Collaborative Research: Advanced Excimer Laser Measurements and LES Modeling of Supersonic Combustion.

摘要

Accurate numerical predictions are essential to the design of scramjet combustors, and in order to develop and properly validate these predictions accurate temperature, species concentration, and velocity measurements must be obtained. Large eddy simulation (LES) promises to give improved predictions of turbulent, supersonic combustion relative to CFD RANS models, and therefore, a LES approach employing a subgrid turbulent mixing model was selected to model both reacting and non-reacting flow in a cavity- stabilized supersonic combustor. Hydroxyl tagging velocimetry (HTV) measurements were made in a non-reacting Mach 2 air flow over the cavity with and without an upstream strut. Velocity profiles were compared to LES simulations with good agreement in both configurations. In the flow with an upstream strut, there were some model-data discrepancies in the strut wake region where better resolution of the shear layer compression wave interactions were needed. UV Raman scattering was used to obtain temperature and major species concentrations in a Mach 2 flow over a cavity fueled with a 30% H2/70% CH4 mixture. UV laser-induced fluorescence obscured the Raman spectra in rich regions but data was obtained in most of the cavity. The Raman composition and temperature data were in reasonable agreement with the LES simulations.