Influence of film cooling on the secondary flow in a turbine nozzle

An annular film cooled turbine nozzle with cooling air ejection from a single row of holes on the stator suction side near the trailing edge is experimentally and numerically investigated concerning the influence of film cooling on the secondary flow development. The location and intensity of the secondary Bow vortices are analyzed with varied blowing rates. The flowfield downstream of the nozzle is measured using a five-hole probe. Furthermore, oil flow experiments are carried out to visualize the areas on the blade surface affected by the secondary how A three-dimensional Navier-Stokes solver numerical simulation of the stator Bow including cooling air ejection supports the measurements. This gives an insight to vortex generation and development in Bow regions, where measurements are difficult or impossible. Depending on the blowing ratio the secondary vortex system is deflected toward the endwalls. A detailed analysis is presented.