FLOW MANIPULATING ARRANGEMENT FOR A TURBINE EXHAUST DIFFUSER
A flow manipulating arrangement for a turbine exhaust diffuser includes a strut having a leading edge and a trailing edge, the strut disposed within the turbine exhaust diffuser. Also included is a plurality of rotatable guide vanes disposed in close proximity to the strut and configured to manipulate an exhaust flow, wherein the plurality of rotatable guide vanes is coaxially aligned and circumferentially arranged relative to each other. Further included is an actuator in operative communication with the plurality of rotatable guide vanes and configured to actuate an adjustment of the plurality of rotatable guide vanes. Yet further included is a circumferential ring operatively coupling the plurality of rotatable guide vanes, wherein the actuator is configured to directly actuate rotation of one of the rotatable guide vanes, and wherein the circumferential ring actuates rotation of the plurality of rotatable guide vanes upon rotational actuation by the actuator.
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The subject matter disclosed herein relates to turbine systems, and more particularly to boundary layer flow control of turbine exhaust diffuser components.
Typical turbine systems, such as gas turbine systems, for example, include an exhaust diffuser coupled to a turbine section of the turbine system to increase efficiency of a last stage bucket of the turbine section. The exhaust diffuser is geometrically configured to rapidly decrease the kinetic energy of flow and increase static pressure recovery within the exhaust diffuser.
Commonly, the exhaust diffuser is designed for full load operation, however, the turbine system is often operated at part load or on a cold day. Therefore, part load performance efficiency is sacrificed, based on the full load design. Inefficiency is due, at least in part, to flow separation on exhaust diffuser components, such as walls and struts, for example. Flow separation often is caused, in part, by swirling of the flow upon exit of the last bucket stage of the turbine section and entry into the exhaust diffuser. The magnitude of swirl may be quantified as a “tangential flow angle,” and such an angle may be up to about 60 degrees during part load and 20 degrees during a cold day, which leads to a higher angle of attack on the exhaust diffuser components, such as the struts, for example. Such a flow characteristic leads to boundary layer growth and flow separation and eventually reduced pressure recovery
BRIEF DESCRIPTION OF THE INVENTIONAccording to one aspect of the invention, a flow manipulating arrangement for a turbine exhaust diffuser includes a strut having a leading edge and a trailing edge, the strut disposed within the turbine exhaust diffuser. Also included is a plurality of rotatable guide vanes disposed in close proximity to the strut and configured to manipulate an exhaust flow, wherein the plurality of rotatable guide vanes is coaxially aligned and circumferentially arranged relative to each other. Further included is an actuator in operative communication with the plurality of rotatable guide vanes and configured to actuate an adjustment of the plurality of rotatable guide vanes. Yet further included is a circumferential ring operatively coupling the plurality of rotatable guide vanes, wherein the actuator is configured to directly actuate rotation of one of the rotatable guide vanes, and wherein the circumferential ring actuates rotation of the plurality of rotatable guide vanes upon rotational actuation by the actuator.
According to another aspect of the invention, a flow manipulating arrangement for a turbine exhaust diffuser includes an inner barrel extending in a longitudinal direction of the turbine exhaust diffuser. Also included is an outer wall disposed radially outwardly of the inner barrel. Further included is a strut extending between, and operatively coupled to, the inner barrel and the outer wall, wherein the strut comprises a leading edge and a trailing edge. Yet further included is at least one guide vane disposed axially upstream of the leading edge or downstream of the trailing edge of the strut, the at least one guide vane selectively circumferentially displaceable relative to the strut.
According to yet another aspect of the invention, a flow manipulating arrangement for a radial turbine exhaust diffuser includes an inner wall. Also included is an outer wall. Further included is a strut operatively coupled to at least one of the inner wall and the outer wall. Yet further included is at least one rotatable guide vane disposed proximate the strut, wherein the at least one rotatable guide vane is selectively rotatable over a range of angular positions and displaceable in at least one of an axial direction and a radial direction.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, 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 invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTIONReferring to
The combustor section 14 uses a combustible liquid and/or gas fuel, such as natural gas or a hydrogen rich synthetic gas, to run the turbine system 10. For example, fuel nozzles 20 are in fluid communication with an air supply and a fuel supply 22. The fuel nozzles 20 create an air-fuel mixture, and discharge the air-fuel mixture into the combustor section 14, thereby causing a combustion that creates a hot pressurized exhaust gas. The combustor section 14 directs the hot pressurized gas through a transition piece into a turbine nozzle (or “stage one nozzle”), and other stages of buckets and nozzles causing rotation of turbine blades within an outer casing 24 of the turbine section 16. Subsequently, the hot pressurized gas is sent from the turbine section 16 to an exhaust diffuser 26 that is operably coupled to a portion of the turbine section, such as the outer casing 24, for example.
