Study on dual-nozzle jet flows for the application of liquid atomization

The liquid atomization through a gas-phase jet flow has various applications of coating, cooling, and material processing. Most studies used a single-stage nozzle, but multi-stage configuration is considered to overcome its limitations. In this study, we experimentally study jet flows through two annular nozzles (upper and lower). To optimize the jet flow, we vary parameters like the pressure of each nozzle, the angle of the lower nozzle, distance between upper and lower nozzles, and so on. For each configuration, the single-phase gas jet flow is measured with PIV quantified focusing on the size of backflow region, turbulent intensity, and the streamwise momentum. It is found that the turbulence intensity and streamwise momentum increase downstream area as the lower nozzle angle increases, and the higher upper nozzle pressure is required to suppress the back flow. To support our understanding, we do preliminary tests of water (and glycerin) atomization and measure the size distribution of atomized droplets. Finally, we try to propose a model for predicting the size of atomized particles according to dual-nozzle configurations.