OpenFOAMin componentdevelopment...
Transcript of OpenFOAMin componentdevelopment...
WERK SALZGITTER
OpenFOAM in component development
Case studies from a productive CFD environment
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 2WERK SALZGITTER
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: 05.11.2008 – 3WERK SALZGITTER
Volkswagen - Business Unit Salzgitter
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 4WERK SALZGITTER
Volkswagen - Business Unit Salzgitter
Diesel engines
2,5 l 5-cylinder
128 kW 400Nm
5,0 l 10-cylinder
230 kW 750 Nm2,0 l 4-cylinder
125 kW 350Nm
1,4 l 3-cylinder
59 kW 195 Nm
6,0l 12-cylinder
309 kW 560 Nm
Automotives
8,0l 16-cylinder
736 kW 1250 Nm
Gasoline engines
3,6 l 6-cylinder
206 kW 360 Nm
1,4l 4-cylinder
59kW 132 Nm
Engines
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 5WERK SALZGITTER
Volkswagen - Business Unit Salzgitter
1,9 l 4-cylinder
44 kW 125 Nm
2,5 l 5-cylinder
121 kW 310 Nm
3,0 l 6-cylinder
165 kW 450 Nm
Marine enginesApplication
Industrial engines
3,2 l 6-cylinder
183 kW 320Nm
1,0 l 4-cylinder
59 kW 86 Nm
1,9 l PD 4-cylinder
74 kW 285 Nm1,9 l 4-cylinder
63 kW 215 Nm
Special engines
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 6WERK SALZGITTER
Volkswagen - Business Unit Salzgitter
Development of componentsProprietary Switching intake tubeDevelopment : Roller cam follower
Oil pumpsVacuum pumpsRails for CR-engines
Optimization of product costs
Spur gear
Oil pan
Bucket tappet
Oil pumpPump-injector drive
Fly wheel Roller cam follower
Rotatory parts
Piston pin
Cubic parts Pumps + otherValve train
Intake tube
Power-train mount
Balance shaft Pump
Bearing Frame
Engine components
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 7WERK SALZGITTER
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: 05.11.2008 – 8WERK SALZGITTER
CFD in component development
CFD
Design details
Problems occuring inprototypes and
production
Design optimization
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 9WERK SALZGITTER
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: 05.11.2008 – 10WERK SALZGITTER
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: 05.11.2008 – 11WERK SALZGITTER
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: 05.11.2008 – 12WERK SALZGITTER
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: 05.11.2008 – 13WERK SALZGITTER
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: 05.11.2008 – 14WERK SALZGITTER
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: 05.11.2008 – 15WERK SALZGITTER
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: 05.11.2008 – 16WERK SALZGITTER
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: 05.11.2008 – 17WERK SALZGITTER
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: 05.11.2008 – 18WERK SALZGITTER
Case study (III)
Design optimization on vacuum pump
inlet and outlet flows.
• 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
Inlet
Outlet
Simplified model of rotary vacuum pump
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 19WERK SALZGITTER
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: 05.11.2008 – 20WERK SALZGITTER
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.
Case study (III)
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 21WERK SALZGITTER
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.
Case study (III)
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 22WERK SALZGITTER
Design iterations and final result.
Minimal pressure loss
Case study (III)
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 23WERK SALZGITTER
Design optimization of vacuum pump outlet region.
Case study (III)
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 24WERK SALZGITTER
Compressible calculation of the evacuation to estimate pressure loss in
the valve.
Case study (III)
2/3 of the pressure loss
take place in the valve.
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 25WERK SALZGITTER
Lessons learned:
• Experiments showed only small differences in evacuation efficiency
with and without valve.
• Calculations confirmed that showing strong recirculation areas.
Simulation results
Valve
No valve
Case study (III)
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 26WERK SALZGITTER
Future plans
This is what we plan for 2009 ...
Volkswagen AG – HS-2 – Dr. Andreas Gitt-Gehrke – Stand: 05.11.2008 – 27WERK SALZGITTER
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: 05.11.2008 – 28WERK SALZGITTER
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: 05.11.2008 – 29WERK SALZGITTER
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.