Oxygen concentration control

[HunterXHunter1997]

Hello all,
I want to decrease the Oxygen concentration in the fluid domain and see the impact on a Heptane pool fire.
Is that possible in Fds/Pyrosim?

[mcgratta]

Y_O2_INFTY

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[HunterXHunter1997]

Hello Kevin, I am not familiar with FDS coding can you please explain more? I am using Pyrosim for my simulations.
BR

[mcgratta]

I am not too familiar with PyroSim. What you need to know is that PyroSim writes a text file with the suffix .fds. This file is read by FDS. You should add Y_O2_INFTY=X to the MISC line in the `.fds file.

[HunterXHunter1997]

Ok I will try it, Thanks!

[HunterXHunter1997]

Hello again,
is there any way to make the Oxygen concentration change during the time?
for example, I want the mass fraction to look like this:
(0-30)sec - 0.23Kg/Kg
(30-60)sec- 0.17Kg/Kg
(60-100)sec- 0.14Kg/Kg
So it is a function of time.
Is that possible in fds?

[mcgratta]

You would have to flush the domain with air that has its oxygen content gradually reduce. Create a SURF with MASS_FLUX's of N2 and O2 such that the O2 concentration decreases and N2 increases.