Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
Schiller Naumann with Mixture Model
Posted 12 juil. 2012, 06:58 UTC−4 Fluid & Heat, Computational Fluid Dynamics (CFD), Studies & Solvers Version 4.2a 2 Replies
Please login with a confirmed email address before reporting spam
I have been trying to use the Schiller Naumann with Mixture Model to simulate a particle flow in water.
I have previously used the Hadamard-Rybczynski model with smaller particles (Rep <1) and had no problems in getting a steady convergence.
However, the Schiller Naumann is not making it easy for me.
With larger particles and higher density I get a Rep roughly in 500. So, the Schiller Naumann applies, and I can't use the Hadamard-Rybczynski model for the drag anymore.
But, I can't seem to get a convergence with the the Schiller Naumann model. I have searched the forum and found that using P=0 in the initial conditions might be the problem so I used about 2000 Pa (rough estimate) but still no convergence. I have attached the convergence plot for a better understanding.
The segregated group 1 is P,V,PHID; The segregated group 2 is k and epsilon; and The segregated group 3 is the slipvel.
Does anyone have some experiences with this or any advices?
Best Regards,
Rui
Attachments:
Hello Rui Silva
Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.
If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.
Please login with a confirmed email address before reporting spam
Hi Rui,
Sorry to bother you but I want to ask that were you able to achieve the convergence with the mixture model coz I am also facing prblems to achieve convergence. Can you plz let me know few tips and tricks. Which type of grid and scaling values you used in artifcial diffusion regarding NS equations and Discrete phase equation.
Kindest regards
Please login with a confirmed email address before reporting spam
I used the mixture model with some modifications, and thus I had some issues with convergence.
If you are using the mixture model, with the Schillher-Naumann slip model, I have found that providing an estimate of the pressure drop and slipvel in the "Initial Values" really helps in the convergence process. Also, I had to use Inconsistent Stabilization for the Disperse Phase because I couldn't get a very fine mesh (due to RAM limitations of my server). In the Scaling for the stabilization I used the initial particle concentration.
Some other tips that I can provide:
- Try refining the mesh near the wall and use a boundary layer;
- Try decreasing the damping value for the segregated Newton Solver in the dispersed phase;
Hope this helps. If you would like you can upload your file and I can take a look at it.
Best Regards,
Rui Silva
Hi Rui,
Sorry to bother you but I want to ask that were you able to achieve the convergence with the mixture model coz I am also facing prblems to achieve convergence. Can you plz let me know few tips and tricks. Which type of grid and scaling values you used in artifcial diffusion regarding NS equations and Discrete phase equation.
Kindest regards