In SQP, the solver repitetively giving "overlap between two superquadric particles is too large!", which is increasing my wall time a lot, how can i fix this?

MFiX How to
#1

image
image816×1554 271 KB

aiche_ar4_1.4vi.mfx (12.7 KB)
particle_input.dat (3.7 MB)
Kindly tell me how can i reduce this repetitive thing "“overlap between two superquadric particles is too large!”
I have attached the input case file along with input particle file. Running on 16 cores on Hpc cluster

#2

You can try to lower the shape exponent m so you have rounder corners, or you could increase the Young’s modulus to make the particle less soft. This warning message has ben disabled in the latest version (24.1.1) so it doesn’t overwhelm the console output.

#3

Will building the latest 24.1.1 solver with dmp will increase the speed of simulation too ? Currently using mfixsolver built on 23.4

#4

There should not be a difference in simulation speed between 23.4 and 24.1.1. You should expect SQP model to be much slower than DEM. You may want to try the new glued sphere model (GSP), this should run faster than SQP.

#5

Thanks for the guidance @jeff.dietiker . I will surely try GSP model. But until then can you tell me ways to speed up my existing sqp simulaitons ?

#6

Try with a 15x100x15 search grid see if this helps a bit. Again you should expect SQP to be much slower than DEM. It is possible that you need more than 16 cores for this simulation. My suggestion is to start with a smaller simulation so you get an idea of what is doable with SQP and your computational resources.

#7

If you check my input file , I am already using a mesh size of 1510015
image

#8

I checked you file, I was talking about the des search grid, which is set to 10x50x10, not the fluid grid:

desgridsearch_imax        = 10                                                                     
desgridsearch_jmax        = 50
desgridsearch_kmax        = 10

However, this won’t work because refining it would make it smaller than the bounding sphere diameter, which is not allowed. Maybe try a 12x80x12 for both the fluid and des search grid. The des search grid can be set in the Solids>SQP pane.