Chemical reactions related to solid+solid → solid+gas

MFiX How to
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#1

I want to conduct chemical reactions related to solid+solid → solid+gas in the DEM model. How should I handle the issue of chemical reaction rate in UDF

#2

Please try to make your question more specific. What have you tried so far, what issues are you having with it?

#3

I want to use DEM to simulate the combustion process of particles during their movement,
I used a two-step reaction to achieve the reaction between solid and solid,
For the sake of simplicity, I have specified the chemical reaction rates for two reactions
However, it cannot be executed at the beginning of the run.
This is currently a simple 2D example, but it cannot run

2D_1.mfx (17.8 KB)

usr_rates.f (3.1 KB)

Thank you for your reply

#4

What do you mean by “it cannot run”? Did you compile the custom mfixsolver for this case? For me, it compiles and runs. The only warning I’m seeing is

Initial condition  2, Phase  1: Unsuccessful seeding

which is not related to chemical reactions.

#5

I have compiled the custom mfixsolver for this case ,When I run this case, the following situation occurs
2D_1 (2).TXT (13.1 KB)
Reading mesh boundary: E:\mfix\2D_1\2D_1_boundary.vtk

MFiX process has stopped

Previous MFiX run is resumable.

#6

How can this case run smoothly?
Thank you for your reply

#7

Your 2D_1 (2).TXT shows the following warnings and errors:

WARNING from des\\generate_particles_mod.f:698
Initial condition  2, Phase  1: Unsuccessful seeding
 

 From : PARSE_RESID_STRING
 Error: Phase index 1 in RESID_STRING P1   out of bounds.                        

 From : PARSE_RESID_STRING
 Error: Phase index 1 in RESID_STRING U1   out of bounds.                        

 From : PARSE_RESID_STRING
 Error: Phase index 1 in RESID_STRING V1   out of bounds.

I can reproduce the “Unsuccesful seeing” warning, but not the PARSE_RESID_STRING errors, given the input files you uploaded.

Note that the 2D_1 (2).TXT file contains:

Project version: 38

while the .mfx file contains:

  project_version  = '30'

so I can see that these are not in sync with each other. If you still need help, please upload a full bug report - go to the main menu, select “Submit bug report” and upload the resulting ZIP file which will contain all the relevant inputs as well as needed information about your system which will help us track down the problem.

Thanks for your patience,
– Charles