EP1531235A2 - Stator for an axial-flow turbine - Google Patents
Stator for an axial-flow turbine Download PDFInfo
- Publication number
- EP1531235A2 EP1531235A2 EP04105587A EP04105587A EP1531235A2 EP 1531235 A2 EP1531235 A2 EP 1531235A2 EP 04105587 A EP04105587 A EP 04105587A EP 04105587 A EP04105587 A EP 04105587A EP 1531235 A2 EP1531235 A2 EP 1531235A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- stator
- portions
- flow direction
- flow
- annular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
- F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
- F01D9/041—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector using blades
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/12—Blades
- F01D5/14—Form or construction
- F01D5/141—Shape, i.e. outer, aerodynamic form
- F01D5/142—Shape, i.e. outer, aerodynamic form of the blades of successive rotor or stator blade-rows
- F01D5/143—Contour of the outer or inner working fluid flow path wall, i.e. shroud or hub contour
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
- F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2250/00—Geometry
- F05D2250/30—Arrangement of components
- F05D2250/32—Arrangement of components according to their shape
- F05D2250/323—Arrangement of components according to their shape convergent
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2270/00—Control
- F05D2270/01—Purpose of the control system
- F05D2270/17—Purpose of the control system to control boundary layer
Definitions
- the present invention relates to an improved stator for axial-flow gas or steam turbines. More specifically, the present invention relates to the contour of the fixed end walls defining the annular conduit in which the drive fluid, i.e. gas or steam, flows axially.
- a boundary layer of low-energy fluid is formed on said walls by friction between the wall and the stream of drive fluid.
- the boundary layer increases in thickness in the flow direction, and, in the presence of pressure gradients, may produce dissipative vortices or so-called "secondary flows" (shown schematically and indicated 24 in Figure 3) resulting in fluid-dynamic loss along the walls of the conduit.
- the flow sections of the conduit must be relatively small and therefore of limited radial height; and, for mechanical reasons, the stator vanes in these stages are relatively long in a direction parallel to the turbine axis, so that the radial height of the stator nozzles is less than or more or less equal to the axial length of the vanes.
- the drive fluid flowing inside the stator nozzles flows over a relatively large area of the conduit walls, thus producing thick boundary layers and secondary flows which, given the small radial height of the nozzles, may take up the entire flow section, thus obstructing the primary, i.e. main, flow of the drive fluid and resulting in severe losses.
- a vane stator for an axial-flow turbine; the stator comprising a first and a second surface facing each other and radially defining an annular conduit in which a drive fluid flows in use; said conduit defining, in radial section with respect to the axis of the turbine, a mean flow direction of said drive fluid; characterized in that said first and said second surface comprise respective first annular portions, which both converge, in the flow direction, towards said mean direction.
- Number 1 in Figure 1 indicates as a whole an axial-flow turbine (shown partly and schematically) having an axis 2 and comprising a toroidal manifold 3, which extends about axis 2 and receives, in use and in a manner not shown, a stream of drive fluid, such as gas or steam.
- Turbine 1 comprises a number of vane channels 4 for distributing and axially diverting flow of the drive fluid from manifold 3; and a first stage 5, in turn comprising a stator 6 adjacent to channels 4, and a known rotor 7 rotating about axis 2 and located axially downstream from stator 6 in the flow direction.
- Stator 6 comprises an outer wall 8 and an inner wall 9 (both shown schematically), which are fixed and have respective facing surfaces 10, 11 radially defining an annular conduit 12.
- Conduit 12 receives the stream of drive fluid from channels 4, defines, in radial section with respect to axis 2, a mean flow direction 13, and houses an array of airfoils 14 (Figure 3), which are connected to walls 8, 9, are spaced apart angularly, and divide conduit 12 circumferentially into a number of nozzles.
- surfaces 10, 11 comprise respective annular portions 16, 17, which both converge, in the flow direction, towards direction 13.
- Portions 16, 17 may converge with direction 13 at any angle, e.g. both at the same angle.
- surfaces 10, 11 comprise respective annular portions 18, 19 parallel to direction 13 and axially upstream from portions 16, 17 in the flow direction.
- Portions 18, 19 are connected to the leading portions 20 of airfoils 14, whereas portions 16, 17 are connected to the trailing portions 21 of airfoils 14 ( Figure 3), so that the radial height of the stator nozzles is only reduced at trailing portions 21.
- Surfaces 10, 11 comprise respective annular end portions 22, 23 connected to portions 16, 17, and which extend beyond trailing portions 21 in the flow direction, possibly sloping at different angles from those of portions 16, 17, to direct flow towards the nozzles of rotor 7.
