基于空气辅助喷射不同温度航空煤油喷雾特性可视化研究

Visualization Study of Spray Characteristics of Aviation Kerosene Under Different Temperatures Based on Air-Assisted Injection

为了探明燃油温度和喷油脉宽对空气辅助航空煤油喷雾特性的影响,在定容燃烧弹上搭建空气辅助燃油喷射系统,利用高速阴影成像技术探究了不同燃油温度和不同喷油脉宽下航空煤油的喷雾特性。研究表明,当喷油脉宽为12 ms时,高温燃油液滴更倾向于沿着喷嘴径向运动,低温燃油液滴更倾向于沿着喷嘴轴向运动,燃油温度从40℃降低到-40℃时,平均索特平均直径增大了14.7%,小粒径的占比大幅度减少;燃油温度为-40℃时大喷油脉宽下出现的“两段喷雾”对喷雾前后期的贯穿距和面积有不同的影响,喷雾卷吸幅度和宽度增大,喷油脉宽从5 ms增加到14 ms时,平均索特平均直径增加了22.2%。因此低温冷起动大喷油脉宽时,适当提高燃油温度可有效促进发动机顺利起动。

To elucidate the effects of fuel temperature and fuel injection pulse width on the characteristics of air-assisted aviation kerosene spray,an air-assisted fuel injection system was constructed on a constant volume combustion chamber,and high-speed shadow imaging technology was employed to investigate the spray characteristics of aviation kerosene under different fuel temperatures and injection pulse widths.The results show that when the fuel injection pulse width is 12 ms,high-temperature fuel droplets tend to move radially along the nozzle,while low-temperature fuel droplets tend to move axially.The fuel temperature is reduced from 40℃to-40℃,the average Satuer mean diameter increases by 14.7%,and the proportion of smaller particle sizes decreases significantly.When the fuel temperature is-40℃,the occurrence of“two-stage spray”under large fuel injection pulse widths has different effects on the spray penetration and area during the early and late stages,and the amplitude and width of the spray suction increase.And when the fuel injection pulse width increases from 5 ms to 14 ms,the average Sauter mean diameter increases by 22.2%.Therefore,for cold start at low temperature with large injection pulse width,increasing the fuel temperature appropriately can effectively promote the smooth start of the engine.