Filtered Rayleigh scattering of gaseous hydrocarbon fuel/nitrogen mixtures at elevated pressures

This Letter addresses Rayleigh-Brillouin scattering (RBS) modeling methodology for binary mixtures of nitrogen and gaseous hydrocarbon fuels in the kinetic scattering regime, with its extension to filtered Rayleigh scattering (FRS). Modeled mixture FRS signals were generated by summing mole-weighted FRS signals of mixture constituents, with the required RBS lineshapes for the pure species modeled using the widely accepted Tenti S6 gas kinetics model. The modeled FRS mixture signals were then compared with measurements, and noticeable discrepancies up to 21% were observed. Such deviations demonstrate that the conventional FRS modeling framework for the mixtures of complex hydrocarbon fuels in the kinetic scattering regime requires refinement, with a specific treatment of diffusive effects.