Hi again Nikhil,
I just realized I did not address your full question. My multiphase model will include a liquid and a gas phase. There may be more phases down the road, but I need to get the two-phase models going first. I was thinking of applying population balance methods ( QMOM, inparticular) to model the gas phase. While buidling the model, I discovered that the population balance models are not compatable with LES (which makes sense). Therefore, I was moving towards making use of DPM to incorporate the gas bubbles in the model if I use LES or DES as you mentioned.