The chemical reaction in the simulation was not carried out

[yfwu]

Hello，experts！

In fluidized bed simulation, everything seems normal, with no error occurring, only some warnings and messages.
However, it seems that the chemical reaction did not occur and the temperature did not change. Only the flow of particles was simulated.
I have checked the “ ReactionRates array size ” mentioned in The chemical reaction does not exist - MFiX / How to - NETL Flow Science Software Support. So I don’t know how to solve it now.

There is an additional question, if I want to give a value as a variable, such as the fluctuation of import flow, how can I achieve it?
For example, defining a variable A as a function of time t, such as a sine function or a normal distribution, and define the flow rate m=A (t) * constant, is this feasible in MFIX?

complexr_2024-05-08T235727.646789.zip (72.6 MB)

[cgw]

Hi @yfwu

1. The case you have attached has 36 reactions defined. Which of the reactions is not happening? Can you simplify the chemistry (say, disable some reactions) to help troubleshoot this?

2. You should be able to implement a time-dependent flow rate using usr1_des.f

[cgw]

Here’s a worked example with a sinusoidal input rate:

Sinusoidal particle input

Hi - You should be able to do this using a UDF. See the Conveyor Belt tutorial for an example of varying belt speeds. You can do a similar thing to set the variable BC_MASSFLOW_S. You don’t need to use the key data approach if you just want to hard-code a simple sinusoid in usr1_des.f. If you do that you will just need to rebuild the solver when you change the parameters. – Charles

And another related posting:

Pulsating fluidized bed

Dear developers! I recently worked on a pulsating fluidized bed, which I used as a DEM model. I learned the advanced tutorial, but when I imitated setting multiple different gas mass inlet boundaries, only the gas inlet with BCID=1 corresponded to data_kf_0001.txt, and the rest of the mass inlet did not have gas pulsatile inflow, which confused me. (Also set BCID=2 and data_kf_0002.txt and),can you give me some advice? looking forward to your reply， Thank you very much!

[yfwu]

Thanks for your reply @cgw !
I followed your suggestion and reduced the number of reactions from 36 to 6, conducting another simulation.

I can see from the VTK window that no reactions have occurred in the system, and there is no temperature change in the system (chemical reactions will be accompanied by changes in heat).

I found that only sand particles can be seen, and biomass particles cannot be seen. I speculate that for some reason, biomass particles did not enter the system, so no chemical reaction occurred.

only sands can be seen

biomass particles cannot be seen

An additional issue is that my calculation results may cause crashes in Paraview, and I have already provided feedback to Paraview.
ParaView v5.12 crashed when loading results - ParaView Support - ParaView
Is there any other method for post-processing MFIX-DEM results?

[jeff.dietiker]

The last screenshot suggests there are 42 biomass particles in the system.

If you want to load DEM data into Paraview, you need to load the pvd files, not the *_DES.RES file

[cgw]

I strongly suggest using Monitors to track maximum reaction rate, rather than relying on visual inspection