Abstract
The objective of this study is to investigate the structure and characteristics of premixed turbulent flames in SI engines for the validation and improvement of the numerical simulation. Fractal analysis with LIF technique was performed to analyze the flame of early stages in the cylinder, and the following results were obtained. 1) During the propagation, fractal dimension was almost constant. Only outer cutoff length was increased with flame radius. Therefore it seems that the increase of flame surface area is controlled by the flame own radius. 2) The flame surface area and laminar burning velocities were obtained from the fractal measurements and compared with those of conventional combustion model. Fairly good agreements were obtained.
