feedback control-3

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1、SomethingaboutLearningandStudy教学关键是学！！！SomethingaboutLearningandStudy教师教学目标学习成果学生反馈过程SomethingaboutLearningandStudy学习关键是习！！！学问不问得不到！！！学习的过程创问思习读看听学2.4HeatandFluid-FlowModelsIntheprocesscontrol,HeaterExchangersandtemperatureregulatingaremetfrequentlyPetroleumChemistryFoodPharmacyMetallurgyWhatispr

2、ocess?2.4.1Heatflowwhereq=heatenergyflow,joulespersecond(J/sec)R=thermalresistance,℃/J.sec)T=temperature,℃Ohm’lawHeatenergyflowsthroughsubstancesatarateproportionaltothetemperaturedifferenceacrossthesubstanceT1T2q2.4.1HeatflowwhereThenetheat-energyflowintoasubstanceaffectsthetemperatureofthesubst

3、anceaccordingtotherelationC=thermalcapacityThisisfromthedefinitionofspecificheatcapacity2.4.1HeatflowIfthereareseveralheat-energyflowsintooroutasubstanceCq1，R1q2，R2q3，R3orLargeorlessthan0Largeorlessthan0Largeorlessthan0Example2.12EquationsforHeatflowwhereAroomwithallbuttwosideinsulatedisshownbelo

4、wCI=thermalcapacityofairwithintheroomTI=temperatureinsideTO=temperatureoutsideR1=thermalresistanceoftheroomwallR2=thermalresistanceoftheroomceiling热阻的串并联计算方法和电阻串并联是一样的MoreaboutHeatTransferwheremisthemassofthesubstanceTheSpecificHeatThethermalconductivityHeatcanalsoflowwhenawarmermassflowsintoacoo

5、lermasswhereAisthecrosssectionalareaandlisthelengthoftheheat-flowpathwherewisthemassflowrateofthefluidatT1flowingintothereservoiratT2Example2.13EquationsforModelingaHeatExchangerSteamentersthechamberthroughthecontrollablevalveatthetop,andcoolersteamleavesatthebottom.steam@Tsisteam@TsLiquidTlLiqui

6、dTli@wlcontrollerSensorTmws=KsasConstantflowofliquidthroughthepipethatwindthroughthechambersothatitpicksupheatfromthesteam.TmlagstheTlbytdsecondsExample2.13EquationsforModelingaHeatExchangerOutput:TmInput:asInletflowrateofsteamisproportionaltotheareaofthesteaminletvalvewherews=massflowrateofthest

7、eamcvs=specificheatofthesteamTsi=temperatureoftheinflowsteamTs=temperatureoftheoutflowsteamtheheatflowingouttotheliquidtheheatfromthehotincomingsteamExample2.13EquationsforModelingaHeatExchangerthenCs=mscvsisthethermal