fireFOAM: reactions file setup

ashish.vinayak · March 14, 2017, 11:15

Hi,

I'm reopening this issue of what irreversibleArrheniusSolidReaction means with regard to fireFOAM pyrolysis modelling. I have pretty much looked everywhere including the source code and I still don't know what this means. A further complication thus results, which is, I cannot include the model parameters since they really don't exist anywhere. How can I be sure that the pyrolysis model even works ? I hope someone knows what's going on?

The following reactions file is included with the fireFOAM/LES/simplePMMApanel/constant/panelRegion.

species
(
PMMA
);
gaseousSpecies
(
gas
);
reactions
{
charReaction
{
type irreversibleArrheniusSolidReaction;
reaction "PMMA = gas";
A 1.2e6; // what is this value
Ta 11300.57; // what is this value
Tcrit 400; // what is this value
}

ashish.vinayak · July 5, 2017, 08:44

For anyone who comes looks for this, I found the answer:

Reaction rate is computed based on an Arrhenius Equation, that is set up as follows:

RR = A* exp(-Ta/Tcrit)

where Ta = Ea/R.
A -> pre-exponential factor
Ea -> Activation Energy
R -> Ideal Gas constant.

luca1992 · August 14, 2017, 08:55

Hello, can i ask you some things about fireFoam? I'm trying to simulate a fire in a closed place, but I have doubts.
Thank you, thank you, Luca.

ashish.vinayak · August 14, 2017, 10:09

Quote:

Originally Posted by luca1992

Hello, can i ask you some things about fireFoam? I'm trying to simulate a fire in a closed place, but I have doubts.
Thank you, thank you, Luca.

I'll help you as much as I can

luca1992 · August 14, 2017, 12:08

Hi, thanks very much for the reply, I also asked for help in another forum discussion (both in "fireFOAM: reactions file setup" and in "HRR in fireFoam") and now I do not know what to do. I did not know if anyone answered me since July 30 I had created a post but no one answered me and so I was not very optimistic and so I had written on both posts that had the latest message in 2017, now I could write my question on both of the discussions, but maybe it would be better to unify them, do you know how to do it? Maybe it's better if I publicize my question in my previous post "Simulating fire in a tunnel" so if you can answer me there. Thank you both (Roman1 and ashish.vinayak) let me know if it is all right for you.

March 14, 2017, 11:15	fireFOAM: reactions file setup	#1
ashish.vinayak Member Ashish Vinayak Join Date: Mar 2015 Location: Wuppertal, Germany Posts: 50 Rep Power: 11	Hi, I'm reopening this issue of what irreversibleArrheniusSolidReaction means with regard to fireFOAM pyrolysis modelling. I have pretty much looked everywhere including the source code and I still don't know what this means. A further complication thus results, which is, I cannot include the model parameters since they really don't exist anywhere. How can I be sure that the pyrolysis model even works ? I hope someone knows what's going on? The following reactions file is included with the fireFOAM/LES/simplePMMApanel/constant/panelRegion. species ( PMMA ); gaseousSpecies ( gas ); reactions { charReaction { type irreversibleArrheniusSolidReaction; reaction "PMMA = gas"; A 1.2e6; // what is this value Ta 11300.57; // what is this value Tcrit 400; // what is this value }

July 5, 2017, 08:44	Solution	#2
ashish.vinayak Member Ashish Vinayak Join Date: Mar 2015 Location: Wuppertal, Germany Posts: 50 Rep Power: 11	For anyone who comes looks for this, I found the answer: Reaction rate is computed based on an Arrhenius Equation, that is set up as follows: RR = A* exp(-Ta/Tcrit) where Ta = Ea/R. A -> pre-exponential factor Ea -> Activation Energy R -> Ideal Gas constant. Kummi and Hasnain_1 like this.

August 14, 2017, 08:55	fireFoam	#3
luca1992 New Member Join Date: Jul 2017 Posts: 28 Rep Power: 9	Hello, can i ask you some things about fireFoam? I'm trying to simulate a fire in a closed place, but I have doubts. Thank you, thank you, Luca.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
[swak4Foam] funkyDoCalc with OF2.3 massflow	NiFl	OpenFOAM Community Contributions	14	November 25, 2020 04:30
[OpenFOAM.org] Compile OF 2.3 on Mac OS X .... the patch	gschaider	OpenFOAM Installation	225	August 25, 2015 20:43
[swak4Foam] swak4foam building problem	GGerber	OpenFOAM Community Contributions	54	April 24, 2015 17:02
SparceImage v1.7.x Issue on MAC OS X	rcarmi	OpenFOAM Installation	4	August 14, 2014 07:42
ParaView Compilation	jakaranda	OpenFOAM Installation	3	October 27, 2008 12:46

August 14, 2017, 12:08		#5
luca1992 New Member Join Date: Jul 2017 Posts: 28 Rep Power: 9	Hi, thanks very much for the reply, I also asked for help in another forum discussion (both in "fireFOAM: reactions file setup" and in "HRR in fireFoam") and now I do not know what to do. I did not know if anyone answered me since July 30 I had created a post but no one answered me and so I was not very optimistic and so I had written on both posts that had the latest message in 2017, now I could write my question on both of the discussions, but maybe it would be better to unify them, do you know how to do it? Maybe it's better if I publicize my question in my previous post "Simulating fire in a tunnel" so if you can answer me there. Thank you both (Roman1 and ashish.vinayak) let me know if it is all right for you.