Hi,

I have a problem with modelisation of gaseous diffusion in CFX. In fact I would like to model the diffusion of CH4 in a vertical convergent pipe (it is like a cone without its top). At t=0, there is no ch4 in the volume. But the basis is at a constant concentration c0. And it should diffuse in the volume. I don t know how to input this in cfx (i m a beginner). I tried with a mass flow inlet, but that is not what I want.

Please, can someone help me?

Hi Aboulard. can you please give more details of the problem. I don't understand in what phase methane is diffusing and whether it is mere molecular diffusion or convective diffusion also.

Sameer

Hi Sameer

Sorry for lack of information.

It is molecular diffusion of gaseous methane in air. No convection.

Aboulard

Dear Aboulard, From the details you have given, I would suggest you to use a single domain(with single phase i.e. air) with additional variable for CH4. In domain definition you give molecular diffusivity and use source point for CH4 at desired location in domain. I hope this will work.

Sameer