Hi, I want to simulate a fluid (liquid) flow with particles in the domain. Which model should I use? Multiphase or discrete phase models. I would appreciate if you can clear my doubts on this.

Thanks, Suresh

It depends on your problem and how many particles are in the flow? Describe your problem a bit more.

I wanted to do a simulation on a gravity driven flow of a single phase fluid without heat or mass tansfer.

I just want to know if it can be done. If so, how to do it? Also I want simulate a particle of 20 microns that flows along with the fluid. Even though the fluid is higly viscous 0.035 kg/m-sec, the particle and fluid do not form a slurry. Hope this answers your question.

Yes your problem can be modelled in Fluent.

It sounds like you should go for the Discrete Phase option.