To study the influence of ducts other than circular shapes on spray characteristics of ducted fuel injection (DFI), experimental and simulation methods were used to study the impacts of elliptical ducts on DFI macroscopic spray characteristics. Two elliptical ducts, small and large, were used, with a circular duct for comparison. The small elliptical duct had the same hole cross-sectional area as the circular duct, and the large elliptical duct had a larger cross-sectional area. The DFI spray configuration with the elliptical duct promoted the axial dispersion and weakened the radial dispersion of spray with respect to free spray. Different spray-duct interactions caused differences in spray characteristics, manifested in changes in velocity field and pressure field. The spray velocity field of the circular duct had the best effect on promoting spray dispersion, followed by the small elliptical duct, and finally by the large elliptical duct compared to that of free spray. Furthermore, the pumping effect caused by the pressure differences between inside and outside the duct promoted the thorough mixing of spray and ambient gas inside the duct. From the radial velocity of ambient gas flowing to spray around the duct inlet, the pumping effect of the circular duct was the strongest, followed by the small elliptical duct and finally by the large elliptical duct.

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椭圆风道对管道燃油喷射宏观喷雾特性影响的研究

为了研究圆形以外的管道对管道式燃油喷射 (DFI) 喷雾特性的影响，采用实验和模拟方法研究了椭圆形管道对 DFI 宏观喷雾特性的影响。使用了大小不一的两个椭圆形管道，并使用一个圆形管道进行比较。小椭圆风管的孔截面积与圆形风管相同，大椭圆风管的截面积更大。相对于自由喷雾，椭圆形管道的DFI喷雾配置促进了喷雾的轴向扩散，削弱了喷雾的径向扩散。不同的喷雾管道相互作用导致喷雾特性的差异，表现为速度场和压力场的变化。与自由喷雾相比，圆形导管的喷雾速度场对喷雾分散的促进效果最好，其次是小椭圆导管，最后是大椭圆导管。此外，管道内外压力差引起的泵送效应促进了管道内喷雾和环境气体的充分混合。从环境气体流动到管道入口周围喷雾的径向速度来看，圆形管道的抽气效果最强，其次是小椭圆管道，最后是大椭圆管道。管道内外压差引起的泵送作用促进了管道内喷雾与环境气体的充分混合。从环境气体流动到管道入口周围喷雾的径向速度来看，圆形管道的抽气效果最强，其次是小椭圆管道，最后是大椭圆管道。管道内外压差引起的泵送作用促进了管道内喷雾与环境气体的充分混合。从环境气体流动到管道入口周围喷雾的径向速度来看，圆形管道的抽气效果最强，其次是小椭圆管道，最后是大椭圆管道。