Design of a high-performance centrifugal compressor impeller and an investigation on the linear effects of the hub

Abstract

The performance of the turbocharger can be improved by optimizing the structural parameters of the compressor impeller. In this work, the existing centrifugal compressor impeller was taken as the case study, and the line shape of the hub was modified in order to study the influence of the line curvature of the hub on the compressor performance. Furthermore, the Navier–Strokes flow equation and the fourth-order Runge–Kutta method were used with Numeca software in order to solve the steady-state RANS equation, and the RANS equation is the averaging of unsteady N-S equations on time to solve the engineeringly required averaging. The numerical simulations and the performance predictions were made for each case, and then, the experiments were carried out to verify the accuracy of the aerodynamic performance that was obtained from the numerical simulations. The research results showed that within the design value range, the curvature of the impeller hub profile increased when the flow range and surge margin of the compressor impeller increased. Moreover, the pressure ratio, efficiency, and post-compression temperature increased when the relative Mach number at the inlet of the impeller decreased, the shock wave intensity that was generated by the gas in the flow channel decreased, and the velocity loss decreased. The obtained influence of the compressor impeller hub linearity on the compressor performance provides an opportunity to further improve the performance of the centrifugal compressor.