Real Gas Library in Continuous Phase Propellant Injection Model for Liquid Rocket Engines

Abstract

In this paper we introduce a novel model for liquid rocket engine (LRE) propellant injection. Most academic codes today use an Eulerian-Eulerian (EE) description, i.e. all involved propellants and reaction products are regarded as continuous uids instead of discrete droplets. These models have successfully been improved and are capable of high fidelity studies of single injectors and mixing layers, using LES or even DNS. While impressive, this is prohibitive with regard to the simulation of a full thrust chamber with fast turnaround times - as required in industrial applications. Focusing on a RANS model, we decided to take a different route in terms of enhancement: the equation of state (EOS). State of the art EE models perform a runtime evaluation of the EOS. Thus, its numerical efficiency becomes a constraint. By using a precalculated library for the EOS instead, we succeeded to decouple quality of the EOS and CFD runtime. A multi fluid mixing model is developed which allows for each species to be modeled individually. The approach is embed- ded in a Eulerian-Eulerian homogeneous two phase model, i.e. a thermal and mechanical equilibrium between surrounding gaseous flow and and injected cryogenic fluid is assumed in each numerical cell. Due to the general treatment of the oxygen thermodynamics, the oxidizer phase can assume any thermodynamic state, including gaseous, supercritical, liquid, as well as multiphase vapor liquid mixtures. The model is validated with 0D vaporization processes. As a first application, the supercritical pressure single injector Mascotte A60 test case is treated where cryogenic oxygen is injected. Excellent agreement is found with experimental OH emission data. Especially, maximum OH emission is correctly placed in the hydrogen oxygen shear layer