Influence of spatial laser energy distribution on evaluated soot particle sizes using two-colour laser-induced incandescence in a flat premixed ethylene/air flame

摘要: Time-resolved laser-induced incandescence (LII) has been developed rapidly during the last decade as a useful non-intrusive technique for particle size determination. Still several parameters should be investigated in order to improve accuracy of LII sizing and spatial distribution laser energy is one these. Generally top-hat profile recommended, this ensures uniform heating all particles measurement volume. As it generally not straightforward create beam profile, interest establish influence various profiles on evaluated sizes. In work we present both an experimental theoretical investigation All experiments were carried out using newly setup two-colour (2C-LII) which provides online monitoring temporal well pulse energy. The measurements performed one-dimensional premixed sooting ethylene/air flame, sizes from compared with thermophoretically sampled soot analysed transmission electron microscopy (TEM). results show that although there some modelling experiments, effect substantially smaller than uncertainties gas temperature thermal accommodation coefficient.