MODELING OF GROUP-HOLE-NOZZLE SPRAYS USING GRID-SIZE-, HOLE-LOCATION-, AND TIME-STEP-INDEPENDENT MODELS

Abstract

A new spray computational fluid dynamics (CFD) model that comprises gas-jet and radius-of-influence collision, mean collision time, and interpolation method improvements was used to reduce grid-size, hole-location, and time-step dependencies in modeling group-hole-nozzle sprays. The spray model was validated against experimental results obtained from spray visualization and phase Doppler particle analyzer systems. The spray characteristics including spray penetration and droplet sizes of group-hole nozzles were also studied. Standard CFD spray models show significant dependencies of grid size, hole location, and time step for the calculated spray penetration of group-hole nozzles. On the other hand, the new spray model reduced the dependencies successfully for the present nonevaporating spray cases. The calculated results agreed well with the experimental results in terms of both spray penetration and SMD distributions. It was found that the sprays of the group-hole nozzle exhibit similar spray penetrations to those of a single-hole nozzle with the same overall hole area. The computations indicate that the group-hole nozzle has advantages in the near field for reducing spray droplet sizes.