简介：AnexperimentalsystemofACarcdischargeinwaterwasdesignedwithpole-poleelectrodesandapeakvoltageof1500Vandatestcircuitwassetupusingvirtualinstrumenttechnology.ThemechanismofanACplasmaarcgeneratedinwaterwasanalyzed.ThevoltagecurrentcharacteristicoftheACplasmaarcwasobtainedfromthewaveform.Thetemperaturecharacteristicwastestedwithaspectrumdiagnosissystem,andtheeffectofdifferentelectrodematerialsonthestrikingvoltageandpeakcurrentwasanalyzed.Theresultsshowthatwhenapowersupplyof6kWisappliedonelectrodeswithagapof2mminwater,thestrikingvoltageisfrom900Vto1300V,thearcvoltageisfrom40Vto100V,thearccurrentisfrom2Ato7A,andthezerorestperiodisfrom1msto2ms.Inaddition,thearcvoltageandcurrentaredifferentforelectrodesinaluminum,copperandstainlesssteel.Thearcvoltageislowerandthecurrentishigherforanaluminumelectrodethanthoseforcopperandstainlesssteelones.Thehighesttemperatureofthearcis7643K.

简介：Athreedimensionalsteady-statemagnetohydrodynamicmodelisdevelopedforthearcplasmainaDCsubmergedelectricarcfurnacefortheproductionoffusedMgO.Thearcisgeneratedinasmallsemi-enclosedspaceformedbythegraphiteelectrode,themoltenbathandunmeltedrawmaterials.Themodelisfirstusedtosolveasimilarprobleminasteelmakingfurnace,andthecalculatedresultsarefoundtobeingoodagreementwiththepublishedmeasurements.ThebehaviorofarcswithdifferentarclengthsisalsostudiedinthefurnaceforMgOproduction.Fromthedistributionofthearcpressureonthebathsurfaceitisshownthatthearcplasmaimpingementislargeenoughtocauseacrater-likedepressiononthesurfaceoftheMgObath.Thecirculationofthehightemperatureairundertheelectrodemayenhancethearcefficiency,especiallyforashorterarc.

简介：AwaterplasmawasgeneratedbyDCarcdischargewithahafniumembeddedrodtypecathodeandanozzle-typeanode.Thedischargecharacteristicswereexaminedbychangingtheoperationparameterofthearccurrent.Thedynamicbehaviorofthearcdischargeledtosignificantfluctuationsinthearcvoltageanditsfrequency.Analysesofthehighspeedimageandthearcvoltagewaveformshowedthatthearcdischargewasintherestrikemodeanditsfrequencyvariedwithinseveraltensofkilohertzaccordingtotheoperatingconditions.Thelargerthermalplasmavolumewasgeneratedbythehigherflowfromtheformingsteamwithahigherrestrikefrequencyinthehigherarccurrentconditions.Inaddition,thecharacteristicsofthewaterplasmajetwereinvestigatedbymeansofopticalemissionspectroscopytoidentifytheabundantradicalsrequiredinanefficientwastetreatmentprocess.

简介：CalculationofthenetradiationemittedbyaCH_4-Armixture,inatemperaturerangeof5,000～30,000Kwiththeassumptionoflocalthermodynamicequilibrium(LTE),isconducted.Continuumandlineemissionsaretakenintoaccount.Theradiativetransferofeachlineiscalculatedbymeansofanescapefactordependingontheshapeandbroadeningoftheline.Assumingacylindrical,homogeneous,andisothermalplasma,thenetemissioncoefficientiscalculatedfordifferentpressuresbetween1atmand10atmandarcradiaof0mmto1mm.ResultsshowthattheargonpresenceintheCH_4-Armixturehasasignificanteffectonthetotalradiationemittedforthetemperatureabove17,000KandtheresultsforpureargonagreewiththoseofBAUDERandEVANS.

简介：Theglidingarccanofferhighenergyefficiencyandselectivityforchemicalreactionsandhasbeenwidelyappliedinmaterialprocessing,environmentalprotectionandotherindustrialareas.Butthedischargeproperties,measurementofplasmaparametersandrelatedphysicalpro-cessesoftheglidingarcdischargestillneedtofurtherstudied.Inthisstudy,theglidingarcwasdrivenbythetransversemagneticfieldtoproducethenon-equilibriumplasmaathighpressure.Theparametersoftheplasmaatourobservedpointweremeasuredbyopticalmethods.Theexperimentalresultshowsthattheelectrontemperatureisabout0.6eVandtheheavyparticletemperatureisapproximately2987±250K.

