boundary conditions simultating a "free" spray

mathias

Hi, I want to simulate a water spray hitting a hot plate. Points of interest will be heat transfer and droplet diameters, therefore I use DPM and the built-in injection model ... and hope, that Fluent will do that right.

In the past I´ve only dealt with internal flow problems, but this setup is more or less "free", cause I have only the plate and the "virtual nozzle" in the room and no solid walls.

So I got to the question what type of boundary condition I should choose for the "free" boundarys. At the moment I´m using "pressure outlets" with moderate setting for backflow, but is this the best solution ?? The reversed flow warnings are a bit bugging . Thanks!