New VW Fox Defog / Defrost Air Channel Virtual Development. Tales Adriano Ferreira Volkswagen do Brasil

Transcription

1 New VW Fox Defog / Defrost Air Channel Virtual Development Tales Adriano Ferreira Volkswagen do Brasil

2 Agenda Berechnung Overview Motivations Goals Problem Description Software Tools Numerical Model Simulation Results Air Channel Geometries Experimental Results Final Remarks 2

3 Berechnung Overview DISCIPLINES SOFTWARES STIFFNES / STRENGTH / DURABILITY BIW Stiffness (Static and Dynamic) Trimmed Body and Complete Vehicle Sfiffness Pillars Stiffnes Doors and Lids Trim Compnents Chassis Components MSC Nastran MSC Fatigue Altair Hyperworks IMPACT / CRASHABILITY Crash Repairs Cost Anchorages Components Impact tests Pedestrian Protection Occupants Simulations / Restraint Systems ESI Pamcrash TNO Madymo Vehicle Dynamics Wheel Envelopes "Bodenfreigang" MULTIBODY SIMULATIONS Door / Lids / Mechanisms Dynamics MSC Adams CFD Defog / Defrost Air Ducts Flow Distribution External Aerodynamics Ansys Fluent 3

4 Berechnung Overview Product Development Concept / Design CAD CAE Manufacture Concepts Prototypes- Construction Prototypes - Tests Production Preparation Toll Fabrication Tests Milestone VP-K - Virtual vehicle approval for development continuation. 4

5 Berechnung Overview Constant VW Brazil CAE engineers interchange with Wolfsburg R&D center. VW Brazil CAE environment is an image from the one in Wolfsburg. 5 CAE procedures are standardized with Volkswagen Konzern ones.

6 Motivations A fast and uniform defog/defrost of vehicles glazing is very important for driving safety and occupant s comfort. The short timetable of the vehicles development programs makes not feasible the work being done exclusively on an experimental tests basis. Thus, numerical simulation plays a very important role through an extensive number of virtual testing and a better understanding of the flow. 6

7 Goals Development defrost/defogging air ducts in order to achieve a uniform flow field in windshield and side windows with high velocities. This way defrost/defogging process will be optimized and the standards for certifications will be reached. 7

8 Problem Description The defrost/defogging tests are normalized in United States by FMVSS 103 (SAE J902) and in Europe by 17/317EEC. The C area in windshield (front of driver s view) shall be at least 80% free from ice in 20 minutes. A area shall be 95% free in 40 minutes. Typical C and A viewed from interior of vehicle. Picture from SAE J902 8

9 Software Tools ANSA Geometry preparation and surface mesh Tgrid 4. Volume mesh Fluent 6.3 Solver and post-processor Ensight 8. Post-processor 9

10 Numerical Model Numerical domain and mesh 10

11 Numerical Model Numerical domain and mesh Inlet outlet 11

12 Numerical Model Hypothesis for the flow Steady-state Incompressible Isothermal Turbulent Boundary conditions Inlet: constant velocity-inlet Outlet: constant pressure-outlet Other walls: non-slipping walls 12

13 Simulation Results Windshield velocity vectors colored by velocity First proposal Optimized proposal 13

14 Simulation Results Side windows velocity vectors colored by velocity left right First proposal Optimized proposal 14

15 Air Channel Geometries First proposal Optimized proposal 15

16 Air Channel Geometries A B AA A B Optimized on top first proposal BB 16

17 Experimental Results Defrost test: 20 minutes VW Fox VW New Fox 17

18 Experimental Results Defrost test: 20 minutes left right VW Fox VW New Fox 18

19 Final Remarks VW New Fox defrost/defogging air ducts were developed on a virtual tests basis. This way a great number of virtual analysis was performed and air channel modifications results were faster evaluated than only with experimental tests. A significant improvement was achieved when comparing with the previous VW Fox. 19