Imaging Fourier-transform spectrometer measurements of a turbulent nonpremixed jet flame

Opt Lett. 2014 Apr 15;39(8):2350-3. doi: 10.1364/OL.39.002350.

Abstract

This work presents recent measurements of a CH4/H2/N2 turbulent nonpremixed jet flame using an imaging Fourier-transform spectrometer (IFTS). Spatially resolved (128×192 pixels, 0.72 mm/pixel) mean radiance spectra were collected between 1800 cm(-1)≤ν˜≤4500 cm(-1) (2.22 μm≤λ≤5.55 μm) at moderate spectral resolution (δν=16 cm(-1), δλ=20 nm) spanning the visible flame. Higher spectral-resolution measurements (δν=0.25 cm(-1), δλ=0.3 nm) were also captured on a smaller window (8×192) at 20, 40, and 60 diameters above the jet exit and reveal the rotational fine structure associated with various vibrational transitions in CH4, CO2, CO, and H2O. These new imaging measurements compare favorably with existing spectra acquired at select flame locations, demonstrating the capability of IFTS for turbulent combustion studies.