非定常噴霧の構造に関する研究 : 第2報, 燃料蒸気の濃度・速度分布と着火領域の2次元可視化

抄録

Distributions of fuel vapor concentration, fuel vapor velocity and ignition region in a transient fuel free spray in a rapid compression machine were visualized two-dimensionally by a laser sheet scattering technique called as Silicone oil droplets Scattering Imaging (SSI) method. The residual silicone oil droplets suspended in fuel vapor are illuminated by a sheet of light from copper vapor laser flushing at 20 kHz, and the blight scattering from silicone oil droplets was imaged by a high speed camera synchronized to the laser. The distribution of fuel vapor velocity was analyzed from sequential SSI images by a cross-correlation PIV technique. The ignition region in a spray could be detected as dark regions where the silicone oil droplets were vaporized by local heat release due to ignition. Distibutions of fuel vapor concentration, velocity and ignition region in a transient spray obtained revealed that ignition starts behind the head vortices in a spray where surrounding air is entrained into spray strongly.