Chap. 1 SummaryEnergyTransferEnergyRelationshipstoTransformationsmatterpropertiesThermodynamicsApplicationareasZerothLawThe FirstLawCarnot PrinciplesTheSecondLawAScienceofEnergyTheIncreaseofetcEntropyPrincipleSystemClosed systemOpensystemThermodynamic SystemBoundary/SurroundingAdiabaticsystemIsolatedsystemAsetofpropertiesthatcompletelydescribestheconditionofthesystemStateEquilibrium:: Temperature(T), mechanical (P),phase, chemical State postulate: The state of a simple compressible system is completelyspecified bytwoindependentintensiveproperties.E.g.T(temperature)&v(specificvolume).orP&T (onephase)Isothermal,Isobaric,Path, CycleState 1 to State 2Isometric.IsoentropicQuasi-equilibrium:aprocessinwhichsystemremainsinfinitesimallyclosetoan equilibriumProcessstateaf alltimecReversible processSteadyflowprocessIreversibleprocessExtensivepropertiesV,E,H,SIntensive properties T.P,pPropertiesK273.15Triplepoint=0.01C=273.16K1Pascal=1N/m^2Pgage=Pabs - PatmPvac=Patm - Pabs
Chap. 1 Summary 1 Thermodynamics Energy Application areas A Science of Energy Thermodynamic System Zeroth Law The First Law The Second Law The Increase of Entropy Principle Carnot Principles etc Energy Transformations Relationships to matter properties Closed system Open system Isolated system Adiabatic system Intensive properties T, P, ρ Extensive properties V, E, H,S State State postulate: The state of a simple compressible system is completely specified by two independent, intensive properties. E.g. T(temperature)& ν (specific volume), or P&T (one phase) Equilibrium:: Temperature(T), mechanical (P), phase, chemical Path, Cycle Process State 1 to State 2 Steady flow process T K ℃ 273.15 Triple point=0.01℃=273.16K 1Pascal=1N/m^2 Pgage=Pabs - Patm Pvac=Patm - Pabs Transfer A set of properties that completely describes the condition of the system Properties Quasi-equilibrium: a process in which system remains infinitesimally close to an equilibrium state at all times. Isothermal, Isobaric, Isometric, Isoentropic Reversible process Irreversible process P System Boundary/Surrounding
Chap.2 SummaryTotal Energy, EIntermal Energy,UPotentialEnergy,PEKinetic Energy. KEEnergyForms of EnergyE=U+KE+PE=U+mV2/2+mgzMechanical energy,Nuclearenergy,Chemical Energy,SensibleenergyLatentenergy.Thermalenergy.Heat,Work,FlowworkConvectionTemperature diffBy Heat, QRadiationConductionEnergy Transfer, EForce*distanceBy Work, WForms ofwork:mechanical.shaft,spring,electrical,etcBy Mass, m=o,foraclosedsystemclosed systemQ=△U+ WEin-Eout=AEsystem1stLawofThermodynamicsEnergybalance:Ein-Eout=(Qin-Qout)+(Win-Wout)+(Emass,in-Emass,out)=EsystemEnergyChangeEffciency=desiredoutput/requiredinputEnergy Conversion EfficiencyCombustion efficiency.Overall efficiency,efficiency of generator, motor, pump, turbine, etc.福Energyand Environment
E=U+KE+PE=U+mV2 /2+mgz Chap.2 Summary 2 Forms of Energy Energy Transfer, E Total Energy, E Kinetic Energy, KE Potential Energy, PE Conduction Convection Radiation Effciency =desired output/ required input Ein-Eout= ∆Esystem Internal Energy,U 1st Law of Thermodynamics Energy balance: Ein-Eout=(Qin-Qout)+(Win-Wout)+(Emass,in-Emass,out)= ∆Esystem Energy Conversion Efficiency Energy and Environment Mechanical energy, Nuclear energy, Chemical Energy, Sensible energy, Latent energy, Thermal energy, Heat, Work, Flow work Energy By Heat , Q Temperature diff Forms of work: mechanical, shaft, spring,electrical, etc By Work, W Force*distance By Mass, m =0, for a closed system closed system Q=∆U+ W Energy Change: Combustion efficiency, Overall efficiency, efficiency of generator, motor, pump, turbine, etc
