ENGINES LouisMarie MALBEC IFPEN Mark Musculus W Ethan Eagle Sandia National Labs Amin Maghbouli Gianluca dErrico Tommaso Lucchini Politecnico di Milano Randy Hessel Zongyu Yue University WisconsinMadison ID: 1044002
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1. ECN 4Topic 7 - Spray B in ENGINESLouis-Marie MALBEC, IFPENMark Musculus, W. Ethan Eagle, Sandia National LabsAmin Maghbouli, Gianluca d’Errico, Tommaso Lucchini, Politecnico di MilanoRandy Hessel, Zongyu Yue, University Wisconsin-Madison
2. Identify and understand the differences between the spray B in combustion vessels (no initial velocities, no wall interactions, constant temperature and density…) and in engines.ObjectivesEngine 1Database 1ModelsVessel 1DatabaseVessel N…AnalyzeValidationDifferencesModelsAnalyzeKnown boundary conditionsUnknown boundary conditions≠InsightSpray B in Vessels (Topic 3,5)Spray B in Engines (Topic 7)Validation
3. ParticipantsIstituto Motori: light duty engineEzio MancarusoMany efforts have been done to meet the objectives of Topic 7.Design of a LIF setup for vapor penetration (advanced)Addition of a N2 loop to simulate EGR (work in progress)SNL: heavy duty engineEthan Eagle, Mark Musculus, Louis-Marie MalbecKAIST: light duty engineJaeheun Kim, Choongsik BaePoliMi: Gianluca d’Errico, Tommaso Lucchini, Amin MaghbouliUniversity of Wisconsin: Randy Hessel, Zongyu YueCarnegie Mellon: Satbir Singh - Uncertainty on boundary conditions - Experimental setup not suited for vapor penetration measurementsEngineVesselEngineEngine 1Database 1Models
4. Identify and understand the differences between the spray B in combustion vessels (no initial velocities, no wall interactions, constant temperature and density…) and in engines.ObjectivesEngine 1Database 1ModelsVessel 1DatabaseVessel N…AnalyzeValidationDifferencesModelsAnalyzeKnown boundary conditionsUnknown boundary conditions≠InsightSpray B in Vessels (Topic 3,5)Spray B in Engines (Topic 7)ValidationSandia B211199CMT B211200Sandia B211201
5. Experimental setupCharacteristics of the Cummins optical engine
6. Illumination by a pulsed red LEDDefinition: First occurrence of normalized intensity lower than a threshold (3%) along a spray axis12Liquid / Vapor penetrationMie scatteringColor Phantom v611 Frame rate 67kHz, Exposure: 14usLens =85mm f/1.4SchlierenPhantom v71 Frame rate: 25kHzExposure: 19usLens: 105mm f/2.5
7. Ignition Delay / Lift-off lengthChimiluminescence OH* Intensified Phantom v71 Frame rate: 7.2kHz (1CAD)Exposure 55usLens: 105mm UV f/4.5Broadband ChimiluminescenceColor Phantom v611 Frame rate: 14.4kHz (0.5CAD)Exposure: 65usLens: 85mm f/1.4
8. Experimental resultsMeasures:Liquid lengthVapor penetrationLift-off length and ignition delayAveraged on 30 cyclesReference point:15%O2, 1500b, 900K, 22.8kg/m31200rpm, SOE = 355CAD, i.e. SOI ≈ 357.2CADInjector 211199 (H1:90.9µm; H2:91.7µm; H3:90.9µm)Parametric variations%O2: 13% and 21%Pinj: 500b and 1000bTtdc: 800K and 1000Kρtdc: 15.2kg/m3
9. Engine vs Vessel: Liquid LengthTime ASOE [µs] => Same type of increase and then decrease of the liquid length (vapor angle variation) between SNL engine and vessel. B211200 at CMT behaviors is slightly different.Engine SNL - B211199Vessel SNL - B211201Vessel CMT - B211200B211200CMT (B211200) < SNL ENG (211199) < SNL VSL (211201)But differences come from the test rigs or from the injectors?Malbec et al., SAE paper 2013-24-0037=> Up to 20% variation in liquid penetration for nominally identical injectors in the same test rig!!!
