VARIABLE CLEARANCE MECHANISM FOR USE IN A TURBINE ENGINE AND METHOD OF ASSEMBLY
A variable clearance mechanism for use in a turbine engine is provided that includes a stationary component, a plurality of articulating seal members coupled to the stationary component, and a biasing mechanism including an actuation ring. The variable clearance mechanism varies the position of stationary seal members to provide variable bucket tip clearance as a function of an operating condition of the turbine engine. The biasing mechanism is coupled to the plurality of articulating seal members for use in selectively translating the plurality of articulating seal members when the actuation ring is rotated circumferentially relative to the stationary component.
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The field of the present disclosure relates generally to turbine engines and, more specifically, to a variable clearance mechanism that includes articulating seal members for use in a turbine engine.
Known turbines experience several different phases of operation including, but not limited to, start-up, warm-up, steady-state, shutdown, and cool-down. In at least some of such known turbines, clearances between turbine rotor blade tips and inner surfaces of the surrounding seal members are controlled to facilitate improving operating efficiency. Such clearances generally vary as the turbine transitions from one operational phase to another. More particularly, each operational phase has different operating conditions associated with it, such as temperature, pressure, and rotational speed, which will induce changes in the clearances between turbine components, including static and moving components within the turbine.
In at least some known turbines, the clearances between the turbine rotor blades and the seal members are also controlled to prevent contact-related damage therebetween as the turbine transitions between operational phases. For example, in at least some known turbines, cold, or assembly, clearances are set to be no larger than required for steady-state operation to account for thermal and mechanical differences in the turbine when transitioning between phases of operation. Moreover, as described above, turbine efficiency depends at least in part on the clearance between tips of the rotating blades and seal members coupled to the surrounding casing. If the clearance is too large, enhanced gas flow may unnecessarily leak through the clearance gaps, thus decreasing the turbine's efficiency.
At least some known turbines use abradable and/or labyrinth seals that facilitate reducing leakage flow through the clearance gap. The leakage flow adversely affects turbine performance by bypassing flow around the blades that could be used to provide useful output for the turbine. Moreover, at least some known turbines facilitate reducing operating clearances by forming components from materials having a relatively low coefficient of thermal expansion, and/or with active translation of moveable seal members.
BRIEF DESCRIPTIONIn one aspect of the disclosure, a variable clearance mechanism for use in a turbine engine is provided. The mechanism includes a stationary component, a plurality of articulating seal members coupled to the stationary component, and a biasing mechanism including an actuation ring. The biasing mechanism is coupled to the plurality of articulating seal members for use in selectively translating the plurality of articulating seal members when the actuation ring is rotated circumferentially relative to the stationary component.
In another aspect of the disclosure, a turbine engine is provided. The turbine engine includes a rotor blade assembly including a plurality of rotor blades, a stationary component, a plurality of articulating seal members coupled to the stationary component, and a biasing mechanism including an actuation ring. The biasing mechanism is coupled to the plurality of articulating seal members for use in selectively translating the plurality of articulating seal members when the actuation ring is rotated circumferentially relative to the stationary component.
In yet another aspect of the disclosure, a method of assembling a variable clearance mechanism for use in a turbine engine is provided. The method includes providing a stationary component, coupling a plurality of articulating seal members to the stationary component, and coupling an actuation ring to the plurality of articulating seal members such that the actuation ring is configured to selectively translate the plurality of articulating seal members when the actuation ring is rotated circumferentially relative to the stationary component.
Embodiments of the present disclosure relate to systems and methods for use in controlling blade tip clearance in a turbine engine. More specifically, the systems described herein include articulating seal members that are easily configured to accommodate variations in the blade tip clearance during transient and/or steady-state operational phases of the turbine engine. The articulating seal members are coupled to a biasing mechanism that selectively translates the seal members radially during transitions between the transient and steady-state operational phases. The biasing mechanism includes an actuation ring and a plurality of levers coupled, either directly or indirectly, between the actuation ring and the seal members. As the actuation ring rotates circumferentially, the levers convert the circumferential motion of the actuation ring to a radial motion induced to the seal members. As such, the blade tip clearance may be selectively controlled to facilitate maintaining the integrity of the blade tips and seal members to improve the efficiency of the turbine engine.
As used herein, the terms “axial” and “axially” refer to directions and orientations that extend substantially parallel to a longitudinal axis of a turbine engine. Moreover, the terms “radial” and “radially” refer to directions and orientations that extend substantially perpendicular to the longitudinal axis of the turbine engine. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations that extend arcuately about the longitudinal axis of the turbine engine. It should also be appreciated that the term “fluid” as used herein includes any medium or material that flows, including, but not limited to, air, gas, liquid and steam.
