Size distribution and surface area measurements of gas turbine combustor smoke

Abstract

This work is concerned with measurements of mass concentration, size distribution, and specific surface area of soot particles extracted from a model gas turbine combustor. Particles from a variety of fuels including JP-4, Jet A, and DF-2 were collected using a water-cooled stainless steel probe and a heated filter. A centerline mass concentration profile for DF-2, obtained by measurement of sample mass and gas volume, showed concentrationas greater than or nearly equal to previously reported results for five fuels. Size distribution measurements, obtained both by counting particles shown on electron microscope photographs and by a Stokes flow settling technique, showed no apparent change in size distribution with axial location. Specific surface area measurements were made to try to explain the lack of change in size distribution with axial location. The data show a dramatic decrease in the particle specific surface area as the particles travel from 16.5 cm to 29.2 cm downstream of the flameholder. Three hypotheses have been proposed to explain both the size distribution and specific surface area results.