Why are particles leaking out of the boundary in DEM?

MFiX
#1

hello,everyone,there are some problems when i use dem in win10 OS.
1.There are particles leaking out of the boundary,when using the dem-model, and i don’t know why??

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2.2.I set up the dt=1x10^-6, and uncheck the Detect stall to make the dt=constant, but the mfix still run the dt= 2.75x10^-5, so why??
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7.mfx (12.1 KB)
geometry.stl (4.3 MB)

#2

You are running a pure granular flow. This is not advancing using the fluid time step DT, but using the solids time step:

Info: At time =   0.000000E+00 sec., setting DEM solids time step, DTSOLID (sec) =   0.168684E-05

The leaking is most likely due to particles being too soft. Increase the spring stiffnesses kn and kn_w. This will also decrease the solids time step.

1 Like
#3

thank you verymuch!
and i want to know :Is that mfix can run the simulation which only contains the pure granular flow and with the Energy Equations on?
I mean that the simulation only have heat transfer between the particles and the wall(without fluid). Whether it can be done with mfix?