Cars Study of Premixed Turbulent Combustion in a High Velocity Flow

Premixed turbulent flames offer interesting possibilities to study turbulent combustion and permit confrontation between experiments and calculations. In addition, there is direct application to the design of afterburners for turbojet engines, if the flow veloCity is fast enough. For both reasons ONERA have undertaken continously over the last ten Years an experimental and theoretical study of such a turbulent flame, stabilized either by a planar hot jet parallel to the main stream, or by a sudden enlargment. The studies began with shadowgraphic visualizations and wall pressure measurements, followed by gas sampling and analysis by chromatography in order to know the mean concentration profile inside the flame. The veloCity profile was studied in detail later, with veloCity and turbulence measurements by laser Doppler anemometry. An attempt to measure some aspects of the temperature profile was made also by means of a pneumatic probe and emission-absorption spectroscopy. Very recently, a programme of measurements by CARS (Coherent anti-Stokes Raman Spectroscopy) has led to measurements of the fluctuating temperature. These results are presented here.