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-   -   Ammonia-liquid modelling. Problem with thermal expansion coefficient. (http://www.cfd-online.com/Forums/fluent/72541-ammonia-liquid-modelling-problem-thermal-expansion-coefficient.html)

zhekka February 9, 2010 16:06

Ammonia-liquid modelling. Problem with thermal expansion coefficient.
 
Good day to all,

I'm beginner in fluent modelling and now encounter with problem:

The task is simple- there is a wall modelling (material- ammonia-liquid) with two sides (right- temperature function from x coordinate, y coordinate and time, initial temperature- 293 K and left- temperature constant 360 K)

The problem is next:

When I set material density I use boussinesq, in this case also should be difined thermal expantion coefficient (which is 0.00245 for liquid ammonia). In this case solution is not converged (laminar or other wiscous model- doesen't matter), however if I reduce this coefficient (0.00245*10^-3= 0.00000245) for the solid values (x*10^-6) all converged perfectly (except common sense:))

Also I tried to use piecewise-linear function (using formula: p(t)=p0(1-b(t-t0) for density in second point but the result was the same)

I will be thankful if someone told me where the problem is.


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