[akia]

Hi
I am simulating coal gasification process in fluidized bed with coalchemistryfoam solver in OF 2.3.0. First I start with running it’s tutorial (simplified siwek). When i increase the internal field temperature from 400 to 1400, I meet the JANAF warning and printstack error so running had stopped. I changed the tutorial to my case conditions ( 1 inlet for coal and 1 inlet for air with an outlet at top of gasifier ) I have the same problems. I do the following procedures to solve it but it didn’t work:

1. Turning off chemistry and combustion
2. finer mesh specially near the coal injector and ignition cells
3. reduce courant number to 0.1
4. reduce under relaxation factors to 0.5
5. set many kind of boundary conditions

I want to know it is solver’s problem (which it’s tutorial has error) or I am doing something wrong?



Please help me and give a solution; my project had stopped for 3 month because of this error


The boundary condition is attached.

[akia]

Hi freinds

I want to simulate coal gasification process in fluidized bed with coalchemistryfoam solver in OF 2.3.0. use it’s tutorial (simplified siwek) for this purpose but just by increasing the internal field temperature from 400 to 1400, I meet the JANAF warning and printstack error so running had stopped. I do the following procedures to solve it but it didn’t work:

1. Turning off chemistry and combustion
2. finer mesh specially near the coal injector and ignition cells
3. reduce courant number to 0.1
4. reduce under relaxation factors to 0.5
5. set many kind of boundary conditions

what else should i do?

[wyldckat]

Quick answer:

1. Several bugs have been fixed since 2.3.0 was released. Please try upgrading to the latest OpenFOAM 2.4.0.
2. Don't jump directly from 400K to 1400K. First test what happens when you change to 500K, 600K, and so on, until you find the breaking point.
3. It's possible that this solver was not designed to work at such high temperatures, since other chemical reactions can occur and possibly explosions can also occur at very high temperatures, which would explain the crash. Therefore, again, this is why I suggest you gradually increase the temperature.

[akia]

Dear Bruno Santos

thanks for your answer.
I used OF 2.0.1 - 2.1.0 and 2.3.0 and this error apeare in all of them but i will try in OF 2.4.0 too.
This error occurred after the internal temperature arrive at 900 kelvin, but before and after that any notable thing happened!! I read in other forums that this solver use for gasification that the range of temperature is between 800 to 1500, but i 'm not sure about it.

[wyldckat]

Greetings akia,

So I finally managed to take a look into this and it's a bit disconcerting.
I tested the tutorial "lagrangian/coalChemistryFoam/simplifiedSiwek" with OpenFOAM 2.4.x and the modification you stated, namely of changing the internal temperature from 400 to 1400 K and I ran the case with the Allrun script. There was no crash nor problems with Janaf.
The only issue that occurred were several situations where this output was given:

--> FOAM Warning : 
    From function seulex::solve(scalar& x, scalarField& y, stepState&
    in file ODESolvers/seulex/seulex.C at line 255
    step size underflow :2.710505431e-20

which seems to be a problem with the ODE solver, which is unable to find a proper solution for the problem.

I have not tested with 2.3.0 no 2.4.0, so either the issue you mentioned is already fixed in 2.4.x, or you omitted important details for reproducing the error.

Best regards,
Bruno

[Howard]

Hello,akia
I would like to ask where is the tutorial of this coalchemistryfoam solver in OpenFOAM. I can't find it. Moreover, have you solved the problem? I also meet this kind of problem. Thank you

[wyldckat]

Originally Posted by Howard

I would like to ask where is the tutorial of this coalchemistryfoam solver in OpenFOAM.

Quick answer - Run the following commands:

tut
cd lagrangian/coalChemistryFoam/simplifiedSiwek/
pwd