Has this been done before?
Instead of using compressed air to transfer momentum to a liquid as in paint sprayers or some industrial humidification misters, why not use steam?
Superheat the steam enough so that it will be just saturated as it mixes with the liquid. If the steam - liquid mixture was further expanded in a nozzle some of the sat. steam would turn into liquid droplets as well, depending on the sensible heat of the liquid.
It might create a neat splatter effect applying some paints.
Even more important are those situations where you don't want a lot of air mixing with the liquid.
Bret Cahill