作　　者： ; ; ;

机构地区： 桂林航天工业学院汽车工程系

出　　处： 《车用发动机》 2013年第3期18-23,28,共7页

摘　　要： 使用Fluent双相流模型、RNGκ-ε湍流模型和标准壁面函数模拟喷孔内柴油的气/液双相流,讨论喷孔壁面边界层总厚度相同但网格层数不同对喷孔内湍动能分布的影响。首先与试验结果对比,证明了计算的可信程度。计算结果表明:边界层内网格层数越多,喷孔内最大湍动能越大,随距壁面距离的增大湍动能下降速度加快;在喷孔上游,边界层内网格层数不同,孔内横向湍动能分布形状不同,最大湍动能差别明显;在喷孔的中游,网格层数不同计算得到的湍动能分布形状仍有不同,但最大湍动能的数值差异减小;在喷孔出口区域附近,边界层内网格层数不同,但计算得到的湍动能分布形状相近。边界层内网格层数较少时,随流体向下游流动,壁面附近的湍动能增大;边界层内网格层数较多时,喷孔刚转弯后的湍动能远大于其他剖面的相应值,此后随着流体向下游的流动,各剖面的湍动能值相差不大;边界层内网格再增多,喷孔刚转弯后的湍动能达到最大值,此后,随着流体向下游流动,壁面附近的湍动能值逐渐减小。 Diesel vapor/liquid two-phase flow in nozzle was simulated with the two-phase flow model, the RNGme turbulence model and the standard wall function. Influence of grid layer number on turbulence kinetic energy distribution was discussed under the same total thickness of boundary layer. The calculation results were verified by comparing with the experimental re- sults. The more the grid layer number in the boundary layer was, the larger the maximum turbulence kinetic energy in nozzle was, and the larger the down slope of turbulence kinetic with the increasing distance from wall was. In the upstream of nozzle, the shape of horizontal turbulence kinetic energy distribution and the value of maximum turbulence kinetic energy were obvious- ly different because of grid layer number difference in the boundary layer. In the middle of nozzle, the shape of turbulence ki- netic energy distribution was still different, but the difference between maximum turbulence kinetic energy values decreased. Close to the nozzle exit, the shape of turbulence kinetic energy distribution was similar although the grid layer number in the boundary layer was different. For the less grid layer number in the boundary layer, the turbulence kinetic energy near the wall increased along the flow direction. For the more grid layer number in the boundary layer, the turbulence kinetic energy near the wall just after turning was far larger than the corresponding values on other sections and the difference between turbulence ki- netic energy values was little along the flow direction afterward. With the increase of grid layer number in the boundary layer, the turbulence kinetic energy near the wall just after turning would reach the maximum and decreased along the flow direction afterward.

关 键 词： 柴油 喷孔 湍流 空穴 边界层 网格 数值模拟

领　　域： [自动化与计算机技术] [自动化与计算机技术]