In-flame soot quantification of N-Hexadecane droplets using diffused back-illumination extinction imaging

Abstract

To gain insights into spray combustion, the combustion characteristics of single droplets need be investigate. In this study, soot production measurements were performed on single droplet of N-Hexadecane using the two optical techniques of natural flame luminosity imaging and diffused back-illumination extinction imaging (DBIEI). These measurements were performed in a suspended single-droplet combustion setup under ambient temperature and atmosphere. The experimental results from both methods are positively correlated with the combustion process. The images captured using the two methods clearly show the premixed and non-premixed combustion periods. The ratio of soot radiation to flame radiation is nearly constant in non-premixed combustion. The DBIEI results for the natural soot luminosity indicate a shorter distance than the attenuated soot intensity along the vertical direction. The results demonstrate that DBIEI technique is capable of quantitatively measuring the instantaneous soot formation during single droplet combustion.