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EP2639404A1 - Abgasverteiler für eine Turbine - Google Patents

Abgasverteiler für eine Turbine Download PDF

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Publication number
EP2639404A1
EP2639404A1 EP13158914.5A EP13158914A EP2639404A1 EP 2639404 A1 EP2639404 A1 EP 2639404A1 EP 13158914 A EP13158914 A EP 13158914A EP 2639404 A1 EP2639404 A1 EP 2639404A1
Authority
EP
European Patent Office
Prior art keywords
angle
turbine
guide surface
exhaust
last stage
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Withdrawn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
EP13158914.5A
Other languages
English (en)
French (fr)
Inventor
Prakash Bavanjibhai Dalsania
Joseph Anthony Cotroneo
Sudhakar Neeli
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 Co
Original Assignee
General Electric Co
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 General Electric Co filed Critical General Electric Co
Publication of EP2639404A1 publication Critical patent/EP2639404A1/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Withdrawn legal-status Critical Current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
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/30—Exhaust heads, chambers, or the like
    • 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
    • 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
    • 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

Definitions

  • the present invention relates to an exhaust diffuser for a turbine and to methods for reducing flow separation with over tip leakage flow with shrouded and unshrouded last stage buckets of the turbine.
  • Diffusers are commonly employed in steam turbines. Effective diffusers can improve turbine efficiency and output. Unfortunately, the complicated flow patterns existing in such turbines as well as the design problems caused by space limitations make fully effective diffusers almost impossible to design. A frequent result is flow separation that fully or partially destroys the ability of the diffuser to raise the static pressure as the steam velocity is reduced by increasing the flow area. For downward exhaust hoods used with axial steam turbines, the loss from the diffuser discharge to the exhaust hood discharge varies from top to bottom. At the top, much of the flow must be turned 180° to place it over the diffuser and inner casing, then turned downward. Pressure at the top is thus higher than at the sides, which are in turn higher than at the bottom.
  • an exhaust diffuser for a turbine comprises an inlet configured to receive exhaust gas from a last stage bucket of the turbine; and an exhaust gas guide surface configured to guide the exhaust gas.
  • a curvature of the guide surface comprises a first angle with respect to an axis of the turbine and a ratio of a guide surface axial length to the active length of the last stage bucket which is between about 0.45 to 0.70.
  • a method of diffusing exhaust of a turbine comprises energizing a boundary layer along a curved exhaust flow guide surface of an exhaust diffuser with over tip leakage of a last stage bucket of the turbine.
  • the curved exhaust flow guide surface is at a first angle with respect to an axis of the turbine and a ratio of a guide surface axial length to the active length of the last stage bucket which is between about 0.45 to 0.70.
  • a first exhaust flow diffuser 2 of a steam turbine low pressure section includes an inlet 18 that receives steam passing a last stage bucket 14 of the turbine.
  • the exhaust flow diffuser 2 further includes a steam guide surface 4 that guides the steam flow passing from the last stage bucket 14, and a diffuser end wall 6.
  • a ratio of the axial length L of the diffuser (as measured from a centerline 16 of the last stage bucket 14 to the diffuser end wall 6) to the active length AL of the last stage bucket 14 is approximately 2.0.
  • the centerline 16 of the last stage bucket 14 is a radial line passing through the center of gravity of the bucket's root section.
  • a diffuser 8 of a second, different configuration from the diffuser 2 is also shown.
  • the diffuser 8 has a ratio of axial length L (as measured from the centerline 16 to the diffuser end wall 12) to active length AL of the last stage bucket 14 of approximately 1.35.
  • the first diffuser 2 and the second diffuser 8 have the same diffuser area ratio which results in the second diffuser 8 having a sharper steam guide surface 10 curvature. Maintaining the diffuser area ratio of the second diffuser 8 the same as the first diffuser may lead to a flow separation from the steam guide surface 10 due to higher curvature.
  • the diffuser 8 uses over tip leakage from the last stage bucket 14 to energize a boundary layer along the steam guide surface 10 of the diffuser 8 to reduce, or prevent, separation of the steam from the steam guide surface 10. Reducing, or preventing, separation of the steam from the steam guide surface 10 improves the static pressure recovery.
  • the tip clearance of the last stage bucket 14 may be reduced, or minimized, to increase, or maximize, the work of the fluid (e.g., steam or hot gases) on the rotating blades of the turbine. Some amount of clearance may be provided to reduce the possibility of rub between the blades and the inner casing.
  • the last stage bucket 14 may have a hot radial tip clearance that varies between, for example, about 125 to 200 mils and the leakage flow rate for example, about 0.5% to 2% of the annulus flow rate. It should be appreciated that the tip clearance of the last stage bucket 14 may be otherwise, for example between about 50 to 160 mils.
  • the diffuser 8 having a L/AL ratio of approximately 1.5 has a ratio of the steam guide axial length SGL (as measured from the centerline 16 of the last stage bucket 14 to the end of the steam guide surface 10) to the active length AL of the last stage bucket 14 of approximately 0.45 to 0.70, for example approximately 0.55.
  • the last stage bucket 14 has a tip angle A of, for example, about 0° and the curvature of the steam guide surface 10 may have a first angle B that may correspond to a range of change in the angle over the previous 25% meridional length of the steam guide from the bucket tip slope, for example, 0° to 18°, for example about 2°, 11°, or 14°.
  • the second angle C of curvature of the steam guide surface 10 at the 50% meridional distance may be, for example, a change of 14° to 32°, for example about 20°, 22°, or 28°.
  • the third angle D of the curvature of the steam guide surface 10 at the 75% meridional distance may be, for example, a change of about 16° to 32°, for example about 24°, 26°, or 28°.
  • the turbine may include an inclined shroud 20.
  • the last stage bucket 14 has a tip angle A of, for example, about 25° and the curvature of the steam guide surface 10 may have a first angle B that may correspond to a range of change in the angle over the previous 25% meridional length of the steam guide from the bucket tip slope, for example, 0° to 18°, for example about 2°, 11°, or 14°.
  • the second angle C of curvature of the steam guide surface 10 at the 50% meridional distance may be, for example, a change of 14° to 32°, for example about 20°, 22°, or 28°.
  • the third angle D of the curvature of the steam guide surface 10 at the 75% meridional distance may be, for example, a change of about 16° to 32°, for example about 24°, 26°, or 28°.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP13158914.5A 2012-03-14 2013-03-13 Abgasverteiler für eine Turbine Withdrawn EP2639404A1 (de)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US13/419,860 US20130243564A1 (en) 2012-03-14 2012-03-14 Exhaust diffuser for turbine