Chap.3 SummaryAsinglechemicalelementorcompoundAsubstancethat hasPure substanceHomogeneousmixtureofvariouschemicalelementsorcompoundsafixedchemicalcompositionmixtureoftwoormorephasesapuresubstanceCompressed liguid orsubcooled liquidliquidSaturated liquidSatruated liquid-vapor mixturePhase changeprocessSatruated vaporvaporSuperheatedvapor+Psat,Tsat,Latentheatoffusion/vaporization,sublimationsolidCritical pointSaturated liquid/vapor lineSuperheatedvaporregionT-v,P-v,P-T, P-v-T diagramsTripple pointCompressedliquid regionSaturated liquid-vapor region1Enthalpy/焰:acombinationpropertyh=u+Pv(kJ/kg);Entropy/PropertiestablesSaturated liguid/vaporormixture.ht,ha,haQualityx=[0.1]SuperheatedvaporCompressedliquid P,TReferencestatevalues1PV=RTPV=mRTR,RuIdeal gasequationofstateIdeal-gas/realgasZ=Pv/RTCompressibilityfactorReducedPReducedTequationofstateGeneralizedVanderwallsPrincipleofcorresponding statescompressibility chartequationofstate3
Chap.3 Summary 3 A substance that has a fixed chemical composition Phase change process A single chemical element or compound Enthalpy/焓: a combination property h=u+Pv (kJ/kg); Entropy/熵 Critical point T-v, P-v,P-T, P-v-T diagrams Properties tables Ideal-gas / real gas equation of state Pure substance liquid vapor solid Homogeneous mixture of various chemical elements or compounds mixture of two or more phases a pure substance Saturated liquid Satruated liquid-vapor mixture Satruated vapor Superheated vapor Compressed liquid or subcooled liquid Psat, Tsat, Latent heat of fusion/vaporization, sublimation Tripple point Saturated liquid/vapor line Superheated vapor region Compressed liquid region Saturated liquid-vapor region Saturated liquid/vapor or mixture. hf ,hg,hfg Quality x=[0,1] Superheated vapor Compressed liquid P, T Reference state/values Ideal gas equation of state Pv=RT PV=mRT R, Ru Compressibility factor Z=Pv/RT Reduced P Reduced T Principle of corresponding states Generalized compressibility chart Van der walls equation of state
Chap4 SummaryGeneral:Ow,=Pdy,P-VdiagramThework associatedBoundary workwithexpansionandIsobaricprocess,Pvn=const PolytropicprocesscompressionisothermalprocessofanidealgasW,=P,V,ln(V2/V)AE.(KJ)E-EouEnergyBalancesyatenNet enengy tnansferChange in intemal,kioctic.foranysystemandanyprocessbyhealwortandmasspoteatial,tc,enengis1stlawforclosedsystem=WWWWQ=Qnetin=0-0aet.ououtEnergyBalanceforclosedsystemO-W=AEThe energyrequired to raise T of 1kg ofa substanceby 1K,kJ/(kg.k)ahSpecific heatCv atconstant1Cp atconstantPCp22aTIdealgases:Cp=Cv+R;k=Cp/CvForsolidsand liquids,Cp=Cv=cU,h fromtable.Ah=h-hc,(T)dTepavg(T-T)Changes ofu, h for ideal gasesByusingCvorCpUsingaveragespecificheats.Cv,avg=Cv(T2/2+T1/2)Cp,avg=Cp(T2/2+T1/2)Forimcompressiblec(T)dT=Cav(T2-T)Ah=Au+VAPChanges of u,h for solid/fluidsubstances
