Cambridge_Emissions

2008GT-SUITEConferenceFrankfurt,Germany.20/10/2008EmissionsmodellinginGT-SUITEemployingdetailedchemistryM.Kraft,S.Mosbach,J.Etheridge,L.Cao,H.Su,A.AlDawood,andA.Bhave**alsoReactionEngineeringSolutionsLtd.[reSolutions]SRM-Emissionssimulation•FuelmodelsÆdetailedkineticsdescriptionvalidatedagainstshocktubes,flamesandenginedata•Accountsforinhomogeneitiesincompositionandtemperature,andfluctuationsÆspray,heatloss,turbulentmixingetc.•MultiplecyclesimulationÆacceptablecomputationalexpenseSRM:StochasticreactormodelTemporalevolution(T-Φspace)•Injectionat-40CADATDC•Injectionduration:3CADGT-SUITE•Externalcylindermodel:USERENGCYLINDER(Fortransubroutine)•I/OsÆfmarray,temperatureandpressureavailablefromGTP•GT-Powerhandlesthegasexchange,trappedEGR%•SRMmodelstheclosedvolume:combustionTDCandNVOGT-SUITEGT-SUITESRM:dynamiclinklibrary(dll)Emissionscasestudies1.NOxemissionsinSIcombustion2.SootemissionsÆsizedistribution,morphology,andcompositionSIengineCycletocyclevariation(CCV)observedintheengine.J.Etheridgeetal.,2008SRMapproachforSIBURNEDENTRAINEDUNBURNED•Threezones•Mixingoccurswithineachzone•Theturbulentflamespeedisusedtocalculatethenewflameradius.•Kineticsineachparticle:PRFfuelmodel(157speciesand1552reactions)SISimulation•C-calibratedtomatchrepresentativeslow,mediumandfastcyclesrespectively.•C-randomvariabletomatchGaussiandistributionofpeakpressures•Characteristicflamespeedobtainedfrom:EnginemapinGT-PowerMulti-cycleSISimulation•Multiplecyclesimulation.•40simulatedand200experimentalcycles.•NOxemissions–Simulation=495ppm–Experiments=528ppmSItoHCCItransient•EGRfromdifferentSIcyclesunderthesameconditionsproducedverydifferentHCCIresults.•MightbeimportanttoreduceCCVattransitionspeedsandloadsormeasureindividualcylinderpressurestocontroltransition.Temporalevolution(T-Φspace)Injectiontimingdelayedto:-10CADATDCSootinengines•HCCI,n-heptane•Compressionratio12•Equivalenceratio1.93•Throttled,20%EGRS.Mosbachetal.2007Aggregatesizedistributions(I)SimulationExperimentAggregatesizedistributions(II)recirculatedaggregatesSimulationSampledaggregates(I)SimulationSimulation49.4CADATDC,129primaries,coll.diam.64nmSampledaggregates(II)Experiment,sampledat~46CADATDCAggregatecompositionpdfsRoleofEGRSimulationReal-timetransientsimulation•Studiesoftransientengineoperation,control,DOE,andoptimizationinvolvesimulationsovermanycycles•IncorporatetabulationasexternalcylindermodelintoGT-Power•LiveGT-Power-SRM-TABsimulation…Thankyouforyourattention!