2011 European HyperWorks Technology Conference                                  The Significant Role of AcuSolve          ...
Agenda         A brief introduction to the CFD solver AcuSolve         An Overview about areas of application of AcuSolve ...
AcuSolve Overview         AcuSolve is a powerful general-purpose finite element solver for incompressible         or weakl...
Application of AcuSolve at Visteon Climate Control         First application of AcuSolve for the analysis of the thermally...
Model generation for cabin flow analysis         Geometry modeling through parametric CAD         models of vehicle interi...
Analysis of thermally coupled transient cabin flow         Flow simulation of standard climatic wind tunnel tests         ...
Thermal Comfort Prediction                      Using results from CFD analysis, VISTEON‘s thermal comfort model calculate...
Defrost Performance         The simulation of the defrost performance evaluates the time to melt and the         melting p...
Demist Performance         The simulation of the demist performance evaluates the time dependent         defogging behavio...
Heat Exchanger          A huge variety of plate & fin or tube & fin heat          exchangers exist in automotive applicati...
Heat Exchanger Plate and Fin Analysis          Optimization of enhanced          extended surface geometries          (lou...
EGR Cooler Analysis          The Exhaust Gas Recirculation technique helps reducing NOx emissions          EGR works by re...
EGR Cooler Analysis          Gas Side Streamlines                                                                        C...
HVAC System          Heating, Ventilation, Air Conditioning System          – Provide air to the cabin (fresh or recirc ai...
HVAC analysis preprocessing          Visteon established a new automated                                  CAD model   CAD ...
HVAC analyses                                     Airflow performance prediction                                     Airfl...
Summary          AcuSolve has become the CFD solver #1 at Visteon Climate Control          Areas of application: Thermally...
www.visteon.comPage 18   AcuSolve-at-Visteon_EHTC-2011_2011-11-08   Copyright Visteon 2011
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The Significant Role of AcuSolve at Visteon Climate Control

  1. 1. 2011 European HyperWorks Technology Conference The Significant Role of AcuSolve at Visteon Climate Control Raymond Ambs Nov 08, 2011
  2. 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 2 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  3. 3. AcuSolve Overview AcuSolve is a powerful general-purpose finite element solver for incompressible or weakly-compressible flows AcuSolve’s 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. 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 4 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  5. 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. 6. Analysis of thermally coupled transient cabin flow Flow simulation of standard climatic wind tunnel tests Streamlines – 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 6 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  7. 7. Thermal Comfort Prediction Using results from CFD analysis, VISTEON‘s thermal comfort model calculates transient subjective ratings for each passenger 9 8 comfort rating 7 30 6 29 28 5 27 time to comfort 26 4 0.0 5.0 10.0 15.0 20.0 25.0 30.0 25 time in min. 24 Row1, left Row1, right Row2, left Row2, right 23 22 Whole body comfort ratings 21 versus time 20 Row1, left Row1, right Row2, left Row2, right Time-to-Comfort Local body segment ratings for one passenger after 15 minutes cool-downPage 7 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  8. 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 properties Melt pattern on windshield after 10 Melt front on windshield at different minutes defrost simulation time steps of defrost simulationPage 8 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  9. 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 clearance Development of the clearance zone (blue) on a second row side window glass surface 1 minute 3 minutes 5 minutesPage 9 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  10. 10. Heat Exchanger A huge variety of plate & fin or tube & fin heat exchangers 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. 11. Heat Exchanger Plate and Fin Analysis Optimization of enhanced extended surface geometries (louver fins, dimple pattern) in terms of heat transfer and pressure drop via CFD 2D and 3D fin analyses deliver relations for friction factor and Nusselt number for 1D performance tools 0.8 0.6 0.4 0.2 V / Uinf 0.0 -0.2 -0.4 -0.6 Fin CFD analyses show very good agreement with LDA measurements -0.8 -20.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 220.0 240.0 260.0 x coordinate in mm Laser CFDPage 11 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  12. 12. EGR Cooler Analysis The Exhaust Gas Recirculation technique helps reducing NOx emissions EGR works by recirculating a portion of an engines exhaust gas back to the engine cylinders CFD is used to predict pressure drops and heat transfer capacities Concurrent coupled flow and heat transfer analysis for both media (gas & coolant)Page 12 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  13. 13. EGR Cooler Analysis Gas Side Streamlines Coolant Side StreamlinesPage 13 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  14. 14. HVAC System Heating, Ventilation, Air Conditioning System – Provide air to the cabin (fresh or recirc air moved 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. 15. HVAC analysis preprocessing Visteon established a new automated CAD model CAD model for CFD preprocessing process for HVAC CFD Perfectly adapted CAD models for CFD analyses are now part of CAD process No geometry clean-up necessary Meshing parameters and boundary conditions through geometry independent abstract models Fully automated tetrahedral mesh generation including boundary layer meshing Time from CAD to CFD is dramatically reduced (1-5 days 45 minutes) Time for preprocessing is independent on geometrical complexityPage 15 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  16. 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 requirements Linearity: Vent mode Airflow split: defrost mode Stratification: Bilevel mode 100 80 100 specification vent 70 floor 80 CAE A ra e o tle te p ra re [%] 80 floor-vent spec 60 floor-vent CAE ve g u t m e tu T m e tu [% e p ra re ] 60 50 60 40 40 40 30 20 20 20 10 0 0 0 20 40 60 80 100 0 0 20 40 60 80 100 Temperature door position [%] defrost floor vent center vent side Temperature door position [%]Page 16 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011
  17. 17. Summary AcuSolve has become the CFD solver #1 at Visteon Climate Control Areas of application: Thermally coupled transient cabin flow, defrost & demist performance analyses, heat exchanger thermal flow, HVAC analyses The Finite Element approach causes AcuSolve’s high robustness It shows superior performance on anisotropic tetrahedral meshes Especially the insensitivity to mesh quality combined with accuracy and speed brought AcuSolve into its leading position at Visteon Fully automated preprocessing approaches became reality The time from CAD to CFD could tremendously be reduced from days to less than 1 hour Preprocessing time is now independent on geometrical complexity At 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. 18. www.visteon.comPage 18 AcuSolve-at-Visteon_EHTC-2011_2011-11-08 Copyright Visteon 2011

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