Rotor Axial Aerodynamic Force Analysis Of Automotive Turbocharger

The research on the axial aerodynamic force of turbochargers has always been a difficult point in the field of rotating machinery,and there is less research on the axial aerodynamic force of turbocharger.During the high-speed operation of supercharger,the aerodynamic loads are distributed asymmetrically on both sides of the compressor and turbine wheel to form an axial force.The axial force is one of the most important factors to affect the reliability and the working life of supercharger.Researching the formation mechanism of the aerodynamic axial force could help to improve the predication ability of axial force better and improve the design level of the rotor bearing,thereby the reliability of the turbocharger improved.Therefore,the axial aerodynamic force calculated by the numerical calculation method are compared with the results calculated by the traditional theoretical formula,and the variation of the axial aerodynamic force of the turbocharger rotor with narrow gaps under different working conditions are explored in this paper.In this paper,taking a turbocharger as the research object,the three-dimensional geometric model of the turbocharger turbine and the turbocharger compressor and the overall geometric model of the turbocharger are established.The flow field of the turbocharger compressor and turbine are respectively simulated by the commercial computational fluid dynamics software.The axial force results by the numerical calculation method are compared with the results calculated by the traditional theoretical formula,the axial aerodynamic forces variation of the turbocharger rotor are analyzed under different tip clearance and different operating conditions.The results of this study show that the compressor end axial force are greatly influenced by the blade tip clearance,the compressor end axial force increases with the tip clearance reduce,the axial force variation is more obvious in the high speed.Speed is the vital factor to affect the turbocharger axial force.The compressor axial force,turbine axial force and turbocharger axial force are all increased with the speed increases,but the degree of increase is related to the structure of the turbocharger.The axial force of the turbocharger turbine increases with the expansion ratio increases,and the axial force-expansion ratio is so close to the linear change.The axial force of the compressor increases with the pressure ratio increases and the axial force of the turbocharger increases with the increase of the pressure ratio.