【7A文】航空飞机液压理论英文培训课件.ppt

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1、HydraulicsAirlineTransitionCourseLessonObjectivesDevelopabasicunderstandingofhydraulictheoryandthephysicsrelatedtohydraulicsFluidPowerLawofConservationofEnergyPascal’sLawHydrostaticParadoxMechanicaladvantageBernoulli’sprincipleTypesofFluidHydraulicSystemComponentsFluidPowerTHEORYHy

2、draulicsystemsoperateaccordingtoPascalslaw.ThelawofBlaisePascalsays:'Thepressure,inastatichydraulicfluidinaclosedsystemiseverywherethesame'.However,whenthevelocityoftheflowisconstantonemayapplyPascalsLawaswell.Animation:Whenthemanjumpsonthesmallpiston,heinducesapressureinthesystem

3、.Thispressurealsoworksonthelargepiston:becauseofthelargeareaofthispiston,theforceinducedbythepressureiscapabletoliftthecar.Thepressurecanbecalculatedwiththeformula:where:p=pressure(psi)F=force(pound)A=area(squareinch)FluidPowerForce=energyexerted(F=MA)Pressure=aforcethatisappliedov

4、eragivenarea(usuallyinpsi)Pressure=Force/AreaWork=anytimeaforcecausesanobjecttomoveWork=ForcexDistancePower=theamountofpowerrequiredtoaccomplishagiveamountofworkinacertainperiodoftimePower=(ForcexDistance)/TimeLawofConservationofEnergyWeareabletotakeenergyandchangeit’sform,conserve

5、itforlater,andreleaseitatwill.Wegetthesameamountofenergyoutasweputin.Unfortunatelysomeenergyistransformedandlostintoanunusableform.Ex:Rubbingyouhandstogether,takesyourbodiesenergyandreleasesitasthermalenergy.(UnlessyourinNorthDakotainJan.doingthisisusuallyprettyuseless)Thislossofen

6、ergyisusuallyreferredtoasinefficiencyTwoFormsofEnergyPotential:ExistsinanobjectbecauseofitspositionEx:ArubberbandstretchedoutKinetic:ExistsinanobjectduetoitsmotionEx:ArubberbandafterIhaveletgoofit,asitfliestowardsyourfaceHydrostaticParadoxParadox:Atruestatementthatdoesnotreadilyapp

7、eartobetrue.HydrostaticParadox:Thepressureofafluidatthebottomofthecontainerwillbeeffectedbytheheightofthatcontainerbutnotitsshapeortheamountoffluid.Pascal’sLaw“Pressureinanenclosedcontaineristransmittedequallyandundiminishedtoallpartsofthecontainerandactsatrightanglestotheenclosing

8、walls.Pascal’sLawPressuree