EP1840333A1 - Turbinenschaufel mit Deckbandteile - Google Patents

Turbinenschaufel mit Deckbandteile Download PDF

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Publication number
EP1840333A1
EP1840333A1 EP06112086A EP06112086A EP1840333A1 EP 1840333 A1 EP1840333 A1 EP 1840333A1 EP 06112086 A EP06112086 A EP 06112086A EP 06112086 A EP06112086 A EP 06112086A EP 1840333 A1 EP1840333 A1 EP 1840333A1
Authority
EP
European Patent Office
Prior art keywords
shroud
blade
bending moment
blade row
turbine blades
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Withdrawn
Application number
EP06112086A
Other languages
English (en)
French (fr)
Inventor
James Ritchie
Alexander Mahler
Slawomir Slowik
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Technology GmbH
Original Assignee
Alstom Technology AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Alstom Technology AG filed Critical Alstom Technology AG
Priority to EP06112086A priority Critical patent/EP1840333A1/de
Publication of EP1840333A1 publication Critical patent/EP1840333A1/de
Withdrawn legal-status Critical Current

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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
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/22—Blade-to-blade connections, e.g. for damping vibrations
    • F01D5/225—Blade-to-blade connections, e.g. for damping vibrations by shrouding

Definitions

  • the invention pertains to rotating turbine blades in a blade row for use in a turbine such as a gas or steam turbine, the turbine blades having a shroud with a shape according to the shape of the shroud of an adjacent turbine blade in the blade row.
  • Shrouds on rotating turbine blades are intended to limit the leakage flows between the turbine blade tips and the casing.
  • the blade shrouds are exposed to the hot gas flow.
  • the shrouds In order to prevent hot gas ingestion, that is a channeling of hot gas from the main gas flow channel into the space between the shroud and the casing, the shrouds have a shape that is matched to the shape of an adjacent shroud in a blade row and allowing an "interlocking" of the shrouds such that hot gas is prevented from reaching into the space between shroud and casing.
  • FIG. 1 Two typical blades in a blade row with a shroud are shown in Figure 1. They comprises a blade airfoil 1 extending from a blade root 2 to a blade tip 3, from a leading edge 4 to trailing edge 5, and having a pressure side 6 and a suction side 7.
  • the blade row rotates in the direction indicated by the arrow.
  • the blade shroud 8 extends beyond the cross-sectional extent of the blade airfoil in the manner of a cantilever to the pressure side and the suction side of the blade.
  • the extent of the creep deformation is determined, among others, by the bending moment acting on the shroud, which is defined by the spatial extent of the shroud from the airfoil and the mass of the shroud.
  • the extent of the shroud is greater on the pressure side than on the suction side.
  • the bending moment and the resulting creep deformation is more pronounced on the pressure side than on the suction side and as such in an asymmetric deformation and loading of the shrouds.
  • An asymmetric creep deformation effects a mismatch in the radial direction of the shroud edges of adjacent blades in the blade row.
  • the mismatch in turn allows an opening for hot gas in the turbine to flow into the spaces between the shrouds and the casing and to cause serious overheating and shortening of the operational lifetime of the blades.
  • a measure known in the state of the art to reduce creep deformation in turbine blade shrouds is the reduction of mass of a knife-edge on the shroud, as disclosed for example in DE 10 2004 025 321 .
  • JP 7233703 discloses a gas turbine blade shroud having fillets attached to the lower and upper surface of the shroud in order to limit creep deformation.
  • EP 0 928 880 discloses a tip shroud for a moving blade in a gas turbine comprising grooves on the shroud faces and cooling guide covers. The measures allow increased cooling of high stress regions of the shroud and an increase in creep lifetime.
  • the rotating turbine blades shall develop a reduced creep deformation such that hot gas ingestion is prevented.
  • Rotating blades in a blade row for a gas turbine each comprise an airfoil having a pressure side and a suction side.
  • a shroud attached to the tip of the blade has portions that extend over the suction and pressure side of the blade, where the edge of the shroud portion on the suction side of each blade faces the edge of the shroud portion on the pressure of the adjacent blade in the blade row.
  • the shroud portion on the suction side and pressure side of the blade each have a bending moment.
