航空煤油活塞发动机空气辅助喷射系统喷雾特性试验研究

Experimental Study of Air-assisted Spray Characteristics of Aviation Kerosene Piston Engine

为获得良好的混合气体,保证喷雾特性与缸内时变环境之间的良好匹配,针对航空活塞二冲程煤油发动机空气辅助喷射系统的喷雾特性,开展了系统试验研究。使用高速相机和相位多普勒粒子分析仪并结合图像处理技术,分析了环境压力、温度和喷油脉宽、喷气脉宽等控制参数对喷雾宽度、贯穿距、空间扩散面积和索特平均值的影响。结果表明:控制参数不变情况下,提高环境压力不利于喷雾在空间的扩散,雾化效果也会变差;提高环境温度有利于燃油液滴的蒸发性、破碎;环境条件不变情况下,减小喷油脉宽、增大喷气脉宽有利于喷雾沿喷孔方向延伸,促进液滴膨胀破碎。

Based on the air-assisted spray characteristics of two-stroke aviation kerosene piston engine, the systemic experimental study was performed, and the effects of ambient pressure, temperature and control parameters,including fuel injection duration, interval among fuel and air, and air injection duration, on spray width, penetration, spatial diffusion area and Souter mean diameter were analyzed using a high-speed camera and a phase Doppler particle analyzer combining with image processing technology in order to obtain a desired gas mixture and ensure a good match between the spray characteristics and the time-varying environment of cylinder. The results show that the increased ambient pressure is not conducive to the spray spatial diffusion, while the atomization is worsen;and the increased ambient temperature is beneficial to the evaporation and breakup of fuel droplets in the case of constant control parameters;and the decreased or increased air injection duration facilitates the extension of spray along the direction of the nozzle, and promotes the expansion and breakup of droplets. The experimental results show that the air-assisted injection system has good adaptability.