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Incorporating pyrolysis Model in chtMultiRegionFoam |
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July 11, 2020, 06:04 |
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#21 |
Senior Member
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Hi,
As per your explanation above, you have just one domain/region. Fluid/solid interaction takes place inside one domain. In your case, the source of energy is from fluid, thereby pyrolysing the solid, release the energy from solid and interacts with fluid itself. So, you need to fix appropriate governing equations for fluid model with heat source terms. --> (1) Accordingly, use coupled boundary condition to transfer energy from fluid to solid --> (2) the necessary equations inside solid model simulates pyrolysis and release exothermic heat to fluid--> (3) Here (1) and (3) solves fluid and solid model (2) - Interactions using boundary (but there are more realistic models for interactions) In case of multiregion models, (1) and (3) will be solved in separate domains. For multiregion models, OpenFOAM was constructed with block matrices (separate blocks to solve separate set of implicit/explicit equations for solid and fluid models). Think from application point of view please. Consider a heated rod (solid) in the atmosphere (fluid), convection into acccount - perfectly 2 regions - equs. are solved separately in 2 regions. Another example as same as yours, pyrolysis in the domain - interactions between solid and released pyrolytic gases - here it cant be multiregion problem, because both solid and fluid matters are investigated in the same domain. Hope you are clear now. If not, let me know please. Kindly look into the examples of reactingMultiphaseEulerFoam Thank you |
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July 11, 2020, 08:52 |
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#22 | |
New Member
Armin Alavi
Join Date: May 2019
Location: Tehran
Posts: 22
Rep Power: 7 |
Hi,
Thank you very much, I am looking up the test cases of the solver you mentioned. I think I get what you mean. You suggest that solid and fluid are the parts of one computational domain but treated as two separate phases, Am I right? I don't have the experience with two fluid models such as Eulerian model. I worked VOF model (interFoam) that solves an averaged equation. I think in two fluid models, two equation are solved and they are linked together via source terms of momentum, energy and mass. Although I didn't understand one part, Quote:
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July 11, 2020, 13:12 |
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#23 | ||
Senior Member
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Hello Armin,
Quote:
Quote:
Thank you |
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July 12, 2020, 09:53 |
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#24 |
New Member
Armin Alavi
Join Date: May 2019
Location: Tehran
Posts: 22
Rep Power: 7 |
Hello Kummi,
Thank you very much. I have a lot to do and experience with the vision you gave me. I will try my best to put that in work. Best regards, Armin |
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November 12, 2021, 11:11 |
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#25 |
New Member
Alexis
Join Date: Oct 2021
Posts: 7
Rep Power: 5 |
Hi everyone,
I'm currently trying to do something similar and I have come to the point that I should create my own solver as well. Let me explain you quickly my case. They are three solid regions pyrolysing and producing gases into a fluid region. Then these gases are burning together. My goal is to study how much of the solid has burnt. I tried implementing pyrolysis in chtMultiRegionFoam on OpenFoam 7 thanks to the post of Archana.V but there are always errors while compiling the solver. I don't know what to do with the regionModels:: pyrolysisModels:: pyrolysisModelCollection& pyrolysis = tpyrolysis[i]; because there is no setSolidFields.H I tried adding the line in createPyrolysisModel.H but it gives me "pyrolysis" unused variable and invalid initialization. Does someone have a running solver that could help me a lot? By the way, there is maybe a simpler way to do it but I'm lost. Thanks in advance, alexis |
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November 15, 2021, 10:35 |
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#26 | |
Senior Member
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Quote:
Firstly, I hope you have created 3 pyrolysis solid regions in OF, which is very straightforward. Expand your errors and issues here ! We will find a way ! Good luck |
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November 15, 2021, 13:39 |
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#27 | |
New Member
Alexis
Join Date: Oct 2021
Posts: 7
Rep Power: 5 |
Quote:
