 October, 2018
Chennai Trade Centre, India
F2018-PTE-122
PTE8 : Powertrain Technology – P2
Estimation of Turbulence Level in Spark
Ignition Engine using Experimental Data
of In-Cylinder Pressure
Sjerić Momir , Kozarac Darko, Jakoubek Mateo
University of Zagreb, Faculty of Mechanical Engineering
and Naval Architecture, Croatia
INDIA FISITA 2018
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure
Presentation Layout
• Introduction
• Experimental Setup
• Background of Quasi-D Combustion Model
- Flame Tracking Model
- Evaluation of Flame Front Surface Area
- Turbulence Modelling
• Comparisons of Estimated/Measured Data with Cycle-Simulations
Results- Cycle - Averaged Results
- Cycle - Resolved Results: Cycle-to-Cycle Variations
• Conclusions
• Acknowledgment
F2018-PTE-122
INDIA FISITA 2018
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure
Introduction
F2018-PTE-122
Why the in-cylinder turbulence level of IC engines is of high interest?
➢ affects the heat transfer
➢ defines the fuel/air mixing process and combustion process in CI engines
➢ influences the flame wrinkling and combustion process in SI engines
Measurement
Hot wire anemometers• only motored conditions
Laser – based methods (LDA)• extensive engine modifications• expensive equipment
Simulations Estimations
Computational Fluid Dynamics• DNS - Direct numerical simulation• LES - Large eddy simulation• RANS – Reynolds ave. Navier-Stokes
Cycle - simulations (1-D/0-D)• 0-D: no spatial discretization of
cylinder domain
accuracypredictability
computationaltime
low
high
low
high
Calculated ROHR from measured pressure profiles
+Equation of Quasi-D combustion
model
Turbulence intensity u’Particle Image Velocimetry (PIV)
INDIA FISITA 2018
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
Introduction
Within the cylinder of IC engines the turbulence intensity changes:
➢ Over the cylinder volume,
➢ Over the time, during combustion period
➢ From cycle-to-cycle.
Cyclic combustion variability
averaged cycle
individual cycles
X
✓
✓Assumption that turbulence variation from cycle-to-cycle is
the most dominant effect for combustion variability
Other causes of CCV:
➢ Mixture stratification➢ Location of spark discharge➢ Variation in the shifting
amplitude and shifting direction of flame kernel
INDIA FISITA 2018
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure
Experimental Setup
F2018-PTE-122
Manufacturer/Engine Name Hatz 1D81
Bore 100 mm
Stroke 85 mm
Connecting Rod Length 127 mm
Compression Ratio 11.95
Intake Valve Opens / Closes 36°CA BTDC / 60°CA ABDC
Exhaust Valve Opens / Closes 54°CA BBDC / 21°CA ATDC
Engine Speed 1000, 1500, 2000, 2500, 3000 rpm
Air excess ratio 1.00
Load WOT – wide open throttle
Fuel Type Commercial gasoline (RON95)
Pressure sensor at intake pipe: AVL LP11DAIn-cylinder pressure sensor: AVL GH14DKCrank angle encoder: AVL 365c
Laboratory of IC Engines and Vehicles, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb
AVL IndiCom+
AVL IndiSmartgigabit 612
INDIA FISITA 2018
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure
Background of Quasi-D Combustion Model
F2018-PTE-122
Flame Tracking Model
= =
==
tria
1
3
1
i,
*
jN,
,
sf
sf
1N
j i
t
actj
UZ uAn
Hdt
dmHQ
+−=
4/1
iN
2/1
N
iNit,
'13.137.4,0.1max
Lu
u
uuu
NuMetghalchi and Keck correlation
Look-up tables used in 3D-CFD
eth triangl−j
1 2
3
1t,u 2t,u
3t,u
*
jN,A
Flameorigin
Part of smooth (laminar) flame front entrains the
fresh mixture by the (local) turbulent flame speed
.
