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1、ICSFLUIDFLOWImportantConversionsandEqualities:1Newtonforce(N)causes1kgmasstoaccelerateat1m/s2g=9.81N/kgorm/s21dyneforce(dyn)causes1gmasstoaccelerateat1cm/s2g=981dyn/gorcm/s21poundforce(lbf)causes1slugmasstoaccelerateat1ft/s2g=32.2lbf/slugorft/s21poundforce(
2、lbf)causes1lbmasstoaccelerateat32.2ft/s2g=1.0lbf/lbm1poundalforce(pdl)causes1lbmasstoaccelerateat1ft/s2g=32.2pdl/lbmorft/s21pdl=1lbm×ft/s21N=1kg×m/s2=7.233pdl=105dyn1lbf=1slug×ft/s2=32.2pdl=32.2lbm×ft/s2=4.448N1lbm=0.454kg1kg=2.204623lbm1slug=14.594kg=32.17
3、4lbmg=32.2lbf/slug=1lbf/lbm=32.2pdl/lbm=9.81N/kg=981dyn/g=1037pdl/slugThefollowingconversionsapplyat3.98°Cwherewaterisdensest.rH2O=DH2O=r×g=DH2O=1m=3.28083ft1IMPgal=4.5461L=1.201USgal1USgal=3.7854L=0.8327IMPgal1IMPgalH2O=4.5461L′(1kg/L)′(2.2046lb/kg)=10.02l
4、b/IMPgal1USgalH2O=3.7854L′(1kg/L)′(2.2046lb/kg)=8.345lb/USgalrH2O=62.43lbm/ft3′(1IMPgal/10.0lbm)?6.24IMPgal/ft3rH2O=62.43lbm/ft3′(1USgal/8.345lbm)?7.48USgal/ft3Power=Also,1horsepower(HP)=745.7watts(W)=550ft×lbf×s-1=33000ft×lbf×min-1FLUIDFLOWPage50of50EQUATI
5、ONSFORFLUIDFLOWA=p×d2/4Whenanincompressiblefluidflowsthroughapipeatasteadyflowrate,thequantityofflowpastallpointsinthepipeisconstant.dThefrontofthissectionoffluidmovesadistance‘d’intime‘t’,soitsvelocity,v=d/t.Volumetricflowrate(Q)isthevolumeoffluidpassingac
6、ertainpointperunittime.VolumetricflowratehasunitsofV/t,e.g.,m3/h,L/min,mL/s,ft3/s,gal/h,etc.BecarefulnottoconfuseVforvolumewithvforvelocity.Itisofteneasiertocalculatecrosssectionalareaasp×d2/4ratherthanp×r2.Problem1:ThenozzleofagardenhosehasanI.D.of0.500in.
7、Ifwaterflowsthroughthehoseat10.0USgal/min,findthespeedatwhichitleavesthenozzleinft/s.Ans:16.3ft/sI.D.O.D.wallthicknessI.D.=internaldiameterO.D.=outsidediameterOD–2(thickness)=IDFLUIDFLOWPage50of50THECONTINUITYEQUATIONorSTEADYSTATEFLOWEQUATIONConsiderasteady
8、flowrateofaliquidflowingthroughapipeofvaryingcross-sectionalarea,frompoint2topoint1.Theflowratemustremainconstanteventhoughthevelocitymayvary.2.1.Q1,A1,v1Q2,A2,v2Q1=Q2A1v2Q1=A1×n1andQ2=A2×n2Since