handbook for control valve sizing (parcol-bulletin

Bulletin1-IHANDBOOKFORCONTROLVALVESIZINGpvcpvp1p2Ip2IIp2IIIp2IV2L2vF,C1L1vF,CFFLL12CCvv12=()()∆pFpFLFpvmax1121=−()()∆pFpFLFpvmax2221=−-1-*PARCOLHANDBOOKFORCONTROLVALVESIZINGCONTENTSNOMENCLATUREVALVESIZINGANDSELECTION1PROCESSDATA2VALVESPECIFICATION3FLOWCOEFFICIENT3.1KVcoefficient3.2Cvcoefficient3.3Standardtestconditions4SIZINGEQUATIONS4.1Sizingequationsforincompressibleflu-ids(turbulentflow)4.2Sizingequationsforcompressiblefluids(turbulentflow)4.3Sizingequationsfortwo-phasefluids4.4Sizingequationsfornonturbulentflow5PARAMETERSOFSIZINGEQUATIONS5.1RecoveryfactorFL5.2CoefficientofincipientcavitationxFZandcoefficientofconstantcavitationKc5.3PipinggeometryfactorFp5.4Combinedliquidpressurerecoveryfac-torandpipinggeometryfactorofacon-trolvalvewithattachedfittingsFLP5.5LiquidcriticalpressureratiofactorFF5.6ExpansionfactorY5.7PressuredifferentialratiofactorxT5.8PressuredifferentialratiofactorforavalvewithattachedfittingsxTP5.9ReynoldsnumberfactorFR*PARCOL-2-Note-UnlessotherwisespecifiedSymbolsDescriptionUnits(note)CdSpecificflowcoefficient=Cv/d2variousCvFlowcoefficientU.S.gallons/mindNominalvalvesizemmDInternaldiameterofpipingmmFdValvestylemodifierdimensionlessFFLiquidcriticalpressureratiofactordimensionlessFLLiquidpressurerecoveryfactorforacontrolvalvewithoutattachedfittingsdimensionlessFLPCombinedliquidpressurerecoveryfactorandpipinggeometryfactorofacontrolvalvewithattachedfittingsdimensionlessFPPipinggeometryfactordimensionlessFRReynoldsnumberfactordimensionlessFγSpecificheatratiofactor=γ/1.4dimensionlessKB1andKB2BernoullicoefficientsforinletandoutletofavalvewithattachedreducersdimensionlessKcCoefficientofconstantcavitationdimensionlessKvFlowcoefficientm3/hK1andK2UpstreamanddownstreamresistancecoefficientsdimensionlessMMolecularmassoftheflowingfluidkg/kmolepcAbsolutethermodynamiccriticalpressurebarpvAbsolutevapourpressureoftheliquidatinlettemperaturebarpvcVenacontractaabsolutepressurebarp1Inletabsolutepressuremeasuredatupstreampressuretapbarp2OutletabsolutepressuremeasuredatdownstreampressuretapbarΔpPressuredifferentialbetweenupstreamanddownstreampressuresbarΔpmaxMaximumallowablepressuredifferentialforcontrolvalvesizingpurposesforincompressiblefluidsbarqmMassflowratekg/hqvVolumetricflowratem3/hqm(max)Maximummassflowrateinchokedconditionkg/hqv(max)Maximumvolumetricflowrateinchokedconditionm3/hRevValveReynoldsnumberdimensionlessT1InletabsolutetemperatureKuAveragefluidvelocitym/s-3-*PARCOLSymbolsDescriptionUnitsvSpecificvolumem3/kgxRatioofpressuredifferentialtoinletabsolutepressuredimensionlessxcrRatioofpressuredifferentialtoinletabsolutepressureincriticalconditions(Δp/p1)crdimensionlessxFZCoefficientofincipientcavitationdimensionlessxTPressuredifferentialratiofactorinchokedflowconditionforavalvewithoutattachedfittingsdimensionlessxTPValueofxTforvalve/fittingassemblydimensionlessYExpansionfactordimensionlessZCompressibilityfactor-ratioofidealtoactualinletspecificmassdimensionlessγSpecificheatratiodimensionlessροSpecificmassofwaterat15.5°Ci.e.999kg/m3kg/m3ρ1Specificmassoffluidatp1andT1kg/m3ρrRatioofspecificmassoffluidinupstreamconditiontospecificmassofwaterat15.5°C(ρ1/ρο-forliquidsisindicatedasρ/ρο)dimensionlessνKinematicviscosity(ν=μ/ρ)Centistoke=10-6m2/sμDynamicviscosityCentipoise=10-3Pa⋅s*PARCOL-4-SIZINGANDSELECTIONOFCONTROLVALVESThecorrectsizingandselectionofacontrolvalvemustbebasedonthefullknowledgeoftheproc-ess.1-PROCESSDATAThefollowingdatashouldatleastbeknown:a-Typeoffluidanditschemical-physicalandthermodynamiccharacteristics,suchaspres-sure“p”,temperature“T”,vapourpressure“pv”,thermodynamiccriticalpressure“pc”,specificmass“ρ”,kinematicviscosity“ν”ordynamicviscosity“μ”,specificheatatcon-stantpressure“Cp”,specificheatatconstantvolume“Cv”,specificheatratio“γ”,molecu-larmass“M”,compressibilityfactor“Z”,ratioofvapourtoitsliquid,presenceofsolidparti-cles,inflammability,toxicity.b-MaximumoperatingrangeofflowraterelatedtopressureandtemperatureoffluidatvalveinletandtoΔpacrossthevalve.c-Operatingconditions(normal,max.,min.etc.).d-Ratioofpressuredifferentialavailableacrossthevalvetototalheadlossalongtheprocesslineatvariousoperatingconditions.e-Operationaldata,suchas:-maximumdifferentialpressurewithclosedvalve-strokingtime-plugpositionincaseofsupplyfailure-maximumallowableleakageofvalveinclosedposition-fireresistance-max.outwardsleakage-noiselimitationsf-Interfaceinformation,suchas:-sizingofdownstreamsafetyvalves-accessibilityofthevalve-materialsandtypeofpipingconnections-overalldimensions,includingthenecessaryspacefordisassemblingandmaintenance-designpressureandtemperature-availablesuppliesandtheircharacteristics2-VALVESPECIFICATIONOnthegroundoftheabovedataitispossibletofinalisethedetailedspecificationofthevalve(datasheet),i.e.toselect:-valverating-bodyandvalvetype-bodysize,afterhavingcalculatedthemaxi-mumflowcoefficientCvwiththeappropriatesizingequations-typeoftrim-materialstrimofdifferenttrimparts-leakageclass-inherentflowcharacteristic-packingtype-typeandsizeofactuator-accessories3-FLOWCOEFFICIENT3.1-FLOWCOEFFICIENT“