Towards direct numerical simulation of pressure swirl injectors with realistic geometries

Atomization of hydrocarbon fuels is of critical importance to the transportation sector, in particular for aircraft gas turbine engines. In this work, simulations of a Delevan pressure swirl injector with realistic geometry was investigated. Results were compared with simulations performed by Fuster et al. (Int J Multiphase Flow, 2009) of a swirl jet at lower density ratios. The pressure swirl injector is used for many applications and is a component within air-blast injectors commonly found in gas turbines and aeroengines. Direct numerical simulation of the pressure swirl injection process has the potential to provide much-needed information about the complex physics of atomization in swirling flows, but has yet to be used due to the interaction of a complex turbulent multiphase flow with complicated injector geometries. A variety of novel numerical methods are used to facilitate the numerical simulations including a conservative implementation of immersed boundaries used to represent the injector geometry, an accurate interface transport scheme with mass conservation properties based on a discontinuous Galerkin discretization of the conservative level set method, and a novel discretization of the Navier-Stokes convective term allowing for robust simulations at high density ratios. Simulations were conducted by combining the methods with a fully parallelized computational code called NGA.