WO2000008306A1 - Systeme d'etancheification pour turbomachines - Google Patents

Systeme d'etancheification pour turbomachines Download PDF

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Publication number
WO2000008306A1
WO2000008306A1 PCT/GB1999/002531 GB9902531W WO0008306A1 WO 2000008306 A1 WO2000008306 A1 WO 2000008306A1 GB 9902531 W GB9902531 W GB 9902531W WO 0008306 A1 WO0008306 A1 WO 0008306A1
Authority
WO
WIPO (PCT)
Prior art keywords
turbomachinery
baffles
shroud
cavity
row
Prior art date
Application number
PCT/GB1999/002531
Other languages
English (en)
Inventor
John Douglas Denton
Anne Marjorie Wallis
Original Assignee
Siemens Plc
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 Siemens Plc filed Critical Siemens Plc
Publication of WO2000008306A1 publication Critical patent/WO2000008306A1/fr

Links

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
    • F01D5/14—Form or construction
    • F01D5/141—Shape, i.e. outer, aerodynamic form
    • F01D5/145—Means for influencing boundary layers or secondary circulations
    • 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

Definitions

  • the present invention relates to turbomachinery, and in particular to improving the efficiency of such machinery.
  • An aim of the present invention is to provide means which can be easily incorporated in the design of such turbomachinery which reduces the above mentioned losses.
  • turbomachinery including at least one stage, each stage comprising a stationary blade row and a moving blade row, each moving blade row having a shroud on an end section of the blade row, said end section being located within a cavity formed by a casing of the turbomachinery and having a sealing arrangement positioned in the cavity to substantially reduce the flow of a fluid through the cavity, characterised in that a row of baffles are attached to the turbomachinery in a position adjacent to the trailing edges of the moving blade row, and spaced from the shroud.
  • baffles are formed by thin plates and aligned in an axial direction of the turbomachinery.
  • a plurality of baffles are provided per blade pitch, sufficient, to align the flow into the same direction of a mainstream flow.
  • Each baffle has an aspect ratio of 0.75-1.00.
  • FIGURE 1 shows a cross-section of turbomachinery known in the art
  • FIGURE 2 shows a computer prediction of the type of circulatory flows that occur in the large axial gaps upstream and downstream of the blade row incorporated in the prior art turbomachinery, and,
  • FIGURE 3 is a schematic diagram of turbomachinery including baffles in accordance with the present invention.
  • FIG. 1 there is shown part of turbomachinery comprising a moving blade row 2 having a shroud 4 on the end section of the blade row.
  • This end section is housed within a cavity 10 formed by the turbine casing and an adjacent stator blade section comprising stationary blade rows 6.
  • Fluid passing through the main turbine annulus is turned as it moves through the moving blade row 2 from the left hand side A to the right hand side B.
  • a pressure gradient exists between the sides A and B, which also represent the leading and trailing edges of each blade of the moving blade row 2, respectively. This pressure gradient encourages fluid to leak over the top of the moving blade row 2 across the shroud 4. It passes through a sealing arrangement 8 and re-enters the mainstream downstream of the moving blade row 2.
  • Figure 2 illustrates the type of circulatory motion that develops when the energy in the leakage fluid is insufficient to prevent fluid from the mainstream from spiralling around the inlet and exit gaps. The more effective the seal is, the further the mainstream fluid can penetrate into the shroud cavity generating increased losses.
  • Figure 2 is taken from a computational fluid dynamic simulation of the flow in the shroud cavity above a turbine rotor blade.
  • the figure shows a view of the computational domain looking obliquely inwards onto the shroud surface, with the pressure surface of the blade to the front of the figure.
  • the leading edge of the blade is at the right hand side of the figure so that the blade passage flow is moving from right to left.
  • a selection of streamlines at the principal regions of interest is shown in the view. These streamlines show the movement of the leakage fluid relative to the moving blade, with the double headed arrows indicating the direction of motion.
  • the mainstream fluid approaches the rotor blade row and is deflected upwards into the shroud cavity near the leading edge of the blade. Some of the fluid moves along the cavity in the downstream direction as "conventional" leakage flow 12, but a proportion of it remains in the gap, developing into a vortical motion within the gap 14.
  • mainstream fluid again spirals around the axial gap.
  • Some mainstream fluid enters the gap at the pressure side surface of the trailing edge and rolls up into a vortex which traverses along the gap 18. Close to the suction surface, the fluid re-enters the main passage 20 in a different direction to the mainstream flow causing a mixing loss.
  • the moving blade row 2 is provided with a shroud 4 and is accommodated within the turbine casing.
  • a row of baffles 22 is provided attached to the casing of the turbomachine at the point adjacent to the trailing edges of the blades in the moving blade row 2.
  • the spacing of the baffles is such that the leakage flow is aligned into the same direction as the mainstream flow, with each baffle having an aspect ratio of 0.75-1.0.
  • the gap between the inner radius of the baffle and the shroud is designed to inhibit the ingress of the mainstream fluid from downstream of the moving blade without increasing losses generated by windage.
  • the invention is eminently suitable for application with any turbomachinery, and in particular may be used in relation to commercial steam turbines.
  • baffles Whilst the baffles have been described connected to the casing adjacent to the trailing edges of the moving blade row, they could be connected to the stator blade tips adjacent to the rotor surface.

