Temperature and water mole fraction measurements by time-domain-based supercontinuum absorption spectroscopy in a flame

摘要

In this manuscript, we present the first quantitative multi-scalar measurements by time-domain-based supercontinuum absorption spectroscopy in a flame. Temperature and H_2O mole fraction are determined simultaneously from broadband H_2O spectra ranging from 1,340 to 1,485 nm by a multi-peak least square fit between experiments and simulated spectra. To this end, a combination of the most comprehensive databases, namely the Barber-Tennyson database (BT2) and HITRAN2012, is used. Line strength values listed in BT2 are combined with averaged broadening coefficients and temperature exponents based on the upper rotational quantum number J from the latest HITRAN database to precisely model the line shape function for each transition. The height-dependent temperature and H_2O mole fraction profiles of a premixed one-dimensional flame of a McKenna type burner are reconstructed by direct comparison of experimental spectra with theory. For verification, the temperature data obtained are compared with a profile determined by coherent anti-Stokes Raman scattering.