重型柴油机低温环境喷雾及蒸发特性研究

利用定容燃烧弹结合米散射法、阴影法针对喷孔直径(0.12～0.32mm)和环境温度(550～850K)对重型柴油机低温环境下喷雾特性的影响进行可视化测量。结果表明:不同于轻型柴油机,在各个喷射压力和环境压力下提高环境温度到750K时,表征重型柴油机的0.32mm喷孔下的液相燃油依然持续贯穿,无法达到准稳态或达到准稳态时贯穿距离过长而湿壁。随着环境温度增加,0.32mm喷孔下的液相燃油湿壁量减小。只有环境温度增长到850K时,燃油的蒸发作用足够强烈,液相撞壁喷雾的横向扩展长度和浮起高度才能均达到准稳态。

Spray and Evaporation Characteristics of Heavy Duty Diesel Engines at Low Temperatures

In this paper, the effects of nozzle diameter (0.12~0.32 mm) and ambient temperature (550~850 K) on the spray characteristics of heavy-duty diesel engines are measured visually in a constant volume combustion chamber using Mie-scattering and shadowgraph methods. The results show that, different from the light-duty diesel engines, when the ambient temperature is increased to 750 K un-der various injection pressures and ambient pressures, the liquid-phase fuel under the 0.32 mm nozzle of the heavy-duty diesel en-gines still penetrates continuously and fails to reach a quasi-steady state, or when reaching a quasi-steady state, the penetration dis-tance is too long, which leads to spray impingement. With the increase of the ambient temperature, the adhesion amount of liquid spray under the 0.32 mm nozzle decreases. Only when the ambient temperature increases to 850 K, the evaporation of the fuel is strong enough, and the height and radius of impingement spray can reach a quasi-steady state.