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Transport of dilute species module
Posted 18 feb 2015, 21:23 GMT-5 3 Replies
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Respected Sir,
I want to know how a group of bulk reactions and a group of surface reactions can be written.I am hereby attaching the file.
I will be greatly indebted if any one can help me.
Thank you
I want to know how a group of bulk reactions and a group of surface reactions can be written.I am hereby attaching the file.
I will be greatly indebted if any one can help me.
Thank you
Attachments:
3 Replies Last Post 19 feb 2015, 02:33 GMT-5
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Posted:
9 years ago
Hi
Bulk reactions make reaction terms in the transport equation, i.e. Fick's law. Thus, add 5 reactions in your Transport of Diluted Species node.
Surface reactions make Flux boundary conditions; thus 5 Flux BCs.
I have been struggling with equilibrium reactions in numerical calculus and found it almost impossible. My solution is today to write kinetic equations for reactions and give arbitrary but very high values for the rate constants, so that the ratio of forward and backward rate constant is equal to the equilibrium constant. For example
kf = 10^8 and kb =kf/K where K is the equilibrium constant (all with proper units, naturally).
br
Lasse
Bulk reactions make reaction terms in the transport equation, i.e. Fick's law. Thus, add 5 reactions in your Transport of Diluted Species node.
Surface reactions make Flux boundary conditions; thus 5 Flux BCs.
I have been struggling with equilibrium reactions in numerical calculus and found it almost impossible. My solution is today to write kinetic equations for reactions and give arbitrary but very high values for the rate constants, so that the ratio of forward and backward rate constant is equal to the equilibrium constant. For example
kf = 10^8 and kb =kf/K where K is the equilibrium constant (all with proper units, naturally).
br
Lasse
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Posted:
9 years ago
Thanx a lot sir.I will definitely try it.
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Posted:
9 years ago
One question: Do the species adsorb on the surface before/after reaction? That would complicate things a lot, i.e. the adsorption kinetics should also be taken into account. In the surface reactions, silicon surface is involved, and if there is adsorption, it must be taken into account via the fraction of free surface. If there is no adsorption Si does not need to appear in the equations at all, because the activity of pure solid substance is 1 by definition.
Lasse
Lasse