insight into heavy-duty diesel engine combustion and flow ... · insight into heavy-duty diesel...
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Insight into heavy-duty Diesel engine combustion and flow processes
Dr. Edward Long
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Core IC engines Research 18 Full-time Academic Staff:
Prof. Rui Chen – Combustion
Dr Andy Clarke – Combustion, fuels
Prof. Colin Garner – Fluid flow, combustion, after-treatment
Prof. Kambiz Ebrahimi – Engine control
Prof. Graham Hargrave – Fluid flow, optical diagnostics
Dr. Edward Long – Fluid flow, combustion
Paul King – Tribology, dynamics
Dr Salah Ibrahim – CFD, SI combustion
Prof. W. Malalasekera – CFD, combustion, radiation
Dr Byron Mason – Engine control
Prof. Homer Rahnejat – Tribology, dynamics
Dr Ramin Rahmani – Tribology, dynamics
Dr Thomas Steffen – Engine control
Dr Francois Nadal – Fluid flow
Prof. Stephanos Theodossiades – Tribology, dynamics
Henk Versteeg – CFD, heat transfer, after-treatment
Dr Andy Williams – After-treatment, heat transfer, turbocharging
Dr Huayong Zhao – Combustion, optical diagnostics
Plus >35 full-time research staff,
research students and
technicians
Loughborough University
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Largest UK Campus 437 acres
16,500 students; some 4000 studying engineering
7% of UK Chartered Engineers
Research rating: GPA 3.08 Overall
3.37* for Impact, 3.45 for Environment
127 FTE for Mech/Man/Aero/Auto
Dr. Paul GaynorResearch Associate
Loughborough University
Dr. Ruoyang YuanResearch Associate
Loughborough University
Dr. Suji SogbesanResearch Associate
Loughborough University
Tristan KnightPhD Researcher
Loughborough University
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APC3 – Project ASCENT Advanced Systems for Carbon Emission reduction through New Technology
Collaborating across 4 partners to delivertechnology that will enable a majorupgrade of the Caterpillar C4.4 and C7.1heavy-duty diesel engines by 2018:
CO2 reduction Power density growth
Prof. Graham HargravePrinciple Investigator
Loughborough University
Dr. Edward LongCo-Investigator
Loughborough University
Combustion work-stream
Aftertreatmentwork-stream
Dr Vivian PageThermofluids Team Leader
Caterpillar
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Combustion workstream
To generate design tools and understanding that will enable us to develop
advanced combustion systems for the next generation of heavy-duty Diesel engines
Part of our approach to hit the targets of reduced CO2 and increased energy density
Validate and inform simulation tools
Experimental investigation into the following key aspects:
• In-cylinder flow structure• Fuel injection • Mixing and evaporation processes• Combustion
Development of facilities:
• Single cylinder optical engine• Production thermodynamic engine
with endoscopic access
Application of optical diagnostic techniques
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• Single cylinder, fully optical engine with quartz liner and bowditch piston with quartz window
• Non-firing - intake and compression analysis
• Currently fitted with research head
• Fitted with flat top piston, but this can be changed to a simple bowl configuration
• In-Cylinder flow during intake and compression
₋ High speed PIV of flow structure development
₋ High speed PIV of turbulence during compression
• Provides important data for non-reacting model validation
Application
Engine design
Single-cylinder optical engine
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Complete for intake and compression strokes.
• 1.5kHz PIV rate• Independent port blocking
Tumble plane HSPIV at 800rpm and 1000rpm Imaging region
Laser sheetNd:YAG /
Nd: YLF Laser
Top of image in line with cylinder head
Intake Valves
Exhaust Valves
Optical engine imaging setup
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Complete for intake and compression strokes.
• 1.5kHz PIV rate• Independent port blocking
Swirl plane HSPIV at 800rpm and 1000rpm
Laser Sheet
TDC
45° CA
90° CA
High Speed camera
Optical engine imaging setup
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Ensemble Mean-Averaged vs. Instantaneous Velocity Vectors 180 °CA – 360 °CA
Compression results 1000 rpm
1.5 kHz data rate = 4 CAD
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Compression and intake – RMS turbulence 1000 rpm
Intake Compression
1.5 kHz data rate = 4 CAD
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Simulation results: RMS Comparison
Central tumble plane
Standard k-epsilon
k-epsilon + dynamic
coefficients
RNG k-epsilon
Rapid distortion
RNG k-epsilon
RNG - 1.6
Experimental data (PIV)
Caterpillar simulation study, curtesy of Tushar Shetaji & Vivian Page
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Turbulence – Scale, energy and quantification
Turbulence scale (spatial and temporal) is important
Turbulent structures as they interact with a surface
Turbulence effects key parameters:
• Mixing• Fuel evaporation• Rates of flame propagation• Heat transfer to walls and surfaces
Flame propagation through a turbulent field
This in turn impacts:
• Performance• Emissions• Cooling system requirements• Durability
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Proper Orthogonal Decomposition (POD) of PIV data
=+ +
..+..…+
Mean Mode 1
Mode 2
Mode 19 Mode 70
Energy content (relative) of POD modes at individual crank angles
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Endoscopic access into the Cat® C4.4 ACERT engine for combustion analysis
2. Endoscope introduced through direction of the glow-plug hole
1. Endoscope introduced through the end of the cylinder head – endoscope and pressure window can be swapped for a light guide
Intake portCoolant passage
Coolant passage
1. Access through end of cylinder head
2. Access through glow-plug channel
Piston bowl
Secondary access point for image capture
Camera/mount position (glow plug access)
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Cylinder head
Endoscopic access into the Cat® C4.4 ACERT engine for combustion analysis
Early combustion imagingCold start1000 rpm low load6400 frames/s recording
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Endoscopic optical
techniques
Objectives
Direct Imaging • Spray motion; interaction between fuel jet and in-cylinder flow
• Fuel jet-wall interaction• Combustion event - ignition timing, locations
Two-colour soot pyrometry • Soot/flame temperature• Soot concentration
Chemiluminescence
imaging
• Time-resolved heat release rate• Flame lift-off length• Light-based ignition delay and sites• Whole field technique for engine application
Endoscopic data – further analysis
OH* Chemiluminescence of methane/air flame showing heat release region
Two-colour pyrometryoptical setup
Photo of burner test rig
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Summary
The use of experimental investigation and validated simulation tools to give valuable insight into Diesel engine combustion and flow processes
The importance of accurate turbulence quantification and simulation
The valuable role of optical techniques when coupled with:
• A single-cylinder optical engine• A production engine with endoscopic access
Development of design tools that will enable us to meetthe challenging demands of future generation IC engines
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Insight into heavy-duty Diesel engine combustion and flow processes
Dr. Edward Long