電阻層析成像系統(tǒng)設(shè)計.pdf

1、浙江大學(xué)信息科學(xué)與工程碩士學(xué)位論文電阻層析成像系統(tǒng)設(shè)計姓名：胡松鈺申請學(xué)位級別：碩士專業(yè)：檢測技術(shù)與自動化裝置指導(dǎo)教師：王保良20080601ABSTRACTTwophaseflowisoneofthemostcommonfluidsinnature，whichplaysanimportantroleinmanyindustrialprocesssuchaSchemical，petroleumpharmaceuticalfoodandc

2、osmeticindustryTwo—phaseflowsystemisacomplex，nonlinearanddynamicsystemThereareinterfaceeffectandrelativevelocitybetweenthesetwophasesRealtimeandaccuratemeasurementoftwophaseflowparametersbecomesadifficultissueinthefieldo

3、fengineeringandscientificresearchElectricalresistancetomography(ERT)isoneofprocesstomographytechnologieswhichiswidelystudiedItissuitableforthetwo—phaseflowwherecontinuousphaseiSconductiveERTcanprovide2D／3Dvisualizationin

4、formationofthemultiphaseinsideacloseprocesspipeorvesselandithaSsomebenefitsuchasnoninvasive，lowcost，safeandwidelyapplicationIthasbecomeoneofimportanttechniquesfortwophaSeflowmeasurementHoweveritisstillinthestageoflaborat

5、oryresearchduetoafewdifficultiesBasedontheresearchoftheprincipleofERTanewhighspeedERTsystemWasdesignedtoimproverealtimeperformanceofERTsystemTestresultsshowthatthedatacaptureratemeetstherealtimerequirementofprocessindust

6、ryThemainworksofthisdissertationarelistedaLsfollows：(1)BaSedontheswitchedDCcurrentpulse，anewmeasuringcircuitforweakvariationofresistanceWaSproposedforelectricalresistancetomographyPotentialdifferencemeasurementsweretaken

7、onboththepositiveandnegativehalfcyclesandsubtracted，cancelingthepolarizationeffectsofmeasuringelectrodesthatexistinDCERTsystemAsthesystemWaSregarded嬲beingexcitedbyaconstantdirectcurrentatthedataacquisitionpoint，nocomplex

8、ACcircuitsuchaSfilterwasrequiredItimprovedtherateofdataacquisitionandsimplifiedthecircuitryofERTsystemForfurtherimprovingthedataacquisitionrate，parallel—samplingandserial—measurementwerecombinedinthissystem(2)Anovel16ele

9、ctrodeERTsystemwasdeveloped，whichWaSentirelydesignedaSafieldbusinstrumentDSPWaSusedasthecontrolcoreandCPLDwasusedtoimplementthedigitallogicfunctionSo，thecontrollogicofthesystemcouldbeinsystemprogrammableAhighspeedcommuni