涡轮增压器转子涡轮级气动轴向力数值计算

Numerical Calculation of Aerodynamic Axial Force of Turbine Rotor

应用计算流体动力学软件CFX,以某柴油发动机的涡轮增压器涡轮级为研究对象,对其进行了轴向力传统理论计算与数值模拟计算。计算出不同发动机折合转速下涡轮端轴向力的大小,并与传统计算方法进行对比,通过对窄缝间隙的流场分析,找出两者之间差异的原因。研究结果表明,随着增压器转子转速增加,涡轮端轴向力合力越来越大,且两种计算方法结果差异随之减小,由最大值146.314N减至125.4N,减小了14.3%;研究密封环间隙、叶顶间隙对轴向力的影响,发现叶顶间隙对轴向力影响比密封环间隙小0.155～2.955N,并且发现在整个计算的过程中,传统计算给予的假设近乎理想状态,并非实际情况。

The computational fluid dynamics software CFX, with a diesel engine turbocharger turbine stage for the study is carried out to calculate the axial force in traditional theory and numerical simulation. The· axial force of the turbine end under different engine speed is calculated and compared with the traditional calculation method. Through the analysis of the flow field of the slot gap, the cause of the difference is found out.The results show that as the rotor speed of the supercharger increases, the axial force of the turbine end becomes larger and with the difference between the two methods decreases, the maximum decreases from 146.314N to 125.4N, a decrease of 14.3%.The influence of seal ring clearance and tip clearance on axial force is studied. It is found that the tip clearance had a smaller (0.155~2.955)N effect on the axial force than the seal ring, and it is found that the traditional assumptions given by the near-ideal state, not the actual situation in the whole calculation process.