An Optimum Method of Capturing Interface and a Threshold Weber Number for Inclusion of Surface Tension Force in Simulation of Nozzle Internal Flow in Pressure Swirl Atomizers

Numerical study of internal nozzle flow in simplex atomizer is now well established to represent features of the flow such as turbulence, swirl, and interface between phases. However, an attempt is still needed to introduce an optimum method to capture the interface between liquid and gas with satisfactory level of sharpness. Besides, a detailed study must be dedicated to quantify the influence of surface tension force on evolution of interface shape and flow variables and to determine the necessity of inclusion of this force in molding of this particular type of flow. In the present study RNG K-ε model has been used in Fluent 6.3 to compare performance of four interface schemes and introduce an optimum method in terms of computational effort and grid size requirement. Later, combination of the CSF model, RNG K-ε model and Implicit scheme has been used to introduce a threshold Weber number below which inclusion of surface tension will considerably influence the flow field during intermediate time steps.