Phase doppler particle analyser (PDPA) characterization and modeling of sprays from orthogonally interacting water and air jets

Atomization of a jet in air cross flow has numerous applications in industrial and natural systems. In this study, spray characteristics (i.e., droplet mean diameter, Sauter mean diameter, and volume flux distribution) generated from perpendicularly interacting air jet of 7.5-mm diameter and water jet of 0.8-mm diameter are characterized using a phase Doppler particle analyzer (PDPA) in a forward scattering mode. The investigation is done for seven momentum ratios (q), where the momentum ratios are varied by varying the jet flow rate while keeping air flow rate constant. The jet Weber number is calculated to be 42.56, which is constant for all the cases and falls under the multimode breakup regime. PDPA measurements are done at different spatial locations, 40 mm below the tip of the injector to avoid ligaments and to ensure stable droplets. From the experimental results, it is found that for all flow conditions, volume flux is maximum near the geometric center of the spray and decreases towards the edges indicating the solid cone structure of the spray. The volume flux also increases with increase in q. The maximum of mean droplet diameter (D10) and Sauter mean diameter (SMD or D32) is found at the geometric center of the spray in the x direction, whereas in the y direction the maximum D10 and D32 are shifted towards the windward side of the jet. The diameter–velocity correlation is negative at the center of the spray and positive at the edges for both x and y directions. The correlation model for volume flux is found to be in accordance with the experimental data, while a few outliers are found in the diameter model due to the presence of large droplets that skew the data.