modelling air entrainment in icem
 

Hey guys

I have just started out using ICEM and Fluent for my current project which is doing the flow and heat transfer analysis of the producer gas flow in the mixing tube of a gasifier and hence, have to model primary air entrainment at the nozzle exit boundary and the entry of mixing tube. I have started with a 2D axisymmetric model. I would like to know how to model/define an extended area outside the sketch of the nozzle and the mixing tube walls with atmospheric conditions so as to model air entrainment. also, what should be its boundary definition in fluent?

I have attached the basic outline of the model.

http://www.dropbox.com/s/sf7x0f3e4seiw0l/Untitled.jpg

https://www.dropbox.com/s/sf7x0f3e4seiw0l/Untitled.jpg