Discharge Characteristics of Canonical Sprinkler Sprays

Abstract

Detailed characterization of spray behavior and its relationship to nozzle geometry, fluid properties, and injection characteristics is needed to advance water-based suppression technology and fire related computational fluid dynamics (CFD) tools. In this study, a series of experiments have been conducted to measure discharge characteristics of sprays produced by basic injector configurations modeled after conventional pendant sprinklers. Liquid jets of various sizes were injected downwards onto flat deflectors, tined deflectors, and boss-modified tined deflectors to establish the three canonical configurations explored in this study. Spray measurements including the initial angle of the sheet at the deflector exit, the sheet breakup radius, the drop size distribution 1 m below the deflector surface, and the volume density distribution were performed for these configurations. These systematic experiments provide discharge characteristics of practical interest while providing valuable data for CFD based atomization model development.