涡轮增压器轴向力稳态数值模拟及优化

采用Numeca数值分析软件建立了某增压器涡轮机及压气机端流场网格模型,并计算出发动机不同转速下涡轮增压器的涡轮端及压气机端的稳态轴向力分布,分析得出由涡轮端指向压气机端方向的轴向力值较大,而由压气机端指向涡轮端方向的轴向力值较小。对压气机叶轮流场进行了分析,发现压气机叶轮背部间隙内的静压分布与轴向力大小紧密相关;研究了叶轮叶顶间隙对轴向力的影响,发现叶轮轴向间隙对轴向力的影响比径向间隙大,但效率损失亦较大。在保证涡轮机效率不降低的原则下,对涡轮箱流道截面进行了改进,轴向力在发动机高转速下降低约8N。

Steady Numerical Simulation and Optimization of Turbocharger Axial Force

Turbine and compressor flow field grid models of a turbocharger were established by using Numeca numerical software.At different engine speeds,the axial forces of turbine and compressor in the steady state were computed.It indicates that the axial force that pointed to the compressor from the turbine was larger and that the opposite force was smaller.Besides,the flow field of compressor was analyzed,which was found that the static pressure distribution at the back of impeller correlated with the axial force closely.Further,the influence of tip clearance of blade on axial force was researched,which was found that not only the increasing axial clearance had more positive effect than that of radial clearance to decrease the axial force,but also the efficiency loss was larger.Finally,the turbine efficiency was not reduced when the cross section of volute was modified and the axial force at high speed of engine decreased by 8 N.