Although illustrated and described above as a gas turbine system, it is to be appreciated that the turbine system 10 may alternatively be a steam turbine system. As will be described below, various embodiment of the exhaust diffuser 26 are contemplated, such as an axial exhaust diffuser and a radial exhaust diffuser.
Referring now to
Also disposed between the outer surface 36 of the inner barrel 34 and the inner surface 40 of the outer wall 38 is at least one, but typically a plurality of struts 42, with exemplary embodiments including a number of struts ranging from four (4) to twelve (12) struts circumferentially spaced from each other in a coaxial alignment. The plurality of struts 42 serves to hold the inner barrel 34 and the outer wall 38 in a fixed relationship to one another, as well as providing bearing support. As the strut 42 is disposed within the area between the inner barrel 34 and the outer wall 38, the exhaust flow 30 passes over the strut 42. Therefore, the strut 42 influences the flow characteristics of the exhaust flow 30, and hence the overall exhaust diffuser performance. The plurality of struts 42 is shaped as or surrounded by an airfoil, and it is to be appreciated that the precise geometry and dimensions of the plurality of struts 42 may vary from that illustrated, based on the application. Each of the plurality of struts 42 includes a leading edge 44 and a trailing edge 46.
As the exhaust flow 30 exits the turbine section 16, the last stage bucket exit tangential flow angle (
Referring to
The plurality of rotatable guide vanes 52 is rotatable about an axis defined by the rotatable member 54 over a range of angular positions. The range of angular positions advantageously provides numerous positions of the plurality of rotatable guide vanes 52, thereby accounting for various flow angles of the exhaust flow 30. Specifically, the plurality of struts 42 is aligned in a direction to provide efficient flow characteristics of the exhaust flow 30 within the exhaust diffuser 26 at certain operating conditions, such as a base load, or full-speed, full-load operating condition. However, flow angles of the exhaust flow 30 differ at other operating conditions, such as a part load operating condition, for example. In the alternate operating conditions, efficiency is reduced due to an increase in boundary layer formation. By rotating the plurality of rotatable guide vanes 52 to positions corresponding to appropriate flow manipulating positions, the exhaust flow 30 is manipulated in what is referred to as a “straightening” manner, which results in a desirable flow angle of the exhaust flow 30 upon passage over the plurality of struts 42.
In one embodiment, with reference to
As described above, the plurality of rotatable guide vanes 52 is rotatable over a range of angular positions. The range of angular positions corresponds to a range of operating conditions of the turbine system 10, and more specifically a range of angles of tangential flow of the exhaust flow 30. For example, a first position corresponds to a first condition and a second position corresponds to a second condition. The first position of the plurality of rotatable guide vanes 52 is relatively parallel to the plurality of struts 42 at a first condition corresponding to a full-speed, full-load operating condition of the turbine system 10. As the speed of the turbine system 10 is reduced to a part load condition, such as 60% speed, for example, the plurality of rotatable guide vanes 52 are rotated to an angle that provides desirable manipulation of the exhaust flow 30 to straighten for flow over the plurality of struts 42.
Referring now to
Referring now to
Each of the plurality of guide vanes 202 are aligned in a substantially parallel alignment with the plurality of struts 42, but each stage of guide vanes is adjustable in a circumferentially displaceable manner. Specifically, the plurality of guide vanes 202 are “clocked” to alter their alignment with the plurality of struts 42. For example, in a first position (
As is the case with the previous embodiments described, the flow manipulation arrangement 200 is actuated with an actuator arrangement 204, such as one or more motors that directly or indirectly interact with a circumferential ring 206 that controls the position of the plurality of guide vanes 202.
Referring now to
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
Claims
1. A flow manipulating arrangement for a turbine exhaust diffuser comprising:
- a strut having a leading edge and a trailing edge, the strut disposed within the turbine exhaust diffuser;
- a plurality of rotatable guide vanes disposed in close proximity to the strut and configured to manipulate an exhaust flow, wherein the plurality of rotatable guide vanes is coaxially aligned and circumferentially arranged relative to each other;
- an actuator in operative communication with the plurality of rotatable guide vanes and configured to actuate an adjustment of the plurality of rotatable guide vanes; and
- a circumferential ring operatively coupling the plurality of rotatable guide vanes, wherein the actuator is configured to directly actuate rotation of one of the rotatable guide vanes, and wherein the circumferential ring actuates rotation of the plurality of rotatable guide vanes upon rotational actuation by the actuator.
2. The flow manipulating arrangement of claim 1, wherein the turbine exhaust diffuser is an axial diffuser comprising:
- an inner barrel extending in a longitudinal direction of the turbine exhaust diffuser; and
- an outer wall disposed radially outwardly of the inner barrel, wherein the strut extends between, and is operatively coupled to, the inner barrel and the outer wall, and wherein the plurality of rotatable guide vanes is operatively coupled to at least one of the inner barrel and the outer wall.
