Three-dimensional flow analysis of turbine blade cascades with leading-edge ejection

The results of two different cooling configurations in a turbine cascade, o ne with slot ejection and one with shower-head ejection, are presented. Exp erimental and numerical results of the pressure distribution and the three- dimensional flowfield are compared. The numerical results correspond well w ith the experimental data. The investigations are performed for film-cooled cases with a blowing ratio of M = 1.1. It can be shown that complete discr etization of the cooling channels and the plenum is necessary to obtain goo d aerodynamic results of the main how because the complex flow structure in the ejection channels and the plenum has a significant influence on the ca lculated aerodynamic behavior of the blades. In the leading-edge area, the interaction of the cooling fluid jets and the main flow leads to mixture vo rtices and flow separations. Furthermore, the influence of secondary how ph enomena on the distribution of the cooling fluid along the blade surface is presented. On the suction side, the passage vortex leads to a displacement of cooling fluid in the direction of the midspan.