Thank you Rob, for your comment.nYes, I am using DPM for the discrete phase. nMay I know the reason for your suggestion on using a mixture for the gas phase?nThe injection from the nozzle is a mixture of drug+ethanol+water. The water+ethanol can evaporate once the nozzle is actuated.nAir is already present inside the tube as I have defined it as an open channel. nBased on the above conditions, would you advice me to go with a combination of DPM+Eulerian or DPM+VOF.n