MEASUREMENT OF AIRFLOW THROUGH REGULATORS AND REAL TIME INTEGRATED MONITORING.ppt

NorthAmerican/NinthU.S.MineVentilationSymposium,June2002,KingstonCanada,MEASUREMENTOFAIRFLOWTHROUGHREGULATORSANDREALTIMEINTEGRATEDMONITORING,StewartGilliesTheUniversityofQueensland,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,2,OutlineofPresentation,IntroductionTheoryofRegulatorsFieldTestsofRegulatorsUQEMRealTimeMineVentilationSystemTrialsoftheUQEMSystemConclusions,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,3,THEORYOFMINEREGULATORS,Anartificialresistanceintheofshocklossoralargethinplateinstalledinafluidconduitwithanorifice.Whenadifferenceinpressureexistsbetweenthetwosidesfluidflowsasshown.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,4,MathematicalModellingofRegulators,Irregularityinshapeandsymmetryandtheirpositioninginroughlysquareorrectangularairways,Constructionoftheopening-louvres,slidingdoor,windoworcurtainorplacementofdropboards,andUncontrolledairleakage.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,5,C-SectionDropBoardTypeRegulator,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,6,AnExampleofLouvreRegulator,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,7,DerivationofRegulatorEquation,Bernoulli’sequationcanbeappliedtobothsidesoftheorificetocalculatethevelocityandhencetheairflowquantity.Acorrectionmustbemadeforthecontractionofthejetatthevenacontracta.Velocityattheorificeisobtainedwiththefollowingequation,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,8,DerivationofRegulatorEquationcont.,Airflowquantitythroughregulatorisasfollows.whereCcisthecoefficientofcontractionAc/ArArisorificeopeningareaNistheratiooftheorificeandairwaycrosssectionalarea,Ar/APsisthedifferentialpressureacrossregulatorisairdensity,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,9,FIELDTESTSOFREGULATORS,Toverifyairflowbehaviourthroughadropboardregulator.Airflowquantityandpressuredropacrosstheregulatorweremeasured.Airflowquantitythroughtheregulatorscanalsobecalculatedintheoryfrompressuremeasurements.Resultscomparedwithmeasuredvaluesandthereasonsforsignificantdifferencesinvestigated.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,10,ComparisonofmeasuredandpredictedQ,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,11,ReasonsforthedifferencesinQuantities,ErrorduringmeasurementSmallcross-sectionalareaNo-symmetricalconditionandshapeLeakageoccursduetogapsorholesbetweenboards,regulatorframeandtheairwaywalls.Airflowquantitycanbeexpressedasfollowstoaccountforleakage.whereQlistheleakagequantity,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,12,AirflowPathsinRegulator,RegulatorscanbetreatedasasetoftwoparallelairwaysnamelyRegulatoropeningandLeakagepaths,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,13,ResistanceofRegulator,ThetotalresistanceofregulatorRtcanbemodelledtoconsistoftheregulatoropeningresistanceRoandtheleakagepathresistanceRl.TheregulatoropeningresistanceRocanbecalculatedfromthederivedulaWhereAistheairwaycrosssectionalarea.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,14,ResistanceofRegulator,Whentheregulatorisinafullyclosedcondition,theairflowsthroughtheleakagepathonlywithresistanceRlwhichcanbeempiricallyderived.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,15,MeasuredandPredictedAirflowQuantity,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,16,RegulatorResistancevsOpeningArea,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,17,UQEMRegulatorCharacteristicCurves,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,18,PlanofUQExperimentalMineShowinglocationsofdoorsandsensors,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,19,VENTSIM–RealTimeSimulations,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,20,VENTSIM-RemoteStationDatabaseInterface,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,21,VENTSIM-AirwayEditInterface,ofRemoteStationNumber,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,22,TRIALSOFTHEUQEMSYSTEM,TrialScenariosTheinclinedshaftdoorwasopen,andtheregulatorin116’levelsetonfullyopen.Theinclinedshaftdoorwasopen,andtheregulatorwasset1/5openwith12boardsTheinclinedshaftdoorwasopen,andtheregulatorsetonfullyclosed.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,23,SchematicofUQEMVentilationSystem,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,24,AccuracyofTrialResults,Ventsimmonitoringsystempredictschangeswithreasonableaccuracyalthoughsomedifferencesinquantitieswerelargerthan10.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,25,ConstraintsoftheSystem–TransitionTime,ThetransientperiodinUQEMisshortandthereforeisnotofgreatsignificanceininterpretingthenetworksystem.However,inlarge-scalemines,theperiodcanbeupto10minutesormore.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,26,UpdatingofVentilationSimulationModels,Thetrialdemonstratedtheimportanceandnecessityofupdatingsimulationmodelsafterchanges.Thethreescenarioswereexaminedforhowthenetworkreactedtotheofarealtimefixedquantityintermsofmaintenanceofmodelaccuracywithoutachangetotheregulator/doorRvalueBasedonairquantityobservationsitisnotnecessarytomakeadjustmenttotheregulator/doorRinthemodelaserrorisnomorethan5.Howeverwhencomparingthepredictedpressuredropsacrossregulators,significantneedforadjustmentwasfound.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,27,CONCLUSIONS,Effortstomathematicallymodelsomeoperatingmineregulatorshavebeendescribed.Theoreticalcalculationstopredictairflowquantitythroughregulatorsbasedonmeasuredpressuredropareinadequateduetoleakage,geometryetc.Itisnecessarytoquantifytheresistanceoftheleakagepathbasedonregulatoropeningareaandthenrecalculatethetotalresistanceoftheregulators.,NorthAmerican/NinthUSMineVentilationSymposiumJune2002,KingstonCanada,28,CONCLUSIONSCont.,AninvestigationwasundertakenastowhethertheRealTimeAirflowMonitoringsystemcanaccuratelydetectchangesinaventilationnetworkandidentifyconstraints.Thesystemwasabletodetectchangesandtopredictthechangesaccurately.Limitationscausedbytransientperioddelayshavebeenexamined.Itisimportanttoupdatethesimulationmodelsbasedonrealtimedata.,