Chap4 Summary 4 The work associated with expansion and compression 1st law for closed system General: δWb=Pdv, P-V diagram U,h from table. Specific heat Changes of u, h for ideal gases Changes of u, h for solid/fluid Boundary work Energy Balance for any system and any process Isobaric process, PVn=const Polytropic process isothermal process of an ideal gas Wb=P1V1ln(V2/V1) The energy required to raise T of 1kg of a substance by 1K, kJ/(kg.k) By using Cv or Cp Using average specific heats. Cv,avg=Cv(T2/2+T1/2) Cp,avg=Cp(T2/2+T1/2) Energy Balance for closed system Cv at constant V Cp at constant P Ideal gases: Cp=Cv+R; k=Cp/Cv For solids and liquids, Cp=Cv=C For imcompressible substances
Chap5 SummaryConservation of massprinciple:thenetmasstransfertoorfroma controlvolumeduringatimeintervalisequalto theConservationofmassnetchangeinthetotalmasswithinthecontrolvolumedmcvAmcmoutmindtoutinFlow energy:Totalenergyofaflowingfluidof1kg12(kJ/kg)Waow=PV=h+ke+pe=hgzEnergyofflowingfluid2V2Rate of energy transportE=mo=Igzm2V=大mMassbalanceIncompressibleOUDUinSingle streamPVA=PVA2nmSteadyflowProcess/systemV=V,-VA=VA2IncompressibleSinglestreamIFor△KE=0,△PE=0q-W=h2-hTurbines,compressorsNozzles,diffusersHeatexchangersSteadyflowdevicesPipeand ductflowThrottling valvesMixingchambers5
Chap5 Summary 5 Conservation of mass principle: the net mass transfer to or from a control volume during a time interval is equal to the net change in the total mass within the control volume. Energy of flowing fluid Nozzles, diffusers Steady flow Process/system Steady flow devices Conservation of mass Mass balance Flow energy: Total energy of a flowing fluid of 1kg Enthalpy is associated with the energy pushing the fluid into or out of CV Single stream Incompressible Incompressible Single stream Energy balance for general steady flow systems For For single stream △KE=0, △PE=0 Turbines, compressors Throttling valves Mixing chambers Heat exchangers Pipe and duct flow Rate of energy transport
Chap6 Summary-1Whyweneed2ndLaw?Allprocessessatisfy1stLaw,Satisfying1stdoesnotensuretheprocesscanactuallyoccurIntroductionto2ndLawAprocesshasdirectionEnergyhasqualityandquantityHeat SinkHeat SourceHeatengineThermalenergyReservoirWact.ouOReceiveheatQfromahightemperature sourceHMthQHWConvert part Q to work Wnet.outnetoutOHeatEnginesQTihRejectwaste heatQtoalowtemperature sink92ndlawKelvin-PlanckStatement:Itisimpossibleforanydevicethatoperatesonacycletoreceiveheatfromasinglereservoirandproduceanetamountofwork.No heat engine can haven=100%Refrigerators/heatpump:ThedevicesdriveheatQtransferfromT,toTHW.RefrigeratorTheworkinputtotherefrigerator/heatpumpnet,inwants QLQHeatQabsorbedfromrefrigeratedspaceTHeatpumpQHHeat Qrejected tohightemperature THwants QHRefrigerator,HeatPumpDesiredoulputuDesired outputQ,AirCOPCOPHCOPW.WreLinRequired inputRequired inputConditionerDCEI2nd law,Clausius Statement:Heatdoesnot,of its ownvolition,transferfromacoldmediumtoawarmerone.（热不能自发地、不付代价地从低温物体传到高温物体）6
Chap6 Summary-1 6 Why we need 2nd Law? All processes satisfy 1st Law; Satisfying 1st does not ensure the process can actually occur Heat Engines Refrigerator, Heat Pump Introduction to 2nd Law Refrigerators/heat pump: The devices drive heat Q transfer from TL to TH, Thermal energy Reservoir Receive heat QH from a high temperature source The work input to the refrigerator/heat pump Heat QL absorbed from refrigerated space TL A process has direction Energy has quality and quantity Heat Source Heat Sink Convert part QH to work Wnet,out Reject waste heat QL to a low temperature sink Heat engine 2nd law, Kelvin-Planck Statement: It is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work. No heat engine can have η=100% Heat QH rejected to high temperature TH Refrigerator wants QL Heat pump wants QH COP 2nd law, Clausius Statement: Heat does not, of its own volition, transfer from a cold medium to a warmer one. (热不能自发地、不付代价地从低温物体传到高温 物体) Air Conditioner