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

Selon cette invention, une turbomachine comprend une rangée d'aubes mobiles (2) comportant un carénage (4) sur une partie terminale de la rangée d'aubes (2). La partie terminale est placée à l'intérieur d'une cavité (10) formée par une plate-forme d'aubes et son boîtier d'aubes. Un système de scellement (8) est placé dans la cavité pour réduire sensiblement le flux d'un fluide à travers ladite cavité. Une rangée de déflecteurs (22) est fixée à la turbomachine près des bords de fuite de la rangée d'aubes mobiles (2), à une certaine distance du carénage (4). Les déflecteurs sont formés par des plaques minces, alignées dans une direction axiale de la turbomachine. On a prévu suffisamment de déflecteurs pour chaque pas d'aubes pour diriger tout fluide de fuite dans le sens de l'écoulement principal. Chaque déflecteur (22) possède un allongement de 0,75-1,00. L'espace entre les déflecteurs (22) et le carénage (4) est choisi de manière à limiter l'admission du fluide de courant principal sans pour autant augmenter les pertes dues à la dérive. Les déflecteurs empêchent le courant principal de pénétrer dans la cavité du carénage et orientent le courant de fuite dans le sens de l'écoulement principal avant qu'il ne pénètre de nouveau dans la cavité du carénage.
PCT/GB1999/002531 1998-08-04 1999-08-02 Systeme d'etancheification pour turbomachines WO2000008306A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9816842.0 1998-08-04
GB9816842A GB2340189A (en) 1998-08-04 1998-08-04 A turbomachine shroud seal having baffles

Publications (1)

Publication Number Publication Date
WO2000008306A1 true WO2000008306A1 (fr) 2000-02-17

Family

ID=10836597

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1999/002531 WO2000008306A1 (fr) 1998-08-04 1999-08-02 Systeme d'etancheification pour turbomachines

Country Status (2)

Country Link
GB (1) GB2340189A (fr)
WO (1) WO2000008306A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2031184A1 (fr) * 2007-08-31 2009-03-04 Siemens Aktiengesellschaft Dispositif de rupture de tourbillon pour turbomachine
US20130230379A1 (en) * 2012-03-01 2013-09-05 General Electric Company Rotating turbomachine component having a tip leakage flow guide

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US881474A (en) * 1906-08-14 1908-03-10 Belliss & Morcom Ltd Turbine-motor.
US3251601A (en) * 1963-03-20 1966-05-17 Gen Motors Corp Labyrinth seal
US4239452A (en) * 1978-06-26 1980-12-16 United Technologies Corporation Blade tip shroud for a compression stage of a gas turbine engine
US4370094A (en) * 1974-03-21 1983-01-25 Maschinenfabrik Augsburg-Nurnberg Aktiengesellschaft Method of and device for avoiding rotor instability to enhance dynamic power limit of turbines and compressors
US4571937A (en) * 1983-03-08 1986-02-25 Mtu - Motoren-Und Turbinen-Munchen Gmbh Apparatus for controlling the flow of leakage and cooling air of a rotor of a multi-stage turbine
US4662820A (en) * 1984-07-10 1987-05-05 Hitachi, Ltd. Turbine stage structure
US5489186A (en) * 1991-08-30 1996-02-06 Airflow Research And Manufacturing Corp. Housing with recirculation control for use with banded axial-flow fans

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH529914A (de) * 1971-08-11 1972-10-31 Mo Energeticheskij Institut Turbinenstufe
GB1423833A (en) * 1972-04-20 1976-02-04 Rolls Royce Rotor blades for fluid flow machines
JPS59134302A (ja) * 1983-01-24 1984-08-02 Toshiba Corp 蒸気タ−ビンの腐蝕防止装置
GB2251040B (en) * 1990-12-22 1994-06-22 Rolls Royce Plc Seal arrangement
US5318309A (en) * 1992-05-11 1994-06-07 General Electric Company Brush seal

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US881474A (en) * 1906-08-14 1908-03-10 Belliss & Morcom Ltd Turbine-motor.
US3251601A (en) * 1963-03-20 1966-05-17 Gen Motors Corp Labyrinth seal
US4370094A (en) * 1974-03-21 1983-01-25 Maschinenfabrik Augsburg-Nurnberg Aktiengesellschaft Method of and device for avoiding rotor instability to enhance dynamic power limit of turbines and compressors
US4239452A (en) * 1978-06-26 1980-12-16 United Technologies Corporation Blade tip shroud for a compression stage of a gas turbine engine
US4571937A (en) * 1983-03-08 1986-02-25 Mtu - Motoren-Und Turbinen-Munchen Gmbh Apparatus for controlling the flow of leakage and cooling air of a rotor of a multi-stage turbine
US4662820A (en) * 1984-07-10 1987-05-05 Hitachi, Ltd. Turbine stage structure
US5489186A (en) * 1991-08-30 1996-02-06 Airflow Research And Manufacturing Corp. Housing with recirculation control for use with banded axial-flow fans

Also Published As

Publication number Publication date
GB9816842D0 (en) 1998-09-30
GB2340189A (en) 2000-02-16

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