基于喷雾波动性对贯穿距公式的再思考

Reconsideration of Spray Penetration Model Based on Spray Variations

贯穿距是描述喷雾特性最重要的参数之一,实现贯穿距的准确预测对燃烧系统优化以提高发动机性能、降低排放至关重要。目前已有的贯穿距公式中几乎都忽略了喷雾循环波动性。本研究通过不同喷射压力下的大量高压共轨柴油喷雾试验,发现喷雾循环波动性在喷射后期相当明显,对贯穿距的影响不能忽略。为了对贯穿距进行更合理、更准确表述及预测,本文提出通过引入波动性影响因子对贯穿距预测公式加以修正的方法,修正后的公式可以预测不同喷雾出现概率(presence probability)下的喷雾贯穿距。

Spray tip penetration is one of the most important characteristics of a spray.Realizing accurate prediction of spray penetration is critical to the optimization of combustion systems,which can improve engine performance and reduce emissions.The previous models of diesel spray tip penetration have not considered the cyclic variations of spray.In this study,a large number of experiments of high-pressure common rail diesel spray were conducted under different injection pressures.The results show that the spray variation is quite obvious after end of injection and its effect on penetration cannot be neglected.In order to express and predict the spray tip penetration more reasonably and accurately,this paper proposed a method to modify the penetration models by introducing an influence factor of spray variations,which could predict the spray penetration of each presence probability.