New Paradigms in High Pressure Combustion Dynamics Prediction and Control

ABSTRACT: Stability phenomena that are of vital interest in liquid rocket motor development involve a confluence of diverse physics and interactions across many system components. Any comprehensive, self-consistent numerical model is burdened by a very large computational mesh, stiff unsteady processes which limit permissible time step, and the need to perform tedious, repeated calculations for a broad parametric range. Many simplifications are made to the governing equations based on a-posteriori analysis of these phenomena. Predictive models seem to rely on very large simulations and advanced hardware. Reduced Basis Methods (RBM) have grown in usage during the past decade, as promising new techniques in making very large scale simulations more accessible. These methods create models with far fewer unknown quantities than the original system, by generating"proper"fundamental solutions and their Galerkin projections, while guaranteeing accuracy and computational efficiency. The reduced system involves no new assumptions or simplifications. We will build here a mathematical foundation for efficient RBMs in liquid rocket combustion dynamics. RBM will be extended based on theoretical and empirical insights, and appropriate mathematical and software paradigms will be evolved. HyPerComp will team with the applied mathematics department at Brown University and the computational combustion lab at Georgia Tech. BENEFIT: This work has direct relevance to major ongoing liquid rocket engine programs where stability studies are overwhelmed by the computational problem size, and can benefit from improvements in methodology. The models and methodologies developed here are also directly relevant to solid propellant rockets and gas turbine combustors. The general scope of the methods developed here is indeed rather vast. The reduced basis method has applications in numerous markets: automotive, nuclear, image processing, and atmospheric science to name a few. The project is designed such that success in each technology goal can in itself represent a significant contribution to the state of the art.