Patent Application
20170321565
This disclosure relates to gas turbine engines, and more particularly to the prevention of undesirable leakage between rotating components and stationary components of gas turbine engines.
Ingestion leakage between rotating structures and stationary or static structures of a gas turbine engine are challenging to overcome. If significant amounts of hot gas leak from the flow path of the gas turbine engine to areas outside of the flow path, not only is engine performance degraded, but components outside of the flowpath, which are not constructed to withstand such high temperatures, may be damaged by the hot gas leakage.
Typical configurations often include shiplap features, in which the static component and rotating component overlap radially and/or axially in an effort to prevent leakage. Such configurations, however, have limited success due to clearance gaps required between the static components and rotating components to prevent contact therebetween during operation of the gas turbine engine.
In one embodiment, an arrangement of a rotating component and a stationary component of a gas turbine engine includes a rotating component, a stationary component positioned to define an actual gap between the rotating component and the stationary component, and a flow restriction feature formed at one of the stationary component or the rotating component. The flow restriction feature is configured to induce a recirculation flow at the actual gap, thereby defining an effective gap between the rotating component and the stationary component to reduce a leakage flow therebetween, while maintaining the actual gap greater than the effective gap.
Additionally or alternatively, in this or other embodiments the flow restriction feature is a hook feature formed in the stationary component.
Additionally or alternatively, in this or other embodiments the hook feature is located at an entrance to the actual gap at a hot gas flowpath of the gas turbine engine.
Additionally or alternatively, in this or other embodiments the flow restriction feature has a major axis extending substantially parallel to an airflow direction into the flow restriction feature.
Additionally or alternatively, in this or other embodiments one or more dividing walls are located at the flow restriction feature.
Additionally or alternatively, in this or other embodiments the one or more dividing walls are configured to restrict circumferential flow through the flow restriction feature.
In another embodiment, a turbine assembly of a gas turbine engine includes a turbine rotor rotatable about a central axis of the gas turbine engine, a turbine stator located axially adjacent to the turbine rotor defining an actual gap between the turbine rotor and the turbine stator. The turbine stator is configured to be stationary relative to the central axis. A flow restriction feature is formed at the turbine configured to induce a recirculation flow at the actual gap, thereby defining an effective gap between the turbine rotor and the turbine stator to reduce a leakage flow therebetween, while maintaining the actual gap greater than the effective gap.
Additionally or alternatively, in this or other embodiments the flow restriction feature is a hook feature formed in the stationary component.
Additionally or alternatively, in this or other embodiments the hook feature is located at an entrance to the actual gap at a hot gas flowpath of the gas turbine engine.
Additionally or alternatively, in this or other embodiments the flow restriction feature has a major axis extending substantially parallel to an airflow direction into the flow restriction feature.
Additionally or alternatively, in this or other embodiments one or more dividing walls are located at the flow restriction feature.
Additionally or alternatively, in this or other embodiments the one or more dividing walls are configured to restrict circumferential flow through the flow restriction feature.
In yet another embodiment, a gas turbine engine includes a rotating component, a stationary component positioned to define an actual gap between the rotating component and the stationary component and a flow restriction feature formed at one of the stationary component or the rotating component. The flow restriction feature is configured to induce a recirculation flow at the actual gap, thereby defining an effective gap between the rotating component and the stationary component to reduce a leakage flow therebetween, while maintaining the actual gap greater than the effective gap.
Additionally or alternatively, in this or other embodiments the flow restriction feature is a hook feature formed in the stationary component.
Additionally or alternatively, in this or other embodiments the hook feature is positioned at an entrance to the actual gap at a hot gas flowpath of the gas turbine engine.
Additionally or alternatively, in this or other embodiments the flow restriction feature has a major axis extending substantially parallel to an airflow direction into the flow restriction feature.
Additionally or alternatively, in this or other embodiments one or more dividing walls are located at the flow restriction feature.
Additionally or alternatively, in this or other embodiments the one or more dividing walls are configured to restrict circumferential flow through the flow restriction feature.
Additionally or alternatively, in this or other embodiments the rotating component is a turbine rotor.
Additionally or alternatively, in this or other embodiments the stationary component is a turbine stator.
The subject matter which is regarded as the present disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
In a two-spool configuration, the high pressure turbine 20 utilizes the extracted energy from the hot combustion gases to power the high pressure compressor 16 through a high speed shaft 24, and the low pressure turbine 22 utilizes the energy extracted from the hot combustion gases to power the low pressure compressor 14 and the fan section 12 through a low speed shaft 26. The present disclosure, however, is not limited to the two-spool configuration described and may be utilized with other configurations, such as single-spool or three-spool configurations, or gear-driven fan configurations.
Gas turbine engine 10 is in the form of a high bypass ratio turbine engine mounted within a nacelle or fan casing 28 which surrounds an engine casing 30 housing an engine core 32. A significant amount of air pressurized by the fan section 12 bypasses the engine core 32 for the generation of propulsive thrust. The airflow entering the fan section 12 may bypass the engine core 32 via a fan bypass passage 34 extending between the fan casing 28 and the engine casing 30 for receiving and communicating a discharge flow F1. The high bypass flow arrangement provides a significant amount of thrust for powering an aircraft.
The engine casing 30 generally includes an inlet case 36, a low pressure compressor case 38, and an intermediate case 40. The inlet case 36 guides air to the low pressure compressor case 38, and via a splitter 42 also directs air through the fan bypass passage 34.
Referring now to
Referring now to
To prevent such leakage through the gap 54 either into or out of the hot gas flowpath 52, the turbine stator 50 includes a hook feature 56. In some embodiments, such as shown in
The hook feature 56 is configured to allow an airflow 60 from the hot gas flowpath 52 into the hook feature 56, which results in a recirculation flow 62 at least partially in the hook feature 56, and in some embodiments extending to outside of the hook feature 56. The recirculation flow 62 narrows an effective gap 64 between the turbine rotor 48 and the turbine stator 50 thus restricting airflow from the hot gas path 52 from flowing through the gap 54. In some embodiments, the hook feature 56 is curvilinear and has a major axis 66. The major axis 66 is substantially aligned with the airflow 60 to maximize the recirculation flow 62.
Referring now to
Utilizing the hook feature 56 results in a non-contact flow restriction via the recirculation flow 60, which reduces the effective gap 62 between the turbine rotor 48 and the turbine stator 50. The recirculation flow 60 reduces leakage via reduction of the effective gap 62 while still allowing the actual gap 54 between the turbine rotor 48 and the turbine stator 50 to be large enough to provide adequate operational clearance so contact between the turbine rotor 48 and the turbine stator 50 is avoided during operation of the gas turbine engine.
While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
