Towards quantitative concentration measurement of acetylene in rich hydrocarbon flames using 1D Raman/Rayleigh scattering

This work presents the extension of the established detection of seven major species in 1D Raman/Rayleigh measurements to incorporate acetylene as an eighth species. Acetylene is an important soot precursor which is generated in hydrocarbon flames as an inter- mediate species following decomposition. It occurs over a broad temperature range in the flame and has been identified as a potentially detectable species in 1D Raman/Rayleigh measurements. In this paper, we discuss the Raman spectral signature of acetylene, its temperature-dependence, calibration points, and the interference with other Raman-active species, C₂ and broadband interferences, all of which are essential to quantify for accurate data processing. In this regard, Raman measurements in laminar and turbulent flames of dimethyl ether were aquired. The data was spectrally analyzed, and, in conjunction with laminar flame calculations, the necessary calibration points were derived to place the acetylene signals on an absolute scale. Finally, detection limits of acetylene, signal-to-noise, and signal-to-interference ratios in laminar and turbulent flames are discussed.