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How to apply solid species transport in Comsol?

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When using Transport of Diluted Species in Porous Media (tds), the general equation can be:

where is diffusion and is convection or advection.

Now I want a solid species that works in the sediment itself :

where is biodiffusion/ bioturbation and is sedimentation or burial.

Is it simply making another tds physics where the porosity there is ?

Any other suggestions?

Many thanks,

Yaniv


2 Replies Last Post 2019年6月19日 GMT-4 10:30

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Posted: 5 years ago 2019年6月18日 GMT-4 07:16
Updated: 5 years ago 2019年6月18日 GMT-4 07:38

I think I worked a way around the issue:

My way around was to make another Transport of Diluted Species (tds):

where , is the density of the solid and is its molar weight, both are constant. so I am really solving for porosity change in time and depth.

Does anyone know another solution?

Regards

I think I worked a way around the issue: My way around was to make another Transport of Diluted Species (tds): \frac{\partial c_i}{\partial t} -\nabla\cdot(D_i\nabla c_i)+ u\cdot\nabla c_i=R_i where c_i [\frac{mol}{m^3}] = (1-\phi)\frac{\rho_s [\frac{kg}{m^3}]}{M_w [\frac{kg}{mol}]} , \rho_s is the density of the solid and M_w is its molar weight, both are constant. so I am really solving for porosity change in time and depth. Does anyone know another solution? Regards

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Posted: 5 years ago 2019年6月19日 GMT-4 10:30
Updated: 5 years ago 2019年6月19日 GMT-4 10:30

Hi Yaniv,

Why exactly are you not satisfied with your first solution (new tds entry with porosity ). It seems to be the most intuitive way and I don't see a reason to expect any particular problem with it.

Hi Yaniv, Why exactly are you not satisfied with your first solution (new tds entry with porosity 1 - \phi). It seems to be the most intuitive way and I don't see a reason to expect any particular problem with it.

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