Dear all,
I am trying to simulate particle-gas flows using CFDEM package. But I have a couple of questions. I'm quite familiar with OpenFOAM and had no issues with running several fluid flow simulations in the past. However, I'm not familiar with LIGGGHTS and I'm puzzled as to how to simulate a solid-gas multiphase flow in a simple structure (shown in images attached).I'm interested in understanding the particle dynamics with different obstacles in a channel (shown here is a circle obstruction in a channel), and the fluid pressure and velocities at near inlet/outlets, and particle deposition.
I understand several commands of LIGGGHTS i.e. set up particle properties, create n number of particles, choosing a JKR/DMT contact, etc.
However, I'm not sure exactly how to get a continuous stream of particles to flow from inlet to outlet or at least generate say 5 particles every iteration. 2 possibilities is to have particle and fluid flow at inlet (a.png) or fluid flow only at inlet and particle generation at a distance away from inlet in order for fluid to develop (b.png).
Moreover, I design the geometries in ANSYS or sometimes SOLIDWORKS and save in ascii format for use with OpenFOAM / CFDEM. So I'm not sure how to set the simulation with CFDEM
Particle: Solid Particles i.e. Sandstone ~2600 kg/m^3...particle sizes i.e. say 10 or 50 micrometers.
Fluid: Gas i.e. Air
Channel Size and dimensions shown in pictures. 2D simulation.
Thank you very much for your kind assistance and time.
BR
Lance
| Attachment | Size |
|---|---|
 a.png | 31.24 KB |
| b.png | 33.97 KB |
 start_error.txt | 280 bytes |
| helyxx_mesh_error.txt | 4.03 KB |
| 1.png | 74.65 KB |
| 2.png | 80.53 KB |
richti83 | Thu, 03/05/2015 - 08:58
Help
However, I'm not sure exactly how to get a continuous stream of particles to flow from inlet to outlet or at least generate say 5 particles every iteration. 2 possibilities is to have particle and fluid flow at inlet (a.png) or fluid flow only at inlet and particle generation at a distance away from inlet in order for fluid to develop (b.png).
Have a look at LIGGGHTS\examples\LIGGGHTS\Tutorials_public\insert_stream.
Just make a STL plane at the inlet (or whereever you want), create a PDD out of 1 to N pts and use fix ins all insert/stream with suitable particlerate (unit particle/second)
Moreover, I design the geometries in ANSYS or sometimes SOLIDWORKS and save in ascii format for use with OpenFOAM / CFDEM. So I'm not sure how to set the simulation with CFDEM
I use the powerfull HELYX tool to create the needed 3D Blockmesh for CFDEM by intersection of a qube and a STL.
http://sourceforge.net/projects/helyx-os/
cheers,
Christian.
almonds22 | Tue, 03/10/2015 - 14:32
Helyx, Liggghts
Hi Christian,
Thank you very much for your reply. I studied the liggghts fix ins stream command.Also, I recently installed Helyx. I exported a geometry (designed in Solidworks) in stl format. and copied it to a new case folder in Helyx directory.
However, I was unable to get Helyx to generate any mesh. See document (helyx mesh error.txt). I'm sure I followed the correct procedure in Helyx, I imported the geometry as shown in 2.png and the settings shown in 1.png. Looking at the error generated by helyx, I suspect it's to do with design of geometry or incorrect meshing technique? But I'm not sure how to amend it. I tried to adjust few parameters but the meshing didn't work
Moreover, I notice that everytime I start helyx a notification appears (start error.txt), though i'm not sure if it is responsible for the said error.
I'm using OpenFOAM 2.1.1 and Helyx v1.0.1. ,compatible with OF 2.1.x.
Many thanks for your assistance and time!
Lance