The present disclosure relates to a gas turbine engine, and more particularly to a reduction in purge air.
The core engine of a gas turbine engine typically includes a multistage axial compressor, a combustor and a high pressure turbine nozzle with one or more stages. Typical turbine nozzles, such as high pressure and low pressure turbine nozzles, define annular rings located adjacent to each turbine blade row to define axially alternate annular arrays of stator vanes and rotor blades.
To ensure that the rotatable blades and the static vane components do not contact each other under normal operating conditions, an annular gap is provided between the stator vanes and the bladed rotor. This requires, however, that the hot gases which pass through the turbine do not leak through the annular gap. Such leakage may result in a loss in turbine efficiency.
The conventional method to minimize hot gas leakage is the supply of high pressure purge air into the gap between the stator vanes and the bladed rotor. The purge air is directed radially outwardly over the surface of the rotatable disc and adjacent vane platform structure to exhaust through the gap into the core gas path. This minimizes hot gasses entrance into under-platform regions. These purge flows may cause some aerodynamic losses.