10. Engine vs Vessel: Vapor penetrationCMT – B211200 – 22.8kg/m3SNL – A201677– Vessel – 22.8kg/m3CMT and Sandia Spray B vapor penetrations are similar.Both are significantly lower than Spray A (wider initial spray angle).2 sets of vapor penetrations from CMT and SNL, but at 22.8kg/m3, whereas in engine we have VP at 15.2kg/m3.SNL – B211201– Vessel – 22.8kg/m3Use of the 1d spray model to generate VP at 15.2kg/m3.1d model – 22.8kg/m31d model – 15.2kg/m3SNL - B211199 ENG 5.2kg/m3 Vapor penetrations are “similar”But the measured rate is higher than the one obtained with 1d model
11. Expe. Setup: Vapor detectionInfra-red imagesVolume LIFSChlierenSimultaneous IR, LIF and Schlieren images
12. Expe. Setup: Vapor detectionSchlieren VP also seems to have a higher penetration rate.Simultaneous IR, LIF and Schlieren imagesVery good match between 3 techniques!
13. Engine vs Vessel: ID and Lift-off LengthB211200B211200B211200Ignition delayLift-off lengthCombustion indicators are similar between spray B in vessels and engines
14. Engine vs Vessel: ID and Lift-off LengthThis scaling law has been obtained for a free jet.LOL of spray B in engine has a similar behavior as a free jetWeak influence of confinement, unsteady boundary conditions, and surrounding flowH=C.Ta-3.74.ρa-0.85.d0.34.U0.Zst-1Comparison with the scaling law (Pickett et al., SAE Paper 2005-01-3843)
15. Expe. Setup: LOL detectionHigh-speed color cameraHigh-speed intensified camera
16. Expe. Setup: LOL detectionThe exact same structures can be observed on the blue channel of the color camera and on the intensified camera.Valid if no broadband emission from soot reflects on the background.High speed camera + “blue” filter can be used to detect lift-off
17. Summary: Spray B in Engine vs vesselsLiquid lengthLL in engine shorter than in SNL Vessel slightly higher to CMT vesselSame transient behavior as in SNL vesselVapor penetrationSimilar to SNL/CMT vessels, but rate is slightly differentIgnition delay and LOLSimilar to vessels (slightly lower).LOL: Same trends as scaling law (i.e. as a free jet).Limitations: different injectors have been used in different facilities. Differences between spray B in vessels and in engineCombustion vessels are representative of engine operation!
18. Identify and understand the differences between the spray B in combustion vessels (no initial velocities, no wall interactions, constant temperature and density…) and in engines.ObjectivesEngine 1Database 1ModelsVessel 1DatabaseVessel N…AnalyzeValidationDifferencesKnown boundary conditionsUnknown boundary conditions≠InsightSpray B in Vessels (Topic 3,5)Spray B in Engines (Topic 7)ModelsAnalyzeValidation
19. Models descriptionMesh SpecificationGeometry120 degree sector cylindrical mesh# of cells~ 35000RadialAxialAzimuthalDimensions5.4 cm3 cm120˚Resolutions2.35 mm1.30 mm2.2˚ UWMPOLIMI KIVA-3vr2 Open FoamSpray breakupKH-RT instabilityKH-RT modelDroplet collisionRadius of influence (ROI) modelNo collision model appliedNear nozzle momentum exchangeGas-jet modelGas-jet modelDroplet evaporationDiscrete-multi-component modelSpaldingTurbulenceGeneral renormalized k-ε modelStandard k-ε modelHeat TransfersLaw of the wallRanz-MarshallInjectionBlob-injector modelBlob-injector modelChemical MecanismPeiPeiCombustion Model Homogeneous reactorRIF / CCMBDCNumber of cells: 341562 Min volume = 1.2e-11 m3 Max volume = 1.1e-08 m3Mesh non-orthogonality Max: 59.82 average: 24.41TDCNumber of cells: 45916 Min volume = 1.21e-11. m3 Max volume = 9.85e-09 m3Mesh non-orthogonality Max: 48.76 Average: 11.16
20. Operating conditionsPOLIMI: Several parametric variations, only in engineUWM: 2 parametric variations, in engine and vesselOperating ConditionsUWMPOLIMI Spray B ENG, VSLENG 800KENG, VSLENG 1000K ENG 13% O2 ENG 21% O2 ENG 15.2kg/m3 ENG 500bar ENG 1000bar ENG
21. CFD resultsUWM
22. CFD results: Spray BPOLIMIUWM
23. CFD results: Spray BPOLIMIUWM
24. Summary: Spray B in Engine vs vesselsLiquid lengthLL in engine shorter than in SNL Vessel slightly higher to CMT vesselSame transient behavior as in SNL vesselVapor penetrationSimilar to SNL/CMT vessels, but rate is slightly differentIgnition delay and LOLSimilar to vessels (slightly lower).LOL: Same trends as scaling law (i.e. as a free jet). Differences between spray B in vessels and in engineCombustion vessels are representative of engine operation!
