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identity pairs / maping operators

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hallo to all,

im simulating a sold body in a gas stream. the solid (diffusion) and the gas (convection and diffusion) are in interaction. they are onnected via an identity boundary pair.
the solid has an initial concentration c and the gas c2 of the same species. the concentration of the surface of the solid (=boundary between gas and solid) is directly influenced by the concentration c2 in the gas.
how can i use the concentration c2 from the gas as a variable to calculate the surface concentreation of the solid?
i tryed to work with maping operators (src2dst_ip1(c2)) but without succes.
can anybody help my?
thanks

matthias

2 Replies Last Post 06.07.2009, 05:44 GMT-4

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Posted: 1 decade ago 06.07.2009, 03:36 GMT-4
If I understand your problem right, you are making it more complicated than needed. Identity couplings variables are not necessary. When you say "influenced" I am guessing that you have a phase partition equilibrium law. Have a look at this model to see how it's done:
www.comsol.com/showroom/gallery/258.php

Niklas

hallo to all,

im simulating a sold body in a gas stream. the solid (diffusion) and the gas (convection and diffusion) are in interaction. they are onnected via an identity boundary pair.
the solid has an initial concentration c and the gas c2 of the same species. the concentration of the surface of the solid (=boundary between gas and solid) is directly influenced by the concentration c2 in the gas.
how can i use the concentration c2 from the gas as a variable to calculate the surface concentreation of the solid?
i tryed to work with maping operators (src2dst_ip1(c2)) but without succes.
can anybody help my?
thanks

matthias


If I understand your problem right, you are making it more complicated than needed. Identity couplings variables are not necessary. When you say "influenced" I am guessing that you have a phase partition equilibrium law. Have a look at this model to see how it's done: http://www.comsol.com/showroom/gallery/258.php Niklas [QUOTE] hallo to all, im simulating a sold body in a gas stream. the solid (diffusion) and the gas (convection and diffusion) are in interaction. they are onnected via an identity boundary pair. the solid has an initial concentration c and the gas c2 of the same species. the concentration of the surface of the solid (=boundary between gas and solid) is directly influenced by the concentration c2 in the gas. how can i use the concentration c2 from the gas as a variable to calculate the surface concentreation of the solid? i tryed to work with maping operators (src2dst_ip1(c2)) but without succes. can anybody help my? thanks matthias [/QUOTE]

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Posted: 1 decade ago 06.07.2009, 05:44 GMT-4
hallo and thanks
The model you want me to have a look at, I know. The transport over a membrane is defined using the stiff-spring model. I am afraid this will not work in my case.

The concentration of the solid is depending on temperature AND concentration in the gas. So, there is a diffusive transport of the species from the centre of the solid to the surface and finally into the gas. This occurs until a defined equilibrium is reached.

My idea is to define a boundary condition at the surface of the solid that is defined by the concentration in the gas and the temperature.

The flux in to the gas must be calculated from the quantity of loss of concentration in the solid … somehow or other ….
hallo and thanks The model you want me to have a look at, I know. The transport over a membrane is defined using the stiff-spring model. I am afraid this will not work in my case. The concentration of the solid is depending on temperature AND concentration in the gas. So, there is a diffusive transport of the species from the centre of the solid to the surface and finally into the gas. This occurs until a defined equilibrium is reached. My idea is to define a boundary condition at the surface of the solid that is defined by the concentration in the gas and the temperature. The flux in to the gas must be calculated from the quantity of loss of concentration in the solid … somehow or other ….

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