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INTERNAL COMBUSTION ENGINES SIMULATION IN INTERNAL COMBUSTION ENGINES SIMULATION IN OPENFOAM Tommaso Lucchini Dipartimento di Energetica , ... “Internal Combustion Engine Simulation

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  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    INTERNAL INTERNAL

    COMBUSTION COMBUSTION

    ENGINES ENGINES

    SIMULATION IN SIMULATION IN

    OPENFOAMOPENFOAM TommasoTommaso LucchiniLucchini

    DipartimentoDipartimento didi EnergeticaEnergetica,,

    POLITECNICO DI MILANOPOLITECNICO DI MILANO

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    TOPICSTOPICS

    •• ENGINE SIMULATION IN ENGINE SIMULATION IN OpenFOAMOpenFOAM

    oo State of ArtState of Art

    oo engineFOAMengineFOAM

    oo dieselEngineFOAMdieselEngineFOAM

    •• RESULTSRESULTS

    oo Engine Case: FiatEngine Case: Fiat--LanciaLancia 16V VIS16V VIS

    oo Spray Case: Spray from a pressureSpray Case: Spray from a pressure--swirl Injectorswirl Injector

    •• FUTURE DEVELOPMENTS FUTURE DEVELOPMENTS ((collaboration with Dr. collaboration with Dr. JasakJasak))

    oo Topology modifiers applied to engine meshesTopology modifiers applied to engine meshes

    oo FourFour--Stroke Engines (valve action)Stroke Engines (valve action)

    oo Two Stroke EnginesTwo Stroke Engines

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    ENGINE SIMULATIONENGINE SIMULATION

    •• COMPLEX PHYSICAL MODELSCOMPLEX PHYSICAL MODELS

    oo Compressible (transonic) flowCompressible (transonic) flow

    oo Turbulence, Combustion, ChemistryTurbulence, Combustion, Chemistry

    oo LagrangianLagrangian Particles for SprayParticles for Spray

    •• COMPLEX GEOMETRY HANDLINGCOMPLEX GEOMETRY HANDLING

    oo Moving MeshMoving Mesh

    oo Topological Changes (valve action)Topological Changes (valve action)

    •• MODEL TO MODEL INTERACTIONMODEL TO MODEL INTERACTION

    •• NEW PHYSICAL AND NUMERICAL MODELSNEW PHYSICAL AND NUMERICAL MODELS

    oo ImplementationImplementation

    oo TestingTesting

    oo ObjectObject--Oriented StructureOriented Structure

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    ENGINE MODELLING IN OPENFOAMENGINE MODELLING IN OPENFOAM

    •• SOLVERSSOLVERS

    oo engineFOAMengineFOAM

    oo dieselEngineFOAMdieselEngineFOAM

    •• engineFOAMengineFOAM

    oo SparkSpark--ignition enginesignition engines

    oo RANS combustion RANS combustion modelingmodeling of premixed combustionof premixed combustion

    oo Weller combustion model (also known as bWeller combustion model (also known as b--ΞΞ))

    •• dieselEngineFOAMdieselEngineFOAM

    oo Diesel enginesDiesel engines

    oo EulerianEulerian--LagrangianLagrangian approach for spray trackingapproach for spray tracking

    oo RANS combustion RANS combustion modelingmodeling of nonof non--premixed combustionpremixed combustion

    oo Chalmers Partially Stirred Reactor Combustion ModelChalmers Partially Stirred Reactor Combustion Model

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    ENGINE SOLVERSENGINE SOLVERS

    Thermodynamic ApproachThermodynamic Approach

    Spray particles trackingSpray particles tracking

    Chemistry Model for chemical source termsChemistry Model for chemical source terms

    Mesh handling and “engine components”Mesh handling and “engine components”

    src/thermophysicalModels/combustionsrc/thermophysicalModels/combustion

    src/lagrangian/dieselSpraysrc/lagrangian/dieselSpray

    src/thermophysicalModels/chemistryModelsrc/thermophysicalModels/chemistryModel

    src/OpenFOAM/meshes/fvMeshsrc/OpenFOAM/meshes/fvMesh

    src/topoFvMeshsrc/topoFvMesh

    srcsrc/engine/engine

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    PREMIXED COMBUSTION (PREMIXED COMBUSTION (engineFOAMengineFOAM))

    FLAMELET APPROACH: burnt and unburned gases are FLAMELET APPROACH: burnt and unburned gases are

    divided by a thin and wrinkled turbulent flame front.divided by a thin and wrinkled turbulent flame front.

