CFDEM®coupling - User Forum

Hi, everyone here.
I have a quite simple and 'stupid' question : )

In my cases, i'm using 'cetre voidfractionModel' and 'dense averagingModel' for that my particle radius is quite smaller than CFD cell and that particles are dense. Please correct me if i'm wrong.

It seems that too small ratio would cause a problem for dense packings. So can anyone tell me, how i set proper RATIO of DEM particle diameter(radius) with CFD cells ?

Regards,
Mq

I see two ways:

1) timestep integrating all the contact forces (normal and tangential - according to e.g spring dashpot model described in Kloss, Goniva, Hager et al papers)
which gives the velocity changes, new normal and tangential displacements and hence new values of forces

2) assuming the selected model and knowing the impact velocities, the loss of energy during the impact, collision duration and other parameters are calculated analytically which gives the after impact values of linear and angular velocities.
(looks like much faster way)

Dear community,

the problem I want to model is based on the sealing of a fluidic channel by a large particle. I am quite new (and very fascinated) to the DEM-part of the CFD-DEM world and I need some input from you.

I prepared a small test-case that is modelling the closing of a ball check valve-type structure. I tried two solvers, Piso and IB. I figure IB is probably the right choice, but Piso is faster and I would prefer to use it. As you can see in the result plots, the channel isn't sealed fully by the particle with either solver:

I am quite new in the CFDEM-coupling and after successfully install OpenFoam2.3. and LIGGGHTS-PUBLIC, I am trying to build the programs-solvers for CFDEM-coupling but I got an error during the compiling process after launching cfdemCompCFDEM
'could not open file mpi.h for source file subModels/forceModel/checkCouplingInterval/checkCouplingInterval.C due to No such file or directory'

of course the system include path includes /opt/mpich/include but still not functioning for this compiling case??

Where is my mistake ?
thanks for your help.

Hi all,

I want to simulate the combustion of char in a screw conveyor with CFDEM, but i am still fairly new to CFDEM and even if I have an idea on how to write the fluid part (i have already wrote the particle part) I would like to use the oxygen concentration in the gas phase to evaluate a combustion kinetic expression in the LIGGGHTS input. Is it possible with CFDEM? if yes, how?

thanks for your attention,

Hi

I downloaded and built LIGGGHTS and CFDEM (basically following the steps in the CFDEM Coupling.pdf) with OpenFOAM-2.1.1 that was already installed on my system. As far as I can tell everything built correctly, but when running the twoSpheresGlowinskiMPI tutorial I find a strange error where the two particles don't appear to interact with the fluid in any way. I was wondering if anyone else had experienced an error like this?

Hi,
I am new user to this CFDEM. Recently I downloaded and installed the LIGGGHTS and CFDEMcoupling packages as described in the installation manual.

Hi everyone,

I have a problem with the test twoSpheresGlowinski.
Other tests are working (ErgunMPI, settlingTestMPI, packedBedTemp), so I presume that cfdemSolverPiso and cfdemSolverPisoScalar do work normally.

What could cause a particular solver to be not compiled properly?

Are there any more tutorials/examples available?
Such as those shown in CFDEM-FEATURES page.
In particular I would be interested in "Sedimentation" , "multisphere method" and "fluidised bed" test cases.

Hi

I am using Ubuntu 14.04, Liggghts 3.0.0, OpenFoam 2.2.1 and CFDEM 2.6.1.

to compile the CFDEM follow the tutorial that appears on the page, which is: