CFD-2012-01_CAST-Tilted-New mesh generation-

2012-02-23 E. Da Riva

Summary

2012-02-23 E. Da Riva

1. Mesh generation2. First results3. Thermal b.c. improvement?

2012-02-23 E. Da Riva

Symmetry

• Focus on modeling and understanding physical phenomena (instead of reproducing the exact experimental number of moles)

• Interconnection between cold-bores neglected (Adiabatic in most simulations + Horizontal -> small influence on natural convection)

• Axisymmetric fluid domain -> good mesh• Symmetry plane b.c. -> better exploitation of computational resources• No changes for the thermal b.c.

MESH:CAST-15Feb2012.msh6 106 cells

2012-02-23 E. Da Riva

Wall meshing

• Cell thickness close to wall: 50 μm• Grow ratio: 1.2• # layers: 10• Cell longitudinal size increasing from 1 mm at the windows up to 15 mm at 3.5 m from the

cold-bore center

2012-02-23 E. Da Riva

Polypropylene window

• Thicker window with fake non-isotropic conductivity did not work.• Propylene window modeled with real thickness and conductivity.• Non-conformal interface between steel net and poplypropylene.

2012-02-23 E. Da Riva

First results

• Ideal Gas.• Pressure 37.1 mbar• Hot window (Tw=63 K, TCB=1.798K)

2012-02-23 E. Da Riva

Velocity @ MFB

Fluent

Star-ccm+

2012-02-23 E. Da Riva

Temperature @ MFB

Fluent

Star-ccm+

• Sleeve not taken into account in the Star-ccm+ simulations.

b.c. T = 1.798 K

b.c. T = 1.798 K

2012-02-23 E. Da Riva

First results

• Ideal Gas.• Pressure 37.1 mbar• Hot window (Tw=63 K, TCB=1.798K)

2012-02-23 E. Da Riva

0

0.1

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-6 -4 -2 0 2 4 6

Dens

ity [k

g m

-3 ]

Axial position [m]

Star-ccm (Van Der Waals)Fluent (ideal gas)

Density along axis

2012-02-23 E. Da Riva

Thermal b.c. improvement?