OpenFOAM in component development. Case studies from a productive CFD environment WERK SALZGITTER

Transcription

1 OpenFOAM in component development Case studies from a productive CFD environment

2 Agenda 1 Presentation of Volkswagen Salzgitter 2 CFD in engine component development 3 Reasons for using OpenFOAM 4 Case studies 5 Future plans 6 Concluding remarks Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

3 Volkswagen - Business Unit Salzgitter Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

4 Volkswagen - Business Unit Salzgitter Diesel engines Engines 1,4 l 3-cylinder 59 kw 195 Nm Automotives 2,0 l 4-cylinder 125 kw 350Nm 5,0 l 10-cylinder 230 kw 750 Nm Gasoline engines 1,4l 4-cylinder 59kW 132 Nm 2,5 l 5-cylinder 128 kw 400Nm 3,6 l 6-cylinder 206 kw 360 Nm 6,0l 12-cylinder 309 kw 560 Nm 8,0l 16-cylinder 736 kw 1250 Nm Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

5 Volkswagen - Business Unit Salzgitter Industrial engines Special engines 1,9 l 4-cylinder 63 kw 215 Nm Application 1,9 l PD 4-cylinder 74 kw 285 Nm 3,2 l 6-cylinder 183 kw 320Nm Marine engines 1,9 l 4-cylinder 44 kw 125 Nm 1,0 l 4-cylinder 59 kw 86 Nm 2,5 l 5-cylinder 121 kw 310 Nm 3,0 l 6-cylinder 165 kw 450 Nm Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

6 Volkswagen - Business Unit Salzgitter Valve train Pumps + other Cubic parts Rotatory parts Intake tube Spur gear Pump-injector drive Oil pan Fly wheel Roller cam follower Balance shaft Pump Power-train mount Piston pin Engine components Oil pump Development of components Proprietary Development : Switching intake tube Roller cam follower Oil pumps Vacuum pumps Rails for CR-engines Optimization of product costs Bucket tappet Bearing Frame Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

7 CFD in component development All sorts of guided flow systems Oilpumps External gear pumps Gerotor pumps Control pistons Vacuum pumps Intake tubes / charge air systems Other flows Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

8 CFD in component development Design details Design optimization CFD Problems occuring in prototypes and production Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

9 Reasons for using OpenFOAM OpenFOAM is easy to use (from a UNIX perspective) variable and extendable adjustable to individual problems cost efficient. As pre- and post-processors ANSA and Ensight are used. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

10 Case studies The case studies on three different components presented here involve only simple CFD are directly validated via prototypes and experiments. The engineers rely on the CFD results. CFD is highly appreciated within the design process. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

11 Case study (I) For quality assurance the final common rail assembly is analyzed with respect to dirt particles via random sampling. The aim was to optimize the rinsing procedure used for the analysis. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

12 Case study (I) From RANS calculations the best setup for the analytic rinsing procedure could be computed. Estimates for minimal rinsing time and suggestions for further improvements could be made. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

13 Case study (I) From RANS calculations the best setup for the analytic rinsing procedure could be computed. Estimates for minimal rinsing time and suggestions for further improvements could be made. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

14 Case study (I) From RANS calculations the best setup for the analytic rinsing procedure could be computed. Estimates for minimal rinsing time and suggestions for further improvements could be made. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

15 Case study (II) The control piston of an oil pump was adjusted to fit dynamic pressure effects. The original design showed some hysteresis effect. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

16 Case study (II) Calculation: Model including gaps Various positions of the piston The same inlet flow rate for all positions Outlet pressure from measurements Results: Stable pressure spring force balance At least one more metastable balance position (bifurcation problem) Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

17 Case study (II) To avoid the transition to the metastable trajectory the dynamic behaviour of the control piston needed to be changed. Introduction of a small concentric groove reduced the side forces by a factor of three without showing leakage effects. The changes were successfully implemented. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

18 Case study (III) Design optimization on vacuum pump inlet and outlet flows. Inlet Outlet Simplified model of rotary vacuum pump Start with maximum design space Apply a 0th order adjoint topology optimization (Dr. Othmer, Volkswagen Research Department) Iterate between topology optimization and design restrictions Final model with minimal pressure loss Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

19 Case study (III) Maximum design space for the inlet. Three variants attaching the pump chamber at the side and at the bottom at the side only at the bottom only. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

20 Case study (III) Maximum design space for the inlet. Three variants attaching the pump chamber at the side and at the bottom at the side only at the bottom only. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

21 Case study (III) Maximum design space for the inlet. Three variants attaching the pump chamber at the side and at the bottom at the side only at the bottom only. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

22 Case study (III) Design iterations and final result. Minimal pressure loss Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

23 Case study (III) Design optimization of vacuum pump outlet region. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

24 Case study (III) 2/3 of the pressure loss take place in the valve. Compressible calculation of the evacuation to estimate pressure loss in the valve. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

25 Case study (III) Simulation results Valve No valve Lessons learned: Experiments showed only small differences in evacuation efficiency with and without valve. Calculations confirmed that showing strong recirculation areas. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

26 Future plans This is what we plan for Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

27 Future plans This is what we plan for 2009 and 2010 we would like to be able to do it in OpenFOAM!!! Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

28 Concluding Remarks Despite the growing number of hexaedral meshers there is still the need for purely polyhedral mesh generators to suit complex geometries better. A more generalized scheme for dynamic mesh movement would be great, probably based on (pre-)defined trajectories of the boundaries. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand:

29 Concluding Remarks OpenFOAM is a good choice for daily productive work if you have a decent pre- and postprocessing tool and you don t mind doing the job without a GUI. Volkswagen AG HS-2 Dr. Andreas Gitt-Gehrke Stand: