Simuating the diffusion of 2 gases

[Anonymous]

Hi,

I'm trying to simulate the diffusion of 2 gases (gas 1 and gas 2). The system I'm trying to simulate is the flow of gas through a system with 1 inlet and 1 outlet. Initially the gas in the system is gas 1, gas 2 then flows into the system from the inlet and mixes with gas 1. Can I get some tips on how to simulate this as I have no experience doing transient analysis. Also how would I use mesh adaptation with a transient analysis, is it any different to using with a steady state analysis?

I have attached my attempt at this simulation to the post. My plan was to do an initial simulation for 20 time steps then use mesh adaptation to simulate the first 5s. Am I on the right lines with my attempt?

Thanks,

Joe

[Anonymous]

You will need to use the scalar transport option to simulate the 2 gases.  You cannot directly model 2 different fluids touching each other.

The mesh adaptation option does not work for transient analyses.

[Anonymous]

How can I do that?

Thanks,
Joe

[Anonymous]

Go to the online help for CFD and search for "scalar mixing".

[marwan_azzam]

Hello,

You would want the scalar boundary condition at the inlet, and not outlet (i.e. where you have the flow rate not the zero pressure).

There would only be one fluid and the density will be a function of scalar.

Please watch the following webinar:

https://www.youtube.com/watch?v=nlr8CHQhigs

Marwan