[dan86]

I have for some time been attempting to model a spray of water into a cylinder of air (air initially stationary) using the coupled DPM model in fluent (version 14).
I'm presently trying to get a converged 2d simulation but am struggling to understand if I am using the correct kind of boundary conditions for my domain.

The 2d domain is a simple 400 x 400 mm box, with 1mm hex mesh. I'm using a pressure outlet BC (12 mm length) in the top right corner. The spray is injected into the lower left corner. Lower edge is 'axis' and all other edges are 'walls' (asymmetric model). Using the 'group' injection with 100 particle streams representing a total flow of 0.028 kg/s. Radius of injection set to 5mm, injected half cone angle equates to 32.5 degrees. Should the point of injection be set to one of the Inlet type BC's to allow for air to flow into the domain or is injecting from the wall O.k? I'm trying to simulate a full cone type nozzle (i.e only water injected, no air).

I have been through tutorials and lots of info that I could find online regarding fluents coupled dpm approach, and from what I can find it seems before particles/droplets are injected into the domain, should already have a converged continuous flow field. The problem that I have is I am starting out with no flow. Should I include a velocity inlet at the same position as my injection, with air velocity equal to velocity of my injected droplets? Running the simulation till its converged before injecting droplets.

The end result that I am interested in, is heat transfer from the sprayed droplets into a target material placed inside of the spray chamber. I began with a 3d simulation, but soon realised the complexity of the coupled model and so I've stepped back to 2d to see if I can get that working first. I'm running the simulation as transient at the moment.

Thank you very much for taking the time to read and please provide any information that you may have to give.

Thank you very much.