On the accuracy of temperature measurements in turbulent jet diffusion flames by coherent anti-stokes-raman spectroscopy

Abstract

Coherent anti-Stokes-Raman spectroscopy (CARS) has been applied to determine profiles of mean and standard deviation of temperature and of probability density functions for the Delft turbulent jet diffusion flames fed with Dutch natural gas. Several improvements to the CARS data reduction are introduced and special attention is paid to the effect of spatial averaging. It is shown that the error due to the limited resolution is at most 40 K for mean temperatures around 750 K. The CARS results are compared to the Raman-Rayleigh results obtained earlier for the same flames. Within experimental uncertainty, the results from the two independent nonintrusive laser diagnostic techniques are the same, except for the low central part of the flames. The difference can be a consequence of the occurrence of large methane concentrations and of the sensitive dependence on upstream boundary conditions.