Heat transfer in a solid particle receiver

MFiX
#1

I’m trying to simulate the heat transfer within a solid particle receiver. there’s also interstitial gas in-between the particles.
I don’t really know what the issue is.
can someone take a look and tell me where I might be making a mistake?
thank you!

hexrec_2023-02-06T164251.331425.zip (303.1 KB)

#2

The LOG file says:

Velocity exceeds limit:   10.000
in cell: I =   23   J =    3   K =   14
 Epg =  0.98954     Ug =  -16.641     Vg = -0.15856     Wg =  -2.8817
To change the limit, adjust the scale factor MAX_INLET_VEL_FAC.
 <<<<<=================================================================
 t=     0.0180 Dt= 0.1000E-01 NIT=  2MbErr%=-0.7049E-03: Run diverged/stalled :-(


 >>>>>#################################################################
ERROR from time_step.f:193
DT < DT_MIN.  Recovery not possible!
 <<<<<#################################################################

You have large velocities (larger than the limit with is controlled by MAX_INLET_VEL_FAC). This should trigger a time step decrease. However, you have set both DT_MIN and DT_MAX to 0.01 second, so there is no room to adjust the time step.

You should set DT_MIN to a much lower value (say 1E-6 s), to let the time step adjust if needed. If you still reach DT_MIN, then try to increase MAX_INLET_VEL_FAC to allow for larger velocities.

#3

Thanks jeff,
that fixed it!

also if I have an error with convergence.
is the issue usually with the mesh or the boundary condition??

#4

It is hard to tell, could be the mesh, the Boundary Condition or even even the Initial Conditions. It always pays off to check the mesh first in my opinion.