  • the shroud portion having the smaller bending moment comprises at its edge facing the adjacent blade a radially outer part that extends in circumferential direction beyond a radially inner part of that shroud portion, and the shroud portion having the greater bending moment comprises at its edge facing the adjacent blade a radially inner part that extends beyond a radially outer part of that shroud portion.
  • the radially outer and inner parts of each shroud portion of adjacent blades in the blade row are shaped such that the radially outer parts of the portions with the smaller bending moments protrude over the radially inner parts of the shroud portion with the greater bending moments of the adjacent blade.
  • the shroud portion having the smaller bending moment is the shroud portion on the suction side
  • the shroud portion having the greater bending moment is the shroud portion on the pressure side.
  • the shroud portion on the suction side of each blade shroud comprises a radially outer part that protrudes beyond a radially inner part of that shroud.
  • the radially outer part of the suction side portion protrudes over the radially inner part of the pressure side shroud portion of the adjacent blade in the blade row.
  • the shrouds have portions shaped such that there is an overlap of adjacent shrouds.
  • the shroud portion on the suction side of a blade, having the smaller bending moment overlaps on its radially outer side the shroud portion on the pressure side of the adjacent blade, having the greater bending moment.
  • This effects that the shroud portion on the pressure side of a blade, which has the greater bending moment and normally develops the larger creep deformation, is now prevented from deforming in the radially outward direction by the overlapping portion on the suction side of the adjacent shroud.
  • the shroud portion on the suction side of the blades thus supports the shroud portion on the pressure of the blade shrouds. As a result, the loading is spread more evenly over the blades in the blade row.
  • the shroud portions having the smaller bending moments support the shroud portions having the larger bending moments.
  • the invention is described above for typically turbine blades with a shroud having a greater bending moment on the pressure side of the blade and to a measure to reduce the creep deformation of the shroud on that pressure side.
  • a turbine blade has a shroud with a greater bending moment on the suction side of the blade.
  • the measure according to the invention of overlapping shroud portions of adjacent blades is equally well applicable to blades having a greater bending moment on the pressure side as to blades having a greater bending moment on the suction side.
  • the scope of the invention therefore includes the measure for both types of shrouded blades.
  • the radially outer part and radially inner part of the shroud edges are shaped in a step-like manner. That is, beginning at the radially inner surface of the shroud, the shroud edge first extends over the first portion in the radial direction, then extends for example at right angle to the first portion in the circumferential direction, and finally extends again in the radial direction to the radially outer surface of the shroud.
  • the step-like shape is realised with a angles that are approximately a right angle.
  • the shroud edges are slanted compared to the radial direction where the slant angles of adjacent blade shrouds are matched.
  • the radially outer part of a shroud portion again overlaps the radially inner part of the shroud portion of the adjacent blade.
  • the shroud edges have a first, radially inner part and a second radially outer part.
  • the first part extends from the radially inner surface of the shroud in the radial direction
  • the second part extends from the first part at an angle to the radially outer surface of the shroud.
  • the shroud edges comprise the supporting structure with protruding portions according to the invention at least in the thicker regions of the shroud.
  • the supporting structure extends over the region of the knife-edges. In these regions of the shroud the supporting structures are also most effective because the bending moments are typically the largest.
  • blade shrouds comprise the supporting overlapping structure in the knife-edge regions as well as in the center regions of the shroud. This embodiment however is conditional on a sufficient thickness of the shroud.
  • Figure 2 shows in solid lines the same two blades for a gas turbine as in figure 1.
  • the broken lines show the blades after a certain time in operation.
  • the shroud portions on the pressure side of the blades have developed creep deformation due to centrifugal forces and the high temperatures in the gas turbine.
  • the edges of the shrouds have deformed by an amount indicated by ⁇ .
  • Such deformations are most pronounced where the shroud experiences the greatest bending moment, that it where it extends the most away from the airfoil and/or where it has its greatest mass.
