Real Time Coherent Anti-Stokes Raman Spectroscopy (CARS) in a Semi-Industrial Furnace

摘要

The Coherent Anti-Stokes Raman Spectroscopy (CARS) technique is described, and measurements on a small methane furnace and a large furnace fed by various fuels are discussed. Results show that reliable operation of the CARS spectrometer is possible, with extraction of real time, precise quantitative temperature and concentration measurements even from large, sooty flames. The density gradients caused by turbulence do not cause a significant loss in Anti-Stokes signal generation efficiency. However, laser beam wandering forced the use of an optical fiber with a 10 to 20 loss factor in the coupling with the available polychromator, and limited the applicability of BOXCARS single shot techniques. This difficulty can be overcome by using a higher peak power laser and a shorter focal length polychromator. The consequent reduction of the spectral resolution should not affect measurement accuracy.