Comparative analysis of drop-size measurement in highly dense sprays using shadowgraphy, PDA, and SLIPI

Atomization is a physical phenomenon that is widely encountered in many engineering and industrial applications, such as in combustion engines, spray coating, spray dryers and many more. Spray characterization involves the determination of the droplet size and velocity distributions (both probability density function and spatial). To determine these parameters experimentally, traditionally, microscopic shadowgraphy and Phase Doppler Anemometry (PDA) are used, because of their relative ease of use and high accuracy. However, the application of these techniques is limited to relatively less dense sprays. In highly dense sprays, the strong multiple scattering effects cause significant errors in the determination of relevant parameters. Therefore, the Structured Laser Illumination Planar Imaging (SLIPI) technique is adopted. In this work, comparative measurements are reported to assess the capabilities of these techniques for drop-size measurements in a highly dense spray originating from a pressure swirl nozzle.