简介：Inthispaper,a3Dmagneto-hydrodynamic(MHD)arcsimulationmodelisappliedtoanalyzethearcmotionduringcurrentinterruptioninacertainaircircuitbreaker(ACB).Thedistributionsofpressure,temperature,gasflowandcurrentdensityofthearcplasmainthearcregionarecalculated,andthefactorsinfluencingthecommutationprocessareanalyzedaccordingtothecalculatedresults.Basedontheairflowinthearcchamber,thecausesofarccommutationasynchronyandthebackcommutationareinvestigated.Itindicatesthatareasonablecontactspacedesigniscrucialtoasuccessfularccommutationprocess.Toverifythesimulationresults,theinfluenceofcontactspaceonarcvoltageandarccommutationistested.ThisresearchcanprovidemethodsandreferencestotheoptimizationofACBdesign.

简介：Ahigh-currentvacuumarc(HCVA)withtheconsiderationofanodevaporismod-eledandsimulated.First,fromtheHCVAcolumnmodel,theheatfluxdensitytotheanodeisobtained,whichisputintotheanodeactivitymodel,andtheparameterdistributions(suchasthevaportemperatureandvelocity)ofanodevaporareobtainedfromthesimulationresultsoftheanodeactivitymodel.Then,byiteratingandcalculatingtheHCVAcolumnmodelandanodeactivitymodel,theinteractionbetweentheHCVAcolumnandtheanodevaporissimulatedandanalyzed.Inthesimulation,thedistributionoftheaxialmagneticfield(AMF)generatedbytheelectrodesystemiscalculatedbysoftwareANSYS.Thesimulationresultsshowthattheinfluenceofanodevaporontheparameterdistributionsinthearccolumnissignificant.Thesimulationresultsarealsocomparedwiththevacuumarcphotograph.

简介：Flyashfromamunicipalsolidwasteincinerator(MSWI)withoutpreprocessing(originalflyash,OFA)wasmeltedbyadirectcurrent(DC)plasmaarcfurnacetoinvestigatehowthefeedformsgovernedtheresults.Dioxinsinfluegasfromstackandbag-filterash(BFA)weredetected.ThedistributionofheavymetalsofPb,Cd,As,andCralongthefluegasprocesssystemwasanalyzed.Throughacomparisonoftheresultsfordioxinsandheavymetalsinthisstudyandpreviouswork,carrying-overofflyashparticleswiththefluegasstreamcanbededuced.BasedonthemagneticinductionequationandNavier-Stokesequations,amagnetohydrodynamic(MHD)modelfortheplasmaarcwasdevelopedtodescribetheparticle-carryingeffect.Theresultsindicatethat,a.whenmelted,thefeedformsofMSWIflyashaffecttheresultssignificantly;b.itisnotpreferabletomeltMSWIflyashdirectly,andeffortsshouldbemadetolimitthemasstransferofOFAfromtheplasmafurnace.

简介：ThispaperpresentsabriefoverviewofCO2reformingofCH4（CRM）byvariousformsof'arc'plasma,whichismoresuitabletoCRM,andtheenergyefficiencyisusedtoevaluatedifferentplasmaprocessesspecifically.Accordingtothereportedresults,thearcthermalplasmawithbinodeexhibitedbetterperformance.Moreover,theplasmaCRMprocesswascomparedwiththereportedplasmasteamreformingofCH4（SRM）process,andtheresultsshowedthattheformerprocesshasadvantagesonenergyefficiencyandCH4consumption.Additionally,itisbelievedthattheplasmaCRMprocesswouldbecompetitivewiththeconventionalSRMprocessinbothenergyefficiencyandCO2emissiononcetheheatmanagementisemphasizedandtherenewablepowerisused.Finally,aconceptofplasmareactorforindustrialapplicationisproposed.

简介：ThepreparationofcrystallineC_3N_4filmswasinvestigatedusingpulsedarcdischargefrommixedmethanolandammoniawateratatmosphericpressure.TheX-raydiffraction(XRD)patternsofthefilmspreparedatasubstratetemperatureof450℃suggestedthatthefilmwascomposedofα-C_3N_4andβ-C_3N_4crystallites.RamanspectraexhibiteddistinctpeakswhichareingoodagreementwiththosepredictedtheoreticallyforC_3N_4crystallites.

