Two-component swirling jet atomization with static vortex generators

We present a numerical study of geometry modification inside a swirl nozzle and its effect on characteristics of a two-component spray of immiscible liquids. Water and kerosene are separately supplied into the swirl nozzle through two channels, each with a flow rate of 1 ml/s. The discharge from the nozzle occurs through a central circular orifice with a diameter of 800 μm. The Reynolds numbers for water and kerosene are 3200 and 1350, respectively. The nozzle is modified by adding static cylindrical obstacles inside the inlet channels to improve mixing. It was found that the presence of obstacles does not significantly increase the pressure at the nozzle inlet but changes the process of jet breakup. Without the obstacles, the jet breakup begins at a noticeable distance from the nozzle outlet. Water and kerosene jets remain separated accompanied by the formation of a few large droplets. Adding obstacles induces vortex shedding inside the nozzle, enhancing the interaction between immiscible flow components and promoting earlier jet atomization. The swirling rate of the jet is higher for the modified nozzle. Jet separation is reduced, and the mean droplet size is decreased. The results obtained can be useful for optimizing the design of nozzles and improving the spray characteristics.