EP2826961A1 - Turbomachine avec débit de fuite d'extrémité réduit - Google Patents

Turbomachine avec débit de fuite d'extrémité réduit Download PDF

Info

Publication number
EP2826961A1
EP2826961A1 EP13177237.8A EP13177237A EP2826961A1 EP 2826961 A1 EP2826961 A1 EP 2826961A1 EP 13177237 A EP13177237 A EP 13177237A EP 2826961 A1 EP2826961 A1 EP 2826961A1
Authority
EP
European Patent Office
Prior art keywords
turbomachine
flow
dimples
dimple
delimiting
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Withdrawn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
EP13177237.8A
Other languages
German (de)
English (en)
Inventor
Vasileios Stefanis
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 EP13177237.8A priority Critical patent/EP2826961A1/fr
Publication of EP2826961A1 publication Critical patent/EP2826961A1/fr
Withdrawn legal-status Critical Current

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
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • 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
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/02—Preventing or minimising internal leakage of working-fluid, e.g. between stages by non-contact sealings, e.g. of labyrinth type
    • 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
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/10—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator using sealing fluid, e.g. steam

Definitions

  • the present invention relates to the field of turbomachines. It refers to surface features of the flow-delimiting contours within the clearance gap between the tip of a blade or vane row and an opposite wall segment for reducing the leakage flow of the working medium through this gap.
  • the performance and efficiency of a turbomachine are, amongst others, critically affected by the tip clearances between its rotating and stationary components within the flow duct for the working medium.
  • the clearance gaps between the tip of a rotating blade and the radially opposite stationary vane carrier provide a narrow flow passage between the high pressure side and the low pressure side of a blade row, resulting in a detrimental leakage mass flow.
  • Increasing clearance gaps decrease the efficiency, but decreasing clearance gaps increase the risk of blade rubbing and consequential machine damages. Accordingly, the designer aims to maintain the clearance gaps at an inevitable minimum without affecting the structural integrity of the involved components.
  • Shrouded blades can be employed to reduce leakage around the blade tip.
  • a seal can be produced between the blade shroud and the radially opposite casing wall.
  • one or more radially aligned fins extend into the gap between the stationary and the moving components to hinder leakage flow.
  • the fins of each blade shroud or casing segment abut the fins of the adjacent blade shrouds to provide one or more complete circumferential fins around the circumference of an assembled blade row. Additional steps in axial direction between the fins may be provided to improve seal effectiveness.
  • the document WO 2004083651 discloses a surface structure for optimized flow properties in view of friction resistance and heat transfer. Accordingly, that document proposes a surface, comprising a number of dimples of a defined geometry with rounded edges, forming a central dimple area and a curvature area for each dimple, which continuously connects the dimple with the surrounding surface. Such a geometry improves the flow properties with respect to friction resistance and additionally with respect to heat transfer.
  • the dimples have essentially the form of a segment of a sphere or an ellipsoid.
  • the underlying principle are secondary vortices, originating in the dimples and leading to an organized transportation of gas flow from the surface to the main flow. Due to the reduced pressure inside the vortex flows the boundary layer is sucked in, so that the thickness of the boundary layer does not increase.
  • a turbomachine such as a turbine or a compressor
  • the invention is based on the idea to provide a number of dimples, impressed at least in part into the surfaces of the flow-delimiting contours within the clearance gap between the stationary and rotating components.
  • the radially outer surface of the blade shroud and/or the opposite casing wall are provided with a dimple array.
  • the key advantage of the invention is especially to be seen in the fact that the leakage flow of the working medium through the gap along the surface portions, structured in such a way, initiates the formation of three-dimensional energy dissipating vortices in the flow structure. This significant development of turbulence increases the amount of pressure loss in the gap and - as a consequence of these losses - the amount of over-tip leakage flow is reduced to a respective degree.
  • the impressed dimples have a circular rim, the rim being the interface between the dimple and the surface, and are shaped as a spherical segment.
  • the maximum depth of a dimple, designed in this way, is to be limited to less than half its diameter.
  • dimple designs for promoting losses in the clearance gap are possible, such as dimples of elliptical or rectangular shapes (in top view) and with curved or straight wall and bottom sections.
  • Another advantage of this solution is its flexibility and broad applicability. It is not bound to a certain sealing system, e.g. a sealing system as described below in an exemplary embodiment, but can be coupled with other known sealing systems too.
  • Another embodiment of the invention is distinguished by the fact that the flow delimiting contours in the clearance gap, at least in part, are equipped with periodic arrays of dimples, consisting of rows of dimples arranged in a staggered manner in the flow direction.
