Proper orthogonal decomposition assisted inverse design optimisation method for the compressor cascade airfoil

Abstract

Inverse design is by far the most physically explicit method in the turbomachinery field for designing a cascade airfoil shape for a prescribed distribution of aerodynamic parameters on the airfoil surface. However, a vital drawback of the available inverse design methods for cascade airfoils is the lack of effective techniques to specify optimal target aerodynamic parameters, particularly optimal pressure distribution on the airfoil surface. This drawback hinders the wide application of inverse design optimisation methods in the turbomachinery field. To overcome this vital drawback, we proposed a proper orthogonal decomposition (POD) assisted inverse design optimisation method for cascade airfoils, in which an optimal pressure distribution on airfoil surface was automatically obtained by solving a direct design optimisation problem and accurately parameterised via the POD method. The effectiveness of the proposed inverse design optimisation method was demonstrated using the inverse designs of a compressor cascade airfoil with two different optimisation objectives. Results highlighted the proposed inverse design method's capability to significantly improve the aerodynamic performance of the compressor cascade. The POD method can provide an adequate and flexible description of airfoil surface pressure distribution with a small number of POD modes. This work is valuable for the further development of inverse design optimisation methods for advanced compressor blades.