空气运动对小型直喷式柴油机着火前喷雾混合过程的影响

Effect of Air Motion on Fuel Spraying and Mixing Process Before Ignition in Small D.I. Diesel Engines

本文在单缸试验柴油机上，采用同步摄影技术，研究了空气运动对小型直喷式柴油机着火前喷雾混合过程的影响。试验结果表明，进气涡流对油束的吹偏作用较小；提高涡流强度使油束保持不被“撕裂”的初始段减小，碰壁前油束端部平均速度降低，油束喷雾锥角增大。提高涡流强度还使油束背风面的“撕裂”程度加剧，顺涡流方向壁面油束扩展加快。着火前燃油喷雾沿燃烧室径向分布与涡流强度和在周向气流作用下油束碰壁后的“撕裂”程度有关。

In this paper, using simultaneous photography technique the effect of air motion on fuel spraying and mixing process before ignition in small D.I. deisel engines has been studied. The experimental results show that the angle of deviation of fuel jet from the injection direction is much small owing to the action of intake swirl. By increasing intake swirl ratio, the length of the initial part of fuel jet which is not torn and the mean velocity of the tip of fuel jet are decreased, the angle of fuel spray is increased. Also by increasing intake swirl ratio, the fuel jet which is torn is intensified on the lee side and wall jet is accelerated on the windward side. The distribution of fuel spray on the radial of combustion chamber is related to the swirl ratio and the torn level of fuel jet after jet impinging on the wall by the action of swirl flow.