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-   -   How can define different diffusion coefficients (http://www.cfd-online.com/Forums/cfx/75294-how-can-define-different-diffusion-coefficients.html)

FrankW April 21, 2010 09:24

How can define different diffusion coefficients
 
Hi,

i will solve a fluidsystem (Water) with an porous domain. To simulate Oxygen transport in this system i use an Additional Variable. My problem is i can't define different diffusion coefficients in different domains. If i change in one domain the diffusion coeff. than is this cofficient in the other domain the same. What do i wrong or is't such possible.

best regards
Frank

gypas July 31, 2010 09:43

Don't know if you solved your problem yet there is a way of disabling constant physics in domains, actually there are a couple of threads describing how
http://www.cfd-online.com/Forums/cfx...s-cfx-pre.html
http://www.cfd-online.com/Forums/cfx...nt-domain.html
However, when I used this method the solver was very unstable and did not get accurate solutions.
Depending on the problem you are trying to model, you might be better off by assigning different fluids, values to different domains setting user parameters
for instance
domain 1 = domain1
domain 2 = domain2
fluid name1 = Water
fluid name2 = Vapor
but have not tried that myself
i only used user parameters in single flow simulation
I will be going back to multiphase domains later this year (beginning of November to be exact) and will discuss it in length with my support.
If by then you haven't sort it things out you are more than welcome to email me and I will give you further details.


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