Experimental and numerical study of a water spray in the wake of an axisymmetric bluff body

Abstract

An experimental and numerical study was made of a water spray issuing into a recirculating flow behind a bluff body disk mounted in a nozzle. A two-component laser-Doppler/phase-Doppler anomometry system was used to characterize the mean and turbulent dispersed phase. The numerical prediction of the hollow-cone spray was based on an Eulerian-Lagrangian stochastic hybrid model. The continuous gas flow field was predicted using a differential Reynolds stress transport model whereas the particulate droplet flow field was predicted using an improved Lagrangian stochastic dispersion model. Comparison of numerical predictions and experimental measurements was carried out for droplet mean and fluctuating velocities, number mean diameters, and mass fluxes. Results indicate that the droplet dispersion characteristics are strongly influenced by the presence of flow recirculation due to different particle Stokes numbers, yielding recirculation or penetration of particles through the separated flow region. Predictions of droplet axial and radial rms velocities obtained with the Lagrangian stochastic model are less satisfactory than those of other simple gas spray flows.