Uncertainty quantification of typical deviations on the centrifugal impeller performance across multiple tolerance zones

To investigate the impact of manufacturing deviations on centrifugal impeller performance, this research focuses on the Krain high-pressure-ratio centrifugal impeller. The non-intrusive polynomial chaos method is employed for uncertainty quantification. Seven typical manufacturing deviations across three tolerance zones are considered, and their influence on aerodynamic performance is quantitatively evaluated. The results indicate that, at the peak-efficiency condition, blade thickness deviation has the most significant impact on the uncertainties in isentropic efficiency and total pressure ratio. At near-stall conditions, the sensitivity of parameters such as leading-edge radius and leading-edge tip clearance increases significantly. The reduction in performance fluctuations across different manufacturing precision levels exhibits marginal effects; therefore, tailored manufacturing strategies should be adopted for different deviations. Furthermore, deviations in the leading-edge radius, blade thickness, and tip clearance show significant negative correlations with aerodynamic performance, whereas inlet and outlet geometric angles exhibit positive correlations. Uncertainty analysis of flow field further shows that the difference in sensitivity ranking between the PE and NS conditions is related to the change in sensitive flow regions. This study establishes a quantitative mapping between geometric uncertainty and aerodynamic performance, providing theoretical support for centrifugal impeller design and the formulation of tolerance standards.