1. 2011 European HyperWorks Technology ConferenceThe Significant Role of AcuSolveat Visteon Climate ControlRaymond Ambs Nov 08, 2011

2. Agenda A brief introduction to the CFD solver AcuSolve An Overview about areas of application of AcuSolve at Visteon Climate Control Analysis of the thermally coupled transient cabin flow Analysis of the defrost and demist performance Analysis of thermal heat exchanger flow Analysis of Heating, Ventilation and Air Conditioning (HVAC) systems SummaryPage 2AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 3. AcuSolve Overview AcuSolve is a powerful general-purpose finite element solver for incompressible or weakly-compressible flows AcuSolves differentiation via Finite Elements: Robustness Relatively insensitive to element topology and mesh quality Superior performance on anisotropic tetrahedral meshes Speed Scalable parallel on shared and distributed memory parallel machines Accuracy Highly accurate in space and time while globally and locally conservative All variables, including turbulence are discretized to second order accuracy Especially the insensitivity to mesh quality combined with accuracy and speed brought AcuSolve into the leading CFD solver position at Visteon Fully automated preprocessing approaches became realityPage 3 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 4. Application of AcuSolve at Visteon Climate Control First application of AcuSolve for the analysis of the thermally coupled fully transient cabin flow Simulation of standard climatic wind tunnel tests (Cool-Down & Heat-Up) Prediction of subjective passenger thermal comfort Prediction of defrost and demist performance Analysis of thermal heat exchanger flow Plate analyses Fin analyses Combined analyses of EGR cooler Analysis of Heating, Ventilation and Air Conditioning (HVAC) systems Airflow performance & airflow distribution analyses Heat exchanger coverage analyses Temperature linearity and temperature stratification analysesPage 4AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 5. Model generation for cabin flow analysis Geometry modeling through parametric CAD models of vehicle interiors Reduced preprocessing time Avoidance of lengthy data acquisition Suitable conformance with wind tunnel tests 3 steps from CAD model to CFD model Fully automatic mesh generation Definition of remaining boundary conditions Sun load calculation (if required)Page 5 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 6. Analysis of thermally coupled transient cabin flow Flow simulation of standard climatic wind tunnel testsStreamlines Heat soak pre-analysis (if required) Simultaneous calculation of transient coupled equations for velocity, pressure and temperature Automatic time step control Thermal shell elements for adequate modeling of heat conduction through outer walls Empirical equations for the adequate modeling of convective heat transfer to the exterior Consideration of pre-calculated sun load Consideration of radiation heat transfer Consideration of air humidity 10 min.20 min.30 min. Air temperature after 15 min.Page 6AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 7. Thermal Comfort PredictionUsing results from CFD analysis, VISTEONs thermal comfort model calculatestransient subjective ratings for each passenger 9 8comfort rating 730 62928 527time to comfort26 4 0.0 5.0 10.0 15.0 20.0 25.0 30.0 25time in min.24Row1, left Row1, right Row2, leftRow2, right2322 Whole body comfort ratings 21versus time 20 Row1, left Row1, right Row2, left Row2, rightTime-to-Comfort Local body segment ratings for one passenger after 15 minutes cool-downPage 7AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 8. Defrost Performance The simulation of the defrost performance evaluates the time to melt and the melting pattern of a thin layer of ice on the outer side of the windshield and front row side glass The layers of ice and glass are modeled using thermal shell elements with appropriate thickness and appropriate material propertiesMelt pattern on windshield after 10 Melt front on windshield at differentminutes defrost simulation time steps of defrost simulationPage 8AcuSolve-at-Visteon_EHTC-2011_2011-11-08Copyright Visteon 2011 9. Demist Performance The simulation of the demist performance evaluates the time dependent defogging behavior on the inner side of the windshield and side glasses under humid conditions Enough warm and dry air must reach the windshield and the side glass to guarantee clearanceDevelopment of the clearance zone (blue) on a second row side window glass surface1 minute 3 minutes 5 minutesPage 9AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 10. Heat ExchangerA huge variety of plate & fin or tube & fin heatexchangers exist in automotive applications: Radiator, condenser, charge air cooler, oil cooler,evaporator, heater core, etc.Page 10 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 11. Heat Exchanger Plate and Fin AnalysisOptimization of enhancedextended surface geometries(louver fins, dimple pattern) interms of heat transfer andpressure drop via CFD2D and 3D fin analyses deliverrelations for friction factor andNusselt number for 1Dperformance tools 0.8 0.6 0.4 0.2V / Uinf 0.0 -0.2 -0.4 -0.6Fin CFD analyses show very good agreementwith LDA measurements -0.8-20.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 220.0 240.0 260.0x coordinate in mm Laser CFDPage 11 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 12. EGR Cooler AnalysisThe Exhaust Gas Recirculation technique helps reducing NOx emissionsEGR works by recirculating a portion of an engines exhaust gas back to the engine cylindersCFD is used to predict pressure drops and heat transfer capacitiesConcurrent coupled flow and heat transfer analysis for both media (gas & coolant)Page 12AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 13. EGR Cooler AnalysisGas Side StreamlinesCoolant Side StreamlinesPage 13AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 14. HVAC SystemHeating, Ventilation, Air Conditioning System Provide air to the cabin (fresh or recirc airmoved by blower) Provide clean air (dust, pollen, odour or combi-filter integrated to remove particles) Heat air Cool air De-humidify air (re-heat: first cool =>condensate, warm up => reduce rel.hum.) Distribute air (wind screen for defrost/demist,floor, panel, others e.g. rear floor, B-pillar, etc)Page 14 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 15. HVAC analysis preprocessingVisteon established a new automatedCAD model CAD model for CFDpreprocessing process for HVAC CFDPerfectly adapted CAD models for CFDanalyses are now part of CAD processNo geometry clean-up necessaryMeshing parameters and boundary conditionsthrough geometry independent abstract modelsFully automated tetrahedral mesh generationincluding boundary layer meshingTime from CAD to CFD is dramatically reduced(1-5 days45 minutes)Time for preprocessing is independent ongeometrical complexityPage 15 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 16. HVAC analyses Airflow performance prediction Airflow distribution prediction Heat exchanger coverage prediction Temperature linearity prediction Temperature stratification prediction Simulation based optimization of all preceding requirementsLinearity: Vent modeAirflow split: defrost mode Stratification: Bilevel mode 100 80100specificationvent 70floor 80 CAE A ra e o tle te p ra re [%] 80floor-vent spec 60floor-vent CAEve g u t m e tuT m e tu [% e p ra re ] 605060 40 40 40 30 202020 10 00 0 2040 6080 10000 20 406080100Temperature door position [%]defrost floor vent centervent sideTemperature door position [%]Page 16 AcuSolve-at-Visteon_EHTC-2011_2011-11-08Copyright Visteon 2011 17. SummaryAcuSolve has become the CFD solver #1 at Visteon Climate ControlAreas of application: Thermally coupled transient cabin flow, defrost & demistperformance analyses, heat exchanger thermal flow, HVAC analysesThe Finite Element approach causes AcuSolves high robustnessIt shows superior performance on anisotropic tetrahedral meshesEspecially the insensitivity to mesh quality combined with accuracy and speedbrought AcuSolve into its leading position at VisteonFully automated preprocessing approaches became realityThe time from CAD to CFD could tremendously be reduced from days to lessthan 1 hourPreprocessing time is now independent on geometrical complexityAt the same time more accurate CFD approaches are now possible(complex geometry in conjunction with boundary layer meshing)Page 17 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011 18. www.visteon.comPage 18 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011