Object-Oriented Approach For Engine Simulation - NASA
NASA Technical Memorandum 106970Object-Oriented Approach for Gas TurbineEngine SimulationBrian P. Curlett and James L. FelderLewis Research CenterCleveland, OhioJuly 1995[NASA-T@-1059?0)OBJECT-ORIENT @APPWdAEH F O R G A S T U R B I N E f N G 1 W ESIHUtbTIUf4(NASA. C e & i s Resem-chCenter) 3 4 pNational Aeronautics andSpace Administration
Object-OrientedApproachEngineBrianNationalfor Gas TurbineSimulationP. Curlettand JamesAeronauticsL. Felderand ioSummaryAn object-orientedgas turbineenginesimulationprogramwas developed.This programisa prototypefor a more complete,commercialgrade engine performanceprogramnowbeing proposedas part of the NumericalPropulsionSystem Simulator(NPSS). This reportdiscussesarchitecturalfrom developingpose tmodulesand userlessonswill be capablein whichthe equationsolver,Also documentedmodulesthesimu-in this reportand the inter-componentof the codepur-to modelconfiguration.was the gineincludemodulefor somethemodelsThe productionany turbineof the simulationclass hierarchiesandis a fully functional,for this ventbasedsystemonly the componentof almostwill interact.data model,is the componentnicationmodelingthe architecturalsoftwarehowever,test rig have beenstate and transientsoftwarecode. The prototypeprogram,compressorof steadyof this complexthe prototypesimulationa transientChiefissuescommu-are given.1.0 IntroductionThe aerothermodynamicbineengines.used duringdevelopment,the performancecapital.simulationof the engineIt is the first tool engineerstestinglevelsFinally,playsand certification.guaranteeddiagnosticsrole in the entirenew engineAs a generatorto the customerit is used to providea pivotaluse to evaluateon whichconcepts.of customera companyfor engineslife cycleIt is verydecks,stakesof turheavilyit calculatesits reputationandin service.p-The ssumptionssystems.of studyprogramstudies.and rotationalfor missionIn fact,fromThe enginecalculatesIt provides:speedsanalysis,andcost, to environmentalcomputer1) keyneededend,NASAObject-OrientedLewishasstartedan effortApproach for Gas Turbine Engine Simulation3) thrustneededcriticalfordesign,2) tempera-levelsand fuel con-to buildinformationandtestcontrolfor everytypeto reliability.code is so importantdevelopment,and maintenance,it is imperativebest simulationtool possible to help maintainprovidesit also is the nexusfor rmance,dimensionsfor structural4) transientthe aerothermodynamicsimulationnot only engineto everyaspectof the aircraftenginedesign,that the US aircraft engine manufactureshave thetheir leadershipin the world market place. To thisto developa newenginesimulationprogram,called1
STEPEThis newthe full life cyclesoftwareof an engine.throughdevelopmentSTEPPwill be lyprojectmethodologieswe determinedsolutionsapplieddisciplines.to overcomeprototypewasmanyproblems.testingThis prototypingandThis reportorsizeofcoversof this projectwas extremelytheandof a new aircraftof STEPP.outtimes.a full understandingpitfallseffortscopingan easyfrom end users,in the developmentto insureandwill takefor fast turnaroundof the potentialideas,programIt will havelots of inputneededtest dataanalysis,also be established.this newrisks in the developmentuncovertheserequirements,out plan,designand it will "couple"languages.capabilitieslike what is donethe technologythat helpedprocessingflowwillforthis capability,prediction,fidelityFurthermore,a well thoughtMuchdisciplinesprocessconceptualparasiticof greaterand programmingand distributedfromTo provideperformancedetailedwith othertechniquesthat a functioningeffortsof gatheringdevelopmentfor otherto succeed.and to reducethe prototypingand transientto modelssimulationsimulationin the field.generation,to "zoom"of this size requiresengine,the problemtoolsuser interfaceenginesstatedecksystemto do systemfor interfacingcomputationalproventermsstandardsto modelingto use graphicalsteadycustomerthe capabilityof modernA softwareto performNewthe aerothermodynamicas well as supportoptimization,tasks.supportIt will be designedand testingwill haveadvantagewilland thevaluableof theinfinalsoftwareThe mainmodulestask.The prototypesystemconsistsof fourmainmodulesand someutilityclasses.are the simulation(or analysis),the data model, the user interface,and the solver. The latter threeare documentedin references1, 2, and 3, respectively.This report covers the simulationmoduleand