简介：Thispapermainlysummarizestherecentprogressesforthecavitationstudyinthehydraulicmachineryincludingturbopumps,hydroturbines,etc..Especially,thenewlydevelopednumericalmethodsforsimulatingcavitatingturbulentflowsandtheachievementswithregardtothecomplicatedflowfeaturesrevealedbyusingadvancedopticaltechniquesaswellascavitationsimulationareintroducedsoastomakeabetterunderstandingofthecavitatingflowmechanismforhydraulicmachinery.Sincecavitationinstabilitiesarealsovitalissueandratherharmfulfortheoperationsafetyofhydromachines,wepresentthe1-Danalysismethod,whichisidentifiedtobeveryusefulforengineeringapplicationsregardingthecavitatingflowsininducers,turbinedrafttubes,etc.Thoughbothcavitationandhydraulicmachineryareextensivelydiscussedinliteratures,oneshouldbeawarethatafewproblemsstillremainsandareopenforsolution,suchasthecomprehensiveunderstandingofcavitatingturbulentflowsespeciallyinsidehydroturbines,theunneglectablediscrepanciesbetweenthenumericalandexperimentaldata,etc..Tofurtherpromotethestudyofcavitationinhydraulicmachinery,someadvancedtopicssuchasaDensity-Basedsolversuitableforhighlycompressiblecavitatingturbulentflows,avirtualcavitationtunnel,etc.areaddressedforthefutureworks.

简介：Inordertosolvethehigh-priceandshort-lifetimeproblemsofthecutterofagriculturalmachinery,andimprovethewearresistanceofthecutter,theTiCN/FemetalceramiccompositecoatingwaspreparedonthesubstrateofQ235steelbyreactionnitrogenarccladdingtechnique.ThemixturepowderoftitaniumandgraphitewaspreplacedontheQ235steelsurfaceafterintensivemixingbyplanetaryballmillandgluingwithstarchbinder.Themicrostructureandphaseofthecoatings,interfacebehaviorbetweencoatingsandthesubstratewereinvestigatedbyscanningelectronicmicroscopeandX-raydiffractometer.Themicro-hardnessdistributionofthecoatingsectionwastestedbymicro-hardnesstester.Frictioncoefficientandwearweightlossweremeasuredbyabrasionmachine.Wearingsurfacemorphologywasinvestigatedbyscanningelectronicmicroscope.TheresultsshowthatanexcellentbondingbetweenthecoatingsandtheQ235steelsubstrateisensuredbythestrongmetallurgicalinterfaceandphaseofthecoatings.ThecoatingsaremainlycomposedofTiCN.Thehighestmicrohardnessofthecoatingsreaches1089HVO.2,whilethemicro-hardnessofQ235steelsubstrateisonlyabout286HVO.2.Theanti-abrasivetestresultsshowthatthewearresistanceofthecladdingcoatingisbetterthanthatofquenchedandtempered65Mnsteelwhichisoftenusedascutterofagriculturalmachinery.ThefieldtestresultsshowthattheTiCN/Femetalceramiccompositecoatingpreparedbyreactionnitrogenarccladdingisfeasibletothemanufactureandremanufactureofthecutterofagriculturalmachinery.