Aerodynamic optimization design of centrifugal compressor's impeller with Kriging model

In the modern design system of centrifugal impellers, numerical simulations by computational fluid dynamics (CFD) have played a vital role. Despite the rapid growth in computer capability and the maturation of CFD software, the optimization design of centrifugal impellers, which rely fully on numerical simulations, is currently impractical due to the large computational costs required. An approximation model can be applied to overcome this obstacle. This article investigates the application of the Kriging model in the optimization of a centrifugal impeller. First, the feasibility of the Kriging model is verified by a test function and a measure to improve the accuracy of solution is proposed. Following this, on the basis of the impeller's parametric modelling, the Kriging model method is applied to the optimization of a typical industrial centrifugal impeller. It is found that the isentropic efficiency at the design point is increased by 2.49 per cent, and a distinct improvement is made in the flow inside the impeller.