CARS thermometry in practical combustors

The feasibility of coherent anti-Stokes Raman spectroscopy (CARS) for remote, spatially and temporally resolved, measurements in practical combustion systems is demonstrated. N₂ CARS temperature measurements are reported for two different liquid-fueled combustors, a swirl burner, and a JT-12 combustor can, operated at atmospheric pressure and situated in a 50-cm diameter tunnel. Crossed-beam phase-matched CARS was employed to ensure good spatial precision. Delicate instrumentation was housed in a control room adjacent to the burner test cell and the CARS signals were piped out employing 60-μ diameter fiber optic guides. Average temperature measurements and demonstrations of single-pulse thermometry were performed.