Prediction and Analysis of Combustion Instabilities in a Model Rocket Engine

Abstract

This paper is a compilation of the research efforts of five different groups (Bertin Technologies with Centre National d’Etudes Spatiales, Institut de Mécanique des Fluides de Toulouse, ONERA, Purdue University, and Technische Universität München) on the prediction of combustion instabilities in a model rocket engine. This research was initiated by the Rocket Engine Stability Initiative group for the 2nd Rocket Engine Stability Initiative Workshop on Combustion Instability Modeling, which took place in October 2010 at Astrium, GmbH, in Ottobrunn, Germany. The target experiment consists of a single shear coaxial injector using methane and decomposed hydrogen peroxide as reactants. Both the inlet of the injector and the outlet of the chamber are choked, resulting in well-defined acoustic boundary conditions. The length of the oxidizer tube could be varied continuously, and its influence on the stability is studied. Many numerical strategies are tested, addressing different physical phenomena at play during unstable combustion. Acoustic solvers, both with and without mean-flow effects are used to draw stability maps. The weak spot of these solvers is that they require the flame response to acoustic perturbations as an input. Large-eddy simulations, requiring no such a priori knowledge, are performed with the intent to elucidate flame stabilization and flame response mechanisms.