Chap6 Summary-2SystemAprocesscanbereversedwithouleavinganytraceonthesurroundingsSurroundingsReversible ProcessesInternal RevExternal RevWhy need RevIrreversible:heattransferThe bestknown reversible cycle; four reversible processesIsothermal expansionAdiabatic expansionIsothermalCompressionAdiabaticcompressionCarnotCycleCarnotheatengineReversed CarnotCycleCarnotrefrigerator/heat pumpCarnot Principle 1:Given T,andTh,Nth.irrev<.Nth,revCarnot Principle 2:GivenT,andTh,Nth.all rev=Nth,revThe heat engine operates on the reversible Carnot Cycleirreversibleheat engineMhrevCarnot HeatEngineTLQLreversible heat engineTth,revThTih.revTHOn二impossibleheatengineTih,reyThe refrigerator / heat pump operates on a reversible Carnot CycleCarnotRefrigeratorCOPR.ECOPRIEVirreversiblerefrigeratoTH/T,-1Carnot Heat PumpCOPCOPRrevreversiblerefrigeratorCOPHPeCOPR.revimpossiblerefrigeratorI-TL/TH
Chap6 Summary-2 7 A process can be reversed without leaving any trace on the surroundings. Carnot Cycle Carnot Refrigerator Carnot Heat Pump Reversible Processes The heat engine operates on the reversible Carnot Cycle The best known reversible cycle; four reversible processes Carnot heat engine Carnot Principle 1: Given TL and TH, ηth,irrev < ηth,rev System Surroundings Internal Rev External Rev Why need Rev Irreversible: heat transfer Isothermal expansion Isothermal Compression Adiabatic compression Reversed Carnot Cycle Carnot refrigerator /heat pump Carnot Principle 2: Given TL and TH, ηth,all rev = ηth,rev Carnot Heat Engine The refrigerator / heat pump operates on a reversible Carnot Cycle Adiabatic expansion
Chap7 SummaryClausiusinequality:thecyclicintegral ofisalways≤zeroEntropy（熵）60QAS= S, -SiASEntropyIsoTTotintrevEntropychangeofaclosedsystemASm=S,-S,ReversibleprocessIrreversibleprocess2ASm-S1-S1-JSm= S,-S,>IncreaseofEntropySgen≥0Principle(摘增原理Increaseofentropyprinciple（孤立系统炳增原理，简称摘增原理）：theentropyofanisolatedsystemduringaprocessalwaysincreaseor,inthelimitingcaseofareversibleprocessremainsconstant.（孤立系统的焰可以增大，或保持不变，但不可能减少）AS=mAS=m(S.EntropychangeofpuresubstancesS0,0,ASsys=S.S2,IsentropicprocessadibaticReversibleas=03,T-S,h-sdiagramsdsAeSomeremarks4,The3rd lawof thermodaynamics:The entropy ofapurecrystallinesubstance atabsolutezerotemperatureiszerodhvdpPdvdudsas5,Tds relationsTTTT6,reversibleworkoutputAkeADC8o
Chap7 Summary 8 Clausius inequality: the cyclic integral of is always ≦ zero Increase of Entropy Principle(熵增原理) Entropy (熵) 1, Entropy change of pure substances: Entropy change of a closed system: Increase of entropy principle (孤立系统熵增原理，简称熵增原理)：the entropy of an isolated system during a process always increase or , in the limiting case of a reversible process remains constant. (孤立系统的熵可以增大，或保持不变，但不可能减少) Entropy Some remarks Iso T Reversible process Irreversible process ≥ 0 sf at 0.01℃=0 kJ/kg.k 2, Isentropic process 0, adibatic 0, Reversible 3, T-S, h-s diagrams = 4, The 3rd law of thermodaynamics: The entropy of a pure crystalline substance at absolute zero temperature is zero 5, T ds relations: 6, reversible work output >
