Analysis of the influence of blade's machining error on aerodynamic performance of impeller based on NUMECA

Abstract

As the core component of centrifugal compressor impeller, blade's performance quality has a crucial influence on the structure strength and aerodynamic performance of the compressor. In this paper, by using NUMECA software to solve the Reynolds averaged Navier-Stokes (RANS) equation to simulate centrifugal impeller passage of steady three-dimensional viscous flow, the impellers whose different parts of the blade surface contain profile error and the impellers which contain different sizes of surface profile error have been carried on the numerical analysis. Finally compared with the designed impeller, the influence of machining error on the impeller aerodynamic performance is analyzed. The results show that the machining error makes an impact on the performance of the impeller, leading to the decrease of the impeller efficiency and pressure ratio. For the front, middle and back of the blade, the machining error which is located in the middle of the blade has the greatest influence on the performance of the impeller, and considering the error of the front, middle and back, the error of regular S-type is the biggest of all. After adding different size of regular S-type surface profile error, efficiency and pressure ratio lost maximum occurring under the condition of the surface profile of 0.15 mm, rather than in the maximum surface profile of 0.2 mm.