Learning Forum

[James]

Hello everyone!

I am trying to write a UDF for adsorption in the porous media and I have a few questions.

1. This may be a stupid question but when fluent solves the transport equation in the porous media, what scalar does it choose? I mean, when I turn on the porous media option in the cell zone condition, does it automatically choose a scalar to solve for (Perhaps mass fraction)?
2. Below is the equation I am using to model adsorption:

Where C is the concentration, epsilon is the porosity and q is the amount of adsorbate adsorbed. Is there a way for me to use concentration in place of mass fraction? I am aware that I can just add an expression that converts concentration into mass fraction but if I created a UDS, it would not be associated to the adsorbate properties, right?

3. And finally, in the above equation, dq/dt can be given using k1(qe - qt) where k1 is a constant, qe is the amount of adsorbate adsorbed at equilibrium and qt is the amount of adsorbate adsorbed at time t. Does anyone know how I could predict the values of qt given k1 and qe?

Any help would be appreciated! Thank you

 

[Federico Alzamora Previtali]

Hello James, 

our models are documented in our User Manuals and Theory Guides. You may find answers to your questions of the treatment of governing equations for Porous Regions here 7.2.3 Porous Media Conditions (ansys.com)