喷射压力和喷孔直径对柴油机混合燃料喷雾特性的影响

Investigation on the Influence of Injection Pressure and Nozzle Diameter on the Spray of Blended Fuel in Diesel Engine

应用平面激光诱导荧光(PLIF)技术研究了喷射压力、喷孔直径对混合燃料喷雾特性的影响.结果表明:在相同的喷射压力下,混合燃料的挥发性越高,喷雾前锋贯穿距离和喷雾锥角(远场和近场)越大;随着喷射压力的提高,喷雾锥角增加,喷雾前锋贯穿距离呈现出一定程度的线性增长,但混合燃料挥发性对喷雾前锋贯穿距离的影响有所减小;在喷雾发展过程中,近场锥角呈现出先减小再保持在一个相对稳定的数值趋势,而远场喷雾锥角呈现先减小然后保持不变之后再增大的趋势,但全程远场喷雾锥角的变化不大;在相同喷孔直径下,混合燃料的挥发性越高,喷雾前锋贯穿距离越长,喷雾锥角越大,当喷孔直径从0.18,mm缩小到0.10,mm时,挥发性对喷雾锥角增长率的影响略有减小,随着喷孔直径的增大,喷雾前锋贯穿距离呈现出一定程度的线性增长,但喷孔直径对远场喷雾锥角的影响大于对近场喷雾锥角的影响.

Injection parameters such as injection pressure and nozzle diameter were investigated using the planar laser induced fluorescence technique.Results show that,at the same injection pressure,high volatile fuel gives long spray penetration and large spray cone angle（far field and the near field）.With the increase of injection pressure,spray angle increases and penetration distance shows a linear growth,while the effect of volatility of blended fuel on penetration distance is decreased.During the spray development,the near-field cone angle shows a first decreasing and later maintains a constant value.The far-field spray cone angle shows a first decreasing and then keeps constantly and later a increasing.Generally,the variation of the far-field spray angle is small.For the same nozzle diameter,high volatile fuel gives long penetration distance and large cone angle.When decreasing nozzle diameter from 0.18,mm to 0.10,mm,the effect of volatility on the growth rate of spray cone angle is decreased.With the increase of nozzle diameter,penetration distance shows a linear growth.The effect of nozzle diameter on the far-field spray cone angle is larger than on the near-field spray cone angle.