  • a gas turbine comprises an annular hot gas channel 1 with a rotor at its central axis. At least one row of turbine blades 2 extends from the periphery of the rotor into the hot gas channel 1. An airfoil 8 of blade 2 extends outwardly through the hot gas channel 1, where the working medium 9 executes a motive force on it. At its outer tip portion the blade 2 is equipped with a shroud 3 defining a clearance gap 4 to the outer delimiting wall 5 of the hot gas channel 1. The shrouds 3 of adjacent blades 2 of a blade row contact one another to form a closed circumferential ring. In flow direction of the working medium 9 the outer surface 7 of the shroud 3 is designed with a stepped contour. From the outer wall 5 flow restricting sealing fins 6 extend radially inwards towards the outer surface 7 of the shroud 3.
  • the performance and efficiency of the turbine is, amongst others, critically affected by the over-tip leakage flow of working medium through the clearance gap 4, as illustrated in Fig. 1 , because this leakage flow does not exert motive forces onto the blade airfoil 8.
  • a reduced leakage flow increases the turbine efficiency. Therefore it is a permanent aim to minimize the leakage flow through said gap 4 under operation conditions.
  • This invention discloses a way to further minimize the leakage flow by increasing the flow resistance within the leakage gap 4, i.e. between the outwards facing surface 7 of the shroud 3 of a blade row and the inwards facing surface of the opposite outer wall 5.
  • Figures 2 and 3 show the essential elements of the leakage gap 4, applying the measures which are proposed according to the invention.
  • a plurality of dimples 10 is impressed onto an extensive area of the surfaces facing the gap 4.
  • At least a portion of the outwardly facing surface 7 of the shroud 3 is equipped with arrays of dimples 10.
  • the dimples 10 may have the same shape and size. The latter, however, is not compulsory. If the conditions of the specific application should require, the dimensioning of the individual dimples 10 or dimple arrays can be altered continuously or in steps corresponding to the requirements, such as the flow parameters in selected operation modes of the machine.
  • the leakage flow 13 of the working medium 9 through the gap 4 along the structured surface portions 7 and/or 14 of the flow delimiting contours 3, 5 initiates the formation of three-dimensional energy dissipating vortices in the flow.
  • This significant development of turbulence within the individual cavities between the sealing fins 6, sequently located in the gap 4 increases the amount of pressure loss in the gap 4. As a consequence of these losses the amount of over-tip leakage flow is reduced.
  • the dimples 10 can form different patterns on the surface 7. In principle, they can be arranged periodically or in random order. In the interests of foreseeable fluidic effects and continuity in the mechanical properties of the involved elements 5, 7 in the gap 4 preference is to be given, however, to a periodic pattern, as is reproduced, for example, in Fig. 3 in the form of rows of dimples 10 of equal dimension which are arranged in a staggered manner.
  • Fig. 4a schematically shows a sectional view through a shroud (3) or a wall (5) segment with a number of dimples 10, impressed into the surface 7, 14 of said segment (only one dimple is shown).
  • Arrow 12, 13 symbolizes the tip leakage flow of the working medium and its direction through the gap 4.
  • Two alternative designs of the dimple 10 are touched in this sketch.
  • Preferably circular dimples 10, i.e. dimples 10 with a (in top view) circular rim 11, whereby the rim 11 is defined as being the interface between the dimple 10 and the surface 7, 14, may be formed as a spherical segment, symbolized by curve 15 in Fig. 4a .
  • the dimple 10 may have a polygon-like design with straight wall and bottom sections, symbolized by the dashed line 16 in Fig. 4a .
  • Fig. 4b shows a top view on a non-circular dimple 10, impressed into the surface 7, 14 of the flow delimiting contour 3, 5 within the gap 4.
  • the non-circular dimple 10 comprises a length (L), defined as being the maximum extension of the rim 11 in a first direction, e.g. in the flow direction 12, and a width (W), defined as being the maximum extension in a second direction, perpendicularly to said first direction.
  • L length
  • W width
  • the most preferred embodiment of this category of forms are elliptical dimples 10, whereby Fig. 4b shows a configuration with the longitudinal axis of the ellipse parallel to the direction 12 of the leakage flow 13. However, this alignment is not obligatory.
  • the longitudinal axis of the dimple 10 may be arranged with an angle between 0 ° and 90 ° to the flow direction 12.
  • the dimples 10 which are impressed into the flow delimiting contour 7, 14 have a diameter (D) and a depth (S) with the proviso that S max ⁇ D/2 (circular dimples) or S max ⁇ L/2 (non-circular dimples).
  • D diameter
  • S depth
  • the flow-delimiting contours (3, 5) are equipped with arrays of dimples 10, the maximum depth of which is S max ⁇ D/4 (circular dimples) or S max ⁇ L/4 (non-circular dimples).
  • the distances (a) between adjacent dimples 10 inside an array are not to exceed five-times their diameter (D) or length (L), that is to say are to follow the inequation 0 ⁇ a ⁇ 5 D or 0 ⁇ a ⁇ 5 L.
  • the preferred order of magnitude of the distance (a) lies with the range of 1 D ⁇ a ⁇ 3D or 1L ⁇ a ⁇ 3L.
EP13177237.8A 2013-07-19 2013-07-19 Turbomachine avec débit de fuite d'extrémité réduit Withdrawn EP2826961A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP13177237.8A EP2826961A1 (fr) 2013-07-19 2013-07-19 Turbomachine avec débit de fuite d'extrémité réduit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP13177237.8A EP2826961A1 (fr) 2013-07-19 2013-07-19 Turbomachine avec débit de fuite d'extrémité réduit

