[Laexzzz]

I have a problem with chem.reaction modeling in Fluent (laminar Finite-rate model)

Boundary conditions:

Mixture - 3 species

Mass fraction of I0 = 0.001
Mass fraction of R0 = 0
Mass fraction of M = 0.999

Mixture flows into the tube

Reactions:

I0 -> 2R0
M is not involved into reaction.

After calculation, mass fraction of specie I0 become 0, mass fraction of specie R0 become 0.0015, and mass fraction of M become 0.9985 (so, M turns into R0, BUT M should not react and change own mass fraction).

I tried to use stiff solver, but result is the same.

Any ideas?

I can attach files with solution if it's necessary

[Laexzzz]

Also one more problem.

Reaction reaction does not proceed to the end.



But reagent concentration must constantly fall

[macfly]

A numerical solution is not an analytical solution, there is some discrepancy depending on the numerical implementation. You get a discrepancy of 0.05% between the analytical value of Y_M and the numerical value, that's fine with me.

[Laexzzz]

Originally Posted by macfly

A numerical solution is not an analytical solution, there is some discrepancy depending on the numerical implementation. You get a discrepancy of 0.05% between the analytical value of Y_M and the numerical value, that's fine with me.

Thank you for your response.
What can be done to minimize this error?