Measurements of multiple mole fraction fields in a turbulent jet by simultaneous planar laser-induced fluorescence and planar Rayleigh scattering

Abstract

This paper presents two-dimensional measurements of all individual mole fractions in a three-species, non-reacting turbulent flow, using planar laser-induced fluorescence (PLIF) and planar laser Rayleigh scattering. The flow is an axisymmetric jet of acetone and helium in an air coflow. PLIF measures the acetone mole fraction, while Rayleigh scattering measures a linear combination of the acetone and helium mole fractions. The simultaneous implementation of these techniques allows for the calculation of the helium and air mole fraction fields. The results of this diagnostic method are being used for the study of multicomponent molecular transport effects in turbulent fluid mixing.

Transient effects of fuel–air mixing in a partially-premixed turbulent swirl flame

“…In the present study, the ratio of diffusivities, α Ac /α Me =3, is considerably smaller than in the study of Ref. [25], α Ac /α He =8. This suggests that for length scales larger than the fuel channel width (d=0.5 mm), differences of acetone and methane concentration are significantly lower than 5% in the present experiment.…”

“…The differences of S L for 0% and 9% acetone are within the measurement uncertainty of 1.5 cm/s for φ<1.25, and below 5 cm/s for φ>1. 25. Since the present flame is operated at φ global =0.65, no major changes of S L are expected for the 9% acetone level used in this work.…”

“…The fluorescence of acetone may thus not accurately represent the distribution of methane, and it is therefore desirable to estimate the magnitude of their differential mixing. In a recent experimental study, Brownell & Su [25] investigated differential diffusion from a jet of acetone and helium (α He =0.8 cm 2 /s) in an air coflow. They found that at length scales larger than the jet nozzle diameter, the relative differences between acetone and helium concentrations are typically less than 5%, while at smaller scales differences up to 10% may occur.…”

Quantitative gas property measurements by filtered Rayleigh scattering: a review

“…In the traditional (unfiltered) Rayleigh scattering approach, the intensity of the scattered light is directly proportional to the scattering gas' number density [8]. This allows for quantitative measurement of density [9][10][11][12][13], mixture fraction [14][15][16][17][18][19][20][21], or, if the gas' pressure is known, temperature can be recovered using the ideal gas law [22][23][24].…”