Absorption, quenching, and enhancement by tracer in acetone/toluene laser-induced fluorescence*

Abstract

To measure the equivalent ratio distribution of the two-stage lean premixed (DLP) flame, we propose using acetone/toluene planar laser-induced fluorescence (PLIF) technology to simultaneously measure the concentrations of the two components. Appropriate excitation laser wavelength and filters are used to assess the influence of acetone and toluene on each other’s fluorescence signal at room temperature. Experimental results show that acetone has a strong absorption effect on toluene’s fluorescence signal, the effective absorption cross-section is 5.77 × 10−20 cm−2. Acetone has an obvious quenching effect on the toluene fluorescence signal, and the Stern–Volmer coefficient is 0.50 kPa−1. The collisions between the molecules of toluene and acetone will lead to the enhancement of the fluorescence signal of acetone, and the enhancement coefficient is exponential with the acetone’s concentration. The quantitative relationship between the fluorescence intensity and the concentrations of the two tracers is obtained by establishing the photophysical model of toluene and acetone’s fluorescence signals.