Numerical analysis of 3-D potential flow in axial flow turbomachines

A numerical method is developed for the analysis of a three-dimensional steady incompressible potential flow through a cascade in axial flow turbomachines. The functional minimization finite element method using hexahedral trilinear elements is employed to determine the velocity potential of the absolute flow, and a finite-difference method based on a quadratic polynomial approximation is developed to calculate the velocity. Vortex sheets shedding from the trailing edge of blades can be analyzed by the finite element procedures using this method. This method is applicable to more general design conditions including nonuniform blade loadings. The example of the flow through a moving compressor cascade is computed.