CAPE Forum

Ansys => Fluent => Topic started by: pitney1 on February 11, 2012, 01:54:52 PM

Title: How to identify cells at the interface for heat and mass transfer in VOF Fluent?
Post by: pitney1 on February 11, 2012, 01:54:52 PM

Hi,

How do I identify the cells at the interface for heat and mass transfer at the interface in VOF model in fluent? Can any one help here?

Thanks.

Title: Re: How to identify cells at the interface for heat and mass transfer in VOF Fluent?
Post by: william on February 11, 2012, 01:57:53 PM

While modeling heterogeneous mass and heat transfer using the VOF model, it is often required to define a mass transfer coefficient only in cells that contain the interface.
For a simple two phase model, it is easy to locate cells on the interface by looking at the phase fraction value. The phase fraction will be either zero or one inside the individual phases but will have intermediate values in cells on interface

Hence, the DEFINE_MASS_TRANSFER udf macro can use a test like the following to locate cells that contain the interface:

vof_cutoff = 0.05;
if ( (C_VOF(c,t) > vof_cutoff ) && (C_VOF(c,t) < (1 - vof_cutoff) )
{ < cell is on the interface> }
else
{ < cell is inside a phase> }

The DEFINE_MASS_TRANSFER macro is described in the UDF Manual:

http://hpce.iitm.ac.in/website/Manuals/Fluent_6.3/fluent6.3/help/html/udf/node57.htm