    UnburntUnburnt gas properties:gas properties:

    TTuu, , hhuu, , ρρuu Burnt gas properties:Burnt gas properties:

    TTbb, , hhbb, , ρρbb Cell properties:Cell properties:

    T, h, T, h, ρρ, p, b, ft, p, b, ft Laminar flame speed SLaminar flame speed Suu

    bb--ΞΞΞΞΞΞΞΞ Combustion Model by WellerCombustion Model by Weller

    ( ) ( ) bSbDbU t

    b uub

    ~~~~ ~

    2 ∇Ξ−=∇∇−∇+ ∂

    ∂ ρρρ

    ρ

    solvesolve

    ((

    fvmfvm::::ddtddt((rhorho, b), b)

    + + mvConvectionmvConvection-->>fvmDivfvmDiv((phiphi, b), b)

    + + fvmfvm::::divdiv((phiStphiSt, b, ", b, "divdiv((phiStphiSt,b)"),b)")

    -- fvmfvm::::SpSp((fvcfvc::::divdiv((phiStphiSt), b)), b)

    -- fvmfvm::::laplacianlaplacian((turbulenceturbulence-->>muEffmuEff(), b)(), b)

    ););

    GulderGulder correlation for laminar flame speed Scorrelation for laminar flame speed Suu

    hhuCombustionThermohhuCombustionThermo

    inhomogeneousMixtureinhomogeneousMixture

    sutherlandTransportsutherlandTransport

    specieThermospecieThermo

    janafThermojanafThermo

    perfectGasperfectGas

    laminarFlameSpeedlaminarFlameSpeed

    b: normalized fuel fractionb: normalized fuel fraction

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    LAGRANGIAN SPRAY MODELLINGLAGRANGIAN SPRAY MODELLING

    INJECTION (INJECTION (injectorModelinjectorModel))

    ATOMIZATION (ATOMIZATION (atomizationModelatomizationModel))

    BREAKUP (BREAKUP (breakupModelbreakupModel))

    EVAPORATION (EVAPORATION (evaporationModelevaporationModel))

    COLLISION (COLLISION (collisionModelcollisionModel))

    WALL IMPINGEMENT (WALL IMPINGEMENT (wallModelwallModel))

    DRAG (DRAG (dragModeldragModel))

    HEAT TRANSFER (HEAT TRANSFER (heatTransferModelheatTransferModel))

    TURBULENT DISPERSION (TURBULENT DISPERSION (dispersionModeldispersionModel))

    The spray is a The spray is a CloudCloud of of parcelsparcels, and evolves according to:, and evolves according to:

    MASS, MOMENTUM AND ENERGY EXCHANGE WITH THE GAS PHASEMASS, MOMENTUM AND ENERGY EXCHANGE WITH THE GAS PHASE

    ADDITIONAL SUBADDITIONAL SUB--MODELS (MODELS (spraySubModelsspraySubModels))

    dieselSpray.evaporationSourcedieselSpray.evaporationSource()()

    dieselSpray.momentumSourcedieselSpray.momentumSource()()

    dieselSpray.heatTransferSourcedieselSpray.heatTransferSource()()

    RUNRUN--TIME SELECTION TABLES ALLOW TO EASILY DEFINETIME SELECTION TABLES ALLOW TO EASILY DEFINE

    NEW SPRAY SUBNEW SPRAY SUB--MODELSMODELS

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    DIESEL COMBUSTION (DIESEL COMBUSTION (dieselEngineFOAMdieselEngineFOAM))

    TURBULENCETURBULENCE--CHEMISTRY INTERACTIONCHEMISTRY INTERACTION

    Partially Stirred Reactor ConceptPartially Stirred Reactor Concept

    i

    chemmix

    chem iRR ω

    ττ

    τ &

    + =

    RRRRii : Chemical Source Term: Chemical Source Term

    ωωii : Reaction Rate: Reaction Rate ττchemchem : Chemical Time: Chemical Time

    ττmixmix : Mixing Time: Mixing Time

    A chemical system has to be solved to provide A chemical system has to be solved to provide ωωωωωωωωii

    ODE, Sequential, ODE, Sequential, EulerImplicitEulerImplicit Chemistry solversChemistry solvers

    Reaction mechanism in Reaction mechanism in chemkinchemkin or or foamChemistryfoamChemistry formats formats

    Cell propertiesCell properties

    T, h, T, h, ρρ, p, Y, p, Yii

    hCombustionThermohCombustionThermo

    reactingMixturereactingMixture

    chemistryModelchemistryModel

    chemistrySolverchemistrySolver

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    ENGINE MOVING MESHENGINE MOVING MESH

    STATE OF ARTSTATE OF ART

    Moving and deforming mesh, without topological changesMoving and deforming mesh, without topological changes

    Algorithm specified in Algorithm specified in src/engine/include/movePiston.Hsrc/engine/include/movePiston.H

    Piston Bowl Points: Piston Bowl Points: Move with piston displacementMove with piston displacement

    Liner Points: Liner Points: DeformationDeformation

    Head Points: Head Points: Do not moveDo not move

  • TommasoTommaso LucchiniLucchini: “Internal Combustion Engine Simulation in : “Internal Combustion Engine Simulation in OpenFOAMOpenFOAM”, 01”, 01--2828--20062006

    RESULTSRESULTS

    Gasoline spray emerging from a pressureGasoline spra