Chap8 SummaryBasicconsiderations:actual cycle,ideal cycle,carnot cycle,P-V,T-sAssumptions ofgasairstandardassumptions(标准假设）：1）air=idealgas，Cv=powercyclesconst;2)internalreversibleprocess;3)combustion>heatadditionprocess;4)exhaustheatrejectionprocessTDCBDCMEPStrokeBoreIntakevalveExhausevalveReciprocatingenginesReciprocatingenginesareclassifiedasspark-ignition(Sl)engines(点燃式内燃机)compression-ignition（cl)engines（压燃式内燃机)Fourstrokes:compressionstroke,expansionorpowerstrokeexhauststroke,intakestroke.（压缩冲程、做功（燃烧、膨胀）冲程排气冲程和吸气冲程TheidealOttocycle:Slengines-Ottocycle1-2isentropiccompression（等煽压缩）2-3constantVheataddition(定容吸热);Mth,Olto3-4isentropicexpansion(等熵膨胀);4-1constantvheatrejection（定容放热）The idealDiesel cycle:(等压缩)1-2isentropiccompressionClengine-DieselCycle2-3constantPheataddition（定压吸热）；Mth.Diese!（等墙膨胀）3-4isentropicexpansion4-1constantVheatrejection（定容放热）
Chap8 Summary 9 Basic considerations : actual cycle, ideal cycle, carnot cycle, P-V, T-S Reciprocating engines Assumptions of gas power cycles TDC air standard assumptions(空气标准假设): 1) air=ideal gas, Cv = const; 2) internal reversible process; 3) combustion➔heat addition process; 4) exhaust➔ heat rejection process SI engines-Otto cycle Four strokes：compression stroke, expansion or power stroke, exhaust stroke,intake stroke. (压缩冲程、做功（燃烧、膨胀）冲程 、排气冲程和吸气冲程) CI engine-Diesel Cycle The ideal Diesel cycle: 1-2 isentropic compression (等熵压缩) ; 2-3 constant P heat addition (定压吸热); 3-4 isentropic expansion (等熵膨胀); 4-1 constant V heat rejection (定容放热) Reciprocating engines are classified as spark-ignition (SI) engines (点 燃式内燃机) compression-ignition (CI) engines (压燃式内燃机) BDC Stroke Bore Intake valve Exhause valve MEP The ideal Otto cycle: 1-2 isentropic compression (等熵压缩) ; 2-3 constant V heat addition (定容吸热); 3-4 isentropic expansion (等熵膨胀); 4-1 constant V heat rejection (定容放热)
Chap9Summary1Carnotcycleisnotasuitablemodelforvaporpowercycle,RankineCycleRankinecycle:1-2Isentropiccompression(pump);2-3ConstRankinecycles（朗肯循环P heataddition (boiler):3-4 Isentropic expansion (turbine):4-1ConstPheatrejection(condenser)-Basic idea:increaseThigh.avgforQin,anddecreaseTiow.avg for QWaystoIncreasenof1,Loweringthecondenserpressure(lowerTRankineCycleReheatingHigh-pressureturhinSuperheatingthesteamtohiaherTLow-pressureturbine3.Increasetheboilerpressure(increasReheatcycle:ExpandthesteamReheatrankinecycleintheturbineintwostagesand（再热循环）reheatitinbetweenOURegenerativecycle:extractingregenerativerankinesteamfromtheturbine tohealcycle（回热循环thefeedwaterbeforeboiler10
10 Chap9 Summary Carnot cycle is not a suitable model for vapor power cycle, Rankine Cycle Ways to Increase η of Rankine Cycle Rankine cycles(朗肯循环) Rankine cycle: 1-2 Isentropic compression(pump); 2-3 Const P heat addition (boiler); 3-4 Isentropic expansion (turbine); 4-1 Const P heat rejection (condenser) Reheat rankine cycle （再热循环） Reheat cycle: Expand the steam in the turbine in two stages and reheat it in between. regenerative rankine cycle (回热循环) Regenerative cycle: extracting steam from the turbine to heat the feedwater before boiler Basic idea: increase Thigh,avg for Qin, and decrease Tlow,avg for Qout 1, Lowering the condenser pressure (lower Tlow,avg) 2, Superheating the steam to higher T (increase Thigh,avg) 3, Increase the boiler pressure (increase Thigh,avg)