舷外机空气辅助喷射喷雾特性试验研究

Experimental Study on Spray Characteristics of Air-Assisted Fuel Injection System on An Outboard Engine

基于高速摄影研究平台,开展了空气辅助喷射系统在空气辅助下喷射柴油时的宏观喷雾特性试验研究。高速摄影系统可在1 s内捕获8000张高清图片,此设定能够确保无失真采样。通过此高速摄影平台,可获得不同喷射参数条件下喷雾的贯穿距离和锥角等宏观参数。研究结果表明,喷油脉宽、喷气脉宽等喷射参数均对喷雾宏观特性有明显影响,而油气间隔对喷雾宏观特性影响不大。相同条件下,减小喷油脉宽或增大喷气脉宽均利于喷雾在径向空间延伸,促进液滴膨胀破碎。为空气辅助喷射系统在传统发动机上的应用推广提供理论支撑。

Experimental study was conducted on the macro spray characteristics of air-assisted injection system when injecting diesel fuel with the assistance of compressed air,based on a high-speed photography research platform.The high-speed photography system resolution was set as 8000 frames per second which could ensure that there’s no distortion in the sampling process.The high-speed photography platform was employed to study the macro parameters such as spray penetration distance and cone angle under different injection conditions.The results show that the injection parameters,including fuel injection pulse width,air injection pulse width,have obvious effects on the macro parameters of injection.The fuel-air interval has little effect on the macroscopic characteristics of spray.For the same test conditions,the reduction in fuel injection pulse width or the increase in air injection pulse width could benefit the spray extension in radial space and promote the liquid droplet expansion and fragmentation.The results in this research could provide critical theoretical support for the application and popularization of air assisted injection system on conventional engine.