简介：InspiteofthecurrentprevalenceoftheCVD-basedprocesses,theelectricarcremainsaninterestingprocessforthesynthesisofcarbonnanoforms,thankstoitsversatility,robustnessandeasiness.Italsoallowsperformingin-situsubstitutionofcarbonatomsbyhetero-elementsinthegraphenelattice.Ourworkaimstoestablishacorrelationbetweentheplasmaproperties,typeandchemicalcomposition(andthesubstitutionrate)oftheobtainedsingle-wallcarbonnanotubes.TheplasmawascharacterizedbyopticalemissionspectroscopyandtheproductswereanalyzedbyhighresolutiontransmissionelectronmicroscopyandcorelevelElectronEnergy-LossSpectroscopy(EELS).Resultsshowthatahighboroncontentleadstoaplasmatemperaturedecreaseandhinderstheformationofnanotubes.Thiseffectcanbecompensatedbyincreasingthearccurrentand/oryttriumcontent.Theoptimalconditionsforthesynthesisofboron-and/ornitrogen-substitutednanotubescorrespondtoahighaxialplasmatemperatureassociatedtoastrongradialgradient.EELSanalysisconfirmedthattheboronincorporatesintothegraphemelattice.

简介：Non-contactmagneticmeasurementmethodisaneffectivewaytostudytheairarcbehaviorexperimentally.Oneofthecrucialtechniquesistosolveaninverseproblemfortheelectromagneticfield.Thisstudyisdevotedtoinvestigatingdifferentalgorithmsforthiskindofinverseproblempreliminarily,includingthepreconditionedconjugategradientmethod,penaltyfunctionmethodandgeneticalgorithm.Thefeasibilityofeachalgorithmisanalyzed.Itisshownthatthepreconditionedconjugategradientmethodisvalidonlyforfewarcsegments,theestimationaccuracyofthepenaltyfunctionmethodisdependentontheinitialconditions,andtheconvergenceofgeneticalgorithmshouldbestudiedfurtherformoresegmentsinanarccurrent.

简介：TiBCNnanocompositecoatingsweredepositedoncementedcarbideandSi（100）byacathodearcplasmasystem,inwhichTiB2cathodeswereusedinmixturegasesofN2andC2H2.X-raydiffractionshowsthatTiB2andTi2B5peaksenhanceatlowflowratesofC2H2,buttheyshrinkwhentheflowrateisover200seem.AnincreaseofdepositionratewasobtainedfromdifferentTiBCNthicknessesforthesamedepositiontimemeasuredbyscanningelectronmicroscopy.Atomicforcemicroscopyshowsthatthesurfaceroughnessesare10nmand20nmatC2H2flowratesof0-100sccmandof150-300sccm,respectively.HighresolutiontransmissionelectronmicroscopyandX-rayphotoelectronspectroscopyshowthatthecoatingsconsistofnanocrystalphasesTi2B5,TiB2andTiN,andamorphousphasecarbonandBN.Theaveragecrystalsizesembeddedintheamorphousmatricesare200nmand10nmatC2H2flowratesof200sccmand300sccm,respectively.InRamanspectra,theD-andG-bandsincreasewithC2H2flowsatlowflowrates,butweakenathighflowrates.Themicrohardnessofthecoatingsdecreasesfrom28.6GPato20GPaastheC2H2increasesfrom0sccmto300sccm,andtheball-on-diskmeasurementshowsadramaticdecreaseofthefrictioncoefficientfrom0.84to0.13.ThereasonforthereducedhardnessandfrictioncoefficientwiththechangeofC2H2flowratesisdiscussed.

简介：Ageneratoroftheglidingarcjet(GAJ),whichisdrivenbyatransversemagneticfield,isdevelopedtoproducenon-equilibriumplasmaatatmosphericpressure.ThegastemperatureisestimatedusingthespectrumofOHradicalstobeabout2400±400K.Thedeterminationsofelectrontemperatureandelectrondensitybyusingaline-ratiomethodareelaboratedfortheglidingarcjetplasma.Thisline-ratiomethodisbasedonacollisional-radiativemodel.Theexperimentresultsshowthatelectrontemperatureisabout1.0eVandelectrondensityisabout6.9×1014cm-3.Obviously,theplasmaofGAJisinanon-equilibriumstate.

