Abstract
The authors have conducted experimental studies to clarify the combustion characteristics of unsteady turbulent diffusion flames in relation to the soot formation and oxidation process in a DI diesel engine. In the present study, the effect of fuel vapor concentration on the process of early combustion and soot formation has been investigated using several optical measurements. Laser-induced incandescence (LII) has been used to obtain the 2-D distribution of soot particles in a sooting field. Furthermore, planar laser-induced exciplex fluorescence (LIEF) has been applied to simultaneous visualization of the liquid and vapor phases of the fuel jet in a DI diesel engine. The experimental results present the effect of fuel vapor distribution on the initial soot formation process subsequent to autoignition in addition to its spatial dependence.
