High-Pressure Supercritical Turbulent Cryogenic Injection and Combustion: A Single-Phase Flow Modeling Proposal

Despite recent progress, the complex geometry of rocket engine combustion chambers with several hundreds of injectors and the multifaceted physical processes involved in supercritical conditions still remain difficult to handle by using direct numerical simulation or even large eddy simulation methodologies. Accordingly, with a target of performing the simulation of practical configurations, a hierarchy of Reynolds-averaged Navier-Stokes closures is developed and studied herein. Following the conclusions of previous experimental investigations, including supercritical conditions, mixing, and subsequent chemical reaction between LOx and GH2, the modeling proposals rely on the infinitely-fast-chemistry hypothesis. Within this framework, special care is required to model the turbulent mixing phenomena because they control the whole combustion process. In the supercritical Conditions under consideration, turbulent mixing processes are expected to lie between 1) mixing in gaseous conditions (because surface-tension effects and latent heat of vaporization do not hold above the critical point) and 2) mixing between a gas phase and a liquid phase (because the density variations are very important and are comparable with those encountered in two-phase flows). Three different modeling proposals to represent these specific features associated with supercritical mixing are applied to the calculation of a reference cryogenic turbulent jet flame.