Analysis by droplet size classes of the liquid flow structure in a pressure swirl hollow cone spray

In this work the structure of a spray resulting from the break-up of a conical liquid sheet was investigated through experimental techniques. The disperse and continuous phase velocities and the size of droplets were measured using a phase Doppler particle analyzer. A data post-processing, applying the generalized integral method, was used to evaluate liquid volume fluxes for different droplet size classes.The spatial distribution of the liquid flow was characterized by the radial mean spread and spatial dispersion parameters. It was found to be mainly influenced by the differences in droplet inertia and by the droplet collision phenomena. A high dispersion of droplet velocity module was measured at the spray densest region predicting high droplet collision rates. As a consequence of the coalescing collisions, a liquid flow rate transfer between size classes was detected as the spray developed. This process favoured the large size classes and caused the progressive increase of the droplet mean diameter.