Aerodynamic Inverse Blade Design of Axial Compressors in Three-Dimensional Flow Using a Commercial CFD Program

Abstract

An aerodynamic inverse design method is developed for the simulation of three-dimensional viscous flow over blades, it is implemented into a commercial CFD program, namely ANSYS-CFX, and it is applied to the design of a transonic compressor stage. The implementation is validated for Rotor 37; it is then assessed in the redesign of Stage 67 stator. One set of design choices is to prescribe a target blade pressure loading and blade thickness distributions and a stacking line from hub to tip. The blade walls are assumed to be moving with a virtual velocity that would asymptotically drive the blade to the shape that would correspond to the specified target pressure distribution. This virtual velocity distribution is computed from the difference between the computed and the target pressure distributions. This inverse design approach is fully consistent with the viscous flow assumption and is independent of the CFD approach taken. The Arbitrary Lagrangian-Eulerian formulation of the unsteady Reynolds-Averaged Navier Stokes equations is solved in a time accurate fashion with the blade motion being the source of unsteadiness. At each time step, the blade shape is modified and dynamic meshing is used to remesh the fluid flow domain. To demonstrate the ability of this approach, it is applied to redesign the stator of a transonic axial fan, Stage 67, to improve its performance.