DROP FORMATION MECHANISMS AND SIZE DISTRIBUTIONS FOR SPRAY PLATE NOZZLES

This article describes the results of an experimental investigation of drop formation mechanisms and drop diameter distributions for spray p late nozzles. Spray plate nozzles are comprised of a distribution nozz le which projects a high velocity jet Of water concentric on a plate. The resultant water film flows radially outward on the plate and break s into drops after the liquid detaches from the plate and flows outwar d as a sheet. The drop size distribution is determined by a balance be tween shear forces with air and how instabilities and turbulence in th e liquid sheet flow, which tend to fracture the liquid sheet and drops , and surface tension forces, which tend to hold the liquid sheet and drops together. Experimental results include short duration photograph s of nozzle jet flow, liquid film flow, and of water drop formation. D rop diameter distributions were obtained with a phase Doppler particle analyzer (PDPA). The variations of drop mean diameter, volumetric mea n and Sauter mean diameters as functions of pressure, distribution noz zle-to-plate distance, and plate diameter are quantified. Copyright (C ) 1996 Elsevier Science Ltd.