Rotational CARS for simultaneous measurements of temperature and concentrations of N_2, O_2, CO, and CO_2 demonstrated in a CO/air diffusion flame

摘要

Rotational coherent anti-Stokes Raman spectroscopy (CARS) has over the years demonstrated its strong potential to measure temperature and relative concentrations of major species in combustion. A recent work is the development and experimental validation of a CO_2 model for thermometry, in addition to our previous rotational CARS models for other molecules. In the present work, additional calibration measurements for relative CO_2/N_2 concentrations have been made in the temperature range 294-1246 K in standardized CO_2/N_2 mixtures. Following these calibration measurements, rotational CARS measurements were performed in a laminar CO/air diffusion flame stabilized on a Wolfhard-Parker burner. High-quality spectra were recorded from the fuel-rich region to the surrounding hot air in a lateral cross section of the flame. The spectra were evaluated to obtain simultaneous profiles of temperature and concentrations of all major species; N_2, O_2, CO, and CO_2. The potential for rotational CARS as a multi-species detection technique is discussed in relation to corresponding strategies for vibrational CARS.