the frameworkthe solverit uses in cooperationmodule,and someThe simulationcodetest rig modelexercisestecture.reasonsThe codereportfirstonly the codebackgroundmodules.utilityand ose.necessaryon someenginearchi-the compressorengineinlet,compressorthe systemto modelotherinclude:relatedin this report.A transientfor testingto modelwrittenof the data model,is includedand is adequateis completeTheA synopsisclassesfor the componentsarchitecturemodels are added.and motor.givesrelatedthus far is functionalmost of the codeswritten.if other componentnozzle, shaft, load,ThiscompletedFor theserig werewith the otherof the cemodelingactivities.Next the system requirementsand design for the prototypesimulationcode are presented. Then the framework,data model, and class structureare discussed.A method for intercomponentreporteventscommunicationsis then presentedalongwiththe rationalfor this selection.Nexttheelaborateson the componentsand other engineeringmodules.Finally, the compile/linkduring the model buildingprocess are discussed.We assume the reader has a basic under-standingof turbineC programmingenginesimulationlanguage(ref. 4), object-orientedprogrammingterminologyand the(ref. 5).2.0 BackgroundThis researchanalysisSystemwas conductedof SS)modelingApproachas part of a largerpropulsionsystems.(ref. 6). The NPSSfromfor Gas Turbineits inception.EngineSimulationeffortThisthat involveslargerprojectThis sectioneffortthe completeis callhas been involvedreportssomemultidisiplinarythe NumericalPropulsionwith overallenginecycleof the previouseffortsto do2
cyclesimulationdecisionas part of the NPSSto developTherehave beenNPSS.Mostboth in-houseof the earlyit to demonstrategoingfrom a low his type of msdifficultno. NAS3-25951,in LispGeneralwith componentobject-orientedthat it is oftento writelike DIGTEM,the FORTRANhad imensionalAlthoughsomeNEPPlimitsbe possiblemorefull featuredtask,and wouldseveralreasonssystem.for this. Onealmostcompletereworkinggramin an object-orientedoroussoftwareObject-Oriented1 codequalityresultscontrolprocedures,Approach for Gas Turbine Engine Simulationof an enginezooming.percentagedoinghenceof the NEPPa cleanstarta completereducingblockfutureit lacksThe short-evolvebe a moredealsstructurewouldmaintenancethatinto adifficultTherearewith movingresultus to implementallowsdesignstructurefrom scratch.programallowsrewritecycle,it couldthat this woulda new programthis common(ref. 9).(3) no multipointto supportour experienceas the NPSSsystem.frameworkthan to writefeedfactorsnomenclaturethatwasthe AVS frame-evaluatedsimulationsuchcalledin use.industriesto modifycapability,of NEPPeasilyThe two limiting(4) an . al. in the AVSin NEPP),Changingof the code.language.moreReed,wasistrue whenThe AVS frameworkin NPSSin a full featuredstructurethis workcurrentlycapabilityit has beenis that a largeblocks.beensystem.NNEP89)(2) no data reductionthe programHowever,fromthisto (andan old FORTRANcodeand the inabilitya.k.a.howIf the FORTRANhaveprograms,to as a levelneedsaboutThis is particularlyblocks.Mod0.for a productionwith multimodeless desirableinto and out of commonmakethe greatest(ref. 7). Althoughmuchdone by Johnas NPSSobject-orient(NEPP,and (5) an unsuitableproducea tablean object-orientedconclusionit couldwassoftwarethat industryto modifymajorcommondoes a good job of the aerothermodynamicits expandability,It wouldOneblocks)to industryreferredmodeling,codeframework.of DIGTEMProgramcode,(not to be confusedofprogramwouldofferdevelopedthis is not the case with mostenvironmentPerformanceare; (1) no transientcapabilityarchitecturesthan to try to re-engineercommonhowever,fees for the commercialcapabilitiesand(two or three-of usingarchitectureswe did learnuse of globalwas deliveredstateDIGTEMsimulationinsteadon the DIGTEMscratchtool for distributedsteadyof the majorcomingsdataextensivewas that this is not a suitablewere the high licencework.ofone of the key mentation(ref. 8). This codeas an orientedframeworkis an engineas partis the processmodelis consideredcommonit into an object-orientedmakemodularan ctionnew codeand odelson developingbetterof zoomingwith FORTRANsimulationto a high fidelityZoomingor impossible.cyclefor zooming.compressorourzooming.how not to) developcode,An examplefor calculatingfor engineanalysis)in understandilqgprogram.the transienttransparently.codeimplementwas not focusedeffortshas centeredadditionto successfullystudyfocusmodelis importantsimulationdifferentanda streamlineengineand contractedthat is part of NPSS.invokingThis informationan all new, object-orientusingdimensionalproject.us to applyin anthe promorerig-efforts.3
