Presentation on theme: "AMESim Fan Drive Thermal Model"— Presentation transcript:
1 AMESim Fan Drive Thermal Model CAViDS OverviewApril 14, 2017CAViDS ConsortiumAMESim Fan Drive Thermal ModelA CAViDS Consortium ProjectAdvisory Committee ReportAugust 22, 2012
2 CAViDS OverviewApril 14, 2017CAViDS ConsortiumProject ObjectiveDevelop heat generation modeling capability for Model 662B viscous fan drive to predict temperature rise for general operating conditions. This model will be used in conjunction with CFD modeling to determine enhanced design for higher heat rejection from the drive. Higher heat rejection will allow longer operation at fan drive speeds that allow optimal vehicle operation.
3 CAViDS OverviewApril 14, 2017CAViDS ConsortiumWork Plan1. Develop AMESim thermal model based on heat flow predictions from previous modeling, within AMESim and from available literatureCompare temp rise measurements with AMESim predictions for six operating conditionsDetermine predicted heat flow throughout drive for these operating conditionsPerform CFD analysis on convective heat flow from body of drive for a selected operating conditionsDetermine effect of fan drive body rib configuration on convective heat flow with CFDIncorporate CFD results into AMESim model through empirical relationships establishedConvert AMESim model into Borg Warner compatible software to be used as a design tool
4 CAViDS OverviewApril 14, 2017CAViDS ConsortiumAMESim Thermal Model
5 CAViDS OverviewApril 14, 2017CAViDS ConsortiumAMESim Thermal ModelUsed proven simple transmission based basic approach for fluid convection, bearing and linear conduction, and radiationUsed external convection-to-air equations based on technical paper (Nusselt number = * Re ^0.8)Developed new sub-models for fluid convection to link heat transfer equations to instantaneous fluid properties and speed variationDeveloped new sub-models for air convection based on variable drive speed as input to convection equationsInput silicon fluid properties in table as fluid referenceUsed rib spacing as critical dimension for Reynolds number for air convection from bodyUsed fluid gap between grooves as critical dimension for Reynolds number for fluid convection to body and clutch
6 Temp Rise Prediction Results CAViDS OverviewApril 14, 2017CAViDS ConsortiumTemp Rise Prediction ResultsEnd temperature of fluid is closeCause of early fluid temperature discrepancy is TBD
7 Heat Flow Predictive Results CAViDS OverviewApril 14, 2017CAViDS ConsortiumHeat Flow Predictive ResultsEnd Conditions WattsInput Heat FlowFluid Convection to Drive Body CoverFluid Convection to Rear Drive BodyFluid Convection to Clutch PlateFluid Convection to ReservoirDrive Body Cover Convection to Air 1291Rear Drive Body Convection to AirDrive Body Cover Radiation to AirRear Drive Body Radiation to AirRear Drive Body Conduction to FanClutch Plate Conduction to EngineOther (including heating of parts)
8 Non Steady State Test Conditions CAViDS OverviewApril 14, 2017CAViDS ConsortiumNon Steady State Test Conditions
9 Preliminary Parametric Sensitivity CAViDS OverviewApril 14, 2017CAViDS ConsortiumPreliminary Parametric SensitivityEffect of enhancing parameter by factor of two in end fluid temperatureBaseline end fluid temperature CDouble drive body area CHalve drive body critical length -11 CDouble drive body/clutch fluid groove area - 8 CHalve drive body/clutch fluid critical length - 5 CChange radiation emissivity from 0.62 to CDouble fluid volume C
10 CAViDS OverviewApril 14, 2017CAViDS ConsortiumConclusions to DateNeed constant speed testing at less than 3 HP slip heat at various fan speeds to determine end steady state thermal conditions (heat flow and part temperatures) without exceeding silcone 450 F temperature limit. This will allow significant model simplification and parametric variation of speed and torque.Need to measure temperature of oil, clutch plate, and body halves to correlate to predictions. to explain discrepancies in oil temperature rise between measured and predicted results, and to tune fluid convection parametersOverall fan drive heat rejection is primarily through convection from body to airBody area is most sensitive body-to-air convection parameter discovered to dateIntegration is by DASSL (Adams and Back Differentiation Function) techniques with Jacobian evaluations. Minimum step size is 2E-15 second. Maximum step size is second. Over steps were used over a 693 second simulation.
11 Next Month Document integration techniques for our simulations CAViDS OverviewApril 14, 2017CAViDS ConsortiumNext MonthDocument integration techniques for our simulationsPerform literature search on convection from rotating disksPerform simulations with actual active groove area covered by silcone fluid for each condition and actual gap dimension used as the critical length for the fluid convection Reynolds number.Start on CFD simulations of flow conditions