Confusion in Inputting Rolling Friction Coefficient in Mfix-DEM 24.4

MFiX
1

Hello,

Can anyone please clarify for the below:

For my Mfix-DEM simulation, I am not using any fortran source code for performing simulation.

I wanted to input experimental rolling friction coefficient (non-dimensional) for particle-particle and particle-wall.

Also, I wanted to know whether I have to convert into dimensional rolling friction coefficient by multiplying with particle diameter or Mfix is automatically multiplying it?

Also, please comment on the below:

I found out they have modified the torque equation below where they multiplied rolling friction coefficient with R* = (ri * rj)/(ri + rj).

But in the fortran code diameter is being multiplied.

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A Comparison of Ansys Fluent and MFiX in Performing CFD-DEM Simulations of a Spouted Bed.pdf (2.8 MB)

Do I need to modify anything on fortran code?

Please clarify.

Thanks.

2

The rolling friction model is that of the Zhou et al. paper, but it is non-dimensionalized by the particle diameter. I don’t think you need to modify the code, just make sure your friction coefficient is equivalent to the other model you want to compare with.

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3

Okay, so in the MFix DEM simulation:

Do I need to input non-dimensional rolling friction coefficient [no unit] or do I need to input dimensional rolling friction coefficient by multiplying with particle diameter (m)?

Please clarify this out to me.

Thanks.

4

You need to input the non-dimensional rolling friction coefficient.