The sameconcernslic domain.theaboutThusneedsthereof NASAthe NEPPcodeis no adequateandcomputertechnology,new code.industryandnewapplyto otherenginein theengineperformancepublicpredictiondomain.uses for evelall leadin the pub-that is suitablemodelingneeds,to the decisiontomodemto developa3.0 RequirementsThissectionThesedescribessomeof therequirementscomefromby the developmentteambasedhighlevelthe projectbleobject-orientedrithmswereThe hroughthe physicalA secondThatvolumewhichin the simulation.naturebe performedis that thereof this languageplethis softwaresional)it cannotmodels.storageFifth,eliminatedwe wereenjoinedthesesomelow levelObject-OrientedgeneralclassesApproachmustas computa-to the decisioncomponentthe computationalwill haveprocessestocontrolpresentincomponent.on the typesor numbersof the class structure.modelsaddsthefromcapabilityof componentsThe structurerequiringof C .frameworkof the system.for higherrequirementorderedneedsto bemodificationto theThe object-orientedwhichallowsnewcomponentany numberof wapor three-dimen-distributedmodelsout sim-processingwill run on the samecan be requiredfor computationmodels.must be able to run in both graphicalformatleadThat is, it must be able to dynamicallythat the higheras the restto edit file formatdevelopedThisbe assumedthe codeThestructurebe modeledThisAll the significantmemoryalgo-in the simulation.computationalof the high orderedmodels.an opendynamicempiricalplatforman easyThezooming.efficiencyFourth,us to constructtype to appearcomputermusttypes and other disciplineswithoutof this criterionleads to the selectionallowedcomputationalbecauselevelsand solveris that the classsimulation.flux must pass.insidemust facilitateone-dimensional,pro-but are still sub-(ref. 10, 11).of an enginemust be no restrictionscan be derived.and any givenThird,simulationeffortthe componentframeworkin thefor componentand energyAt least not in the highestand an end product,for the simulationjustextendablefor new componentbasic architecture.The effecttypeseffort.are self-imposedsimilarto the productionand not re-engineeredis, physicalall hto a controlsurfacesprototypingand/orfrom developingcarry forwardand not produceavailabledesigncomponentsof thepartners,of this code was to performa one-dimensionalsteady state and transientof a gas turbine engine. The focus of this effort was to prototypea possi-frameworktakenimposedour industryon our own experiencesgrams. These requirementswill most likelyject to approvalby our industry partners.The basic ,was requiredfor programthe considerationto not baseutilitythe codetype routines,detractedfor Gas Turbine Enginefrominputs.modes.For batchThis requirementof the use of persistentobjecton any commercialsoftware.such as list management.that availableSimulationand batchto creatinghighermodeoperationa humanreadablestorage.As a resultThe time spentlevelof this wedevelopingengineeringclasses4
uniqueto this problemdomain.cessingand for the graphicalimpactof futureSixth,this codecycleing,certification,4.0user interface.to otherThissystemprogramdesignor ign,analysis,we requiredsystemfor dis.tributedthe designanalysispreliminaryandtransientthe requirementsto any enginepro-to minimizethefieldneedsdesign,for the entirelifesupport.developmentFulllifecycleand testsupportalsoanalysis.userwere dardfor the simulationis that anya settypesof portsber or typesof portsassemblycomponents.This greatlyage globaldata. pts;and,theircomponents,of interconnectedcomponentscanof interestby usinginterconnections.ports,and connec-components.be connected.to otherconnectorsThewith r example,aare no limitson the num-to "wire"togetherportsof differentin the enginemodelof componentsallowsthe engineof the hierarchyports.ports,the availablemodelsinto the components.Ratherand are constructedfromthe connectionsan inputfile or atuser interface.and outputof components,(withinare not hard codedand subassembliestion and engineeringmore in section 8.0.Object-Orientedof theTheeach of thesealthoughthe flux of gas out of a turbine.is madea type of componentcomponentto makemodulestogether.lay-can have.are specifiedassembliesassemblymadethe majorworkdetailedof