I am doing some research about gas diffusion.Is it possible to simulate gas diffusion using fluent?If it can ,are there any difference between diffusion simulation and flow simulation? thank you for help.

Assuming you assume a continuum approach, I'm pretty sure this is possible - in essence you just ensure no convection in the domain and then all changes in concentration will be governed by diffusion. I haven't tried it with zero convection, but with very low values of the velocity inlets, I have (accidently in my case) generated solutions which are diffusion dominated.

Accuracy? not sure.

Greg

thank you very much.Your answer gives me confidence in continuing my research.Because I am a beginner in CFD,espeacially in flunet,I am very glad to have your help. I have another question:which model may I chose in simulation,k-e model or spart-alpla model or big turbo simulation model or some others? How can these model present the charactristic of diffusion? thanks a lot.

These models are for modelling turbulence. If you only want to model diffusion, you should choose a laminar flow, turn on species, define your material/species properties and importantly define you mass diffusivitity (m2/s) - this will determine the rates of diffusion of the various gas species in your domain.

I suggest you do some reading on cfd and fluid mechanics - convection, diffusion and turbulence.

Greg

[Akshaya nachankar]

I m using species transport. But I m beginner for cfd. I m not getting how to model diffusion of gas in closed space