Numerical Studies of Blade Sweep Effects on Losses

Abstract

A turbine airfoil aerodynamic design process, similar to the current indust ry practice, is used to design turbine airfoil sections. The airfoil generator code employs Bezier polynomial curves to produce smooth airfoil shapes. For the calculations of the airfoil pressure distributions a discrete vortex method is used after the airfoil is designed and the novel Navier -Stokes (N -S) solver is developed for further examination of the airfoil performance. The vortex method can provide a fast way to calculate the airfoil pressure distributions. The N -S code is used to obtain the blade -to-blade quasi -three dimensional, turbulent, and viscous flow characteristics. The time -dependent N -S equations are discretized and integrated in a coupled manner based on a finite -volume formulation as well as a flux -difference splitting. The flux -difference splitting method enables us to compute with a rapid convergence. After the flow solver is validated with experimental data, this new code is further used to obtain an optimal airfoil design by analyzing the cascade flows. The present N -S code can handl e computations of both subsonic and supersonic flows and can be connected to an external optimizer code with the airfoil generator.