  • the greatest deformations occur at the corner on the pressure side of the shroud where the deformation is indicated by ⁇ .
  • Figure 3 shows a cross-section of the knife-edges 25 of the adjacent blade shrouds in a blade row of figure 1.
  • the knife-edges extend in the circumferential direction on the leading edge side of the blade shroud.
  • the blade shrouds each have a portion on their suction side and a portion on the pressure side, where the portion on suction has a smaller bending moment compared to the portion on the pressure side.
  • the cross-section shows in particular the supporting, overlapping structure of the knife-edges.
  • the knife-edge of a first blade shroud 8 has at its edge on the suction side portion 8 SS facing the adjacent blade shroud 8' a first, radially inner part 11 and a second, radially outer part 12, which extends in circumferential direction beyond the first part 11.
  • the knife-edge of the adjacent blade shroud 8' has at its edge on the pressure side portion 8' ps of the adjacent blade shroud 8' has a radially inner part 13 that extends beyond a radially outer part 14.
  • the parts 11-14 are shaped and dimensioned such that the shapes of the adjacent shroud edges are matched to one another and an overlap of the step-like features is established.
  • the overlapping edge of the suction side portion 8s s provides a support of the pressure side portion 8' ps and prevents a deformation of part 13 in the radial direction.
  • Figure 4 shows a variant of the overlapping, supporting structure.
  • the edges are slanted at angle ⁇ with respect to the inner and outer surface of the shroud.
  • the edge on the suction side portion of the shroud essentially has a radially inner part 15 and a radially outer part 16 that extends in circumferential direction beyond the radially inner part 15.
  • the edge of the shroud on the pressure side of the adjacent shroud has a radially inner part 17 and a radially outer part 18, where the radially inner part 17 protrudes beyond the radially outer part 18.
  • the edges are shaped such that their shapes are matched to that of the adjacent edge.
  • the edge of the suction side portion 8 ss having the smaller bending moment overlaps the edge of the pressure side portion 8' ps of the adjacent shroud such that a creep deformation in the radial direction of the pressure side portion 8' ps is prevented by the supporting suction side portion 8 ss .
  • the slant angle is dimensioned in order according to the prevailing bending moments and to provide a sufficient support. Values for the slant angle ⁇ are chosen in view of two criteria. On one hand, the angle is minimized in order to achieve greatest possible overlap and thus maximised prevention of the creep deformation in the radial direction of the shroud portion having the greater bending moment.
  • the angle is maximized in order that the shroud portion with the smaller bending moment does not extend too far in the circumferential direction and develop too great a bending moment itself.
  • Suitable angles may for example be in a range less than 80°, preferably in a range between 30° and 60°. A particularly suitable angle may be approximately 40°.
  • Figure 5 shows a further variant of the overlapping, supporting structure.
  • the edges of the shrouds have in this case first parts 19, 20 extending radially from the inner surface of the shroud and slanted parts 21-24, extending from the first part to the outer surface of the shroud at a slant angle ⁇ to the outer surface of the shroud.
  • the slanted parts have radially inner parts 21, 23 and radially outer parts 22, 24.
  • the edges of adjacent shrouds again are matched in shape to one another for the same purpose as mentioned in connection with figure 3 and 4.
  • the radially extending parts 19, 20 are spaced at a distance a for tolerance purposes.
  • the distance a is chosen large enough in order to provide the necessary space for installation of the blades on the rotor, in particular the last blade of the blade row. It must however also be chosen small enough to prevent a gap between adjacent blade shrouds during operation when the thermal expansion and an untwisting of the blades occurs.
  • the overlapping and supporting contour of the shroud edges extends according over the region of a knife-edge 25 (as indicated in figure 1 and 2) of the shroud.
  • the overlapping edges can be realised over the entire length of the edge facing the adjacent blade shroud. This is possible provided the thickness of the shroud in its center region is sufficient regarding manufacturability and strength considerations.
  • Such a shroud is applicable for example to blades for steam turbines.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
EP06112086A 2006-03-31 2006-03-31 Turbinenschaufel mit Deckbandteile Withdrawn EP1840333A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP06112086A EP1840333A1 (de) 2006-03-31 2006-03-31 Turbinenschaufel mit Deckbandteile

