Abstract This investigation utilized four gasoline direct injection (GDI) injectors with different nozzle lengths and step hole diameters to analyze the influences of nozzle structure on the superheated plume and spray collapse under different superheat degrees. The spray behaviors of were recorded by using high-speed shadowgraphs. In addition, the spray concentration distribution, spray development, and spray swelling characteristics under different superheat conditions were analyzed. The experimental results showed that hole length and step hole diameter affected the widths of the spray plumes, which then affected the spray characteristics. Wider spray plumes enhance plume interactions and promote reduced spray penetration. This causes spray to enter the transition regime at a lower degree of superheat. In addition, the transition regime exhibits better spray characteristics than the subcooled and flare flash boiling regimes. Injector with smaller hole length and larger step hole diameter exhibits stronger adaptability while utilizing the remarkable spray characteristics in the transition regime, owing to the greater length of the spray transition regime.

中文翻译：

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闪沸条件下不同喷嘴配置的直喷喷射器的喷雾特性

摘要 本研究利用四种不同喷嘴长度和阶梯孔直径的汽油直喷（GDI）喷油器，分析了不同过热度下喷嘴结构对过热羽流和喷雾坍塌的影响。喷雾行为是通过使用高速阴影图记录的。此外，还分析了不同过热条件下的喷雾浓度分布、喷雾发展和喷雾膨胀特性。实验结果表明，孔长和阶梯孔直径影响喷雾羽流的宽度，进而影响喷雾特性。更宽的喷雾羽流增强了羽流相互作用并减少了喷雾渗透。这导致喷雾以​​较低的过热度进入过渡状态。此外，过渡状态比过冷和火炬闪蒸状态表现出更好的喷雾特性。由于喷射过渡区的长度较大，因此具有较小孔长和较大阶梯孔直径的喷射器在利用过渡区显着的喷雾特性的同时具有更强的适应性。