Flow dynamics of a liquid–liquid bi-swirl injector

Abstract

This work presents detailed two-phase flow simulations of liquid–liquid bi-swirl injectors for engineering applications. Liquid oxygen and kerosene are delivered into the injector, which is initially filled with air. A parametric study is conducted on the recess length of the inner tube to investigate its effect on the flow dynamics and spray pattern. The simulations are performed using an improved multiphase flow solver in OpenFOAM, which employs the volume-of-fluid approach for interface tracking and the large-eddy simulation technique for turbulence modeling. Detailed flow dynamics of both fuel and oxidizer, along with their spray patterns, are examined systematically. A comprehensive account is provided on the impact of the recess length on flow evolution, including the film thickness, air core diameter, and spray cone angle. Spectral and dynamic mode decomposition analyses are performed to further examine the flow structures and dynamics. Results from this study can be effectively used to facilitate the design optimization of injectors for liquid-fueled propulsion systems.