In the exemplary embodiment, turbine engine 10 is a single-flow steam turbine engine. Alternatively, turbine engine 10 may be any type of steam turbine, such as, without limitation, a low-pressure turbine engine, an opposed-flow high-pressure and intermediate-pressure steam turbine combination, a double-flow steam turbine engine, and/or other steam turbine types. Moreover, as discussed above, the present invention is not limited to only being used in steam turbine engines and can be used in other turbine systems, such as gas turbine engines.
In the exemplary embodiment shown in
In the exemplary embodiment, turbine engine 10 also includes a stator component 44 coupled to casing 16. Casing 16 and stator component 44 each extend circumferentially about shaft 14. Shaft 14 includes a plurality of turbine stages 12 through which high-pressure, high-temperature operating fluid 40 is passed via turbine inlet 46. Turbine stages 12 include a plurality of nozzles 48. Turbine engine 10 may include any number of nozzles 48 that enables turbine engine 10 to operate as described herein. For example, turbine engine 10 may include more or less nozzles 48 than are illustrated in
During operation, high pressure and high temperature operating fluid 40 is channeled to turbine stages 12 from an energy source, such as a boiler (not shown), wherein thermal energy is converted to mechanical rotational energy by turbine stages 12. More specifically, operating fluid 40 is channeled through casing 16 from HP inlet 20 where it impacts the plurality of rotor blades 38, coupled to shaft 14 to induce rotation of shaft 14 about centerline axis 24. Operating fluid 40 exits casing 16 at LP outlet 22. Operating fluid 40 may then be channeled to the boiler (not shown) where it may be reheated or channeled to other components of the system, e.g., a condenser (not shown).
In the exemplary embodiment, turbine engine 10 also includes a variable clearance mechanism 100. Variable clearance mechanism 100 includes a biasing mechanism 102 and articulating seal member 104 coupled to biasing mechanism 102. Biasing mechanism 102 selectively translates articulating seal member 104 to facilitate modifying clearance 23 as turbine engine 10 transitions between a transient operational phase and a steady-state operational phase.
Biasing mechanism 102 also includes an actuator 114 coupled to actuation ring 110. Actuator 114 may be any device that induces circumferential rotation to actuation ring 110 during operation. For example, exemplary actuators may include, but are not limited to, a motor-driven device, a hydraulic device, and a pneumatic device. In the exemplary embodiment, actuator 114 includes a casing 116 and a piston 118 selectively translatable within casing 116. Piston 118 is coupled to actuation ring 110 via a pivot point 120. In operation, piston 118 selectively translates generally linearly within casing 116, and pivot point 120 converts the linear motion of piston 118 into a circumferential rotation of actuation ring 110.
Referring to
In the exemplary embodiment, articulating seal members 104 are translated radially outward by rotating actuation ring 110 in a first circumferential direction 122. More specifically, articulating seal members 104 are coupled to actuation ring 110 such that rotation of actuation ring 110 in first circumferential direction 122 facilitates increasing clearance 23 and increasing a gap 124 formed between adjacent articulating seal members 104. Actuation ring 110 may be rotated in first circumferential direction 122 by any circumferential amount that enables variable clearance mechanism 100 to function as described herein. As such, clearance 23 is selected as a function of a degree of circumferential rotation of actuation ring 110. Moreover, levers 112 are coupled between actuation ring 110 and each articulating seal member 104 to enable articulating seal members 104 to selectively translate simultaneously as actuation ring 110 is rotated.
Referring to
In the exemplary embodiment, biasing mechanism 102 includes a biasing element 135 that facilitates ensuring articulating seal members 104 are biased in a radially inward direction as turbine engine 10 (shown in
Referring to
In the exemplary embodiment, articulating seal members 104 are translated radially inward by rotating actuation ring 110 in a second circumferential direction 136. More specifically, articulating seal members 104 are coupled to actuation ring 110 such that rotating actuation ring 110 in second circumferential direction 136 facilitates decreasing clearance 23 and reducing gap 124 (shown in
The systems and methods described herein facilitate clearance control between a rotor assembly and adjustable seal members in a turbine engine. More specifically, the variable clearance mechanism described herein includes a biasing mechanism that selectively translates the adjustable seal members radially to modify a clearance between the rotor assembly and the seal members while closing a clearance between adjacent seal members. The biasing mechanism includes an actuation ring coupled to the seal members with a system of levers. The levers facilitate selectively translating the seal members radially as the actuation ring rotates circumferentially. By actuating the seal members with the circumferential rotation of the actuation ring, the biasing mechanism is not limited by radial movement constraints defined by the casing of the turbine, and can be actuated with a single mechanism. As such, the variable clearance mechanism facilitates selectively modifying the clearance between the rotor assembly and the adjustable seal members as the turbine engine transitions between operational phases.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims
1. A variable clearance mechanism for use in a turbine engine, said mechanism comprising:
- a stationary component;
- a plurality of articulating seal members coupled to said stationary component; and
- a biasing mechanism comprising an actuation ring, said biasing mechanism coupled to said plurality of articulating seal members for use in selectively translating said plurality of articulating seal members when said actuation ring is rotated circumferentially relative to said stationary component.
