简介：Inthisstudy,anelectro-mechanicalvalve(EMV)systemfortheintakevalveofafourstroke,singlecylinder,overheadvalveandsparkignition(SI)enginewasdesignedandconstructed.AnenginewiththeEMVsystemandastandardengineweretestedtoobservetheeffectsoftheEMVonengineperformanceandemissionsatdifferentspeedsunderfullload.TheEMVengineshowedimprovedenginepower,enginetorqueandbreakspecificfuelconsumption(BSFC).A66%decreaseinCOemissionswasalsoobtainedwiththeEMVsystem,buthydrocarbons(HC)andNOxemissionsincreasedby12%and13%respectively.

简介：Inthispaper,thetheoryofQuasi-steadyisappliedtothecalculationsofturbochargersmatchingtothedieselenginesandperformanceprediction.Theengineperformancepredictionprogramswritteninlanguaechavebeenusedforcalculationsofvariousturbochargeddieselengines.Ithasbeenconfirmedbythecomparisonswithexperimentaldatathattheresultsofthecalcuationarereasonable,reliableandsatisfiedfortheengineeringapplications.

简介：Systemsofphotosyntheticreactioncentreshavebeenmodelledasheatengines,whileithasalsobeenreportedthattheefficiencyandpowerofsuchheatenginescanbeenhancedbyquantuminterference—atraitthathasattractedmuchinterest.Wecomparetwodefinitionsoftheworkofsuchaphotosyntheticheatengine,i.e.definitionAusedbyWeimeretal.andBbyDorfmanetal.Wealsointroduceacoherentinteractionbetweendonorandacceptor(CIDA)todemonstrateareversibleenergytransport.Weshowthatthesetwodefinitionsofworkcanimpartcontradictoryresults,thatis,CIDAenhancesthepowerandefficiencyofthephotosyntheticheatenginewithdefinitionBbutnotwithA.Additionally,wefindthatbothreversibleandirreversibleexcitation-energytransportcanbedescribedwithdefinitionA,butdefinitionBcanonlymodelirreversibletransport.Asaresult,weconcludethatdefinitionAismoresuitableforphotosyntheticsystemsthandefinitionB.

简介：Preliminarydesignandsimulationofafreepistonenginesuitableforsmall-scaleenergyproductionindistributedenergysystemsispresentedinthispaper.Theproperties,particularlythepropertiesofgassealsoftheenginearesimulatedusingasimulationprogramdevelopedforthiscase,andtheresultsareutilizedinpreliminarymaindesignparameterselection.TheenginesimulationprogramwasdevelopedbycombiningandmodifyingthesourcecodesofthesimulationandcalculationprogramsobtainedfromHelsinkiUniversityofTechnology,TampereUniversityofTechnology,andLappeenrantaUniversityofTechnology.Becauseofthecontact-freelabyrinthsealusedinthepiston,theefficiencyofthemotorislowerthantheefficiencyofaconventionalmotorwithoillubricatedpistonrings.Ontheotherhand,thelackofbearinglosses,andthelackoflossesassociatedwithacrankshaftsystemandagearbox,aswellasthelackoflubricationoilexpenses,compensatesthiseffect.Asanetresult,thisnewmotorwouldperformslightlybetterthantheconventionalone.Beingcompletelyoil-free,itisveryenvironmentallyfriendly,anditsexhaustgasesarecompletelyfreeofoilresidualswhicharecausingproblemsinnormalgasmotors.

简介：

简介：Themarinemedium-speeddieselenginesarestartedbytwomethods;oneistheelectricmotors,andtheotherairstartingmotors.Eventhoughairstartingmotorisdependentoftheenginetypesandsizes,ithasbeenwidelyusedinthisareaduetoitssimplicity,convenienceandreliability.Thepurposeofthispaperistogivethedesigningparametersinordertomakeaproper'AirStartingMotor'usingCFD.Theaerodynamicapproachesweregiventounderstandtheinternalflowcharacteristicsoftheairstartingmotor.Inaddition,wehavecarriedouttheinvestigationofeffectsoftipclearance.Inthecalculationsthetipclearanceofairstartingmotorhasbeenvariedbetween0,2.8,4.3and5.7%ofbladespan.Theresultsofcomputationarethetipclearanceincreasedto2.8%,thetorquedecreased24%,andtherewasnomorelargechangeswhentheclearancesincreasedto4.3%and5.7%.

