[jpesich]

Hello,

I am modeling a cryogenic storage tank with saturated liquid/saturated vapor hydrogen. It's a spherical tank so I am using 2D axisymmetric, laminar, VOF solver. All second order schemes except 1st order time stepping. My initial conditions are T=20K and P=saturation pressure at 20K, zero velocity. Gravity is at 1g. The tank is halfway filled with liquid.

My only boundary condition is ~0.6mW uniform heat source on the tank wall.

I have constant material properties except ideal gas for vapor phase and polynomial in T for liquid phase. The expected change in temperature is very small.

My temperature contours look as expected but the flow structures around the axis boundary condition are not expected at all. I would expect the flow to rise up to the surface and fall down the middle (in the direction of gravity). Am I off base on this? My courant number at the interface is <0.7. I have not adjusted any values except applying a phase interaction and momentum interface damping. This should not affect anything near the axis except at the interface.

[reino]

Hello,

I'm attempting to simulate a very similar problem for a school project (but with LN2) and I'm facing convergence issues. Would it be possible to have some additional information on how you achieved the shared results (namely the phase interaction models and solver parameters) ? As I'm pretty stuck (and for some time now), any additional information you could share would be of great help.

Thank you.

[jpesich]

This post was actually the inception of finding a bug in the STAR-CCM+ code. Only for 2D axisymmetric problems where the axis intersects a wall boundary, a spurious pressure gradient appears near the intersection of the two boundaries. Currently, the code is unable to solve axisymmetric problems other than ones with an inlet and outlet and each end.

I have been collaborating with them and they have shown me results proving the bug is fixed. The version with the bug fix will be tentatively released in February 2020.

[cwl]

Thank you jpesich for that important note!