简介:Theeffectofpressureoncombustionandheattransferisanalyzed.Theresearchisbasedonthebasiccombustionandheattransfertheorem.Acorrectionfortheheatcalculationmethodforpressurizedfurnaceismadeonthebasisofthenormalpressurecase.Thecorrectiontakestheeffectofpressurizingintoaccount.Theresultsshowthatthecorrectionisreasonableandthemethodisapplicabletocombustionandheattransferofthemarinesuperchargedboiler.
简介:Inthehostileandhighlycorrosivemarineenvironment,advancedcompositematerialscanbeusedinmarinecurrentturbinesduetotheirhighstrength-to-weightratiosandexcellentresistancetocorrosion.Acompositematerialmarinecurrentturbine(CMMCT),whichhassignificantadvantagesovertraditionaldesigns,hasbeendevelopedandinvestigatednumerically.Asubstantialimprovementinturbineperformanceisachievedbyplacementofaducttoconcentratetheenergy.Computationalfluiddynamics(CFD)resultsshowthattheextractedpowerofaductedCMMCTcanbethreetofourtimesthepowerextractedbyabareturbineofthesameturbinearea.TheresultsprovideaninsightintothehydrodynamicdesignandoperationofaCMMCTusedtoshortenthedesignperiodandimprovetechnicalperformance.
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%.