severalThe connectorcarries data directly between the ports on the connectedcomponents.reduces the global name space. It also eliminatesroutines otherwiserequired to man-run time with the graphicalHavingbasicinformationrepresentinga componentof componentsotherhowmodel)on componenthas threeto whichdataas all theis composedmodules.can be composedstandardspecifiesandIndependent,majoris basedmodulesystemand containport may be an objectbetweenmodule3.0 as wellThe designhas beenas possible.for each of theseof the simulationideasolver,5.0. An effortas independentin sectionprogram.The frameworkinterface,is the topic of ules of the frameworkThisconceptualbe able to performers. At the top is the systemandcasessoftwareDesignrequirementsAnthird partypackages.so as to fullyincludesderivativethat this codeuse of someIn thesesoftwaremust be structuredof the engine.mandatedThechangesWe did makeand connectorsas muchresources).as possible.Approach for Gas Turbine Engine Simulationto be organizedis arbitrary.Assemblieshardwareis vary importantmodelto our design.into nestedA subassemblyis treatedmoreis totallyof globaldata andseparatesthe data communica-freeInter-componentcommunicationanas any otherare explainedThis designin sectionMakingsubassemblies7.0.is infinitelyis discussed5
5.0 System FrameworkThesystemModel,codeframeworkis basedor simulation,portionby a data model.on whatwe callof the codethe Model-Data-Viewis separatedfromarchitecture.the View,That is, theor graphical,In this way the data used by both the user interfaceportionof theand the simulationpor-tions of the code only needs to be describedonce. The user interfaceis adaptive.If the simulationadds data to or modifiesa datum in the data model the user interfacewill automaticallyadapt tothese changesthe simulationand updateand userthroughthe datahandlerare documentedarchitecturemodelthe display. Figure 1 is a high level view of this architecture.Noticeinterfacehave no direct communication.The flow of informationand the eventhandler.in referencesis documentationChaining,Curlett,B.P.].these other modules.model,1, 2, and 3, respectively.in a internalThisThe datareportmemofocuses[Visualon theMODELuserinterface,The nd eventportionDistributedandhowDATAthatisof thisProgramit workswithVIEWfIIcCi o nmlpi ac i:k1. SystemIIIIIIIIIIkFramework:Whena component,objectand, if applicable,responsibleobjects.pendentThefor thehandler.but is not requiredThe simulationObject-OrientedallowscodeIwhois createdThe sametheframeworkobjectdata modelthe simulationare typicallyprogrammer.the solverto haveat least threeApproach for Gas Turbine Engine Simulationis sharedthe tasksafe, easy accessmethodsis handleditself.of writingmodelsto all systemof integrationand isand GUIthroughcompletelysimulationtheindg -This is a mostunderstandprogrammingwith componentworkby the simulationand the GUImusta simulationthe "engineering"code can be developedassignedany graphicsto communicate/first constructsdoesfor the interfaceThe engineerperformkArchitectureThe simulationbetweento actuallyprovidesI/and with little regardis also programmedThe data modelIIn this way the simulationinterfaceengineersIError CheckingCalculatorModel-Data-Viewits data model.the aid of a professionalThe solverD ata ModelDefinitionStorageI/Oobject.all communicationand eventIor connectora GUIfrom the userfeaturewithoutport,for loadingAlmostdata modelmodel111/FIGUREable111desirmodelsthe use of the datain this framework.throughparameterswith the userthe data model.by name.interface.6
1. It can be looselywhichintegrated;that is, the user interfacecan be used to invokemost separationof the engineering2. It can be tightlyshares the samebetweenSupportconnected;connection.i.e. programfor all threechainingof theseThe best methodthetighterprototypethe user severaland programmethodsis builtThe2 and/ormodeland it providesthetask.user3 whileadvantages;if'scenarios.with the GUI through1) multiplezoomingsimulationscan be preformedthe user interfaceinterface.versionsThefor looseusercan be runthis method.interfacesimulationarchitecturesof theseusingwith the simulation12.0). The prototypestill providing"whatcommunicatesis built into the simulation,(see sec.productioncoderapid2) simulationscan be executedon compute serversand 3) other codes can be integratedwith the cycle sim-for integratinggraphicalintegration.methodsthe datasolutionthe user to