Hi Kummi, Thanks for your help. 1. The 3 pyrolysis regions are created using splitMeshRegions -overwrite Overall, the mesh and geometry are well defined. 2. There is no error with the lines added in createSolidFields.H 3. Here is the file createPyrolysisModel.H forAll(solidRegions, i) { Info<< "Creating pyrolysis model" << endl; regionModels:: pyrolysisModels:: pyrolysisModelCollection& pyrolysis = tpyrolysis; } 4. Here is the readPyrolysisTimeControls.H scalar maxDi = tpyrolysis.maxDiff(); tpyrolysis was suggested instead of pyrolysis 5. I try pyroltysis.evolve() in the main code but I used tpyrolysis.evolve() since it was also suggestde instead. 6. Here are the errors I have error: invalid initialization of reference of type 5 | isModels:: pyrolysisModelCollection& pyrolysis = tpyrolysis[i]; warning: unused variable ‘pyrolysis’ [-Wunused-variable] 5 | regionModels:: pyrolysisModels:: pyrolysisModelCollection& pyrolysis = tpyrolysis[i]; error: ‘class Foam::PtrList<Foam::regionModels:: pyrolysisModels:: pyrolysisModel>’ has no member named ‘maxDiff’ 32 | scalar maxDi = tpyrolysis.maxDiff(); error: ‘class Foam::PtrList<Foam::regionModels:: pyrolysisModels:: pyrolysisModel>’ has no member named ‘evolve’ 86 | tpyrolysis.evolve(); 7. By the way, about the pyrolysis. I have two issues. - I only have Solid = gas and not Solid = solid + gas. It's not working with the model from the oppositeBurningPanles tutorial. There is pyrolysisChemistryModel.H but I don't know neither if it can help nor how it works. - As a consequence I have no way to track the gases, there is no field associated. So they can be used in the combustion reaction in the fluid region. 8. All the files are in the .zip folder If you want, we can discuss in private to avoid a long conversation in the thread. Thanks, alexis |
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November 17, 2021, 01:55 |
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#28 | |
Senior Member
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Hello Alexis,
1. Hope you made 3 pyrolysis regions using the following commands: blockMesh >> topoSet >> splitMeshRegions -cellZones -overwrite Points 2-6 are bit confusing unless I understand your problem better. 7. Are you looking for such kind of reactions as mentioned below? Quote:
8. From your solver attached, I couldn't able to understand the application behind your work. But no worries, this is how every researcher try to explore the problem. I'm hereby attaching my part of the code designed for pyrolysis. Hope it helps. Yes, you can contact me by yahoo mail - found in my profile page. However we discuss in private, try to update your progress here in this forum page, so others might get benefited in nearby future. Feel free to contact. Thank you. Good luck |
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April 1, 2022, 16:07 |
Pyrolysis and flame spread of PMMA
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#29 |
New Member
Argha Bose
Join Date: Feb 2022
Posts: 4
Rep Power: 4 |
hey kummi,
I am new to both OpenFOAM and C++, I am trying to simulate flame spread over PMMA. Let me elaborate, I have a PMMA surface that is thermally thick now I would like to set it on fire. I was thinking of using fireFOAM in the OpenFOAM version2112. Do I require a solver merger if I want to simulate a case of pyrolysis followed by thermal oxidation of fuel? or is it sufficient to incorporate necessary boundary conditions? now the second part of my doubt is that I want to run the pilot flame for a fixed amount of time till the pyrolytic gases create a self-sustaining flame at the surface. I haven't come across such a condition yet. Is it possible to incorporate this? |
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April 2, 2022, 00:02 |
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#30 |
Senior Member
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Hello Abose,
PMMA is non-charring process right ? PMMA --> GAS PMMA undergoes both pyrolysis and thermal oxidation ? If then (if only solid), no need to merge with fluid part. In fireFoam-dev ☞ charOxidation model will give you better idea. Regarding pilot flame, I haven't done that yet either. In general, fluid model is necessary here to capture the flame. In order to implement in solid model, there might be some other way, not sure though. Should check it. Thank you |
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April 2, 2022, 02:05 |
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#31 | |
New Member
Argha Bose
Join Date: Feb 2022
Posts: 4
Rep Power: 4 |
Quote:
I am trying to simulate wall fire where we are taking PMMA as a solid region and there is a fluid region. |
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April 2, 2022, 03:11 |
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#32 |
Senior Member
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Well then fireFoam is the suitable solver in your case
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