Spray visualization and characterization of a multi-jet cross-stream airblast injector

The objective of the present study is to visualize and characterize the spray in model multi-jet crossflow airblast atomizers using Laser sheet imaging (LSI) and Phase Doppler Particle Analyzer (PDPA) techniques. The atomizers allow lateral injection of multiple liquid jets into swirling crossflow of air. Two different atomizers with injection of six jets and two jets are considered. The instantaneous spray images were captured in vertical and horizontal planes using LSI. This was helpful to visualize the spray structure and distribution of droplets not only along the spray axis but also across the spray in the cross-stream direction. The variation in the spray cone angle for a wide range of operating conditions is reported. Comparison of the spray structure between multi-jet and twin-jet atomizers highlighted interaction of adjacent spray plumes. The size and three-component velocity measurements of the spray droplets at different radial and axial locations by application of the PDPA technique are reported for the twin-jet atomizer. The mean droplet size and mean components of droplet velocity are observed to first increase and then decrease significantly along with axial direction downstream of the atomizer.