No reactions happend

MFiX
#1

Demtutorial3.tar (25.5 MB)

Hello, everyone.

I am a beginner. The edition I used is MFiX-20.4.2. I want to add one simple reaction following the tutorial case ‘silane_pyrolysis_pic_3d’:
‘SIH4–>SI+2H2’

I used the DEM model. Then, I modified the “usr_rates_des.f” (copy the content in the tutorial case). And I rebuild the solver through GUI rebuild button. Everything is fine EXCEPT nothing happened about the reaction. I tried to solve the problem for several weeks.

Could someone help me? Thanks very much!

#2

There are a couple of issues:

  1. You turned off the call to UDFs. These must be on when you have chemistry. Go to the “model” pane and check the “Enable user-defined subroutines”
  2. Np, pM and IJK must be defined as integers in usr_rates_des.f:
  INTEGER, INTENT(IN) :: NP ! Global particle index
  INTEGER, INTENT(IN) :: pM ! Particle solid phase
  INTEGER, INTENT(IN) :: IJK ! Fluid Cell Index

You may want to use the equation of states for the gas density instead of constant density.

#3

Thanks very much for your key guidance. The reaction happens. :grinning:
Best regards!

#4

Hi, Jeff. I am a Ph.D in geotechnical engineering. I find that MFiX is suitable for investing the dissolution mechanisms of methane hydrate.

Nevertheless, the stress state of the particle assembly is an important influential factor for geomechanics. So I wonder if your team could implement a servo-wall algorithm in DEM part of MFiX. I think it will promote the application of MFiX in a wider field.