i am working on atomizer and spray. i dont know how to model spray in CFX. plz reply me soon my project is stoped

In CFX, you have two ways to model a spray : either a lagrangian approach (particle tracking) or an eulerian approach (multi-fluid). Without any other information I advice you to set up a lagrangian simulation for your spray. Activating a lagrangian simulation is quite easy : check the box "Particle Tracking" in the Default Domain Panel. Then you have to select the dispersed fluid and the physical models for each phase. For more insight just look at the CFX Modelling Guide (p. 203 and following)