25. CFD results: Liquid penetrationFrom UWM, liquid length in engine is shorter than in vessels, similar to what is observed in experiments (B211199 in engine vs B211201 in vessel).
26. CFD results: Liquid penetrationLL shorter in engine until about 1.2ms. Hypothesis:Swirl promotes droplet break-up and thus vaporizationAt later timings (>1.2ms), swirl intensity decreases, and thus we obtain the same LL.UWMUWM
27. CFD results: Vapor penetrationFuel penetrates faster in vesselSmaller bowl leads to higher pressure gradient?Squish flow?SNL - B211199 ENG 5.2kg/m3 SNL - B211199 ENG 5.2kg/m3 POLIMIUWMSpray B in vesselSpray B in engine22.8kg/m315.2kg/m3Vapor penetrationCFD in engine matches expe in vessel at 22.8kg/m3 CFD in engine lower than expe in engine at 15.2kg/m3
28. CFD results: Ignition delayPretty good match between expe and simu (except for LOL at 900K for UWM).
29. Identify and understand the differences between the spray B in combustion vessels (no initial velocities, no wall interactions, constant temperature and density…) and in engines.ObjectivesEngine 1Database 1ModelsVessel 1DatabaseVessel N…AnalyzeValidationDifferencesKnown boundary conditions≠Spray B in Vessels (Topic 3,5)Spray B in Engines (Topic 7)ModelsAnalyzeValidationInsightUnknown boundary conditions
30. CFD results: Insight in boundary conditionsThe TDC temperature (core gases) in the engine is computed considering that the gases follow an isentropic compression.The compression computed in CFD could be used to validate this hypothesisUWMPOLIMI Ttdc CFDTtdc isoS. Spray B922925 800K837840 1000K10671076 15.2kg/m3959965
31. Volume LIFPimax (Intensified CCD) Lens: 105mm UV f/4.5 Frame rate: 1 image / cycleExposure: 2µs (Gain=80)LIF / Schlieren / IRSchlierenPhantom v71 Lens: 50mm f/11Frame rate: 25kHz Exposure 10µsDichroïcBand pass filter,320nm, width 70nmSpatial filter (pinhole)Pulsed blue LEDYAG Laser - 266nm70mJ/pulse – Volume illumination (approx. 30x30mm)Fuel: dodecane, no tracerSimultaneous LIF and Schlieren???
32. Simultaneous LIF and SchlierenLIF / Schlieren / IR
33. Conclusions: Wish list / Future workCharacterize the same injector in vessel and enginesThis will allow a better quantification of differences between vessel and engines operations.Define a methodology to produce CFD resultsAbsolute accuracy of the model is maybe not necessary, just the relative variation between engine and vessel.Define a methodology to compare CFD and experimental resultsWhat is to be trusted in expe/CFD results?
34. Conclusions: BenefitsEngine operationImprovement of the control of the boundary conditionsComparison with vesselsUse of CFD to validate the assumptions on boundary conditionsBetter understanding of the phenomena affecting the jets in enginesCombustion modelingUse of the “unique” consistent database between engine and vessels to:Validate the impact of mesh on performancesValidate the modeling of confinement, flow/spray interactions…
35. ConclusionsFor this first session of Topic 7:2 modeling groupsAccessible without too much additional work for modelers already working on spray B in vessels1 experimental group (2 additional probably in near future)Small bore engines are an expected next stepSo……..
36. Compare AHRR reacting
37. Compare Chemical HRR reacting