[Paulo SPS]

Hi there,
I am new to openfoam, so hopefully a solution to my problem is achievable.
I am trying to model a two phase problem, one solid phase and one fluid phase, multi species problem in which species from the fluid phase diffuse into the solid and vice-versa. There are a different set of reactions in both phases and I need to see the species gradient in the solid region.


1)Is there a solver that can do that straight away?


2)Because I didn't find a better way I'm trying to add reactions and mass transport to chtMultiRegionFoam. With "solidReactionThermo.H" I managed to get composition fields into the solid region but I'm struggling to add the reactions and evaluate the rates because as far as I can see all reaction models are for fluid phase reactions. Do I have to write code from scratch for solid phase reactions?


3)The other idea I have is to run reactingTwoPhaseEulerFoam with alpha.fluid and alpha.solid fixed, is that possible?


Cheers and thanks in advance

[gridley2]

Hey Paulo,


I'm currently encountering a similar difficulty, namely that there seems to be no built-in way to model interfacial chemistry between phases. My current thoughts are to code a new phase system into reactingMultiPhaseEulerFoam for myself that does this.


Have you made any headway on the issue?

[Paulo SPS]

Hey Gavin,
so far I haven't made much headway into this subject. I'm dedicating myself more to the chtMultiRegionFoam solution because it appear to suit my needs a bit better.
I found a constructor for a class of gas/solid reactions in "/src/thermophysicalModels/solidChemistryModel/pyrolysisChemistryModel/pyrolysisChemistryModel.C" but it appears to be only for reactions of the type "Solid1 = Solid2 + Gas", which is nice but I would need more.


Cheers,
Paulo

[Kummi]

Hello Paulo,
Hope in your case two solvers are mainly involved. One is Firefoam and other is chtmultiregionfoam.

Its super complex to add reactions in chtmultiregionfoam. Instead, modify the firefoam solver as per your need depending upon fluid and solid regions. If Im not wrong, you are looking into chtmultiregionfoam concerning different regions. If so, simply adopt the couple boundary conditions to couple 2 or more regions as per your problem requirement. Thats how I solved my case months before.

And in above explanations, I don't find clear objective. It ll be good, if you explain right on the content related to applications with figures.

Nothing is impossible. Cheers.. Good luck ^^

[gridley2]

Paulo, thanks for the info. I'm curious, what is the "more" you need than what you described? I'm curious to find out if what we're working on has any overlap.

[Paulo SPS]

Dear Kummi,
I understood from digging in the code that fireFoam can only handle pyrolysis reactions (Solid1 = Solid2 + Gas) in a 1D model for the solid phase, am I wrong in that?

My problem needs to account for gas diffusion into a solid, where gas and solid react with each other (several reactions with both gas and solid products). Unfortunately I have no pictures as of this moment. The pyrolysis model solves part of my problem but I need to account for complex char reactions. (Hopefully this answers Gavin's question also).


I'll try to implement the couple boundary condition into fireFoam as you suggested because I'm also getting to the conclusion that adding reactions do chtMultiRegionFoam is more complicated.


Cheers,
Paulo

[Kummi]

Hello Paulo,

I understood from digging in the code that fireFoam can only handle pyrolysis reactions (Solid1 = Solid2 + Gas) in a 1D model for the solid phase, am I wrong in that?

Yes, pyrolysis can handle only such simple reaction. To include additional reactions, refer this article below with solver attached. It might help you to add additional reactions, and add n number of reactant and product species too.

https://www.researchgate.net/publica...ed_on_OpenFOAM
https://www.researchgate.net/publica...tallPack_10tar

The pyrolysis model solves part of my problem but I need to account for complex char reactions. (Hopefully this answers Gavin's question also).

irreversibleSolidArrheniusHeterogeneousReaction
char + CO2 = 2 CO
(1.5e7 324 800 2 0.27)

Are you looking for such kind of reaction?

My problem needs to account for gas diffusion into a solid, where gas and solid react with each other (several reactions with both gas and solid products).

Can you suggest any real time applications related to it ? Is that a kind of porous media problem.

[Paulo SPS]

Dear Kummi,
the solver you refered solves my issues.


Many thanks

[atulkjoy]

Originally Posted by Paulo SPS

Dear Kummi,
the solver you refered solves my issues.


Many thanks

Hi I can help you out if you can elaborate things more

[sante]

Greeting
I followed the thread of your exchanges. And one of the solvers caught my attention. It's biomassGasificationFoam.
I have a problem with this solver. When I launch it I have no problem with the evaporation reaction of water and the pyrolysis of biomass. But when I add the equations of gasification of the char and combustion of the char, the calculation crashes after a number of iterations.
And I would also like to work in a fixed-bed combustion furnace. Please, I need your help.

Sincerely!!!

[Kummi]

Hello Sante,
I have checked out now for few iterations. Both combustion and gasification works well for me in biomassGasificationFOAM.
char + O2 --> CO2 + ash &
char + CO2 --> 2CO + ash

I guess, there should be some problem with your installation or chemistry setup files. Not sure though.

