【7A文】航空飞机液压理论英文培训课件.ppt

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1、HydraulicsAirlineTransitionCourseLessonObjectivesDevelopabasicunderstandingofhydraulictheoryandthephysicsrelatedtohydraulicsFluidPowerLawofConservationofEnergyPascal’sLawHydrostaticParadoxMechanicaladvantageBernoulli’sprincipleTypesofFluidHydraulicSystemComponentsFlu

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

3、,heinducesapressureinthesystem.Thispressurealsoworksonthelargepiston:becauseofthelargeareaofthispiston,theforceinducedbythepressureiscapabletoliftthecar.Thepressurecanbecalculatedwiththeformula:where:p=pressure(psi)F=force(pound)A=area(squareinch)FluidPowerForce=ener

4、gyexerted(F=MA)Pressure=aforcethatisappliedoveragivenarea(usuallyinpsi)Pressure=Force/AreaWork=anytimeaforcecausesanobjecttomoveWork=ForcexDistancePower=theamountofpowerrequiredtoaccomplishagiveamountofworkinacertainperiodoftimePower=(ForcexDistance)/TimeLawofConserv

5、ationofEnergyWeareabletotakeenergyandchangeit’sform,conserveitforlater,andreleaseitatwill.Wegetthesameamountofenergyoutasweputin.Unfortunatelysomeenergyistransformedandlostintoanunusableform.Ex:Rubbingyouhandstogether,takesyourbodiesenergyandreleasesitasthermalenergy

6、.(UnlessyourinNorthDakotainJan.doingthisisusuallyprettyuseless)ThislossofenergyisusuallyreferredtoasinefficiencyTwoFormsofEnergyPotential:ExistsinanobjectbecauseofitspositionEx:ArubberbandstretchedoutKinetic:ExistsinanobjectduetoitsmotionEx:ArubberbandafterIhaveletgo

7、ofit,asitfliestowardsyourfaceHydrostaticParadoxParadox:Atruestatementthatdoesnotreadilyappeartobetrue.HydrostaticParadox:Thepressureofafluidatthebottomofthecontainerwillbeeffectedbytheheightofthatcontainerbutnotitsshapeortheamountoffluid.Pascal’sLaw“Pressureinanenclo

8、sedcontaineristransmittedequallyandundiminishedtoallpartsofthecontainerandactsatrightanglestotheenclosingwalls.Pascal’sLawPressuree