The effects of particle size distribution on soot particle measurement by the transmissive light extinction method.

Abstract

This paper presents the effects of particle size distribution on the soot measurement method. The principal equations are rearranged into a concise form, and a wide variation of size distribution functions are introduced to calculate the effects. It is found that the mean extinction coefficient is very weakly dependent on the size distribution, and can be approximated to that for the Sauter mean diameter with a small margin of error. Single color light transmittance measurement can give the volumetric density of soot particles, and is affected only by the estimated value for the Sauter mean diameter. The error due to the estimation is under 5%. Meanwhile, the light transmittance measurement can hardly give the size distribution or the Sauter mean diameter with good accuracy.