简介：Inthispaper,amulti-objectiveparticleswarmoptimization(MOPSO)algorithmandanondominatedsortinggeneticalgorithmⅡ(NSGA-Ⅱ)areusedtooptimizetheoperatingparametersofa1.6L,sparkignition(SI)gasolineengine.Theaimofthisoptimizationistoreduceengineemissionsintermsofcarbonmonoxide(CO),hydrocarbons(HC),andnitrogenoxides(NOx),whicharethecausesofdiverseenvironmentalproblemssuchasairpollutionandglobalwarming.Stationaryenginetestswereperformedfordatageneration,covering60operatingconditions.Artificialneuralnetworks(ANNs)wereusedtopredictexhaustemissions,whoseinputswerefromsixengineoperatingparameters,andtheoutputswerethreeresultingexhaustemissions.TheoutputsofANNswereusedtoevaluateobjectivefunctionswithintheoptimizationalgorithms:NSGA-ⅡandMOPSO.Thenadecision-makingprocesswasconducted,usingafuzzymethodtoselectaParetosolutionwithwhichthebestemissionreductionscanbeachieved.TheNSGA-Ⅱalgorithmachievedreductionsofatleast9.84%,82.44%,and13.78%forCO,HC,andNOx,respectively.WithaMOPSOalgorithmthereachedreductionswereatleast13.68%,83.80%,and7.67%forCO,HC,andNOx,respectively.

简介：Gas-liquidcouplingoscillationisanovelapproachtoreducingtheresonantfrequencyandtoelevatingthepressureamplitudeofathermoacousticengine.Ifathermoacousticengineisusedtodrivelow-frequencypulsetuberefrigerators,thefrequencymatchingbetweenthethermoacousticengineandtherefrigeratorplaysanimportantrole.Basedonanacoustic-electricanalogy,alumpedparametermodelisproposedtoestimatetheresonantfrequencyofastanding-wavethermoacousticenginewithgas-liquidcouplingoscillation.Furthermore,asimplifiedlumpedparametermodelisalsodevelopedtoreducethecomputationcomplexity.Theresonantfrequencydependenceonthemeanpressure,thegasspacevolume,andthewatercolumnlengthiscomputedandanalyzed.Theimpactofdifferentworkinggasesontheresonantfrequencyisalsodiscussed.Theeffectivenessofthemodelsisvalidatedbycomparingthecomputedresultswiththeexperimentaldataofthegas-liquidcouplingoscillationsystem.Anincreaseinthemeanworkingpressurecanleadtoariseintheresonantfrequency,andalowerresonantfrequencycanbeachievedbyelongatingtheliquidcolumn.Incomparisonwithnitrogenandargon,carbondioxidecanrealizealowerfrequencyduetoasmallerspecificheatratio.

简介：Icing(oriceaccretion)isaphenomenoninwhichsuper-cooledwaterdropletsimpingeandaccreteonabody.Itiswellknownthaticeaccretiononbladesandvanesleadstoperformancedegradationandhascausedsevereaccidents.Althoughvariousanti-icinganddeicingsystemshavebeendeveloped,suchaccidentsstilloccur.Therefore,itisimportanttoclarifythephenomenonoficeaccretiononanaircraftandinajetengine.However,flighttestsforiceaccretionareveryexpensive,andinthewindtunnelitisdifficulttoreproduceallclimateconditionswhereiceaccretioncanoccur.Therefore,itisexpectedthatcomputationalfluiddynamics(CFD),whichcanestimateiceaccretioninvariousclimateconditions,willbeausefulwaytopredictandunderstandtheiceaccretionphenomenon.Ontheotherhand,althoughtheicingcausedbysuper-cooledlargedroplets(SLD)isverydangerous,thenumericalmethodhasnotbeenestablishedyet.ThisiswhySLDicingischaracterizedbysplashandbouncephenomenaofdropletsandtheyareverycomplexinnature.Inthepresentstudy,wedevelopaniceaccretioncodeconsideringthesplashandbouncephenomenatopredictSLDicing,andthecodeisappliedtoafanrotorblade.ThenumericalresultswithandwithouttheSLDicingmodelarecompared.Throughthisstudy,theinfluenceoftheSLDicingmodelisnumericallyclarified.

简介：为了在impellers压制成穴并且做涡轮泵，更长生活，inducer与主要impeller被分开，两impellers独立地被驾驶。在impellers附近的泵和流动条件的表演试验性地被调查，下列结果被获得。(1)主要impeller贡献在inducer和主要impeller之间的流动相互作用。(2)两impellers的旋转速度能独立地被控制以便同时总体上压制成穴不仅impeller，而且在inducer。

简介：Toensureareliableoperationofthe2.5MWgasturbineengine(GTE-2.5)withtheinletgastemperatureTIT=1623K,studieswereperformedoverthethermalstateofthenozzleguidevanesandrotorbladeswiththetemperatures,ratesandflowsoftheworkingmediaandcoolingairsimulatingallthepotentialturbinestageoperatingduties.Thesteadystateandthermal-cyclictestshavingbeenaccomplished,therewasnovisibledefectontherotorbladesandthenozzlevanes.Afterwards,theysurvivedtheendurancetestsattheratedcooling.Therefore,thefunctionalityoftheshellthin-wallhybridnozzlevanesandrotorbladesunderthevariableoperatingdutiesofthegasturbineatthe'shock'and'cyclic'loadsoftheworkingmediatemperaturevariationshasbeendemonstrated.