Optical determination of temperature and concentrations of homogeneous turbulent gas mixtures

In this study, a previously developed inverse radiation model for a single gas species is extended to mixtures of the combustion gas species CO2, H2O and CO. Time-averaged transmissivities and their root-mean-square (rms) values are successfully related to time-averaged temperatures, species concentrations and their rms values by considering interactions between turbulence and radiation (TRI). The sensitivity of the rms transmissivity spectra to all the parameters to be retrieved are examined and optimal wavenumber ranges for retrieving turbulent scalars of the gas mixtures are discussed. To validate the models, measured spectra are synthesized for different combinations of species concentrations, temperatures, turbulent intensities, pressure path length and turbulent length scales. Results show that mean and rms temperature and species concentrations and other turbulent scalars can be retrieved accurately from turbulent transmissivity measurements as long as the turbulent intensity is below 15% and the pressure path length for the gas mixture is less than 60 bar·cm.