1BasicConceptsofThermodynamics

1-1ThermodynamicsandEnergyThermodynamicsisdefinedasthescienceofenergy.Engineeringthermodynamicdealswiththeprinciplesofenergyandenergyconversioninengineeringandthethermalpropertiesofsubstancesaswell.1-1-1DefinitionofThermodynamicsTheBasicLawsofThermodynamics:(1)TheFirstLawofThermodynamics:anexpressionofthequantityrelationshipduringenergychange(2)TheSecondLawofThermodynamics:anexpressionofthequalityrelationshipduringenergychange1-1-2ContentsofThermodynamicsItcanbedividedinto:ClassicalThermodynamics--------macroscopicapproachStatisticalThermodynamics--------microscopicapproach

ThePropertiesofMaterial(1)IdealGas(2)Vapor:WaterSteam,Freon,Ammonia(3)Mixtures:Gasmixture,Gas-vapormixturePracticalApplicationGasPowerCycleVaporandCombinePowerCycleRefrigeration

AnyphysicalquantitycanbecharacterizedbydimensionThearbitrarymagnitudesassignedtothedimensionsarecalledUnitsPrimary(foundamental)dimensionsandunits:Massm,LengthL,timet,temperature,T,molSecondarydimensions:velocityV,energyE,volumeVEnglishsystem:AlsoknownastheUnitedStatesCustomarySystem(USCS)SI:InternationalSystem1-1-3DimensionsandUnitsFromLeSystemeInternationald’UnitesHistory:1.1790FrenchNationalAssemblychargedtheFrenchAcademyofScience2.1875TheMetricConvectionTreatywassignedby17nations.GeneralConferenceofWeightsandMeasures(CGPM)wasestablished3.1960theCGPMproducedtheSI

SomeSIandEnglishunitsRefertoourTextbookDimensionalHomogeneityEveryterminanequationmusthavethethesameunits.*thestudentmustkeepinmindth