喷油嘴偶件喷雾特性计算分析

Simulation Analysis on Spray Characteristics of Nozzle

将喷油嘴内部空穴流动和喷雾计算耦合在一起,首先进行了喷油嘴内部流动计算,然后将喷油嘴内部流动计算结果作为边界条件进行喷雾模拟,包括计算所得到喷孔出口处的速度、空穴、湍流动能等,通过此方法研究了喷油嘴偶件结构参数,如喷孔K系数、喷孔入口圆角半径等对喷雾特性的影响规律;同时,研究了喷孔加工误差(喷孔粗糙度)、喷油压力、背压等对喷雾特性的影响。结果表明:喷油压力、背压、K系数和喷孔入口圆角半径对喷雾特性影响较大。

Spray properties and mixture formation strongly depend on nozzle flow characteristics.This part will describe the coupling of the diesel nozzle cavitating flow with the spray simulations.The nozzle cavitating flow simulations are obtained with the multiphase sol-ver.The flow field values at nozzle outlet will be linked to the inlet boundary conditions of the multiphase spray model.Local values at nozzle outlet have subsequently to be extracted,involved the velocity,the turbulent kinetic energy,cavitations,etc.Based on SAC nozzle,spray characteristics with various nozzle geometry,such as K-factor,radius of rounded inlet are studied in this paper.At the same time,the influence on spray characteristics from production error,injection pressure,chamber pressure are also studied.The re-sults indicate that injection pressure,chamber pressure,K-factor and radius of rounded inlet have great influence on flow characteris-tics.