用COMSOL设计新型管道消音器PPT文件格式下载.ppt

用COMSOL设计新型管道消音器PPT文件格式下载.ppt

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Transmittedsoundwavetothedownstream.,4,AdvantagesoftheNewSilencer,Environmentally-friendly.（noairpollution,betterthanSAM）.,Broadbandnoisereductionatlowfrequencies（comparedwiththeexpansionchamberofthesamegeometry）.,（Huang,2002.Figure3（a）,5,SeveralPrototypes,Left:

2DPlatesilencer（Balsawood）TopRight:

Circularchamber+rectangularductBot.Right:

Fourcavities.,6,NumericalDesign:

Overview,KeyIssueintheNumericalModeling,FEMVSAnalyticalMethod,TheUseofCOMSOLMultiphysics,tosolvethefullsound-structurecoupling,includingtheeffectofflowinthemainduct.,Aneffectivedesigntool.,7,Outline,IntroductionontheductsilencerdesignFEMModelingof2DSilencerNumericalresultsfor2DConfigurationExtensionto3DDesignSummary,8,2DDrumSilencer:

FEMModeling,Multi-physicsDomains,Vibro-AcousticCoupling,BackingCavity（HelmholtzEquation）,MainDuct（ConvectiveWaveEq.）,Membrane（StringVibration）,Membrane:

drivingforce,Duct+Cavity:

InterfaceBoundaryConditions.,9,SelectionofApplicationModes,10,Sub-Domainsinthe2Geometries,Geom1:

Duct+Cavity,Geom2:

Membrane（string）,11,BoundaryConditions:

AcousticDomain,NeumannBC,12,Vibro-AcousticCoupling,AcousticpressureinthegoverningEq.formembranevibration:

Boundaryconditionsattheinterfacesoftheductandcavity:

Coupledvia“ExtrusionCouplingVariables”.,13,Outline,IntroductionontheductsilencerdesignFEMModelingof2DSilencerNumericalresultsfor2DConfigurationExtensionto3DDesignSummary,14,PrimaryResultsforSingleFrequency,Top:

Velocitypotential（F）atf=0.14Bottom:

AmplitudeoftheAcousticPressurealongthecrosssection.,F,Pressure,15,PerformanceIndicator:

TransmissionLoss,Definition:

Thelogarithmicratiobetweenthesoundpowerincidenttothesilencerandthetransmittedsoundpowerforthecasethereisano-reflectionterminationonthedownstreamside.,CalculationinCOMSOLMultiphysics:

.,16,Performanceofa2DDrumSilencer,P1,P2,P3,L:

TLcomparisonbetweentheFEMsimulationandtheexactsolution.,R:

Membranevibrationatthethreespectralpeaks.,（Note:

configurationsarespecifiedinHuang,2002）,TL=0.02dB,17,EffectofMeanFlow,L:

TLcomparisonbetweentheFEMsimulationandtheexactsolution.,TR:

TLvariationwithMachnumber（predictedbyCOMSOL）.,DR:

Experimentalverification,（Note:

TheresultswerepublishedinChoyandHuang,2005）,18,SimulationforPlateSilencer,L:

TLcomparisonbetweentheFEMsimulationandtheexactsolution.Simply-supportedplate.,R:

TLcomparisonbetweentheFEMsimulationandtheexactsolution.Clampedplate.,19,Outline,IntroductionontheductsilencerdesignFEMModelingof2DSilencerNumericalresultsfor2DConfigurationExtensionto3DDesignSummary,20,Simulationfor3DPlateSilencers,2DModel,Examplesof3Dmodels,MotivationsTosatisfypracticalrequirement;

Morecompactinsize;

Betterperformance?

（Note:

SomeresultsinthispartwerepublishedinWangandHuang,2008）,21,QuarterModelofthe4-CavitySilencer,AquarterFEMmodel,Thefullgeometry,22,3DEffectofthe4-CavityPlateSilencer,L:

Contourofthevelocitypotentialintheductatx=0（mid-point）.,R:

InstantaneousVelocityresponseoftheplate（f=0.05）.,23,TLComparisonBetween2Dand3D,2D,3D,L:

TLComparison,R:

Cross-sectionofthesilencers,24,SimulationforaHybridSilencer,HybridArrangement,L&

RCavities:

FilledwithSoundAbsorptionMaterials,T&

BCavities:

Empty.Functionasaplatesilencer.,25,SoundIntensityintheHybridSilencer,26,ComparisonwithPureAbsorption,Hybridsilencer,2cavitiesforreflection;

2cavitiesforabsorption.,Pureabsorption,Allthe4cavitiesarefilledwithabsorptionmaterial.,Lowerlimits:

f=0.0237,0.0451,0.0284,27,Summary,28,Thefiniteelementmodeling（COMSOLMultiphysics）ofanovelflow-throughductsilencerispresented.Thesound-structureinteractionissolvedinafullycoupledmanner.ResultsshowthatCOMSOLMultiphysicsisausefuldesigntoolfortheproposedrum/platesilencer.,MainReferences,L.Huang,“Modalanalysisofadrum-likesilencer”,J.Acoust.Soc.Am.,112,2014-2025,2002.L.Huang,“Broadbandsoundreflectionbyplatescoveringside-branchcavitiesinaduct”,J.Acoust.Soc.Am.119,2628-2638,2006.C.Wang,J.Han,L.Huang,“Optimizationofaclampedplatesilencer”,J.Acoust.Soc.Am.121,949-960,2007.*Y.S.Choy,L.Huang,“Effectofflowonthedrumlikesilencer,”J.Acoust.Soc.Am.118,3077-3085,2005.*C.Wang,L.Huang,“Analysisofabsorptionandreflectionmechanismsinathree-dimensionalplatesilencer”,J.SoundVib.313,510-524,2008.C.Wang,L.Cheng,L.Huang,“Realizationofabroadbandlow-frequencyplatesilencerusingsandwich”,J.SoundVib.318,792-808,2008.L.Huang,“Membranecoveredductliningforhigh-frequencynoiseattenuation:

PredictionusingaChebyshevcollcationmethod”,J.Acoust.Soc.Am.124,2918-2929,2008.*Y.S.Choy,L.Huang,“Multipledrumlikesilencerforlowfrequencyductnoisereflection,”Appl.Acoust.70,1422-1430,2009.,（*:

TheFEMsimulationbyCOMSOLMultiphysicsarereported）,29,30,