A pressure-based numerical Framework for highly stratified transcritical real-fluids simulations

High-efficient and compact devices for space propulsion combustion applications rely on the utilization of high-pressure and cryogenic temperature injection conditions. Such extreme operating regimes limit the amount of data that can be extracted from experimental diagnostics, which makes high-fidelity fluid dynamics numerical simulations crucial to achieving elevated reliability and readiness levels to develop new technologies. Dealing with these flows involves numerical challenges: due to the strong non-linear coupling between the real-fluid thermodynamics and governing equations, unphysical pressure oscillations may occur. To address these challenges, in this contribution we present a pressure-based numerical framework capable to handling large-density gradients and high-Reynolds number flows. The presented framework is tested and validated against a numerical benchmark configuration, comprising a liquid-Oxygen gaseous-Hydrogen mixing layer in Liquid-Rocket-Engines (LREs) relevant conditions. The effective role of diffusion models of increasing complexity is investigated in the context of practical Large-Eddy-Simulations of LREs coaxial injectors.