轴承、阻尼器和密封对压缩机振动的影响.pptx

轴承、阻尼器和密封对压缩机振动的影响.pptx

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,Bearing,Dampers,andSealEffectsonCompressorVibrations,PaulAllaire&TimothyDimondROMACUniversityofVirginiaAdditionalMaterial:

JoyMartin&ChesterLeeSolarTurbinesSteveEdney&JohnNicholasRMT/LufkinEdMemmott-DresserRand,1,CompressorVibrations.August2011,WhatIsTheCompressorVibration/InstabilityProblem?

OftenHighPressure300to550barExampleCO2Re-InjectionCompressorOftenLimitedOEMExperienceForSomeApplicationsLongHistoryofSomeHighVibrationProblemsinCompressorsUsuallySubsynchronousInstabilityNoOEMIsPerfectNeedLotsofDampingMinimizeCrossCoupledStiffnessEffects-SealsCostofHighPressureOEMTest-ExpensiveCostofAnyMajorProblemVery,VeryExpensive,2,CompressorVibrations.August2011,NewAPISpecifications,-8thEd,2010PreparedByAPI684TaskForceChair-JohnKocur,ExxonMobilTotalCommitteeAbout40PeopleManyOEMs,EndUsers,ComponentVendors,1ProfessorNewSpecificationsPendingwithAPI,3,CompressorVibrations.August2011,NewAPI6178thEd.Specifications,Objective:

EliminateProblemCompressorsWillReplaceCurrentAPI617,7thEd.,2002SoonCriticalSpeeds/UnbalanceResponse/StabilityUnbalanceResponseRubofInternalClearances?

MostImportant-CompressorStabilityDetermineSystemOperatingLogDecrementStrongEmphasisonRotorCalculationwithAllExcitationsLevelIandLevelIIStabilitySynchronousvs.Non-SynchronousTiltPadBearingK&COEMPressurizedTest?

4,CompressorVibrations.August2011,1.UndampedCriticalSpeeds,MajorspecificationregardsthecontentorpresentationoftheresultsUndampedcriticalspeedmapDetermineapproximatelocationofcriticalspeedsBothhorizontalandverticalbearing/supportstiffnessvaluesmustbeusedAnalysisshallidentifythefirstfourundampedcriticalspeedsandmustinclude,astheminimum,thesupportstiffnessrangefrom0.1Xto10XApproximatefeelforbearingdampingeffectivenessUseofCampbelldiagramrecommedforillustratingundesirablerunningspeedsUndampedcriticalspeedmodeshapesGuidesunbalanceplacementsinrotorBearingdampingeffectiveness,5,CompressorVibrations.August2011,UndampedCriticalSpeedMap,Differencebetweenhorizontalandverticalcriticalspeedsmayindicateasplitcritical,Rigidshaftregion,Flexibleshaftregion,Approximatelocationofcriticalspeed,NOTE:

Criticalspeedsareindicatedbytheintersectionofthestiffnesscurvew/thelinesofcriticalspeeds,BearingX&YStiffness,6,CompressorVibrations.August2011,UndampedModeShapes,7,CompressorVibrations.August2011,CampbellDiagram,8,2.UnbalanceResponse,PrincipletoolforsynchronousbehaviorLocatecriticalspeeds（peakresponse）Determinemodaldamping（amplificationfactor）PredictinternalrotordisplacementsProvidesananalysisthatisverifiableontestSpecificationssetforththefollowing:

OperationnearlightlydampedmodesrestrictedRotorresponsivenesstounbalanceislimitedVibrationamplitudelessthat1.0mils（0.0254mm）pk-pkRestrictoreliminateinternaldamage,9,CompressorVibrations.August2011,Enforcement,OperationnearlightlydampedmodesRestrictwithaseparationmodebasedonAFNoneneededforAF2.5AF=2.5selectedbecausewerequire100%operabilitywithnospecialbalancingrequirementsLimitresponsivenesstounbalanceRotorshouldNOTexceedvibrationlimitatanunbalanceoftwicetheresidualunbalanceovertheoperatingspeedrangeResidualunbalanceis4W/N_mc（SI-6350W/N_mc）withN_mc25,000rpmPlace8W/N_mconrotormodelandensurethatthevibrationislessthanvibrationlimit（SI2x6350W/N_mc）withN_mc25,000rpm,10,CompressorVibrations.August2011,UnbalanceSensitivity,Responseshouldbelessthanvibrationlimitinthisspeedrange.,11,CompressorVibrations.August2011,UnbalancePlacement,12,CompressorVibrations.August2011,InternalClearanceCheck,Limitingvibrationat8W/NisnotenoughtoensurethelackofdamageMachinemayoperateuptothevibrationlimitonthestandCheckinginternalresponselevelsatvalueslessthanthevibrationlimitismisleadingNeedtoraisetheproberesponseintheoperatingspeedrangetothevibrationlimitAccomplishedtwowaysIncreasetheunbalanceweightuntilthevibrationlimitisreachedScaletheresponseobtainedwiththe8W/NweightTakesadvantageofthelinearnatureoftheanalysis-doubletheweight,theresponsedoublesSensitivitycheckissimple（scalefactormustbegreaterthanone）Taskforcedecidedtolimitunbalanceto50%greaterthantheoriginallimitof32W/NMaximumunbalancetobeusedis48W/NThisimpliesamaximumscalefactorof6,13,CompressorVibrations.August2011,ResponseScaling,6*8W/Nmid-spanunbalanceweight,clearances,Thismayimplythatoperationaaddtedt.hReespvonibserationlimit,canprCohedckuincteernaal,calculatedrubatacloseclearancelocation,withintherotor.（ProbablyVibmrationoLirmeitlikelywiththepreviousspecifications.）,Maximumresponseisnowlessthanthevibrationlimit,14,CompressorVibrations.August201