performthat is, the simulationThis giveson how the simulationwithdevelopmentThis allowsin parallel from a single user interface,while the GUI runs as a local process,modules.code. This is the simplestand GUIand simulation.3. It can be remotelyulation,a file fromintegrated;that is, the simulationcode is compiledalong with the GUI anddata model. This solution providesthe user with the quickest interactionthe GUIa remotea simulationcan createcodescodeof bothwill be moreand datacodeis looselyof thesetightlymodelwill tion.6.0 Data ModelThe internaldata modelall data input/outputmajormodulesmodelwhichis responsible(I/O).in the framework.is necessaryThis simulationare sometimesfor the descriptionIt is also the mechanismThissectionto the understandingframeworkcalled "dataof the data, organizationused to communicateexplainssomeof remainedof the data, andinformationof the basicamongconceptstheof the dataof this report.uses a simple data model based on variabletables. Tables like thesedictionaries".Variable tables are hierarchalin nature; similar to direc-tories in a DOS or UNIX file system. We use one table, possibly with subtables,for each component in the simulation.Each variablein a table representsan attributein the simulation.Inadditionto the valuemation,of the attribute,such as: a descriptionWe foundthesevariabletransferTherefile, numerical,a defaultto be a good e,storagefor otherrelevantinfor-and limits.for: definingand catalogingour data, useraccess functions,and insuring integrityof data that would otherwiseWe also added methodsto the variableclasses for interprocessordataand an interpretiveare six basicof the attribute,tablesfriendlyi/o, standardizinghave to be made global.the variableclassesmap,andfor programmingrelationshipsthat are used for six differentenumerationdatatypes.betweendata types,Thereare alsonumericalthesevariables.include:a couplestring,of specialtypes. The VarLink class is a templateclass to link variable informationto data stored elsewhere.The VarTable class holds other variablesand tables and providessearch routines for locating variables. All variable classes are derived from the Var class which stores informationcommonto alltypes,such as nameand labelIn additionto catalogingmechanismfor movingObject-Orienteddatadata.string.and performingPorts(boundaryApproach for Gas Turbine Engine SimulationdataobjectsI/O, the variableon components)tablesprovidean excellentcan use the variabledata7
typeslistedaboveto buildfrom one componentstion.Thisis howexplaineda VarTableport to anotherthesend()more in sectionand writingthemselvesof componentand port wouldcodeduseddisplay.attributesto haveclassesprovidingmodelas a meansstandardnot be locatedand calls"smartfor organizingmessageClass StructureThis sectionhighembedscoverssomestructuretheof the productionated. Otherlevelof our gure2 showsKey-(onetoma, )ponentI PsEngC mpofyou will see howcode.This classthisstructurethe final classof the prototypeto be testedof the engineand evalusimulationITk 2IIPsConnectorI1PsRem teC nnect rIPsGasStateI\Pslnlet/IIPsDuctIII t s om r ssorlI PsNozzle][ PsSha ] I]FIGURE 2. High Level Class Structure with AssociationsApproachtheas a means2[[PsEng mblyObject-Orientedif you viewclassthe class structureIPsGasFluxI PsEngineto be hardthe data modelthis is not necessarilyAIPsMechP rtII,/\[for the ever,paradigm.PsPortI- remoteeach/\Il PsCorrThis per-structure,wouldattributes,PsPartInheritance lfor readingbuffers.At the surfacetheseHowever,This is the structurewill be explored.methodspassingfor thedecisions.areto be addedand the VarTableand locating7.0 Simulationhaveparadigm.attributes",to the object-orientedor similarat run time.of the object-orientedfunc-processes.wouldto theseby namecopyConnectorsmethodsmessagefor I/O, copying,methodsbe copiedthe VarTablebuilt-in(PVM)in a VarTable,its own methodscan thenis implemented.haveMachinedata accessof makinginterfacesis an enhancementclassesand port datacouldhere may look like a breakdownvariablethe variableV'mualDataby callingclassnot be placedFurthermore,to get at componentbecausesimplyclass to send data to remotecouldhaveportsattributes.connectorParallelto the connectorand port attributestem solverof the8.0. Furthermore,If componentimportantcomponentsmethodto and frommits an easy extensionand user interfaceof all theirfor Gas TurbineEngineSimulationPsMotor][PsLoadand Aggregations8
