Temperature and soot volume fraction statistics in toluene-fired pool fires

Abstract The probability density functions and the temporal characteristics of local instantaneous emission and absorption properties in strongly radiating toluene pool flames are presented. Measurements show a large dynamic range in the data resulting from the distribution of soot particles in narrow regions within the fire and from the nonlinear dependence of Planck's function on temperature. The importance of the different frequencies of turbulent fluctuations of emission properties and their effect on monochromatic radiation intensity is investigated using a filtering technique. This technique found that the fluctuations in local emission intensities made the largest contribution to the fluctuating nature of the radiation leaving the flame. The pulsation frequency of the large-scale motion of the fire was found to be the cutoff below which the removal of turbulent fluctuations would affect the mean and RMS intensity. Resolution of frequencies above this limit leads to reasonable estimates of mean and RMS intensity.