Abstract
Non-reactive Lagrangian two-phase flow Large-Eddy Simulations (LES) of an industrial aeronautical injector are carried out with the compressible AVBP code and compared with an experimental database in an industrial context. While most of the papers are focused on simplex atomiser with only one fuel passage, we propose to account for specific industrial configurations based on duplex atomiser where both the primary and the secondary passages operate. For the second passage, the fuel spray angle is wider, leading to spray / wall interactions and airblast atomization.
The computation domain consists in the experimental mock-up without the fuel atomizer part. The liquid-injection boundary condition is applied through the phenomenological FIM-UR model, which prescribes droplet velocities and diameter distribution at the atomizer tip based on both the atomizer characteristics and the liquid mass flow rate. No specific models are used for spray / wall interaction, and droplets are assumed to slip on the walls. The numerical results are compared with the experimental database for Jet-A1 fuel, built through Phase Doppler Anemometry instrumentation, allowing access to local information regarding the droplets velocity components.
Three LES are performed for pressure loss ranging from 1 to 3%, covering an important part of the engine operating conditions, from high altitude relight to cruise operating point. Mean and fluctuating velocity profiles show a relatively good agreement with measurements, for all the operating points. It confirms that the spray/wall interactions, airblast and secondary breakup models may be neglected as a first approximation for configurations where only a relatively small amount of fuel impacts the wall.