Why there are many particle clusters in my liquid-solid fluidised bed

MFiX
#1

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Hi I am simulating a liquid-solid fluidised bed. However, when particles are rising, there are many particle groups, colored by reaction rates.
I am wondering whether this is normal.

#2

The clustering doesn’t look right to me, especially after 6 seconds of simulation. What model is it (DEP,CGDEM,PIC). The coloring may not be significant since the numbers are so small (1E-14).

#3

Hi, jeff,
This is a dem model. Actually i am simulating a pulsating fluidised bed.
Thus, the fluid injection starts from 6 s. When the whole bed move upward, in the rising process, there are particle clusters. I am not sure whether this is normal or i choose a wrong setting.

Regards
Yuanhe

#4

You may want to play with the grid spacing to see if this helps. We have seen some levitating effect on shallow beds (not the same as your case), but refining the mesh helped (https://doi.org/10.18141/1476713).