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP06112086A EP1840333A1 (de) 2006-03-31 2006-03-31 Turbinenschaufel mit Deckbandteile

Publications (1)

Publication Number Publication Date
EP1840333A1 true EP1840333A1 (de) 2007-10-03

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Family Applications (1)

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EP06112086A Withdrawn EP1840333A1 (de) 2006-03-31 2006-03-31 Turbinenschaufel mit Deckbandteile

Country Status (1)

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EP (1) EP1840333A1 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2460979A1 (de) * 2010-12-03 2012-06-06 MTU Aero Engines GmbH Schaufelsegment einer Strömungsmaschine mit radialen Anlageflächen
EP2612996A1 (de) * 2012-01-04 2013-07-10 General Electric Company Vorrichtung und Verfahren zur Ausrichtung von Spitzendeckbänder
WO2015031160A1 (en) 2013-08-30 2015-03-05 United Technologies Corporation Mateface surfaces having a geometry on turbomachinery hardware
EP2852736A4 (de) * 2012-05-22 2016-04-13 United Technologies Corp Steckseitenabdichtung bei einem flügel

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2220918A (en) * 1938-08-27 1940-11-12 Gen Electric Elastic fluid turbine bucket wheel
FR1374917A (fr) * 1963-11-21 1964-10-09 Ass Elect Ind Perfectionnements aux déflecteurs d'étanchéité des aubes mobiles de turbines et de compresseurs à écoulement axial
JPH07233703A (ja) 1994-02-23 1995-09-05 Mitsubishi Heavy Ind Ltd ガスタービン動翼のシュラウド
US5511948A (en) * 1994-02-18 1996-04-30 Kabushiki Kaisha Toshiba Rotor blade damping structure for axial-flow turbine
EP0928880A1 (de) 1997-06-26 1999-07-14 Mitsubishi Heavy Industries, Ltd. Deckband für gasturbinenschaufelspitzen
DE102004025321A1 (de) 2004-05-19 2005-12-08 Alstom Technology Ltd Strömungsmaschinenschaufel

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2220918A (en) * 1938-08-27 1940-11-12 Gen Electric Elastic fluid turbine bucket wheel
FR1374917A (fr) * 1963-11-21 1964-10-09 Ass Elect Ind Perfectionnements aux déflecteurs d'étanchéité des aubes mobiles de turbines et de compresseurs à écoulement axial
US5511948A (en) * 1994-02-18 1996-04-30 Kabushiki Kaisha Toshiba Rotor blade damping structure for axial-flow turbine
JPH07233703A (ja) 1994-02-23 1995-09-05 Mitsubishi Heavy Ind Ltd ガスタービン動翼のシュラウド
EP0928880A1 (de) 1997-06-26 1999-07-14 Mitsubishi Heavy Industries, Ltd. Deckband für gasturbinenschaufelspitzen
DE102004025321A1 (de) 2004-05-19 2005-12-08 Alstom Technology Ltd Strömungsmaschinenschaufel

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2460979A1 (de) * 2010-12-03 2012-06-06 MTU Aero Engines GmbH Schaufelsegment einer Strömungsmaschine mit radialen Anlageflächen
EP2612996A1 (de) * 2012-01-04 2013-07-10 General Electric Company Vorrichtung und Verfahren zur Ausrichtung von Spitzendeckbänder
EP2852736A4 (de) * 2012-05-22 2016-04-13 United Technologies Corp Steckseitenabdichtung bei einem flügel
WO2015031160A1 (en) 2013-08-30 2015-03-05 United Technologies Corporation Mateface surfaces having a geometry on turbomachinery hardware
EP3039249A1 (de) * 2013-08-30 2016-07-06 United Technologies Corporation Mateface-oberflächen mit einer geometrie auf einer turbomaschinen-hardware
EP3039249A4 (de) * 2013-08-30 2017-03-29 United Technologies Corporation Mateface-oberflächen mit einer geometrie auf einer turbomaschinen-hardware
US10577936B2 (en) 2013-08-30 2020-03-03 United Technologies Corporation Mateface surfaces having a geometry on turbomachinery hardware

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