摘要：基于有限元液体连续相湍流仿真模型,研究柴油机用等径喷嘴内部油液的流动情况,分析入口压力对气相体积分数、湍动能和对称轴线速度的影响。结果表明:压力下降明显发生在喷嘴入口处,喷孔入口处靠近孔壁位置的湍流能最大,油液的轴向移动速度和承受的压强成反比;随着入口压力的增大,气相体积分数呈单调增加的趋势,当入口压力增大到120 MPa后,气相体积分数稳定在100%;湍动能最大处的位置由开始的喷孔入口中心轴处逐渐转移到喷嘴入口壁面上,入口压力与流速近似于呈线性变化规律;综合分析确定入口压力在100~120 MPa对保障压力型等径喷嘴燃油雾化效率是较为有利的。

关键词：柴油机；喷嘴；流动特性；入口压力

Abstract：Based on the finite element liquid continuous phase turbulent flow simulation model, the internal oil flows of diesel engine equal diameter nozzle were studied. The effect of inlet pressure on the gas phase volume fraction, turbulent kinetic energy and symmetric axis linear velocity were analyzed. Results show that the pressure drop apparently occurs at the entrance of nozzle, the turbulence occurs at the entrance of nozzle and near the location of hole shows the biggest. The oil axial movement is inversely proportional to the speed and under pressure. The gas phase volume fraction has a monotone increasing trend with the increase of inlet pressure. When the inlet pressure increases to 120 MPa the gas phase volume fraction steadys at 100%. The location of the turbulent kinetic energy maximizes by the beginning of the nozzle entry central axis then gradually transfers to the nozzle inlet on the wall and the relationship between inlet pressure and flow rate has a linear change rule. Comprehensive analysis to determine the inlet pressure to guarantee in 100~120 MPa pressure type fuel atomization diameter nozzle efficiency is more beneficial.

Keywords: diesel engine；nozzle；flow characteristics；inlet pressure