I’m working with the MFIX software and I want to create a flow with cylindrical particles. To do this, I’ve selected the SUPERQUADRIC PARTICLE DEM solver and I’ve set up my flow with the boundaries and everything else I need, but I get this error message:
Error: Solver crash!
The MFiX solver has terminated unexpectedly
Error information:
float overflow in __sq_rotation_mod_MOD_qincrotate2
at des/sq_rotation.f:624
And this is the line of the code : fqc = 1.D0/SQRT(Qc_new(1)**2+Qc_new(2)**2+Qc_new(3)**2+Qc_new(4)**2)
I think is division by 0 but u don’t knox how to fix this ? experience-cylindriques.mfx (21.3 KB)
I am seeing an overflow, not a division by zero when the particle hit the wall. Not sure how to fix, we have seen this with superquadrics, and it is challenging to fix. I noticed you have a normal restitution coefficient of 1 and a tangential restitution coefficient of zero. Maybe you can adjust these to see if it makes a difference, as well as the Young’s modulus. There is also an option to turn off floating point exception trapping in the Numerics>Advanced pane that sometimes helps.
I am not seeing the unphysical bouncing when I don’t use a mass inlet BC. Can you please verify that it works fine if you just put some particles near the top (in an IC region)? I would not use a restitution coefficient of one though.
I am tracking a possible bug in the mass inlet BC, I will report back when I have made more progress. Sorry about the inconvenience.
there are always rebounds, even if you experiment with restitution coefficients equal to 0.1. There must be a problem somewhere else. I’ll try to compare with the spherical study where the particles stuck to the wall.
I made a little bit of progress. I found a bug in the mass inlet BC code with SQP. We will release the fix in the next point release but in the meantime you can use the attached file (mass_inflow_dem.f). Copy it in your project directory and build the solver. With that fix, I get reasonable results when particles collide with the ramp. I am still having issues with unphysical bouncing off of the small cylinders. It may be due to the cylinder small radius of curvature compared with the spheroid. It gets better when I refine the cylinders but it slows down the simulation, so I don;t have a good solution for that right now.
Please try this one. We put the fix in 24.2.1 point release so if you install 24.2.1 you can use the default solver (you don’t need the mass_inflow_dem.f from my previous reply).
Subject: Collaboration Proposal for the Use of MFIX in the Study of Solid Waste Combustion
Dear Jeff Dietiker,
I am writing to you on behalf of the University of Algarve, where we are currently conducting research into the combustion of solid waste in incinerators as part of energy recovery projects. In this context, we have identified your MFIX software as a potentially very beneficial tool for our work.
Our main objective is to improve the efficiency of waste combustion, in order to increase the rate of energy produced in relation to the quantity of waste treated. We strongly believe that the use of MFIX could significantly improve the accuracy of our modeling and simulations, enabling us to achieve this goal more efficiently.
We see several mutual advantages to a collaboration:
Validation and promotion of MFIX: By integrating your software into our study, we will help validate and demonstrate its effectiveness in a real-life industrial context. The results of our research, which we will publish in scientific journals and present at international conferences, will include references to MFIX, increasing its visibility and recognition in the field of waste recovery.
Feedback and Improvement: In the course of our use of MFIX, we will be able to provide detailed feedback on its performance and usefulness in specific waste combustion scenarios. This feedback could be invaluable in helping you to improve and adapt the software for similar future applications.
Joint Development Potential: This collaboration could pave the way for future developments, where we could work together to add new features or optimize certain parts of MFIX to better meet the needs of the waste recovery industry.We would be delighted to discuss the details of this collaboration in more detail, and to answer any questions you may have.We sincerely believe that this initiative could be mutually beneficial, and would be honored to work with you and your team.We look forward to hearing from you.
Please accept, Mrs Jeff Dietiker, the assurances of our highest consideration.
