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-   -   mass sink UDF (http://www.cfd-online.com/Forums/fluent/35020-mass-sink-udf.html)

H November 8, 2004 00:00

mass sink UDF
 
I am modeling a diffusion problem 2D axisymmetric geometry. I am using mixture template (CO2, N2, O2) The model is for a cylindrical tank with conical headspace. CO2 gas source terms are at the bottom of the tank. Gravity is OFF in my model. Thus only force is the diffusive force. There are vents at the top of the tank and I want to maintain concentration of CO2, N2, O2 at those vents the same as that found in ambient air. How do I do this in fluent? I guess modeling vents as pressure outlet will not work. I NEED SOME TYPE OF MASS SINK TERMS AT THE VENT BOUNDARIES. I AM THINKING I SHOULD WRITE A UDF TO MAINTAIN CONCENTRATION OF CO2, N2 AND O2 IN VENT BOUNDARY CELLS SAME AS AMBIENT AIR. Will this automatically work as the mass sinks that I am trying to put? What macro should I use to write my UDF?

H November 8, 2004 23:44

Re: mass sink UDF
 
If species transport is ON (Define --> Models --> Species --> Species transport) how do I access mass fraction of a particular gas species in a UDF? For example, in a cell, you get mass fractions for all the species present, but how do I access it in a UDF? plz do let me know as soon as possible.


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