antec 2004 extrusion simulation and experimental validation to optimize precision die design by...
Post on 19-Dec-2015
221 views
TRANSCRIPT
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
EXTRUSION SIMULATION AND EXTRUSION SIMULATION AND EXPERIMENTAL VALIDATION TO EXPERIMENTAL VALIDATION TO
OPTIMIZE PRECISION DIE DESIGN OPTIMIZE PRECISION DIE DESIGN
by Srinivasa Rao Vaddiraju, M. Kostic
L. Reifschneider, A. Pla-Dalmau, V. Rykalin, A. Bross
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
IntroductionIntroductionTwin-screw extrusion lineTwin-screw extrusion lineFermi National Accelerator Laboratory (FNAL)Fermi National Accelerator Laboratory (FNAL)Northern Illinois Center for Accelerator and Northern Illinois Center for Accelerator and
Detector Development (NICADD) Detector Development (NICADD) Department of Mechanical EngineeringDepartment of Mechanical Engineering
Cast plastic scintillator - $40/kgExtruded plastic scintillator - $10/kg
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Berstorff 40-mm diameter, 1.36 m long, Berstorff 40-mm diameter, 1.36 m long, twin-screw extrudertwin-screw extruder
Two K-Tron automated feedersTwo K-Tron automated feedersConair downstream equipmentConair downstream equipmentNovatec compressed-nitrogen drier Novatec compressed-nitrogen drier
Profile Extrusion Line at FNALProfile Extrusion Line at FNAL
Gear pump
Cooling
Dry
er
Cutter
FeedingHopper
Extruder
Die
Calibrator Measurement
Haul-off
Polymer pellets Dopants
Breaker plate
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Required Extrudate profileRequired Extrudate profile
2.0
1.00.11
All dimensions are in cm
Rectangular cross section of 1 cm 2 cm with a circular hole of 1.1 mm diameter at its center, to accommodate wavelength-shifting optical fiber.
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Typical extrudate sample profile
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Effective die design strategyEffective die design strategy
Die swell and optimum die profile-shapeDie swell and optimum die profile-shape
Flow and heat transfer SimulationFlow and heat transfer Simulation
Integrate the simulation results with the Integrate the simulation results with the experimental dataexperimental data
ObjectivesObjectives
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
PolyflowPolyflow
Finite-element CFD codeFinite-element CFD code
Three-dimensional free surfaces Three-dimensional free surfaces
Inverse extrusion capability Inverse extrusion capability
Strong non-linearities Strong non-linearities
Evolution procedure Evolution procedure
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Flowchart for Numerical Simulation1. Draw the geometry using a CAD software
2. Mesh the geometry
3. Specify Polymer properties and boundary conditions
6.Is the solution
converged?Stop
4. Specify remeshing technique, solver method and evolution parameters
Yes
No
5. Solver solves the conservation equations using the specified data and boundary
conditions
Modify remeshing techniques, solver
methods and/or evolution parameters
Modify the mesh
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
General Assumptions
and incompressible
Body forces and Inertia effects are negligible in comparison with viscous and pressure forces.
The flow is steady
Specific heat at constant pressure, Cp, and thermal conductivity, k, are constant
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Material DataMaterial Data
Styron 663, with Scintillator dopant additivesStyron 663, with Scintillator dopant additives
Carreau-Yasuda Law for viscosity data:
Measured by, Datapoint Labs, NY
NOTE: Viscoelastic properties were neglected in our simulation
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Styron viscosity data, with and without Scintillator dopants
Shear Rate (1/s)
200 0C180 0C
220 0C
η – Styron 663
ηd– Doped Styron 663
106
105
104
103
102
10-2 10-1 100 101 102 103
Vis
cosi
ty (
Pa-
s)
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Exploded view of the extrusion dieExploded view of the extrusion die
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Section 1
Section 2
Section 3
Die lip
Melt flow
direction
Half domain of the extrusion die
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Simulation domain with Simulation domain with boundary conditionsboundary conditions
1. Inlet (Fully Developed Flow)
2. Wall (Vn = 0, Vs = 0)
3. Symmetry (Vn = 0, Fs = 0)
4. Free Surface (Fs = 0, Fn = 0, V.n = 0)
5. Outlet (Fn = 0, Vs = 0)
1
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Melt flow direction
Die Lip
30,872 elements
Skewness < 0.33
Finite element 3-D domain and die-lip mesh
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
19 hours and 36 minutes of 19 hours and 36 minutes of CPU timeCPU time
Windows XPWindows XP2.52 GHz Processor2.52 GHz Processor1 GB RAM1 GB RAM
Computation timeComputation time
Parametric Studies:Parametric Studies:preland and dieland, much fasterpreland and dieland, much faster
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Die lip
Melt flow
direction
Contours of static pressure
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Die lip
Melt flow
direction
Contours of velocity magnitude at different iso-surfaces
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Melt flow
direction
Die lip
Contours of temperature distribution
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Contours of shear rate
Melt flow
direction
Die lip
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Existing die, corresponding simulation and new improved-die profiles
0
1
2
3
4
5
6
7
0 10X (mm)
Y (
mm
)
New Die (Simulated)Existing Die
Desired ExtrudateExisting-Die Extrudate
(Simulated)
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
2 D-View of the extrusion die
Melt flow direction
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
ConclusionsConclusionsOptimum dimensions of the die Optimum dimensions of the die Effect of inertia terms – negligibleEffect of inertia terms – negligibleExponent of the Carreau-Yasuda model - Exponent of the Carreau-Yasuda model - significant effectsignificant effectFlow in the die: no re-circulation regionsFlow in the die: no re-circulation regions
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Recommendations for future Recommendations for future improvementsimprovements
Include polymer viscoelastic propertiesInclude polymer viscoelastic propertiesInclude cooling, solidification and thermo-Include cooling, solidification and thermo-mechanical stresses in and after the calibratormechanical stresses in and after the calibratorRadiation heat transfer for free surface flow Radiation heat transfer for free surface flow Pulling force at the end of the free surfacePulling force at the end of the free surfaceNitrogen pressure inside the hole Nitrogen pressure inside the hole More non-uniform mesh More non-uniform mesh
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
NICADD (Northern Illinois Centre for NICADD (Northern Illinois Centre for Accelerator and Detector Accelerator and Detector
Development), NIU Development), NIU
Fermi National Accelerator Laboratory, Fermi National Accelerator Laboratory, Batavia, ILBatavia, IL
NIU’s College of Engineering and NIU’s College of Engineering and Department of Mechanical EngineeringDepartment of Mechanical Engineering
AcknowledgementsAcknowledgements
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
QUESTIONS ?QUESTIONS ?
www.kostic.niu.edu/extrusionwww.kostic.niu.edu/extrusion ANTEC 2004ANTEC 2004
Contact InformationContact Information
mailto: mailto: [email protected]@niu.edu
www.kostic.niu.eduwww.kostic.niu.edu
mailto: mailto: [email protected]@yahoo.com
www.vaddiraju.comwww.vaddiraju.com
Department of Department of Mechanical EngineeringMechanical Engineering
NORTHERN ILLINOIS UNIVERSITYNORTHERN ILLINOIS UNIVERSITY