Numerical simulation of two-phase flow within an aerated liquid injector

This work investigates the flow structure within an aerated-liquid (barbotage) injector designed to facilitate the rapid breakup of a hydrocarbon fuel jet prior to its entering a high-speed combustor. Simulations of the three-dimensional, two-phase flow within an aerated-liquid injector operating at different gas-to-liquid (GLR) mass ratios are performed and the results compared with experimental pressure measurements. The numerical method solves a "mixture" model of two-phase flow using a preconditioning strategy. Two discretization techniques, one based on conventional TVD shock-capturing schemes and the other incorporating a sharp-interface capturing method, are used. The simulation results highlight the effects of mesh refinement, discretization scheme, and turbulence model on the predicted solutions. The pressure drop across the injector is predicted reasonably well by the computational methodology, and the trend of increasing injector pressure with increasing GLR is captured properly. Predictions of the absolute pressure level within the injector show some discrepancies in comparison with experimental data but agree well with theoretical estimates. The sharp-interface capturing techniques provide detailed predictions of the initial stages of primary breakup of the liquid jet as it is impacted by the injected gas jets, but mesh resolution limits force a transition to a more "mixed-out" state near the discharge tube exit.