简介：Theeffectofarcplasmaonelectrodeerosioninaliquidmetalcurrentlimiter(LMCL)isstudied.Basedonasimplifiedtwo-dimensionalmagnetohydrodynamicmodel,theelongatedGaInSnmetalvaporarcanditscontractionprocessinaliquidmetalcurrentlimiteraresimulated.Thedistributionsoftemperature,pressureandvelocityofthearcplasmaarecalculated.Thesimulationresultsindicatethattheelectrodeerosionismainlycausedbytwohightemperaturegasjetflowsarisingfromthepressuregradient,whichisaresultofthenon-uniformarctemperaturedistribution.Thegasflows,whichactasjetsontotheelectrodesurface,leadtotheevaporationoftheelectrodematerialformthesurface.Aredesignstructureoftheelectrodeisproposedandimplementedaccordingtotheanalysis,whichgreatlyincreasedtheservicelifeoftheelectrode.

简介：Theplasma-neutralgasstructuregeneratedinamagnesiumcathodicarcoperatedwithoxygengasataconstantcurrentof50Ahasbeeninvestigatedbyemployingasimplifiedone-dimensionalfluidmodel.Themodelincludeselasticcollisionsandcharge-exchangereactionsbetweenmetallicparticlesandgasmolecules,andalsogenerationandrecombinationofgaseousionsbyelectronimpact.Thedistributionprofilesofdensityandvelocityofspeciesalongtheaxialdirectionwereobtainedatdiferentbackgroundgaspressures(intherangeof0.7~3.0Pa)bythismodel.Acomparisonwiththeexperimentswasmade.Atlowergaspressures,thedepositingparticlesweremainlythemetallicionswithalargerkineticenergy.Asthegaspressureincreased,themagnesiumatomswithsmallerkineticenergyactedasthedominantdepositingspecies.Determinedbytheminimizationofthesystem’stotalenergy,MgO(100)or/andMgO(110)orientationappearedeasilyintheMgOfilmsatlowergaspressures,andathighergaspressures,thefilmpreferredorientationwasMgO(111).

简介：Amodellingstudyisperformedtocomparetheplasmaflowandheattransfercharacteristicsoflow-powerarc-heatedthrusters(arcjets)forthreedifferentpropellants:hydrogen,nitrogenandargon.Theall-speedSIMPLEalgorithmisemployedtosolvethegoverningequations,whichtakeintoaccounttheeffectsofcompressibility,LorentzforceandJouleheating,aswellasthetemperature-andpressure-dependenceofthegasproperties.Thetemperature,velocityandMachnumberdistributionscalculatedwithinthethrusternozzleobtainedwithdifferentpropellantgasesarecomparedforthesamethrusterstructure,dimensions,inlet-gasstagnantpressureandarccurrents.Thetemperaturedistributionsinthesolidregionoftheanode-nozzlewallarealsogiven.Itisfoundthattheflowandenergyconversionprocessesinthethrusternozzleshowmanysimilarfeaturesforallthreepropellants.Forexample,thepropellantisheatedmainlyinthenear-cathodeandconstrictorregion,withthehighestplasmatemperatureappearingnearthecathodetip;theflowtransitionfromthesubsonictosupersonicregimeoccurswithintheconstrictorregion;thehighestaxialvelocityappearsinsidethenozzle;andmostoftheinputpropellantflowstowardsthethrusterexitthroughthecoolergasregionneartheanode-nozzlewall.However,sincethepropertiesofhydrogen,nitrogenandargon,especiallytheirmolecularweights,specificenthalpiesandthermalconductivities,aredifferent,thereareappreciabledifferencesinarcjetperformance.Forexample,comparedtotheothertwopropellants,thehydrogenarcjetthrustershowsahigherplasmatemperatureinthearcregion,andhigheraxialvelocitybutlowertemperatureatthethrusterexit.Correspondingly,thehydrogenarcjetthrusterhasthehighestspecificimpulseandarcvoltageforthesameinletstagnantpressureandarccurrent.Thepredictionsofthemodellingarecomparedfavourablywithavailableexperimentalresults.