Aero-thermal investigation of end wall and showerhead cooling in a nozzle vane cascade

The aerodynamic and thermal performance of a gas turbine cascade with slot platform and vane showerhead cooling was investigated. The cascade was tested at a high inlet turbulence intensity level (Tu1 = 9%) and at variable cooling injection conditions of the upstream slot. Showerhead blowing ratio was maintained at the nominal value. Secondary flows and platform film cooling effectiveness measurements provided a comprehensive picture of the aerodynamic and thermal performance of the vane cascade. Slot cooling was found to slightly affect secondary flows. At small injection rates thermal coverage of the platform is limited to the front part, up to the passage vortex separation line, while for higher values a good thermal protection is obtained on the whole end wall surface. Showerhead injection contributes to cool the platform leading edge region and to reduce secondary losses.