[cryabroad]

Hi guys,

I started to work on liquid-particle simulations (mainly DPM, the DDPM is not suitable for my case) couple weeks ago and as usual I read the User's Guide and some other materials online. However I was not able to find out if Fluent has restrictions on the mesh size when using DPM.

I went through a lot of research papers (some of them use different CFD softwares) and it seems like the mesh size has to be larger than the particle size. Some state that the ratio of mesh size to particle diameter has to be larger than 4.

I double checked the User's Guide but didn't find any statement about this. Any help is welcome!

Plus, if it turns out that the mesh size does have to be larger than the particle, how can I model a liquid-particle case where the particles are generally several times larger than the mesh?

Thank you very much.

[DnyanMiri]

Hi Ruiyan,
Did you find the answer to your question? I would be interested in learning the answer.

Thanks

[vinerm]

This information is given in user manual, though not explicitly. For the assumptions in DPM to be valid, particles cannot occupy more than 10-12% of the volume, locally as well as globally. That means, even the smallest cell size should have its volume at least 10 times the volume of largest particle size.

[pigpig]

Originally Posted by vinerm

This information is given in user manual, though not explicitly. For the assumptions in DPM to be valid, particles cannot occupy more than 10-12% of the volume, locally as well as globally. That means, even the smallest cell size should have its volume at least 10 times the volume of largest particle size.

Hi，
The thickness of the first layer of the boundary layer must be greater than the particle size?

[Lube23]

Originally Posted by vinerm

This information is given in the user manual, though not explicitly. For the assumptions in DPM to be valid, particles cannot occupy more than 10-12% of the volume, locally and globally. That means, even the smallest cell size should have its volume at least 10 times the volume of largest particle size.

Hello, but don't forget to consider that the volume fraction is:
number of particles * Volume of particle / Volume of cell

I found the following paper:

Coupled CFD-DEM Simulation of Seed Flow in an air Seeder Distributor Tube
Author: Leno Guzman, Ying Chen and Hubert Landry

Where a relation between the volume of the cell and the diameter of the particle is three times.

[pigpig]

There is also literature that says that the grid is better calculated between 10-20dp of particles. This is a question that needs some thought