Gas turbine of the axial flow type

摘要

In an axial flow gas turbine (30), a reduction in cooling air mass flow and leakage in combination with an improved cooling and effective thermal protection of critical parts within the turbine stages of the turbine is achieved by providing, within a turbine stage (TS), devices (43-48) to direct cooling air that has already been used to cool, especially the airfoils of the vanes (31) of the turbine stage (TS), into a first cavity (41) located between the outer blade platforms (34) and the opposed stator heat shields (36) for protecting the stator heat shields (36) against the hot gas and for cooling the outer blade platforms (34).

主权项

1. An axial flow gas turbine comprising:
a rotor including alternating rows of air-cooled blades and rotor heat shields; a stator including a vane carrier, alternating rows of air-cooled vanes, and stator heat shields mounted on the vane carrier, wherein the stator coaxially surrounds the rotor to define a hot gas path therebetween, such that the rows of blades and stator heat shields, and the rows of vanes and rotor heat shields, are opposite to each other, respectively, and wherein a row of vanes and an adjacent row of blades in the downstream direction define a turbine stage; wherein the blades comprise tips and outer blade platforms at said tips; at least one first cavity located between at least one of the outer blade platforms and at least one of the opposed stator heat shields; means within at least one turbine stage for directing cooling air that has already been used to cool into said at least one first cavity, for protecting the stator heat shields against the hot gas and for cooling the outer blade platforms; the vanes each comprising an outer vane platform; the means for directing comprising a second cavity for collecting the cooling air which exits the vane airfoil; the means for directing also comprising means for discharging the collected cooling air radially into said at least one first cavity; a shoulder separating the second cavity from the rest of the outer vane platform; and a sealing screen closing off the second cavity.