Hossam Metwally, Fluent Inc'

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Hossam Metwally, Fluent Inc. Mark Landon, Idaho
National Lab Optimal Solutions Software COUPLING
FLOW SIMULATION, SHAPE DEFORMATION,
OPTIMIZATION May 23rd, 2006
2006 CFD Summit Share . Inspire . Learn .
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Objective

• To demonstrate how arbitrary shape deformation
  (ASD) technology can be coupled to computational
  fluid dynamics (CFD) for the process of die
  balancing of
• Spiral mandrel dies (coupling SCULPTOR with
  FLUENT)
• Profile dies (coupling SCULPTOR with POLYFLOW)

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Agenda

• Objective
• Spiral Mandrel Die
• Description
• Computational Model
• Arbitrary Shape Deformation (ASD)
• Results
• Conclusions
• Profile Die
• Description
• Computational Model
• Arbitrary Shape Deformation (ASD)
• Results
• Conclusions

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Spiral Mandrel Die

• Coupling FLUENT with SCULPTOR

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Problem Description
inlet

• Blown film
• Pipe/hose extrusion
• Wire/cable coating

die
mandrel
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Geometrical Parameters
die land
manifold
spiral height
die height
die-mandrel gap
die lip (gap)
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Geometrical Parameters
inlet
helical angle
Spiral depth
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Modeling Techniques

• Many geometrical parameters
• 1d and 2d models
• Fast (allows analytical solutions)
• Can be used for optimization
• Complex geometry effects??
• Full 3d models are also used
• Realistic representation of geometry
• Non-Newtonian behavior highly dependant on
  geometry
• Model creation and update is a time consuming
  process
• CAD
• Meshing
• Set up, simulation, process results

man hours
man/CPU hours
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Ideal Modeling Scenario
Initial Geometry
3d Computational Model meshing, problem set up,
simulation, results interpretation
automated
automated
No
Modify Geometry
Flow Balanced
Yes
Cut and Test Die
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Computational Model

• Full three dimensional
• Model size 1.3 M cells
• Non-Newtonian viscosity (Bird-Carreau)
• ? ?oo (?o - ?oo)1( ??)2(n-1)/2
• ?oo infinite strain rate viscosity 0
• ?o zero shear viscosity 105,059 Pa.s
• ? time constant 0.6509 s
• ? strain rate, s-1
• n power-law index 0.4

?o
?
?oo
?
Values taken from Sun Gupta
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Baseline Model Results
spirals
inlet
inlet
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Arbitrary Shape Deformation

• Shape deformation is applied on an existing
  (baseline) model
• Arbitrary Shape Deformation (ASD) parameterizes
  the geometry and the mesh
• No need to revisit CAD No re-meshing
• Deform manually or perform Automatic Shape
  Optimization
• Smooth Volumetric Deformations maintaining cell
  quality

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Two Parameters Studied
die land
helical angle
helical length const
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Effect of Twist
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die land 11.3 mm const.
helical angle 405? (baseline 45?)
helical angle 315? (baseline - 45?)
helical angle 360? (baseline)
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Deformed Mesh Quality
helical angle 315? Maximum skew 0.73
helical angle 360? Maximum skew 0.71
helical angle 405? Maximum skew 0.77
good
bad
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helical angle 360?
helical angle 315?
helical angle 405?
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Exit Velocity Distribution
inlet
spiral direction
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Effect of Twist and Die Land- die land changed
/- 20 of baseline value- helical angle changed
/-45?
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Pressure drop, Pa
Flow uniformity
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Design Space Map
(1.2, 405?)
(1, 405?)
(0.8, 405?)
(1.2, 360?)
(1, 360?)
(0.8, 360?)
(1.2, 315?)
(0.8, 315?)
(1, 315?)
const. helical angle
const. die land
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Conclusions

• Computational fluid dynamics has been used with
  arbitrary shape deformation to model numerous
  designs of a spiral mandrel die
• Only ONE baseline model was manually created from
  which eight new different designs were
  automatically generated
• The effects of the helical angle and the die land
  were studied on the flow uniformity and pressure
  drop
• A design map can be used to select which geometry
  may be used depending on available pressure drop
• Next step would be to couple an optimizer to
  drive the entire loop
• Additional geometrical parameters

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Profile Die

• Coupling POLYFLOW with SCULPTOR

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Problem Description
plane of symmetry

• Full three dimensional
• Model size 20,000 cells
• Non-Newtonian viscosity (Bird-Carreau)
• ? ?oo (?o - ?oo)1( ??)2(n-1)/2
• ?oo infinite strain rate viscosity 0
• ?o zero shear viscosity 10,000 Pa.s
• ? time constant 0.01 s
• ? strain rate, s-1
• n power-law index 0.25
• No slip occurring on die walls
• Flow rate 320 cm3/s

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Solution Results
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Shape Deformation (I)
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Shape Deformation (II)
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Top only deformed Vmax 7.676e-02 Die balance
6.57
Initial Shape Vmax 8.372e-02 Die balance 6.67

• Best Design
• Notice the equal shades of red at the corners.
  This means a good Die Balance of max velocities
  at the corners.

Bottom only deformed Vmax 7.64e-02 Die balance
6.55
Top and Bottom deformed Vmax 7.936e-02 Die
balance 6.73
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