- portions 16, 17 converge walls 8, 9 to reduce the flow section and accelerate flow, thus reducing the thickness of the boundary layer and the secondary flows shown schematically and indicated 24 in Figure 3.
- conduit 12 The total convergence of conduit 12 is divided between walls 8, 9, and is appropriately distributed to optimize the secondary-flow reduction effect.
- portions 16, 17 is therefore less marked than if convergence were assigned entirely to only one of walls 8, 9, thus preventing local flow-off from portions 16, 17 and/or portions 22, 23 and the formation of vortices which could worsen rather than improve the situation.
- Figure 2 shows a second stage 5a, the component parts of which are indicated, where possible, using the same reference numbers, plus the letter "a", as for stage 5.
- stage 5a receives the stream of drive fluid from a first stage along an annular channel 25 with no manifold or vanes.
- angles of convergence may differ, and/or the length of portions 16, 17 may differ from that shown by way of example.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
Abstract
Description
Claims (5)
- A vane stator (6) for an axial-flow turbine (1); the stator comprising a first and a second surface (10, 11) facing each other and radially defining an annular conduit (12) in which a drive fluid flows in use; said conduit defining, in radial section with respect to the axis (2) of the turbine (1), a mean flow direction (13) of said drive fluid; characterized in that said first and said second surface (10, 11) comprise respective first annular portions (16, 17), which both converge, in the flow direction, towards said mean direction (13).
- A stator as claimed in Claim 1, characterized in that said first and said second surface (10, 11) comprise respective second annular portions (18, 19) parallel to said mean direction (13) and axially upstream from said first annular portions (16, 17) in the flow direction.
- A stator as claimed in Claim 1 or 2, characterized by also comprising an array of airfoils (14) housed in said conduit (12) and spaced angularly apart about the axis (2) of the turbine (1); said first annular portions (16, 17) being associated with the trailing portions (21) of said airfoils (14).
- A stator as claimed in Claim 3, characterized in that said first and said second surface (10, 11) have respective annular end portions (22, 23) connected to said first annular portions (16, 17) and extending beyond said trailing portions (21) in the flow direction.
- A stator as claimed in any one of the foregoing Claims, characterized in that said first annular portions (16, 17) converge at the same angle with said mean direction (13).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ITTO20030894 ITTO20030894A1 (en) | 2003-11-11 | 2003-11-11 | PERFECTIONS IN STATORS OF AXIAL TURBINES. |
ITTO20030894 | 2003-11-11 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1531235A2 true EP1531235A2 (en) | 2005-05-18 |
EP1531235A3 EP1531235A3 (en) | 2006-01-18 |
Family
ID=34430816
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP04105587A Withdrawn EP1531235A3 (en) | 2003-11-11 | 2004-11-08 | Stator for an axial-flow turbine |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP1531235A3 (en) |
IT (1) | ITTO20030894A1 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2447942A (en) * | 1944-12-05 | 1948-08-24 | Rateau Soc | Turbine distributor and nozzle |
US4778338A (en) * | 1981-01-05 | 1988-10-18 | Alsthom-Atlantique | Turbine stage |
US6368055B1 (en) * | 1996-12-27 | 2002-04-09 | Kabushiki Kaisha Toshiba | Turbine nozzle and moving blade of axial-flow turbine |
-
2003
- 2003-11-11 IT ITTO20030894 patent/ITTO20030894A1/en unknown
-
2004
- 2004-11-08 EP EP04105587A patent/EP1531235A3/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2447942A (en) * | 1944-12-05 | 1948-08-24 | Rateau Soc | Turbine distributor and nozzle |
US4778338A (en) * | 1981-01-05 | 1988-10-18 | Alsthom-Atlantique | Turbine stage |
US6368055B1 (en) * | 1996-12-27 | 2002-04-09 | Kabushiki Kaisha Toshiba | Turbine nozzle and moving blade of axial-flow turbine |
Non-Patent Citations (1)
Title |
---|
ATKINS M J: "SECONDARY LOSSES AND END-WALL PROFILING IN A TURBINE CASCADE" IMECHE CONFERENCE ON TURBOMACHINERY: EFFICIENCY PREDICTION AND IMPROVEMENT, vol. 6, 1987, pages 29-42, XP001012087 * |
Also Published As
Publication number | Publication date |
---|---|
EP1531235A3 (en) | 2006-01-18 |
ITTO20030894A1 (en) | 2005-05-12 |
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RIC1 | Information provided on ipc code assigned before grant |
Ipc: F01D 5/14 20060101ALI20051130BHEP Ipc: F01D 9/04 20060101AFI20041203BHEP |
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Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20110601 |