CFD – Modeling nozzle spray distribution
Posted on May 10, 2022 Computational Fluid Dynamics
Liquid sprays are widely employed when a large surface area is required for interfacial interaction. The shape of the spray can vary based on the nozzle design and is chosen based on the application. Among the popular shapes are straight, full cone, hollow cone, and fan. While in some cases the shape of the spray can be easily inferred based on the nozzle geometry and flow features, e.g., swirl, in others—the spray distribution is less intuitive.
Computational fluid dynamics (CFD) modeling can help us understand the spray distribution by simulating physical phenomena taking place inside and outside the nozzle. As an example, a fairly simple convergent-divergent effervescent nozzle produces a combination of a full cone and a hollow cone distribution shown in the figure. The modeling results were validated by the experiments that confirmed model findings at different process conditions.
The likely reason for the presented spray structure is related to the air entrainment into the spray core area. Smaller droplets generated on the outer portion of the spray are being dragged back into the centre.