Theoretical and Numerical Modeling of Multicomponent Transcritical Diffuse Interfaces Under LRE Conditions

In this study, a theoretical and numerical framework for simulating transcritical flows under a variety of conditions of interest for aerospace propulsion applications is presented. A real-fluid multicomponent and multiphase thermodynamic model, based on a cubic equation of state (EoS) and vapor–liquid equilibrium (VLE) assumptions, is presented to describe transcritical mixtures properties. The versatility of this thermodynamic model is reported since it can represent at the same time the supercritical states as well as subcritical stable two-phase states at equilibrium, via a homogeneous mixture approach. The effect this model has on the evaluation of the thermophysical variables will be emphasized. From the Computational Fluid Dynamics (CFD) point of view, the well-known numerical challenges that arise with the coupling between real-fluid thermodynamics and governing equations under transcritical conditions, are addressed by comparing a fully conservative (FC) to a quasi-conservative (QC) numerical schemes, in the context of the advection problem of a transcritical contact discontinuity.