Fluid flow characteristics inside convergent, divergent and straight open-end pressure swirl atomizer

Abstract

Effects of geometrical parameters on the performance of small-scale open-end pressure swirl atomizers (PSA) have been studied using computational fluid dynamics. The shape of the swirl chamber is the main geometrical feature varied in this work. Flow characteristics in PSA's with positive, negative and zero convergence of the swirl chamber are compared. Results show that, convergent open-end has greatest cone angle in comparison to other atomizers. Divergent open-end pressure swirl atomizer has the thinnest liquid film at the exit of orifice section whilst convergent one has the thickest liquid film. Additionally, the liquid sheet is not uniformly shaped, but rather has a complex shape with footprints of inlet slots. These footprints only vanish for convergent open-end PSA, due to higher Swirl number and angular momentum caused by gradual area reduction. Additionally, it has been shown that, straight open-end PSA has the biggest discharge coefficient value in comparison. Finally, variation of Swirl number and angular versus axial momentum inside different atomizers have been compared.