3. The flow manipulating arrangement of claim 2, further comprising a rotatable member operatively coupled to the actuator and extending through each of the plurality of rotatable guide vanes, wherein the plurality of rotatable guide vane is rotatable about an axis defined by the rotatable member.
4. The flow manipulating arrangement of claim 2, further comprising a plurality of struts coaxially aligned and circumferentially arranged wherein the plurality of rotatable guide vanes is disposed in at least one of an axially upstream location and an axially downstream location of the plurality of struts.
5. The flow manipulating arrangement of claim 1, wherein the circumferential ring is operatively coupled to a plurality of bearings configured to facilitate sliding of the circumferential ring within a slot structure.
6. The flow manipulating arrangement of claim 2, wherein the plurality of rotatable guide vanes is circumferentially adjacent to, and axially aligned with, the strut.
7. The flow manipulating arrangement of claim 1, wherein the plurality of rotatable guide vanes is rotatable over a range of angular positions corresponding to a range of exhaust flow conditions.
8. The flow manipulating arrangement of claim 7, wherein the range of angular positions comprises a first position corresponding to a first condition and a second position corresponding to a second condition, wherein the first condition comprises a full speed, full load condition and the second condition comprises a part load condition.
9. The flow manipulating arrangement of claim 3, further comprising a gear arrangement configured to transmit mechanical power from the actuator to the rotatable member.
10. The flow manipulating arrangement of claim 1, wherein the turbine exhaust diffuser is a radial diffuser comprising an inner wall and an outer wall, wherein the strut is operatively coupled to at least one of the inner wall and the outer wall.
11. The flow manipulating arrangement of claim 10, wherein the plurality of rotatable guide vanes is operatively coupled to the strut.
12. The flow manipulating arrangement of claim 10, wherein the plurality of rotatable guide vanes is rotatable over a range of angular positions corresponding to a range of exhaust flow conditions.
13. The flow manipulating arrangement of claim 2, further comprising:
- an outer seal arrangement disposed between the plurality of rotatable guide vanes and the outer wall; and
- an inner seal arrangement disposed between the plurality of rotatable guide vanes and the inner barrel.
14. The flow manipulating arrangement of claim 2, wherein the plurality of rotatable guide vanes is moveable in a radial direction.
15. A flow manipulating arrangement for a turbine exhaust diffuser comprising:
- an inner barrel extending in a longitudinal direction of the turbine exhaust diffuser;
- an outer wall disposed radially outwardly of the inner barrel;
- a strut extending between, and operatively coupled to, the inner barrel and the outer wall, wherein the strut comprises a leading edge and a trailing edge; and
- at least one guide vane disposed axially upstream of the leading edge of the strut, the at least one guide vane selectively circumferentially displaceable relative to the strut.
16. The flow manipulating arrangement of claim 15, further comprising a motor in operative communication with the at least one guide vane and configured to actuate an adjustment of the at least one guide vane.
17. The flow manipulating arrangement of claim 15, further comprising a plurality of struts coaxially aligned and circumferentially arranged, wherein the at least one guide vane comprises a plurality of guide vanes coaxially aligned and circumferentially arranged.
18. The flow manipulating arrangement of claim 17, wherein the plurality of guide vanes are circumferentially aligned with the plurality of struts in a first position during a first condition of an exhaust flow and displaceable to at least one additional position during a second condition of the exhaust flow.
19. The flow manipulating arrangement of claim 15, further comprising a plurality of struts coaxially aligned and circumferentially arranged, wherein the at least one guide vane comprises a plurality of guide vanes coaxially aligned and circumferentially arranged at an axially downstream location of the plurality of struts.
20. A flow manipulating arrangement for a radial turbine exhaust diffuser comprising:
- an inner wall;
- an outer wall;
- a strut operatively coupled to at least one of the inner wall and the outer wall; and
- at least one rotatable guide vane disposed proximate the strut, wherein the at least one rotatable guide vane is selectively rotatable over a range of angular positions and displaceable in at least one of an axial direction and a radial direction.
Type: Application
Filed: Apr 17, 2013
Publication Date: Oct 23, 2014
Applicant: General Electric Company (Schenectady, NY)
Inventors: Srinivas Rao Pakkala (Chintalapudi), Manjunath Bangalore Chengappa (Bangalore), Kamlesh Mundra (Clifton Park, NY), Antanu Sadhu (Bangalore), Kunal Upendra Sakekar (Sangli), Moorthi Subramaniyan (Bangalore), Lisa Anne Wichmann (Simpsonville, SC)
Application Number: 13/864,748
International Classification: F01D 9/02 (20060101);