Experimental Investigation Of Loss In An Annular Cascade Of Turbine Nozzle Blades Of Free Vortex Design

An investigation of the flow pattern immediately downstream of an annular cascade of nozzle blades designed for vortex-type velocity distribution and hub discharge angle of approximately 65 degrees from axial was conducted in order to obtain a better understanding of the processes by which the distribution of losses and deviations from design turning angle occur. For the two Mach numbers investigated, the loass region at the outer shroud decreased while that at the inner shroud increased with increasing Mach number.

In order to increase understanding of the origin of losses in a turbine, the secondary-flow components in the boundary layers and the blade wakes of an annular cascade of turbine nozzle blades (vortex design) were investigated. A detailed study was made of the total-pressure contours and, particularly, of the inner-wall loss cores down-stream of the blades.