APPLICATION OF DIFFUSE BACKGROUND ILLUMINATION FOR STATISTICAL DESCRIPTION OF A TWIN-FLUID SPRAY

Abstract

Diffuse background illumination (DBI) is applied to analyze a cold, nonevaporating spray from a twin-fluid atomizer at typical atmospheric conditions. The DBI technique presented in this work provides liquid probability across the whole field of the spray to quantify liquid dispersal in the radial and axial directions. The spatial resolution is varied in five incremental steps from 25 to 200 µm/px to determine that a finer spatial resolution not only provides a greater fidelity to distinguish phenomenological features of the atomization process but also offers distinct information regarding droplet sparseness quantified by the gap size between droplets. Results from the spatial resolution sweep are analyzed to obtain cumulative probability and histograms of gap sizes at specific pixel locations. The presented analysis offers alternate metrics to characterize twin-fluid atomized sprays for design validation and optimization of combustion performance.