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由于柴油机喷射是瞬态和间歇的,这就要考虑到油粒的尺寸分布是随时间和空间而变化的。因此,为了确定喷雾特性,必须在喷雾的整个空间对喷雾进行微观观察。 本文阐述了喷雾机理、油粒尺寸分布随时间的变化以及喷雾特性的瞬态变化。采用通过改变曝光时间和喷油咀的形式的直接微观照像来观察高压下喷向静止气态介质中的油束。 结果表明:喷雾机理可以分成四个过程,总的油粒尺寸分布可以用一些以喷射开始算起的时间为函数的经验公式来表示。这证实了绍特油粒平均直径,分布均匀性及油粒生成率随时间的改变。此外,对各种喷咀形式所形成的各种油滴直径的油粒数目的增长率加以讨论。
Since diesel engine injection is transient and intermittent, it is important to consider that the particle size distribution varies with time and space. Therefore, in order to determine the spray characteristics, the spray must be microscopically observed throughout the spray volume. This article describes the spray mechanism, the change in the size distribution of the oil particles over time, and the transient change in spray characteristics. Direct micro-photography by changing the exposure time and nozzle shape is used to observe the oil jets sprayed into the stationary gaseous medium under high pressure. The results show that the spray mechanism can be divided into four processes. The total oil particle size distribution can be expressed by some empirical formulas as a function of time from the start of injection. This confirms the change of Sauter oil average diameter, distribution uniformity and oil particle formation rate with time. In addition, the growth rate of the number of oil particles of various droplet diameters formed by various nozzle patterns is discussed.