喷油嘴针阀偏心对内部流动特性的影响

Simulation Analysis on Flow Characteristics Inside Nozzle Effected by Eccentric Displacement of Needle

喷油嘴内燃油流动强烈地影响着喷雾特性和混合气的形成,以某小压力室喷油嘴为研究对象,使用计算流体力学(CFD)计算的方法详细地研究了针阀偏心对喷油嘴内部流动特性的影响规律,计算结果表明:大油量工况时针阀偏心对喷油嘴喷内部流动特性影响较小,但对小油量工况时影响相对较大,随着喷射压力的提高,针阀偏心的影响变大,在满足排放要求范围内,增加压力室容积可以减小针阀偏心对燃油流动的影响。

Spray properties and mixture formation are strongly influenced by the nature of the flow inside the injection nozzle hole. In this paper,a mini-sac nozzle is used the research object,and the influence of needle's eccentric displacement on flow characteristics inside the nozzle is studied in detail using the CFD method. The calculation results show that the influence of needle's eccentric displacement is smaller in the rated power condition of engine and there is the relatively large in the idle state of the engine. As the injection pressure increased,effect of needle eccentricity on the flow field is larger. As nozzle sac volume increased,effect of needle eccentricity on the flow field is smaller.