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February 8, 2013, 09:38 |
Simulating diffusion flames with fireFoam
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#1 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
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Dear Buddies
Hi I want to simulate a diffusion flame with fireFoam. Does any body has any tutorial about this issue? I would be very pleased if an experienced buddy help me on this object. Thanks bobi |
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February 9, 2013, 03:25 |
more information from my work
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#2 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
Rep Power: 15 |
Dear Buddies
Hi I have simulated diffusion flames with reactingFoam earlier. However now I want to simulate them with firefoams using FSD combustion model. I have looked into firefoam tutorials about poolfires. when I start my simulation, I got this error message: Create time Create mesh for time = 0.0522381 Reading g Creating combustion model Selecting combustion model FSD<psiCombustionModel,gasThermoPhysics> Selecting thermodynamics package hsPsiMixtureThermo<reactingMixture<gasThermoPhysic s>> Selecting chemistryReader foamChemistryReader terminate called after throwing an instance of 'std::bad_cast' what(): std::bad_cast Aborted I even deleted the chemistry properties file, made the chemistry solver off,modified the reactions file and the combustion model, Nevertheless I still get this error. I would be very please if an experienced fireFoam man help me. Regards Bobi |
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April 3, 2013, 04:35 |
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#3 |
New Member
Join Date: Apr 2013
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Hi Bobi,
the combustion models have changed in OpenFoam 2.2.0. I don't know why, but some of the combustion models, which worked fine on 2.1.1, don't work on 2.2.0. you can try to replace combustion model FSD<psiCombustionModel,gasThermoPhysics> with combustion model FSD<psiThermoCombustion,gasThermoPhysic> Regards |
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April 4, 2013, 03:49 |
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#4 | |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
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Quote:
Thanks for ur reply. now, I have a question about firefoam in 2.2.x. Does supprot multistep combustion? As u know in 2.1.x firefoam only had singlestep combustion. Regards Bobi |
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April 5, 2013, 06:11 |
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#5 |
New Member
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Hey Bobi,
I've no idea if fireFoam can handle that, sorry. I'm new at simulating with fireFoam and so my experience with it is quite little. I'm still struggling to get my own simulation running . Regards. |
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April 13, 2013, 06:03 |
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#6 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
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Hi matze
I I have a doubt about 0 folder. In this folder we have to create distinct folder for any reactant. however, I want to know the value for each specie in boundary field is in mole or mass fraction? |
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April 17, 2013, 07:41 |
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#7 |
New Member
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Hi Bobi,
in my oppinion just mole fraction makes sense. |
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May 20, 2013, 06:42 |
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#8 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
Rep Power: 15 |
Dear Buddies
Hi I have simulated a cold flow with fireFoam. However, when I tried to ignite combustion by increasing the whole computational domain temperature to 1600 K and then injecting the reactants; I do not have the combustion yet.I think I have set out the chemistry, combustion and reaction files, correctly (according to its tutorials in openFoam). Would somebody PLZ help me on this? I can put any of my files that is needed for investigating my case. However, I should mention that I am trying to simulate one of Sandia flames with fireFoam and with FSD (Flame Surface Density) combustion model. |
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May 22, 2013, 07:20 |
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#9 |
Super Moderator
Tobias Holzmann
Join Date: Oct 2010
Location: Tussenhausen
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Hi,
is your Diffusion flame laminar or turbulent? Maybe you can use the flamelet-model tool (adverticement) But I think bobi could give you a more accurate answer which solver you should use (: PS: for turbulent flames it s possible to use the flamelet-model 2.2.x from my Homepage and for laminar flows, alberto cuoci build a new solver. Tobi |
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May 22, 2013, 07:38 |
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#10 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
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Hi Tobi
I am trying to simulate DLR flame (Sandia CH4-H2-N2) with fireFoam (FSD combustion model) which is a single-step flamelet/progress variable combustion model with LES. Ofcourse I would be so much happy to link the flow solver of fireFoam (LES) with your flamelet code ; However I do not know that how can I link these together can you hint me on this issue? Regards Bobi |
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May 22, 2013, 08:20 |
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#11 |
Super Moderator
Tobias Holzmann
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Hi bobi,
you are still working on flamelet-model RAS reprogramming to LES? Well as in the libOpenSmoke thread I am not familiar with LES modelling and there for I can not give you a advice or any hints to Combine both. *sorry* Do you have to simulate with LES ? RANS flamelet model and DLR flames are working very good. |
