CFDEM®coupling - User Forum

Hello Everybody,

I need to know how to couple time step between liggghts and CFD? I modified deltaT in OpenFoam but I got the error "TS is too big for coupling".

Regards,

Carlos

Hello users:

How does CFDEM calculate particles force on fluid cells?

As I understand , For calculating Drag force on particles we should at first obtain " inter-phase momentum transfer coefficient due to drag" which is shown in Kochhill drag by "betap".

Hi everyone

What is the highest particle volume fraction that runs reliably with CFDEM? Has anyone else had experience with this?

I have been running 20% volume fraction (0.8 voidfraction) quite reliably, but when trying to run 30 or 40%, my simulations become very unstable. I have tried reducing the DEM time step (which is supposed to help) but that only made it worse. Increasing the time step helps a little bit, but I am not sure if this is the most correct thing to do.

Dear community,

I am simulating the packing of a chromatography column at Technical University Munich. Therefore I use CFDEMcoupling 2.7.1, LIGGGHTS 3.0.2 and OpenFOAM 2.3.x. I already built some working small scale models (40.000 particles, 4% of the volume of the fullscale experiment) with a discrete particle distribution based on the Ergun Test Case (reversed flow).

hi, everyone
IncfdemCloud, to calculate the voidfraction, it'll first calculate particle and CFD cell volumes, which defaults to 3d. (also in force model)
When 2d, flow does not have real 'volume'(m^3) and the particles should be disks instead of spheres.

Hi Chris,

I notice that the UEqn.h has some changes in the latest version of cfdemSolverPiso:

Hi Chris,

Recently I upgraded the cfdem scheme from OpenFoam 2.1.1 to OpenFoam 2.2.2 + CFDEMcoupling 2.7.1+Liggghts 3.0.2, However,I am facing some issue regarding the mesh wall for CFD-DEM coupling:


fix mesh_wall all mesh/surface/stress file ../DEM/walls.stl type 1 wear finnie
fix granwalls all wall/gran model hertz tangential history mesh n_meshes 1 meshes mesh_wall


In old version there is no problem importing STL mesh walls for coupling, but in the latest Version of cfdem scheme it seems not working.

Dear all,

I am working on simulation of particle-fluid flow in the pipe.

To reduce the computational domain I use cyclic boundary condition for inlet and outlet of the pipe.

I get some strange results.

I think it is caused by the solver not giving the correct information at the inlet and the outlet.

When a particle flows across the outlet, a part of the particle is in the domain and another part of the particles is out of the domain.

The part of the particle outside the domain and the fluid at the inlet should affect each other.

Hi Everybody,

I am trying to set up CFDEMproject on ubuntu 14.04 LTS, and I am following the same exact steps on githubAccess_public.pdf.

I installed OpenFOAM-2.3.x successfully, and everything went fine up to

cfdemSysTest

and I get some information confirming that the paths are set correctly.

Then I started compiling LIGGGHTS(R) by typing:
cfdemCompLIG

HI,
I am beginner in cfdem and doing fluidised bed simulation and presently facing problem with the contact model for wall.
The coupled simulation runs fine until the particle touches the wall. As the particle touches the wall, it gives the follwoing error.
The contact model used is "gran model hertz tangential history primitive type 1".
Any suggestion would be helpful.

Kind note: DEM and CFD simualation run fine separately and coupling properties settings are good.