Time-series measurements of CH concentration in turbulent CH₄/air flames by use of picosecond time-resolved laser-induced fluorescence

We report a developing technique capable of making continuous time-series measurements of naturally occurring minor-species concentrations. The high repetition rate of the mode-locked laser used in this technique allows for the study of transient combustion events, such as turbulence, and their effect on minor-species concentrations. The technique is applied to make CH fluorescence time-series measurements and to calculate power spectral densities in a turbulent nonpremixed flame. To our knowledge, the reported time series represents the first such measurement for a naturally occurring minor species in a turbulent flame.