Optical Diagnostics and Modeling Tools Applied to Diesel HCCI · Caterpillar Engine Research Diesel...
Transcript of Optical Diagnostics and Modeling Tools Applied to Diesel HCCI · Caterpillar Engine Research Diesel...
Caterpillar Engine ResearchDiesel & Emissions Technology
Optical Diagnostics and Modeling Tools Applied to
Diesel HCCI
Upul DeSilvaCathy Y. Choi
Caterpillar Engine Research
Caterpillar Engine ResearchDiesel & Emissions Technology
Optical Diagnostics and Combustion Modeling
• Diesel HCCI is being pursued in order to meet Diesel 2010 emissions requirements
• Optical Diagnostics– Used to gain fundamental understanding of Diesel
HCCI combustion
– Provide data to the combustion modeling team
• Multidimensional Combustion Modeling – To gain further insight into HCCI
– To optimize HCCI conditions to maximize performance
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Caterpillar Optical Diagnostic Capabilities
• Non-vaporizing spray chambers– 300 and 400 psi chamber pressure capabilities
– Liquid spray penetration and geometry
– Droplet SMD
• Optically accessible reciprocating engine – Providing access for combustion laser
diagnostics
– Chemiluminescence studies (combustion species)
– PLIF (NO and OH)
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Advanced Laser Spray Visualization Facility
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Spray From a HCCI tip
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Droplet Sizing
SOI + 1ms 1.8ms 2.6ms 3.2ms
3mm
23mm
33mm
43mmfromtip
Droplet SizeRed 150 ?
Light Green 80 ?Dark Blue 3 ?
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Comparison of Conventional andHCCI Combustion
Conventional Diesel HCCI
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Reactive CFD Modeling for Diesel HCCI Combustion
• Objective: Optimize HCCI combustion for engine emissions and performance.
• Proprietary multi-dimensional reactive CFD code
• LINUX based code• Portions parallelized to increase
computational speed
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Computational Facilities
• CAT Engine Research LINUX cluster– ~40 nodes 1.2-1.66 Ghz AMD Athlon
single and dual processors– Cluster currently operates at 256
GigaFlops– Ranked 55 out of top 500
supercomputers in the world– Applications include both CFD codes and
metal stress analyses codes.
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HCCI Modeling Issues
• HCCI needs detailed chemistry model– A new combustion model was implemented to
characterize unique aspects of HCCI combustion– Chemistry calculations have been parallelized– Simplified NOx chemistry – Detailed soot chemistry model
• Enhancements to spray submodels– Modified droplet collision model– Modified droplet drag model
-50 -40 -30 -20 -10 0 10 20 30 40 500
200
400
600
800
1000
1200
1400
1600H
RR
, J/d
eg
CA ATDC
• HCCI needs detailed chemistry model– A new combustion model was implemented to
characterize unique aspects of HCCI combustion– Chemistry calculations have been parallelized– Simplified NOx chemistry – Detailed soot chemistry model
• Enhancements to spray submodels– Modified droplet collision model– Modified droplet drag model
Caterpillar Engine ResearchDiesel & Emissions Technology
NOx Chemistry
Very high computational time
Moderate computational time
Least computational time
Predict NOPredict N2OPredict NO2
Predict other species
Predict NOPredict N2OPredict NO2
Predict NO
Above 2000 reactions
Simple reaction scheme ? 10 reactions
Simple 3 reactions
GRI MechCAT developedExt. Zeldovich
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Comparison of NOx Models for a Premixed n-Heptane Flame
0.00E+00
2.00E-03
4.00E-03
6.00E-03
8.00E-03
1.00E-02
1.20E-02
1.40E-02
0 1 2 3 4
Phi
Sp
ecie
s M
ass F
racti
on
NO (Zeldovich)NO (GRI)NO2 (GRI)N2O (GRI)NO (TEB)NO2 (TEB)N2O (TEB)
0.00E+00
5.00E-07
1.00E-06
1.50E-06
2.00E-06
2.50E-06
3.00E-06
0.2 0.25 0.3 0.35 0.4
PhiS
pecie
s M
ass F
racti
on
Zeldovich NOGRI NOGRI NO2GRI N2OCAT NOCAT NO2CAT N2O
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Comparison between Experiments and Simulations
Spray Rig Spray Simulation
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Comparison of Convention Diesel to HCCI Combustion
Injection Timing: TDC Injection Timing: -20 CA ATDC
Early Injection Timing for HCCI
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NOx Emissions Trends
Injection Timing, deg
NO
x, P
PM
Predicted (3171 Engine)Measured at different load (3171 Engine)
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Prediction Comparison between CFD and Sandia Optical Engine Data
Sandia Optical Engine Combustion CFD Results
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• HCCI combustion technology is being pursued in order to meet Diesel emissions requirements for upcoming 2010 regulations.
• Optical diagnostic and computational tools are being used to gain understanding of HCCI
• Continuing collaborations with National Labs and Universities
Summary