[Jakubano]

Hey everyone!

I'm trying to learn how to simulate the pyrolysis process (no O2).

I've created a mechanism at 1500K, 1atm using RMG (Reaction Mechanism Generator, MIT), and then reduced it using chemkin.

I tried to simulate the process in fluent using species transport, importing name_gas.inp file as kinetics input (attached), and thermo.db as thermodynamic database.

3D model is a 250ml cylinder, with up and down faces as inlet and outlet.

Energy- ON
Viscous model- LES (tried k-epsilon too- floating point exception)
Turbulence model- Eddy-Dissipation
Inlet and outlet temperature- 1500K
Wall temperature- 1500K
Inlet species- either 100% ethanol, or 0.01 mass fraction for each species (doesn't make a difference)
I run 500 iterations, at 0.01s step size.

Now what happens is really interesting. A plane across the reactor shows that Ethanol FULLY decomposes into THE LAST SPECIE defined in imported materials (doesn't matter the specie, based on which specie is last in imported file- eg. c2h3o, or c#c)

Chemkin post process shows a much nicer plot of time-mole fractions (attached).

Now, im super new to ANSYS, so im not quite sure if i went through chemkin process right, but the .inp file seems to be fine.

I'm not sure what to do, as i tried a lot of things like running the simulation in larger tank, or playing with temperature etc.

Please help me to understand what am i doing wrong, as i cant seem to find a reason.

[Jakubano]

Using chemkin thermodnamic database fixed the problem.