Numerical simulation of nonswirling and swirling annular liquid jets

A numerical simulation method is described for analyzing the fluid dynamics of nonswirling and swirling annular liquid jets. In the present theoretical study, a general mathematics model for simulating these two types of annular film jets has been established using a curvilinear coordinate system conforming to the film boundaries. The study involves the derivation of governing equations, numerical solutions for annular film flow structure of both nonswirling and swirling cases, and model validation with available measurements. The solutions of flow structure consist of jet velocity, film thickness, and jet trajectory. The present model can predict the transition phenomenon of jet-shape formation from nonswirling bell to swirling hollow cone. In verification studies, first the model is validated against other measurements and analyses of nonswirling bell-like jets. The second case includes a validation study on spray angle of swirling conical sprays and a comparison of fuel spray configuration of a pressure atomizer. The assessment results are encouraging and indicate a good capability of the current model.