An experimental and theoretical investigation of spray characteristics of impinging jets in impact wave regime

TL;DR

This study combines experimental measurements and theoretical analysis to improve the understanding of drop size and velocity in impinging jet atomization within the impact wave regime, highlighting the importance of jet velocity profiles.

Contribution

It introduces analytical expressions considering jet velocity profiles and demonstrates improved prediction accuracy for drop characteristics in the impact wave regime.

Findings

Parabolic and 1/7th power law turbulent profiles yield better predictions.

Jet velocity profile significantly affects drop diameter and velocity predictions.

Experimental data aligns closely with models using turbulent velocity profiles.

Abstract

The current study focuses on experimentally and theoretically improving the characterization of the drop size and drop velocity for like-on-like doublet impinging jets. The experimental measurements were made using phase Doppler anemometry (PDA) at jet Weber numbers We j corresponding to the impact wave regime of impinging jet atomization. A more suitable dynamic range was used for PDA measurements compared to the literature, resulting in more accurate experimental measurements for drop diameters and velocities. There is some disagreement in the literature regarding the ability of linear stability analysis to accurately predict drop diameters in the impact wave regime. This work seeks to provide some clarity. It was discovered that the assumed uniform jet velocity profile was a contributing factor for deviation between diameter predictions based on models in the literature and experimental measurements. Analytical expressions that depend on parameters based on the assumed jet velocity profile are presented in this work. Predictions based on the parabolic and 1/7th power law turbulent profiles were considered and show better agreement with the experimental measurements compared to predictions based on the previous models. Experimental mean drop velocity measurements were compared with predictions from a force balance analysis, and it was observed that the assumed jet velocity profile also influences the predicted velocities, with the turbulent profile agreeing best with the experimental mean velocity. It is concluded that the assumed jet velocity profile has a predominant effect on drop diameter and velocity predictions.