汽油/柴油掺混燃油两段喷射喷雾特性试验研究

Experimental Study on Characteristics of Gasoline-Diesel Blended Fuel Spray with Split Injection

基于定容燃烧弹与超高速数码相机搭建的LED-Mie散射喷雾试验台,研究了不同参数对柴油、汽油质量占比20%的柴汽混合油(记为G20)单段与两段喷射主喷液相喷雾特性的影响。结果表明,单段喷射喷雾贯穿距与喷雾锥角随喷射压力的增大而增大,G20喷雾贯穿距略小于柴油喷雾贯穿距,G20喷雾锥角略大于柴油喷雾锥角。将环境温度由300K升高到850K,喷雾贯穿距变小且喷雾很快达到稳定。冷态环境下(300K),两段喷射主喷喷雾贯穿距起始阶段与单段喷射喷雾贯穿距基本一致,但随着喷雾发展200μs左右后,两段喷射主喷喷雾贯穿距变得略小于单段喷射喷雾贯穿距。两段喷射主喷喷雾锥角略大于单段喷射喷雾锥角,预主喷间隔时间对喷雾锥角影响较小。

The LED-Mie scattering spray test bench was built based on a constant volume combustion chamber and a high-speed digital camera.The effects of different parameters on liquid spray characteristics of diesel and gasoline/diesel blend of 20% gasoline mass fraction(denoted as G20)with single injection and the main injection of split injection(the main injection)were studied.The results show that:The spray penetration length and spray cone angle of both fuels become greater with the increase of injection pressure of single injection,and the spray penetration length of the G20 is smaller than that of the diesel while the spray cone angle of the G20 is larger than that of the diesel.When the temperature rises from 300 to 850 K,the spray penetration lengths of both fuels decrease and the sprays quickly stabilize.In the cold environment(300 K),the two-fuel spray penetrations of the main injection are basically the same as those of the single injection at the first,but when both sprays develope for 200μs,the penetration lengths of the main injection are slightly smaller than those of the single injection.The two-fuel spray cone angles of the main injection are slightly larger than those of the single injection,and the interval between pilot injection and main injection of the split injection has little effect on the spray cone angles.