A Parametric Study of Radial Turbomachinery Blade Design in Three-Dimensional Subsonic Flow

An aerodynamic design method is described and used to implement a parametric study of radial turbomachinery blade design in three-dimensional subsonic flow. Given the impeller hub and shroud, the number of blades and their stacking position, the design method gives the detailed blade shape, flow and pressure fields that would produce a prescribed tangential averaged swirl schedule. The results from that study show that decreasing the number of blades increases the blade wrap, and that the blade loading is strongly affected by the rate of change of mean swirl along the mean streamlines. The results also show that the blade shape and the pressure field are rather sensitive to the prescribed mean swirl schedule which suggests that, by carefuly tailoring the swirl schedule, one might be able to control the blade shape and the pressure field and hence secondary flow.