SAMChapter5

PropertiesofVaporandItsThermodynamicProcess水蒸氣的性質(zhì)及其熱力過程工程熱力學(xué)

EngineeringThermodynamicsSAM第五章水蒸氣的性質(zhì)及其熱力過程

PropertiesofVaporandItsThermodynamicProcessKeynotesThermalEnergyEngineeringDepartment5-1§5-3水蒸氣的熱力過程

ThermodynamicProcessesofVapor§5-2水蒸氣熱力性質(zhì)表和圖

propertydiagramsandtablesofvapor§5-1水蒸氣的發(fā)生過程

Theprocessofvaporgenerateing§5-1水蒸氣的發(fā)生過程

TheProcessofVaporGeneratingSAMThermalEnergyEngineeringDepartment5-2H2O的p-T相圖：臨界點(diǎn)C(Criticalpoint)是汽液相變極限狀態(tài)的標(biāo)志。不同工質(zhì)均有自己確定的臨界參數(shù)，對水蒸氣：三相點(diǎn)O:p0=0.6112kPa,t0=0.01℃,v0=0.001m3/kgabcde§5-1水蒸氣的發(fā)生過程

TheProcessofVaporGeneratingSAMThermalEnergyEngineeringDepartment5-2未飽和水unsaturatedwater過熱蒸汽superheatedvapor飽和水saturatedwater濕蒸汽saturatedmixture干飽和蒸汽saturatedvapor一、水蒸氣的定壓發(fā)生過程SAMThermalEnergyEngineeringDepartment5-3ab:preheatingprocess,

p=const,t,vchangesalittlebcd:Vaporizationprocess,p=const,ts

=const,vde:heatingofsaturatedvapor,p

=const,t,vchangesalittle液體熱過冷度latentheatofvaporization

過熱熱量過熱度汽化潛熱SAMThermalEnergyEngineeringDepartment5-4干度若濕蒸汽可看成飽和水與干飽和水蒸氣的混合物x=0saturatedwaterx=1saturatedvaporSAMThermalEnergyEngineeringDepartment5-7水蒸氣定壓產(chǎn)生過程會出現(xiàn)三個階段和五種狀態(tài)，且p↑→ts↑、v'↑、v"↓、汽化過程bd縮短。二、p-v,T-sdiagramof

vaporSAMThermalEnergyEngineeringDepartment5-6一點(diǎn)：臨界點(diǎn)C二線：上界線BC、干飽和蒸汽線、x=1；下界線AC、飽和水線、x=0。三區(qū)：液態(tài)區(qū)、濕蒸汽區(qū)、汽態(tài)區(qū)。五態(tài)：未飽和水、飽和水、濕飽和蒸汽、干飽和蒸汽、過熱蒸汽。SAMThermalEnergyEngineeringDepartment5-9§5-2水蒸氣熱力性質(zhì)表和圖

propertydiagramsandtablesofvapor國際水蒸氣性質(zhì)會議規(guī)定：取水的三相點(diǎn)（p=0.6112kPa,t=0.01℃）時飽和水的u0=0kJ/kg、s0=0kJ/（kg.K），則在壓力不高時可近似的認(rèn)為h0=0kJ/kg。水蒸氣熱力性質(zhì)表飽和水及干飽和蒸汽表未飽和水與過熱蒸汽表水蒸氣熱力性質(zhì)圖SAMThermalEnergyEngineeringDepartment5-10飽和水及干飽和蒸汽表（p124及附表p300-301）SAMSAMThermalEnergyEngineeringDepartment5-12未飽和水與過熱蒸汽表表5-3未飽和水及過熱蒸汽表的結(jié)構(gòu)（p125）及附表12SAMSAMThermalEnergyEngineeringDepartment5-13SAMSAMThermalEnergyEngineeringDepartment5-14SAMSAMThermalEnergyEngineeringDepartment5-15SAMSAMThermalEnergyEngineeringDepartment5-15水蒸氣熱力性質(zhì)圖討論（1）

已知H2O的（t,p）,如何確定其所處狀態(tài)？（2）

已知H2O的（t,s）,如何確定其所處狀態(tài)？SAMSAMThermalEnergyEngineeringDepartment5-15例5-2試確定壓力為1MPa時，溫度分別為160℃及200℃時水所處的狀態(tài)。例5-3試用h-s圖求下列狀態(tài)的水蒸汽參數(shù)：（1）5MPa，干度＝90％；（2）溫度為200℃的干飽和蒸汽；（3）0.1MPa，300℃。并將上述三個狀態(tài)表示在h-s圖上。例5-1若水蒸氣在150℃時，比熵為6.0886kJ/(kgK)，試確定水蒸氣的狀態(tài)及其它狀態(tài)參數(shù)。SAMSAMThermalEnergyEngineeringDepartment5-15例5-4(書上無)根據(jù)h-s圖確定壓力為2MPa時水蒸氣的氣化潛熱的數(shù)值。SAMSAMThermalEnergyEngineeringDepartment5-15§5-3水蒸氣的熱力過程

ThermodynamicProcessesofVaporConstantVolumeProcessConstantTemperatureProcessConstantPressureProcessConstantEntropyProcessSAMSAMThermalEnergyEngineeringDepartment5-16例5-4某蒸汽鍋爐，給水溫度為150℃，出口蒸汽參數(shù)為3.5MPa，溫度為435℃。試確定鍋爐進(jìn)、出口蒸汽的狀態(tài)，并計算每千克水在鍋爐內(nèi)的吸熱量。SAMSAMThermalEnergyEngineeringDepartment5-17例5-5一剛性容器中裝有1kg汽水混合物，其中蒸汽質(zhì)量占70％，壓力為0.2MPa。若對容器加熱，使水變成干飽和蒸汽，試求：⑴終態(tài)壓力；⑵加入的熱量；（3）終態(tài)溫度。SAMSAMThermalEnergyEngineeringDepartment5-17例5-6假定從鍋爐中輸出的過熱蒸汽（3.5MPa，435℃），在汽輪機(jī)中可逆絕熱地膨脹