[sante]

Originally Posted by Kummi

Hello Sante,
I have checked out now for few iterations. Both combustion and gasification works well for me in biomassGasificationFOAM.
char + O2 --> CO2 + ash &
char + CO2 --> 2CO + ash

I guess, there should be some problem with your installation or chemistry setup files. Not sure though.

hello Kummi.
I add the combustion and gasification equations below and I still have the same problem.
When installation no worries; I think these are the chemistry configuration files.
Here is an attachment that I receive via my terminal

[sante]

Dear Kummi, here is an example of my chemistryPorperties file and the 0 (zero) test case directory below:

[Kummi]

Hello Sante,
I ran the solver with your chemistry properties attached above.
No issues with my solver.

Courant Number mean: 0.25 max: 0.25
Time = 0.01

Evolving pyrolysis
diagonal: Solving for Ycharm, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for Yhumm, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for Yashm, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for Ycelm, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for Yhemm, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for Yligm, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for porosityF, Initial residual = 0, Final residual = 0, No Iterations 0
DICPCG: Solving for Ts, Initial residual = 1, Final residual = 1.74732e-07, No Iterations 7
pyrolysis min/max(T) = 300, 300

Pyrolysis:
Total gas mass produced [kg] = 1.74208e-14
Total solid mass lost [kg] = -1.69453e-14
Total pyrolysis gases [kg/s] = 0
Total heat release rate [J/s] = -5.02617e-05

Solving chemistry
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Ux, Initial residual = 0.00225005, Final residual = 8.14106e-08, No Iterations 5
DILUPBiCG: Solving for Uy, Initial residual = 0.00221622, Final residual = 9.61385e-08, No Iterations 5
DILUPBiCG: Solving for Uz, Initial residual = 1, Final residual = 4.81368e-08, No Iterations 9
DILUPBiCG: Solving for CH4, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for O2, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for CO2, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for H2O, Initial residual = 1, Final residual = 2.83018e-08, No Iterations 12
DILUPBiCG: Solving for CO, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for H2, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for hs, Initial residual = 1, Final residual = 2.25876e-08, No Iterations 13
T gas min/max = 299.994, 300.002
DICPCG: Solving for p_amb, Initial residual = 1, Final residual = 9.79283e-07, No Iterations 42
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.22971e-05, global = -1.22656e-05, cumulative = -1.22656e-05
DICPCG: Solving for p_amb, Initial residual = 0.0262937, Final residual = 9.48924e-08, No Iterations 39
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.23076e-05, global = -1.22714e-05, cumulative = -2.45371e-05
ExecutionTime = 0.41 s ClockTime = 1 s

As per your error stated in above image, it seems there is some problem in evolving the pyrolysis. Have you modified the source file? If so, try to run the default case (unmodified source codes) firstly, and gradually modify step by step to figure out the error in each module. If you got error in default case, then there should be some problem with installation.


BiomassGasificationFoam compiling issue
Check this link for the proper installation file
Thank you

[Kummi]

Hello Sante,
So it stops at 3039s. I didn't notice that before.

I have a problem with this solver. When I launch it I have no problem with the evaporation reaction of water and the pyrolysis of biomass. But when I add the equations of gasification of the char and combustion of the char, the calculation crashes after a number of iterations. And I would also like to work in a fixed-bed combustion furnace. Please, I need your help.

As you stated above, I guess there is no problem with evaporation reaction of water and the pyrolysis of biomass, your solver is converging ?
Have you tried solving gasification alone with pyrolysis, is that works? and similarly for combustion. And so we can exactly find where the problem is -- with gasification or combustion !!

Guess, no issues with A and E values, higher order of reaction - 2, will that be an issue, should think. Have you tried with first order reaction and reduce time step further when Temp reaches around 800K - where both gasification and pyrolysis occurs.
We will discuss!!

[sante]

Hello Kummi
I've read your. And sorry for my long absence, I was a little unwell.
I'll consider your suggestions. I also noticed that combustion is not present in the default test case (constant/combustionProperties). Since this is the case, should we add the CH4 and O2 files in the 0(zero)??? directory?

Thank you for your suggestions!!!

[sante]

Please how to separate the columns of such a file:

[sniggy]

1. I am modeling a counter-current gas-solid packed bed. I am interested to model a heterogeneous reaction of Iron oxide reduction through Gas. But the reaction I am interested is a multi-step reaction. These are following:

Hematite + H2 = Magnetite + H2O
Magnetite + H2 = Wustite +H2O
Wustite + H2 = Fe + H2O
All these reactions go happen in every solid particle. I have already downloaded and performed the installation of BioMassGasificationFoam. I have added the reactionRates K for this reaction in the ReactionRate folder.Can you suggest what else I need to change in order to get these step reactions.

[Kummi]

Hello Snigdha,
Your information was too abstract to guide you. Have you come across this forum page:
Need suggestions about technical difficulties - Drying + Pyrolysis of coal particle
BiomassgasificationFoam is a reference solver. It's application is related to TGA. Feel free to share your thoughts.

Thank you

**------------------------**


Hello sante, I don't know how I missed your questions. Have you solved your problem ?
Thank you

[sniggy]

Thanks Kumaresh for your quick reply. Actually I am not looking for any pyrolysis models of coal. I am interested in modeling iron ore reduction which happens in above mentioned step by step process. Its a solid gas reaction. Hence, I was assuming that biomassGasificationFoam will work for me. However, I am only interested in iron ore reduction model with heat transfer. Do you think bioMassGasificationFoam will be suitable for me? Is there any other in general solver which will be more suitable for my case? Thanks in advance.