An Analysis of Diesel Flame by Picture Processing

抄録

A picture-processing techique is applied to the study of flame motion in a direct-injection diesel engine. From high-speed photographs, two-dimensional cross-correlation coefficients of flame luminosity between two successive frames are obtained. The location and value of the maximum coefficients give us the mean and fluctuating velocities of the flame, respectively. The results show that the fluctuating velocity obtained in a wide region is almost independent of measuring position and size in the middle and later stages of combustion, indicating that the turbulent flow field is almost uniform and isotropic over the space in diesel engines. The effects of the swirl and chamber geometry on flame behavior are discussed in detail.