Abstract The effect of injector nozzle design on the Gasoline Direct Injection (GDI) fuel spray characteristics under atmospheric and flash boiling conditions was investigated using Phase Doppler Anemometry (PDA) measurements. To understand the impact of hole diameter and conicity, experiments were conducted on two bespoke 3-hole injectors in a pressure and temperature controlled constant volume chamber and in the open air. The measurements were taken radially outward from the injector axis to the outer extent of the plume at distances of 15 mm, 25 mm and 40 mm from the injector tip. Observations of the influence of surrounding gas and temperature conditions and hole design on the injector spray performance were made. Under non-flash boiling conditions, it was found that the injection pressure dictates the length of the spray penetration before collapse occurs, with an increase in pressure resulting in an increase in this length. Comparison of mean velocity and droplet diameter data are also made to understand the performance under flash boiling conditions. Results show that, under flash boiling conditions, the droplet velocity significantly increases while the droplet size reduces. More importantly, it is found that the impact of the flash boiling environment on sprays of different hole geometries is different. Some hole designs offer more resistance against spray collapse. It was found that the mid-sized of the three hole diameters tested here was found to produce a spray that more readily collapsed than that of the smaller or larger hole diameters. In addition, it was found that under flash boiling conditions, the convergent hole had a greater propensity to exhibit spray collapse.

中文翻译：

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汽油直喷喷油器孔几何形状对闪蒸和环境条件下喷雾特性的影响

摘要 使用相位多普勒风速仪 (PDA) 测量研究了在常压和闪蒸条件下喷射器喷嘴设计对汽油直喷 (GDI) 燃料喷雾特性的影响。为了了解孔径和锥度的影响，在压力和温度控制的恒容室和露天环境中对两个定制的 3 孔喷射器进行了实验。测量值是从喷射器轴径向向外到距离喷射器尖端 15 毫米、25 毫米和 40 毫米处的羽流外部。观察了周围气体和温度条件以及孔设计对喷射器喷雾性能的影响。在非闪蒸条件下，发现注射压力决定了发生塌陷之前喷射穿透的长度，压力的增加导致该长度的增加。还对平均速度和液滴直径数据进行比较，以了解在闪蒸条件下的性能。结果表明，在闪蒸条件下，液滴速度显着增加而液滴尺寸减小。更重要的是，发现闪蒸环境对不同孔几何形状的喷雾的影响是不同的。一些孔设计提供了更大的抗喷雾坍塌的能力。发现这里测试的三个孔径中的中等尺寸产生的喷雾比较小或较大孔径的喷雾更容易塌陷。此外，