module.phicreuseIn our designbehaviorratherinheritancethanis emphasizedcodeplaysreuse.in our designa moreimportantrole in achievingThe use of utility(see sectionclassesand functionsbut is necessaryrelationshipto hold commonwith a correspondingThe PsComponentsor, burner,or turbineplantsimulation.tions.The PsComponentsimulation.Thisclasssimulation,the simulationclass handlesnents.componenton a component.thingsall componentsis a basepiececodeports and, connectors.does not have physicalthat all partsor a boiler,need,generator,suchas ais handledfor otherto all componentsinformationfor informationtherebe a compresin a powertypesof simula-fromany type offlow into or out ofby the PsComponentclass.flow into and out of compo-is no upperof as controlno assumptioncouldor condenserto be reusedports to handleone or more ports;can be thoughtHowever,a componentthat are commonmust haveclass that provideswill haveof hardware.For example,frameworkof these portslevelComponentsand methodsa physicalin a jet engineThe managementThe PsPortEachrepresentsby this class.For example,the component.informationdoes is madepermitsfor achievingVarTable.class usuallyof what the componentpolymor-11.0).There are three major parts to building a simulation,these are: components,All three of these are derivedfrom the PsPart class. The PsPart classmeaningthe correctvolumeslimit to the numberand portsof portsas the controlsur-faces on that volume. An example of a port is the PsGasFluxclass which representsthe flux of gasacross a control surface. The PsGasFluxclass is derived directly from the PsPort class and is discussedThein romsurethein sectiononepermitsDerivedfromand methodsportto anotherports on differentas a wayport.usingwith gas turbineTheto the otherthe PVM(Engineenginephysicalanotheran stowouldbebe insertedbut it allowsmessagecomponents.by passingconnectorare incompatibleone port typeprocessorsbetweenonethe same as the PsConnectorclass, the PsEngCompto distinguishwithcomponent'sIf the portsfromis functionallythe PsComponentto communicatetypes.that translatesthat are associatedused mostlycomponentsare of compatibleand a componentbetweentwocomponent'sportsuser. The ributesintermediateand logicalby thedata to beclasscomponents.isThiscan be done using the isA () function,which tests class type. A numberof specific componentclasses were written. The seven class derived from the PsEngCompare the seven engine component modelsproblemdevelopedgreatlyfor testinghelpedthe systemin validatingarchitecture.Havingworkingcodeappliedto a realthis architecture.The PsAssemblyclass is a type of componentthat holds other components.No assumptionsaremade on the types of componentscontainedin the assembly.Becausea PsAssemblyis a type ofPsComponent,madeThean to beto any n associationthrougha seriesterminedorder.havemay be part of anotherits ownObject-Orientedis derivedassociatedwithof engineengineApproachThissolver,EnginePsAssemblyof enginemethodsand a methodfor executinga subassemblySimulationif an engine'sPsEngAssemblycomponents.for calculatingis used to makemay be usefulfor Gas Turbinethewith an assemblycyclecomponent,If a PsEngAssemblysolver.fromhigh spoolThisthepathin this prede-this subassemblyhad a muchalso con-computationalthe componentsthenclassholdsdifferentwouldresponse9
time than its low spool. The time constantsfor the high spool subassemblycould be differen thenthose of the rest of the system. If a subassemblyis made using the PsAssemblyclass then it woulduse the samelatingThesolveras the parentsome of the o castof the majorwhatconstitutescodemoduledesignbothburner,at theiror nozzle.physicalmaydata)physicalin Appendixversionlogicalbecauseobject.Each3 showsboxescontainedclassApproachin theseThe problemideawasbe idealto be madetobutwea virtualworksSimulationwasto determineis definedpieceof hardwareas awithsuch aswith boundaries.that componentstransmitinfor-a portto whicha portof anotherbe thesharingof thesameportthat representthelogicalportsconnectiontwo port/connectorconceptsmodelmust demonstrateare two copiesfor creatinglogicor preformare ports,of STEPPevaluatedwas chosenzoomingarefor theand distributedgoals.The largeand destroyingdata, one in eachits own copy of tlto the next by a PsConnectorobject.data. The connec-type of data transformation.boxesand the arrows(fi), flow-outof the "station"other than that to transferany otherin the figureare connectors.