Three-phase flow modelling
 

Hi guys,

Can you suggest a good model for simulating air, water and water vapor?
I am pretty sure for the air-water interface as homogeneous free surface without interphase-mass transfer but not quite sure for the air-water vapor (free surface without interphase mass transfer?) and water-water vapor (particle transport or noe? and cavitation). Does any one have a reference paper for this problem or let me know how we setup this multiphase flow with cavitation in CFX?
Thanks

For multiphase models you need to know more about the flow than what you have specified.

You need to know typical volume fractions, what state it is in (foam, distinct, droplets etc) and what size the multiphase blobs are, and what mass transfer is taking place.

Thanks Glen: I am simulating the flow in a turbine: air-water interface is free surface, water-water vapor is free-surface as well as interphase transfer occurs, and air-water vapor: what model (mixture?) works better, I am not sure. :confused::o

A standard free surface model will usually do for this as you only have two phases, liquid and gas. The gas phase might be a multicomponent gas to handle the air and water vapour.

I reread your first post and note you mention cavitation: You are really pushing the limits of what can be modelled here. Cavitation models are generally developed for pure liquids and their vapours and making it a gaseous mixture means the built in models are unlikely to be suitable. This means you will have to develop your own model. This sounds like a major project, so I hope you have lots of time to research this.

Most cavitation applications do not use a free surface approach for cavitation but a eularian multiphase. See the tutorial examples for how to set this up.