2. The mechanism in accordance with claim 1, wherein said actuation ring is rotated in a first circumferential direction to translate said plurality of articulating seal members radially inward, and said actuation ring is rotated in a second circumferential direction to translate said plurality of articulating seal members radially outward.
3. The mechanism in accordance with claim 2, wherein a degree of translation of said plurality of articulating seal members is selected based on a degree of rotation of said actuation ring in the first and second circumferential directions.
4. The mechanism in accordance with claim 1, wherein said biasing mechanism comprises at least one lever coupled between said actuation ring and at least one of said plurality of articulating seal members, wherein said at least one lever is configured to convert circumferential movement of said actuation ring into substantially linear movement of said plurality of articulating seal members.
5. The mechanism in accordance with claim 4, wherein said biasing mechanism comprises at least one lever coupled between said actuation ring and each of said plurality of articulating seal members such that said plurality of articulating seal members are simultaneously translated when said actuation ring is rotated circumferentially.
6. The mechanism in accordance with claim 1, wherein said biasing mechanism comprises an actuator coupled to said actuation ring, said actuator configured to induce circumferential rotation to said actuation ring.
7. The mechanism in accordance with claim 1, wherein said actuation ring is configured to remain at a substantially uniform distance from said stationary component as said actuation ring rotates circumferentially.
8. A turbine engine comprising:
- a rotor blade assembly comprising a plurality of rotor blades;
- a stationary component;
- a plurality of articulating seal members coupled to said stationary component; and
- a biasing mechanism comprising an actuation ring, said biasing mechanism coupled to said plurality of articulating seal members for use in selectively translating said plurality of articulating seal members when said actuation ring is rotated circumferentially relative to said stationary component.
9. The turbine engine in accordance with claim 8, wherein said actuation ring is rotated in a first circumferential direction to translate said plurality of articulating seal members radially inward, and said actuation ring is rotated in a second circumferential direction to translate said plurality of articulating seal members radially outward.
10. The turbine engine in accordance with claim 9, wherein a clearance between said plurality of articulating seal members and said plurality of rotor blades is selected based on a degree of rotation of said actuation ring in the first and second circumferential directions.
11. The turbine engine in accordance with claim 8, wherein said biasing mechanism comprises at least one lever coupled between said actuation ring and at least one of said plurality of articulating seal members, wherein said at least one lever is configured to convert circumferential movement of said actuation ring into substantially linear movement of said plurality of articulating seal members.
12. The turbine engine in accordance with claim 8 further comprising a slide track coupled to adjacent articulating seal members, said slide track configured to substantially maintain alignment between said adjacent articulating seal members as they selectively translate linearly.
13. The turbine engine in accordance with claim 8, wherein said biasing mechanism comprises a biasing element coupled to at least one of said plurality of articulating seal members, said biasing element configured to ensure the selective translation of said at least one of said plurality of articulating seal members is responsive to the circumferential rotation of said actuation ring.
14. The turbine engine in accordance with claim 8 further comprising a rack and pinion assembly associated with said actuation ring and configured to facilitate translating said plurality of articulating seal members in response to rotation of said actuation ring relative to said stationary component.
15. A method of assembling a variable clearance mechanism for use in a turbine engine, said method comprising:
- providing a stationary component;
- coupling a plurality of articulating seal members to the stationary component;
- coupling an actuation ring to the plurality of articulating seal members such that the actuation ring is configured to selectively translate the plurality of articulating seal members when the actuation ring is rotated circumferentially relative to the stationary component.
16. The method in accordance with claim 15, wherein coupling the actuation ring to the plurality of articulating seal members comprises coupling at least one lever between the actuation ring and the plurality of articulating seal members.
17. The method in accordance with claim 16, wherein coupling at least one lever comprises coupling the at least one lever between the actuation ring and each of the plurality of articulating seal members such that the plurality of articulating seal members are simultaneously translated when the actuation ring is rotated circumferentially.
18. The method in accordance with claim 16 further comprising forming a slot in at least one of the stationary component and the at least one lever, wherein the slot facilitates sliding engagement between the at least one lever and at least one of the actuation ring, the stationary component, and the plurality of articulating seal members.
19. The method in accordance with claim 15 further comprising coupling an actuator to the actuation ring, wherein the actuator is configured to induce circumferential rotation to the actuation ring.
20. The method in accordance with claim 15 further comprising defining a distance between the stationary component and the actuation ring that remains substantially uniform as the actuation ring rotates circumferentially.
Type: Application
Filed: Feb 3, 2014
Publication Date: Aug 6, 2015
Applicant: General Electric Company (Schenectady, NY)
Inventors: Kevin Joseph Barb (Clifton Park, NY), Joseph Anthony Cotroneo (Clifton Park, NY)
Application Number: 14/171,381