(fo), and mechanicalin a push or pull mode.to send its flow-outEnginecouldfrom one componentmodel.ideatwo differentTheclass has no built-in(PsConnector)for Gas TurbinewouldhavePsEng-and has little other interactionby providingarchitecturethat therethey are: flow-innent C 1 can tell the connectorfromA componenta physicalthe differentis responsiblea two port/connectoroutputsthe basicbetweenand cons.(copied)any flow errorin the figure,The connectorObject-Orientedtheetc. MultipleAnotherThisit wouldarchitectureprocessof recordassumescomponentthe connectortor does not calculateare shownconnectionthe newdata. The data is movedIn this modelcomponent.components.has or is associatedlent well to thesemodelbe an enginerepresentsshareof dataA with prosof STEPPPsAssemblyare connected.boundariesTheAs a matterand this conceptcomponentthe smallerSFC,net thrust,PsEngComp.and producesevaluatedor the transmissionThe two port/connectorFigurethrust,becausethat usuallyA componentbe connected.boundary.andhow componentsis an objectand/orstationfor calculatingwas to derivecouldPsComponentthat takes inputsmationprocessingof the problem.plus the methodsof non-enginefor the simulationandconceptsinitialthe solutionCommunicationsAll the isionsA componenta compressor,presentedgrossOne ideaan assemblydowna component(or object)the system.sameinclude:considered.of engine8.0 t havePsEngAssemblywould not be ablebase class.Onedoes not effectis only used for encapsu-This
An object-oriented gas turbine engine simulation program was developed. This program is a prototype for a more complete, commercial grade engine performance program now being proposed as part of the Numerical Propulsion System Simulator (NPSS). This report discusses architectural issues of this complex software system and the lessons learned
Bruksanvisning för bilstereo . Bruksanvisning for bilstereo . Instrukcja obsługi samochodowego odtwarzacza stereo . Operating Instructions for Car Stereo . 610-104 . SV . Bruksanvisning i original
1.Engine Oil SABA 13 1.Engine Oil 8000 14 1.Engine Oil 6000 15 1.Engine Oil 3000 16 1.Engine Oil Alvand 17 1.Engine Oil Motor Cycle Engine Oil M-150 18 1.Engine Oil M-100 19 1.Engine Oil Gas Engine Oil CNG-BUS 20 1.Engine Oil G.I.C.X.LA 21 1.Engine Oil G.I.C.X. 22 1.Engine Oil Diesel Engine Oil Power 23 1.Engine Oil Top Engine 24
Object Class: Independent Protection Layer Object: Safety Instrumented Function SIF-101 Compressor S/D Object: SIF-129 Tower feed S/D Event Data Diagnostics Bypasses Failures Incidences Activations Object Oriented - Functional Safety Object: PSV-134 Tower Object: LT-101 Object Class: Device Object: XS-145 Object: XV-137 Object: PSV-134 Object .
method dispatch in different object-oriented programming languages. We also include an appendix on object-oriented programming languages, in which we consider the distinction between object-based and object-oriented programming languages and the evolution and notation and process of object-oriented analysis and design, start with Chapters 5 and 6;
as object–oriented design. Object–oriented development approaches are best suited to projects that will imply systems using emerging object technologies to construct, manage, and assemble those objects into useful computer applications. Object oriented design is the continuation of object-oriented analysis,
object-oriented programming language is based on a kind of old object-oriented programming language. For example, though C language is an object-oriented programming language, it still retains the pointer which is complex but has strong function. But C# improved this problem. C# is a kind of pure object-oriented language.
Reusability, CK Metric, Object - Oriented. 1. INTRODUCTION Object oriented systems continue to share a major portion of software development and customer base for these systems is on the rise. This is because there are many advantages in taking the object oriented concept. The weakness though is that most object oriented systems tend to be .
Object built-in type, 9 Object constructor, 32 Object.create() method, 70 Object.defineProperties() method, 43–44 Object.defineProperty() method, 39–41, 52 Object.freeze() method, 47, 61 Object.getOwnPropertyDescriptor() method, 44 Object.getPrototypeOf() method, 55 Object.isExtensible() method, 45, 46 Object.isFrozen() method, 47 Object.isSealed() method, 46
