Numerical Analysis of Two-Phase Flow Using 2-D Axi-Symmetric Approach for an Effervescent Atomizer

Effervescent atomization is a type of twin-fluid atomization in which a small amount of gas is bubbled into the liquid before it is ejected from the atomizer. The technique of directly bubbling gas into the liquid stream inside the atomizer body differs significantly from other methods of twin-fluid atomization (either internal or external mixing) and results in significant performance improvements in terms of smaller drop sizes and even relatively lower injection pressures. The internal two-phase flow behaviour inside the injector will significantly affect the downstream spray characteristics. The current study involves the numerical investigation of two-phase flow behaviour inside an effervescent atomizer using a 2-D axi-symmetric computational domain. Both mixture and VOF multiphase approaches with URANS (standard, RNG, and realizable k-ε) turbulence models have been adopted in this study. The effect of turbulence models on the two-phase flow evolution in the injector has been studied with a GLR (gas-to-liquid ratio) of 0.08%. The liquid is taken as ethanol, and atomizing gas is nitrogen for the current study.