1D high-speed Rayleigh measurements in turbulent flames

Time-correlated sampling of quantities in transient combustion processes requires high-speed imaging at repetition rates in the order of typical flame-inherent frequencies. The present study demonstrates the feasibility of temperature measurements in turbulent flames along a line at 10 kHz using Rayleigh scattering. High signal intensities were gained using an 80 W Nd:YAG laser for excitation in combination with an optimized combination of an achromatic lens, an objective lens and a CMOS camera. This allowed achieving signal-to-noise ratios up to 140 at 10 kHz repetition rates. The experimental setup and data processing aspects are described as well as details on the system characteristics are given. Temperature measurements of the DLR-A jet flame with a Reynolds number of 15.200 were compared with high-quality conventional 10 Hz simultaneous Raman/Rayleigh data. The data showed excellent agreement highlighting the reliability of the here demonstrated technique. © 2010 Springer-Verlag.