Publications (1)

Publication Number Publication Date
EP2826961A1 true EP2826961A1 (fr) 2015-01-21

Family

ID=48795503

Family Applications (1)

Application Number Title Priority Date Filing Date
EP13177237.8A Withdrawn EP2826961A1 (fr) 2013-07-19 2013-07-19 Turbomachine avec débit de fuite d'extrémité réduit

Country Status (1)

Country Link
EP (1) EP2826961A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112437832A (zh) * 2018-06-20 2021-03-02 赛峰飞机发动机公司 用于飞行器涡轮机的迷宫式密封接头

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1024251A2 (fr) * 1999-01-29 2000-08-02 General Electric Company Virole de turbine refroidie
US6155778A (en) * 1998-12-30 2000-12-05 General Electric Company Recessed turbine shroud
WO2004083651A1 (fr) 2003-03-19 2004-09-30 Nikolaus Vida Structure de surface tridimensionnelle conçue pour assurer une resistance au frottement reduite et un echange thermique ameliore
DE102007046252A1 (de) * 2006-09-29 2008-04-03 General Electric Co. Feststehende-Rotierende Anordnungen mit Oberflächenmerkmalen zum verbesserten Einschluss von Fluidströmung, und verwandte Prozesse

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6155778A (en) * 1998-12-30 2000-12-05 General Electric Company Recessed turbine shroud
EP1024251A2 (fr) * 1999-01-29 2000-08-02 General Electric Company Virole de turbine refroidie
WO2004083651A1 (fr) 2003-03-19 2004-09-30 Nikolaus Vida Structure de surface tridimensionnelle conçue pour assurer une resistance au frottement reduite et un echange thermique ameliore
DE102007046252A1 (de) * 2006-09-29 2008-04-03 General Electric Co. Feststehende-Rotierende Anordnungen mit Oberflächenmerkmalen zum verbesserten Einschluss von Fluidströmung, und verwandte Prozesse

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112437832A (zh) * 2018-06-20 2021-03-02 赛峰飞机发动机公司 用于飞行器涡轮机的迷宫式密封接头
CN112437832B (zh) * 2018-06-20 2023-04-21 赛峰飞机发动机公司 用于飞行器涡轮机的迷宫式密封接头

Similar Documents

Publication Publication Date Title
JP4929193B2 (ja) タービン翼列エンドウォール
JP4876206B2 (ja) 三日月形斜面付きタービン段
US9476315B2 (en) Axial flow turbine
JP4785511B2 (ja) タービン段
US20080080972A1 (en) Stationary-rotating assemblies having surface features for enhanced containment of fluid flow, and related processes
JP6110666B2 (ja) エーロフォイル
JP6105942B2 (ja) エアーフォイル
JP2005147130A (ja) メッシュ及び渦流式冷却を備えた高温ガス通路構成部品
EP2578810B1 (fr) Structure de joint, machine à turbine équipée de cette structure et centrale électrique équipée de ladite machine à turbine
US20160341058A1 (en) Seal structure and rotating machine
EP3061914A1 (fr) Aube rotorique de turbine et moteur à turbine à gaz associé
EP2878771B1 (fr) Machine à fluide à flux axial
US20080050233A1 (en) Turbo Machine
US20150204237A1 (en) Turbine blade and method for enhancing life of the turbine blade
US20170370237A1 (en) Turbine
RU2647170C2 (ru) Лопаточный аппарат и соответствующий способ изготовления лопаточного аппарата
JP6518526B2 (ja) 軸流タービン
JP2017155625A5 (fr)
EP2826961A1 (fr) Turbomachine avec débit de fuite d'extrémité réduit
JP5852191B2 (ja) 端壁部材及びガスタービン
JP2018048565A (ja) 軸流タービンシール装置
JP5404187B2 (ja) 端壁部材及びガスタービン
JP2009257116A (ja) シール装置および蒸気タービン
JP6436187B2 (ja) タービン
JP5591986B2 (ja) 端壁部材及びガスタービン

Legal Events

Date Code Title Description
17P Request for examination filed

Effective date: 20130719

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20150722