A method for the prediction of the atomization diameter distribution of the spray generated by swirl nozzles

Atomization is an indispensable process for achieving high-efficiency conversion in various energy applications. This study proposes a novel and simplified method to predict the droplet diameter distribution along the spray direction during atomization by swirl nozzles. The method considers the droplet breakup and coalescence and consists of three sub-models, i.e., the primary breakup model, the secondary breakup model, and the velocity model. The prediction method is verified by droplet sizing experiments using typical swirl nozzles. Combining the experimental results, the atomization process from fluid to droplets is analyzed in-depth. Results show that the present method can predict the droplet diameter distribution along the spray direction, with an average error of droplet diameter of approximately 7.7%. The effects of the orifice diameter and water supply pressure of nozzles on droplet diameter distribution are discussed. The droplet diameter decreases in the whole spray field as the water supply pressure rises. When the orifice diameter increases, the mass flow rate and Sauter mean diameter increase in the near-orifice region. However, the droplet diameter difference in nozzles reduces as the position is far away from the orifice. The proposed method can aid the design of some critical energy devices containing the atomization process.