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May 22, 2013, 10:10 |
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#12 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
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Hi Tobi
Unfortunately, As part of my thesis I should combine LES with steady flamelet. I have succeeded this job in two different route. First, I am trying fireFoam; Although with some progress there is still problem in igniting combustion. Second, I am trying your code. At first I was thinking that I should change the simple algorithm to pimple plus changing the stoichiometric chi update formulation + turbulence model. After contacting Dr. Cuoci, I figured out That I just need to change the stoichiometric chi update formula plus changing turbulence model. I am trying both route, and I hope to become successful Regards Bobi |
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May 23, 2013, 07:34 |
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#14 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
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Next Week; I will try again to build LES-Flamelet code
I will tell you the result of the code (compiled or not). I hope to succeed ; cause in the last try my problem was with pimple algorithm Regards Bobi |
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August 27, 2013, 11:01 |
Janaf Thermo crash
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#15 |
Member
Join Date: May 2013
Location: Netherlands
Posts: 30
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All,
As proposed by Bobi on the libOpenSmokeForum I am trying to use fireFoam to model the turbulent mixing of methane jets in a swirling air flow (without combustion involved). However I get an error in a simplified model and I don't know what causes this error. The error is the following: --> FOAM Warning : From function janafThermo<EquationOfState>::limit(const scalar T) const in file /home/.../OpenFOAM/OpenFOAM-2.1.1/src/thermophysicalModels/specie/lnInclude/janafThermoI.H at line 108 attempt to use janafThermo<EquationOfState> out of temperature range 200 -> 5000; T = -4667.51 It starts with some small deviations from the required temperature range but then the deviation starts to grow and finally the model crashes. I use the following boundary conditions: internalField uniform 500; boundaryField { outlet { type zeroGradient; } burnerwall { type zeroGradient; } inletair { type fixedValue; value uniform 500; } inletfuel { type fixedValue; value uniform 500; } } So using this I assume that temperature field normally should be around 500 K and stay around this temperature (since combustion is off). Does anybody know what to do with this? Thank you Last edited by TBO; August 28, 2013 at 03:17. |
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August 28, 2013, 03:02 |
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#16 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
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Hi TBO
I hope to provide helpful suggestions for you. 1) first probability is your CFL number. Its maximum must not exceed about 0.4 2) check your grid quality. Sometimes grid quality at downstream causes this error. 3) Check your maximum DeltaT. It must not exceed 2e-06 4) your boundary conditions does not have impact on this error.Although I suggest to try another condition for burner wall(no slip condition) Regards Bobi |
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September 10, 2013, 03:40 |
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#17 |
Member
Join Date: May 2013
Location: Netherlands
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Thank you for your answer Bobi, I implemented the changes that you proposed. However the problem now is that DeltaT gets very small (1e-12), the result is that the calculation will take extremely long (actually impossibly long, it run for a couple of days on 12 processors and I reached time 0.0001, while I need to go to time 0.3 for a complete throughflow of my domain). This is already the case for a very simplified mesh of 60000 cells, I put a lot of effort in optimizing the mesh, for computional effort I already moved to a cyclic mesh.
How can I speed up the calculation and increase the timestep. In the end, I'm not interested in the transient behaviour but only in the steady state result. I am using fireFoam in OF 2.1.1 without chemistry, to model the mixing of a methane jet in air. Regards, |
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September 13, 2013, 11:32 |
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#18 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
Rep Power: 15 |
Hi TBO
Sorry for late answering, I was a bit busy last days. My best suggestion for your case is this: Be careful that there is a coupling between maximal courant number and time step. If you want to run a LES case, you can adjust your courant number in a way that your maximum time step do not exceed 1e-05. Try raising your CFL number as I mentioned, It speeds your running time. I am sure that you can reach to a acceptable result after a few days. Monitor your maximum time step in a log file to be confident about it. never more than 1e-05. use this directive for monitoring your results in a log file Code:
mpirun -np 12 fireFoam -parallel > log Bobi |
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October 9, 2013, 06:19 |
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#19 |
Senior Member
Bobby
Join Date: Oct 2012
Location: Michigan
Posts: 454
Rep Power: 15 |
Dear Buddies
Does anybody has ever tried to use firefoam code with a mixture of fuel instead of a single fuel. for instance CH4+H2 or C3H8+H2? If there is any try with successful results, I would be very pleased to be informed. Cause I have some questions to ask ? regards Bobi Last edited by babakflame; October 9, 2013 at 09:34. |
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September 16, 2014, 19:04 |
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#20 |
Member
vishal
Join Date: Mar 2013
Posts: 73
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Hello Bobi,
I am sorry.. I don't have much experience in C++ or openfoam. What is "chi"?? |
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