Modelling of spray formation in a pressure swirl atomiser for aircraft engines

The internal flow and the liquid structure exiting the nozzle are investigated in a typical pressure swirl atomizer for aero-engine applications under isothermal non reacting environment, using a two-phase flow modelling according to the VOF numerical methodology. A parametrical analysis is performed to investigate the effect of model numerical parameters on the characteristics of the liquid jet exiting the nozzle and its interaction with the surrounding air. The outputs of the simulations have been used as input conditions for a primary atomization model, which is based on theoretical and empirical models available in the literature and here adapted for swirling flows. The characteristics of the newly formed liquid drops are predicted under the operating conditions suitable for an Ultra Low NOx injection system for aircraft engines.