Comparison of laser-induced incandescence method with scanning mobility particle sizer technique: the influence of probe sampling and laser heating on soot particle size distribution

Abstract

We present a simple method for comparing particle size measurements, obtained with laser-induced incandescence (LII) and a scanning mobility particle sizer (SMPS) in a premixed laminar sooting flame. A quartz cell was installed in line with the SMPS probe to allow LII measurements within the SMPS sample line. In this configuration, the LII and SMPS measurements gave similar results in terms of mean particle size. After the probe, the soot particles appear to be made of tight compact particles. In addition, with this experimental configuration, the influence of the probe in the flame is studied for different particle size ranges by applying LII before and after the probe. Application of SMPS with and without LII in the quartz cell shows that laser heating during LII measurements has an influence on the soot particle size distribution. The method could be used to improve probe sampling of particulate matter in reactive fields as well as to validate the interpretation of relevant physical mechanisms involved in the LII process.

Particle formation from pulsed laser irradiation of soot aggregates studied with a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope

“…They used fluences in the range of 0.1-0.6 J/cm 2 at 1064 nm, for which we measure significant nanoparticle generation. Krüger et al 37 also did not observe new particle formation upon laser irradiation of soot in similar experiments, but their laser fluence (0.12 J/cm 2 at 532 nm) was approximately at our measured threshold for new particle generation, where our observations suggest that new particles are just starting to be observable with an SMPS.…”

Soot characterization with laser-induced incandescence applied to a laminar premixed ethylene–air flame

“…Good agreement between primary particle sizes obtained from LII and from combined scattering/extinction measurements in sooting premixed flames was also obtained by Axelsson et al [23]. In recent years more experimentalists have applied the TiRe-LII method successfully to soot distributions in diverse combustion systems [24,25] and for the measurement of carbon black properties during the production process, for example Dankers et al [26].…”

Modeling laser-induced incandescence of soot: a summary and comparison of LII models

“…LII models typically account for particle heating by laser absorption and cooling by conduction to surrounding gases, sublimation of carbon clusters, and emission of thermal radiation. Some models have been optimized to fit LII signal decay curves for inferring primary particle sizes [19][20][21][22][23][24][25][26][27][28][29][30][31], whereas others have been used primarily to understand the influence of factors such as experimental parameters, particle characteristics, and physical processes that occur during particle heating and cooling [32][33][34][35][36][37][38][39][40][41].…”