*
jN,A
it,u
Turbulent flame speed (Frolov at al. 2015):
Frontal combustion:
External evaluation
Input: CAD model
surface mesh
Icosahedron subdivision of unit sphere
INDIA FISITA 2018
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure
Background of Quasi-D Combustion Model
F2018-PTE-122
Evaluation of Flame Front Surface Area
INDIA FISITA 2018
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure
Background of Quasi-D Combustion Model
F2018-PTE-122
Turbulence Modelling
k - ԑ model:
HHcL L =Iku
3
2'=
Integral length scale
Example of 3-D simulation:Example of 0-D:
( )
−−+
+=
dt
dk
dt
dkU
m
qU
dt
dk
3
2
3
2SS 2
ivcs
c
in
mivcs1000
( )kdt
d
dt
d
m
qp
dt
d 2
2ε
c
in
mc1000 C
12
5
3
4C
3
4CC
−+
+
+=
Turb
ule
nt kin
etic
energ
y
intake compression expansion exhaust
combustion
totUZ
CRANKANGLE
INDIA FISITA 2018
Comparisons of Estimated and Experimental
Data with Cycle-Simulation Results
Cycle – Averaged Results
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
INDIA FISITA 2018
Comparisons of Estimated and Experimental
Data with Cycle-Simulation Results
Cycle – Averaged Results
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
INDIA FISITA 2018
Comparisons of Estimated and Experimental
Data with Cycle-Simulation Results
Cycle – Resolved Results: Cycle-to-Cycle Variations
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
Averaged value: 10%-90% of burned mass fraction n = 1500 rpm
INDIA FISITA 2018
Comparisons of Estimated and Experimental
Data with Cycle-Simulation Results
Cycle – Resolved Results: Cycle-to-Cycle Variations
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
INDIA FISITA 2018
Comparisons of Estimated and Experimental
Data with Cycle-Simulation Results
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
averaged cycleslow burning cycle fast burning cycle
INDIA FISITA 2018
Conclusions
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
• The presented estimation model for in-cylinder turbulence is applicable for operating points of
SI engine whose ROHR is defined by the propagation of flame over the premixed mixture in the
cylinder.
• The estimation model for in-cylinder turbulence level uses measured pressure profiles and it is
based on the newly developed quasi-dimensional combustion model – Flame Tracking Model.
• The model was applied on averaged cycle at full load condition and over the engine speeds
1000 rpm - 3000 rpm. The estimated values of turbulence intensity are close to MPS and it can
be used for the calibration of turbulence sub-model (k-ԑ) of cycle-simulation model. Average
difference between the estimated and simulated turbulence intensities are below 15%.
• For the selected OP (1500 rpm) the estimation of turbulence level was made on the individual
cycles (over 300 cycles) which helps the definition of turbulence perturbation constants for the
simulation of cyclic combustion variability.
• The presented estimation model for in-cylinder turbulence level in SI engines represents
efficient method for the faster calibration of cycle-simulation model, especially when CCV are
studied.
INDIA FISITA 2018
Acknowledgment
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122
This work was done within HrZZ IP-2014-09-1089 project ‘Experimental Research, Optimization and Characteriz
ation of Piston Engine Operation with Dual-Fuel Combustion – DUFCOROC ’ funded by the Croatian Science
Foundation. This help is gratefully appreciated.
Faculty of Mechanical Engineeringand Naval ArchitectureUniversity of Zagreb
Croatian ScienceFoundation
INDIA FISITA 2018
Thank you for your attention!
Contact Information:
Momir Sjerić, Ph.D., Assistant Professor
Faculty of Mechanical Engineering and Naval Architecture,
University of Zagreb
Ivana Lučića 5, 10 002, Zagreb, Croatia
Phone: +385 1 6168 144
Web: http://www.fsb.unizg.hr/miv/
Email: [email protected]
Estimation of Turbulence Level in Spark Ignition Engine
using Experimental Data of In-Cylinder Pressure F2018-PTE-122