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Reactive transport of two species
Posted Feb 5, 2014, 11:14 a.m. EST 3 Replies
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Hi,
I have two streams of water flow into the same conduit under laminar conditions where they mix by diffusion. Flow is from left to right and compound A enters at the top half, whereas B enters along the bottom half of the left side. Compounds mix and form compound C by a reversible reaction, which is described below. A and B are dissolved, so their diffusion constant is 1E-9 m2/s, but C precipitates as a solid with a diffusion constant of 1E-12 m2/s.
I have defined the forward and reverse rates,concentration and reaction in the variable section.
But I think my product C is not precipitating as a solid. Can anyone guide me as to what I have done wrong?
Attached is my model
I have two streams of water flow into the same conduit under laminar conditions where they mix by diffusion. Flow is from left to right and compound A enters at the top half, whereas B enters along the bottom half of the left side. Compounds mix and form compound C by a reversible reaction, which is described below. A and B are dissolved, so their diffusion constant is 1E-9 m2/s, but C precipitates as a solid with a diffusion constant of 1E-12 m2/s.
I have defined the forward and reverse rates,concentration and reaction in the variable section.
But I think my product C is not precipitating as a solid. Can anyone guide me as to what I have done wrong?
Attached is my model
Attachments:
3 Replies Last Post Feb 11, 2014, 10:27 a.m. EST
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Posted:
1 decade ago
Hi,
Anyone. Please help. Why is my precipitate which is solid not settling at the bottom of the pipe. I have added gravity to the laminar flow model by modifying the outlet pressure BC and adding volume force.
I have been stuck with this from past 1 month. Any suggestions/pointers will be very much appreciated.
Attached is my model.
Anyone. Please help. Why is my precipitate which is solid not settling at the bottom of the pipe. I have added gravity to the laminar flow model by modifying the outlet pressure BC and adding volume force.
I have been stuck with this from past 1 month. Any suggestions/pointers will be very much appreciated.
Attached is my model.
Attachments:
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Posted:
1 decade ago
Romani:
The way you have set up the problem, you will not be able to get solid C to precipitate at the bottom. You are solving a single phase problem where both your reactants (A & B) are in the liquid phase and the product (C) is also in the liquid phase. What you need is a system of equations which solves for the reactants in the liquid phase, just the way you have already described, but the product will have to be converted to a solid depending on its solubility in water or whatever liquid phase you need. I have not solved such a problem before so I cannot give you guidance on how to solve it, but I would start with a 2-phase flow interface with solid + liquid phases. I hope this helps.
Good Luck,
Sri.
The way you have set up the problem, you will not be able to get solid C to precipitate at the bottom. You are solving a single phase problem where both your reactants (A & B) are in the liquid phase and the product (C) is also in the liquid phase. What you need is a system of equations which solves for the reactants in the liquid phase, just the way you have already described, but the product will have to be converted to a solid depending on its solubility in water or whatever liquid phase you need. I have not solved such a problem before so I cannot give you guidance on how to solve it, but I would start with a 2-phase flow interface with solid + liquid phases. I hope this helps.
Good Luck,
Sri.
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Posted:
1 decade ago
HI Sri,
Thank you so much for replying..
Romani
Thank you so much for replying..
Romani