diffusion convection issues
Hi, I want to simulate the concentration variation of nano-particle in a micro-fluid channel under magnetic field, and to show nano-particle will build up in the region near the magnet. I have built a...
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I am not 100% sure, but one thing crossed my mind: In the Transport of Diluted Species node, you have User defined velocity field, and there an expression...
View ArticleRe: diffusion convection issues
Hi Lasse， Thanks for your reply. When I change u to spf.u, the expression will become yellow. I figure the spf.u would not be suitable. If I set u and v as 0 in the expression, the result will be...
View ArticleRe: diffusion convection issues
Is 'diluted species' appropriate if you want such high concentrations?
View ArticleRe: diffusion convection issues
I think you can use it. Transport of Concentrated Species node is meant for, e.g. mixtures of solvents where the mass fraction of one species is > 0.1.
View ArticleRe: diffusion convection issues
I am not sure. But if not, does comsol have other module which is appropriate for this issue?
View ArticleRe: diffusion convection issues
Transport of concentrated species is - in my opinion - the best approach, but the Stefan-Maxwell formalism on which it is based contains so many unknown parameters that it is rather difficult to apply.
View ArticleRe: diffusion convection issues
Thank you. Recently, I have read some papers, which mention the false-diffusion errors among the numerical approximations. Is that the point of my problem?
View ArticleRe: diffusion convection issues
Well, is the transport of nanoparticles diffusion in the first place? Diffusion is basicly Brownian motion. But you can estimate the values of the diffusion coefficient with the Stokes-Einstein...
View ArticleRe: diffusion convection issues
Thank you. I know this Stokes-Einstein equation and have used it in the modeling. But it not my issue. I think numerical false-diffusion error should be one reason why the result is not as good as...
View ArticleRe: diffusion convection issues
Hi Yilong, I was curious about this model so I ran it with a minor modification to link Study 1 and Study 2 and I get a peak concentration of 0.46, not 0.08. Is that what you expect? Nagi Elabbasi...
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Hi Nagi, Sorry for such late reply. I just saw your reply. That is what we expect. Could you tell me which minor modification you did to the modeling? Thanks for your help. Regards, Yilong
View ArticleRe: diffusion convection issues
Hi Yilong, I believe I just set the “Values of variables not solved for” setting for Study 2 to point to the solution of Study 1. Otherwise you are not using the flow and magnetic field results in your...
View Articlediffusion convection issues
Hi, I want to simulate the concentration variation of nano-particle in a micro-fluid channel under magnetic field, and to show nano-particle will build up in the region near the magnet. I have built a...
View ArticleRe: diffusion convection issues
I am not 100% sure, but one thing crossed my mind: In the Transport of Diluted Species node, you have User defined velocity field, and there an expression...
View ArticleRe: diffusion convection issues
Hi Lasse， Thanks for your reply. When I change u to spf.u, the expression will become yellow. I figure the spf.u would not be suitable. If I set u and v as 0 in the expression, the result will be...
View ArticleRe: diffusion convection issues
Is 'diluted species' appropriate if you want such high concentrations?
View ArticleRe: diffusion convection issues
I think you can use it. Transport of Concentrated Species node is meant for, e.g. mixtures of solvents where the mass fraction of one species is > 0.1.
View ArticleRe: diffusion convection issues
I am not sure. But if not, does comsol have other module which is appropriate for this issue?
View ArticleRe: diffusion convection issues
Transport of concentrated species is - in my opinion - the best approach, but the Stefan-Maxwell formalism on which it is based contains so many unknown parameters that it is rather difficult to apply.
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