Flow of co2 (gas) into air (gas)
 

I'm performing a 2d simulation of a flow of co2 going out of a nozzle into the air.

I'm not what is the best way to simulate this. Any advice?

What do you want to analyze?
I don´t know how is the model that you want, but I think you can use steaty-state and a multiphase model

You don't need a multiphase model for this, because the 2 components you're looking at can mix. What you need is a species transport model. Enable species transport, select CO2 and air as your fluids, use a velocity boundary condition with the right mass fraction of CO2 for your nozzle (and of course, make sure you have an outlet somewhere), and go for it.

hello..
i am new in fluent, i want to simulate nozzle too..
what kind of boundary and model that i should choose..?

here is my case :
http://4.bp.blogspot.com/-Bz7dJiUTJs...1600/model.jpg

what d you think about my model? is that correct?