Publications (1)

Publication Number Publication Date
EP2639404A1 true EP2639404A1 (de) 2013-09-18

Family

ID=47845843

Family Applications (1)

Application Number Title Priority Date Filing Date
EP13158914.5A Withdrawn EP2639404A1 (de) 2012-03-14 2013-03-13 Abgasverteiler für eine Turbine

Country Status (5)

Country Link
US (1) US20130243564A1 (de)
EP (1) EP2639404A1 (de)
JP (1) JP2013189975A (de)
CN (1) CN103306754A (de)
RU (1) RU2013111162A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3054086A1 (de) * 2015-02-05 2016-08-10 Alstom Technology Ltd Dampfturbinendiffusorkonfiguration
WO2017026904A1 (en) * 2015-08-12 2017-02-16 General Electric Company Diffuser for a turbine engine and method of forming same

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9598981B2 (en) * 2013-11-22 2017-03-21 Siemens Energy, Inc. Industrial gas turbine exhaust system diffuser inlet lip
CN104074554B (zh) * 2014-06-13 2016-01-13 东方电气集团东方汽轮机有限公司 间接空冷末级动叶片
PL3653850T3 (pl) 2018-11-16 2022-02-07 DOOSAN ŠKODA POWER s.r.o. Dyfuzor wylotowy turbiny parowej i odpowiadająca mu turbina parowa

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4214452A (en) * 1977-08-25 1980-07-29 Alsthom-Atlantique Exhaust device for a condensable-fluid axial-flow turbine
EP1178183A2 (de) * 2000-07-31 2002-02-06 Alstom (Switzerland) Ltd Niederdruckdampfturbine mit Mehrkanal-Diffusor
EP2378077A2 (de) * 2010-04-13 2011-10-19 General Electric Company Ummantelungswirbelentferner

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH484358A (de) * 1968-02-15 1970-01-15 Escher Wyss Ag Abströmgehäuse einer axialen Turbomaschine
US4013378A (en) * 1976-03-26 1977-03-22 General Electric Company Axial flow turbine exhaust hood
US5257906A (en) * 1992-06-30 1993-11-02 Westinghouse Electric Corp. Exhaust system for a turbomachine
US5494405A (en) * 1995-03-20 1996-02-27 Westinghouse Electric Corporation Method of modifying a steam turbine
DE19905994A1 (de) * 1999-02-15 2000-08-24 Peter Kraus Vorrichtung und Verfahren zur Aufhebung von Stoß-Grenzschicht-Oszillationen bei kreisringförmigen Diffusoren (axial-radial) an Dampfturbinen
US6261055B1 (en) * 1999-08-03 2001-07-17 Jerzy A. Owczarek Exhaust flow diffuser for a steam turbine
US7780403B2 (en) * 2006-09-08 2010-08-24 Siemens Energy, Inc. Adjustable turbine exhaust flow guide and bearing cone assemblies
JP2010216321A (ja) * 2009-03-16 2010-09-30 Hitachi Ltd 蒸気タービンの動翼及びそれを用いた蒸気タービン
US8439633B2 (en) * 2010-01-04 2013-05-14 General Electric Company Hollow steam guide diffuser having increased pressure recovery
US9249687B2 (en) * 2010-10-27 2016-02-02 General Electric Company Turbine exhaust diffusion system and method
JP5606473B2 (ja) * 2012-02-24 2014-10-15 株式会社東芝 蒸気タービン

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4214452A (en) * 1977-08-25 1980-07-29 Alsthom-Atlantique Exhaust device for a condensable-fluid axial-flow turbine
EP1178183A2 (de) * 2000-07-31 2002-02-06 Alstom (Switzerland) Ltd Niederdruckdampfturbine mit Mehrkanal-Diffusor
EP2378077A2 (de) * 2010-04-13 2011-10-19 General Electric Company Ummantelungswirbelentferner

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3054086A1 (de) * 2015-02-05 2016-08-10 Alstom Technology Ltd Dampfturbinendiffusorkonfiguration
WO2017026904A1 (en) * 2015-08-12 2017-02-16 General Electric Company Diffuser for a turbine engine and method of forming same
US10704423B2 (en) 2015-08-12 2020-07-07 General Electric Company Diffuser for a turbine engine and method of forming same

Also Published As

Publication number Publication date
US20130243564A1 (en) 2013-09-19
JP2013189975A (ja) 2013-09-26
RU2013111162A (ru) 2014-09-20
CN103306754A (zh) 2013-09-18

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