Optimized design of radial flow compressor rotors

In a recent paper, the authors have analyzed the influence of the blade shape on both flow conditions through centrifugal compressor rotors and overall performance. The method of theoretical investigation was based upon a 'quasi-3D' flow model which accounts for the mutual influence of potential and viscous flow. In this way, both flow distribution and performance were calculated in relation to the boundary layer growth along end-walls and blade surfaces. In the present work, the authors aim to show the possibility of improving the aerodynamic design of compressor rotor, by matching the proposed method with an optimizing technique. Examples are presented as regards the dependence of optimal rotor configuration on the assigned objective (i.e. maximum of efficiency for a given pressure ratio) and on constraints imposed. The latter refer to limits on blade loading, relative and absolute Mach number or peripheral velocity. Of course, minimization of total pressure losses will be achieved also by evaluating the influence of rotor geometry and of the number of blades on boundary layer development and profile losses.