Experiments and Large Eddy Simulation of Supersonic Combustion in the Small-Scale Flight Experiment

Abstract

upersonic combustion is a critical area of research for advancing high-speed flight technologies, particularly for the development of scramjet engines for hypersonic vehicles. This study employs Finite Rate Chemistry (FRC) Large Eddy Simulation (LES) together with different experimental techniques to study the supersonic flow and thermochemical processes in the Small Scale Flight Experiment (SSFE) intake and combustor. The study is conducted in the High Enthalpy Shock Tunnel Göttingen (HEG) and aims at providing further insights into realistic scramjet flow and combustion processes. The study focuses on a representative scramjet intake-combustor section under flight-relevant conditions, including high-speed, compressible flow, hydrogen injection, self-ignition, and turbulent combustion. Detailed models for hydrogen-air chemical kinetics and turbulence-chemistry interactions are used to ensure accurate predictions of flame stabilization, heat release, and shock-turbulence interactions. The simulations are validated against data from Temperature Sensitive Paint (TSP), Pressure Transducer (PT), and Frequency Comb Laser Absorption Spectroscopy (FC-LAS) measurement data collected during the experiments. The results generally show good agreement for wall pressure, wall heat-flux, and H2O and NOX emissions. The combined results provide insight into the flameholding mechanisms and the role of shock-waves in enhancing mixing and ignition. This work advances the general understanding of supersonic combustion physics, and provides a framework for further scramjet engine studies for realistic flight vehicles.