【7A文】航空飞机液压理论英文培训课件.ppt

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1、HydraulicsAirlineTransitionCourseLessonObjectivesDevelopabasicunderstandingofhydraulictheoryandthephysicsrelatedtohydraulicsFluidPowerLawofConservationofEnergyPascal’sLawHydrostaticParadoxMechanicaladvantageBernoulli’sprincipleTypesofFluidHydraulicSystem

2、ComponentsFluidPowerTHEORYHydraulicsystemsoperateaccordingtoPascalslaw.ThelawofBlaisePascalsays:'Thepressure,inastatichydraulicfluidinaclosedsystemiseverywherethesame'.However,whenthevelocityoftheflowisconstantonemayapplyPascalsLawaswell.Animation:Whent

3、hemanjumpsonthesmallpiston,heinducesapressureinthesystem.Thispressurealsoworksonthelargepiston:becauseofthelargeareaofthispiston,theforceinducedbythepressureiscapabletoliftthecar.Thepressurecanbecalculatedwiththeformula:where:p=pressure(psi)F=force(pound

4、)A=area(squareinch)FluidPowerForce=energyexerted(F=MA)Pressure=aforcethatisappliedoveragivenarea(usuallyinpsi)Pressure=Force/AreaWork=anytimeaforcecausesanobjecttomoveWork=ForcexDistancePower=theamountofpowerrequiredtoaccomplishagiveamountofworkinacertai

5、nperiodoftimePower=(ForcexDistance)/TimeLawofConservationofEnergyWeareabletotakeenergyandchangeit’sform,conserveitforlater,andreleaseitatwill.Wegetthesameamountofenergyoutasweputin.Unfortunatelysomeenergyistransformedandlostintoanunusableform.Ex:Rubbingy

6、ouhandstogether,takesyourbodiesenergyandreleasesitasthermalenergy.(UnlessyourinNorthDakotainJan.doingthisisusuallyprettyuseless)ThislossofenergyisusuallyreferredtoasinefficiencyTwoFormsofEnergyPotential:ExistsinanobjectbecauseofitspositionEx:Arubberbands

7、tretchedoutKinetic:ExistsinanobjectduetoitsmotionEx:ArubberbandafterIhaveletgoofit,asitfliestowardsyourfaceHydrostaticParadoxParadox:Atruestatementthatdoesnotreadilyappeartobetrue.HydrostaticParadox:Thepressureofafluidatthebottomofthecontainerwillbeeffec

8、tedbytheheightofthatcontainerbutnotitsshapeortheamountoffluid.Pascal’sLaw“Pressureinanenclosedcontaineristransmittedequallyandundiminishedtoallpartsofthecontainerandactsatrightanglestotheenclosingwalls.Pascal’sLawPressuree