Blade cooling and sealing system

Abstract

A cooled component for a gas turbine engine, for example a turbine rotor blade, is provided. The component has an internal cooling flow passage. Cooling air is passed through the internal cooling flow passage to remove heat from the component and thereby reduce its temperature. The cooling air is bled from the internal cooling passage after it has passed through a portion of the passage into an internal bleed flow passage. This bled air is then used in a seal. Thus, some of the cooling air that enters the internal cooling flow passage is used both to cool the component and to form a seal, for example with another component.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is based upon and claims the benefit of priority from British Patent Application Number 1112880.8 filed 27 Jul. 2011, the entire contents of which are incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention concerns cooling and sealing arrangements in a gas turbine engine. In particular, the present invention concerns a method and apparatus for using flow to cool components in a gas turbine engine and seal between components of a gas turbine engine.[0004]2. Description of the Related Art[0005]The performance of a gas turbine engine, for example measured in terms of efficiency or specific output, may be improved by increasing the turbine gas temperature. It is therefore generally desirable to operate the turbine at the highest possible temperature. For a given gas turbine configuration (for example in terms of engine cycle compression ratio or bypass ratio), increasin...

AI Technical Summary

Benefits of technology

[0011]The aerofoil may include aerodynamic surfaces that, in operation, are gas-washed by the working fluid, such as a suction surface, a pressure surface, and a platform from which the suction surface and pressure surface extend. The blade or vane may comprise sealing features which may combine or interact with (for example interlock with, abut, or nearly abut) neighbouring surfaces (for example of neighbouring blades or vanes) of a gas turbine engine to form a seal when assembled. The blade or vane may optionally include a shroud at its tip. The shroud may include sealing features to prevent or reduce over-tip leakage flow, for example in blade embodiments. The shroud may extend around the entire outer circumference of the blades. Alternatively, the blade or vane may have a partial shroud, or winglet, at its tip (for example extending around a portion of the segment between the blades). Alternatively still, the blade or vane may have no shroud at its tip.

[0039]The flow that is used for cooling and sealing may be bled from a compressor of the gas turbine engine before entry into a combustor. Thus, using at least a portion of the flow for both cooling and sealing means that less air needs to be bled from the compressor and / or that more heat can be removed from a given blade or vane for a given amount of air bled from the compressor.

Problems solved by technology

As mentioned above, air that is bled from the compressor prior to combustion (i.e. air that has bypassed the combustor) cannot be used to generate useful work.

Extracting air from the compressor, for example for cooling the hot turbine components or for providing a sealing flow, therefore has an adverse effect on engine performance, such as operating efficiency.

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