EP0194957B1 - Einrichtung um die Blattspitzenverluste bei Kompressoren zu vermindern - Google Patents

Einrichtung um die Blattspitzenverluste bei Kompressoren zu vermindern Download PDF

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Publication number
EP0194957B1
EP0194957B1 EP86630032A EP86630032A EP0194957B1 EP 0194957 B1 EP0194957 B1 EP 0194957B1 EP 86630032 A EP86630032 A EP 86630032A EP 86630032 A EP86630032 A EP 86630032A EP 0194957 B1 EP0194957 B1 EP 0194957B1
Authority
EP
European Patent Office
Prior art keywords
trench
facing surface
stator
fan
wall
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.)
Expired - Lifetime
Application number
EP86630032A
Other languages
English (en)
French (fr)
Other versions
EP0194957A3 (en
EP0194957A2 (de
Inventor
Franz Harter
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.)
Raytheon Technologies Corp
Original Assignee
United Technologies Corp
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 United Technologies Corp filed Critical United Technologies Corp
Publication of EP0194957A2 publication Critical patent/EP0194957A2/de
Publication of EP0194957A3 publication Critical patent/EP0194957A3/en
Application granted granted Critical
Publication of EP0194957B1 publication Critical patent/EP0194957B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F01D5/14—Form or construction
    • F01D5/20—Specially-shaped blade tips to seal space between 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
    • F01D11/08—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
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/16—Sealings between pressure and suction sides
    • F04D29/161—Sealings between pressure and suction sides especially adapted for elastic fluid pumps
    • F04D29/164—Sealings between pressure and suction sides especially adapted for elastic fluid pumps of an axial flow wheel

Definitions

  • This invention relates to axial flow fans/com- pressors of gas turbine engines and particularly to the relationship of the tips of the blades to the adjacent shroud or rub strip.
  • a fan or compressor according to the precharacterizing portion of claim 1 is disclosed in US-A 4 239 452 and in US-A 4 238 170.
  • the tips of the compressor blades extend adjacent the surrounding shroud or rub strip that is trenched or recessed to the dimension complementary to the outer station and tip of the blade.
  • the blades which move radially outward during engine acceleration, machine the groove. Obviously, this technique assures a close fit of the mating parts and helps in avoiding leakage around the tips of the blade.
  • FIG. 1 discloses in Fig. 1 an ambodiment similar to the US patents referred to.
  • Fig. 2 of CH-A 414 681 the trench receiving the blade tips is angularly disposed with respect to the outer flow path surface but the blade tip is parallel with respect thereto.
  • a stator vane is also shown having a tip extending into a trench at the inner flow path wall. The tip of the stator vane and the outwardly oriented surface of the trench are angularly disposed with respect to the inner flow path wall. The vane is adapted to extend deeper into the trench at its leading edge. There is no leakage opposing pumping action against a downstream vertical side wall of the trench.
  • a ducted propeller is disclosed wherein the inwardly facing surface of the trench converges or diverges with respect to the outer flow path surface, but the blade is parallel with respect thereto, thus providing the disadvantage referred to above.
  • GB-A 882 015 the blade tip and the inwardly oriented surface of the trench are angularly disposed with respect to the outer flow path surface.
  • the maximum penetration is at the blade leading edge.
  • GB-A 2 034 435, Fig. 4 wherein a turbine blade tip is shown received in an annular trench in the outer flow path wall. Cooling fluid under pressure is discharged into a cavity formed between the turbine blade tip and the trench to oppose blade tip leakage. The inwardly oriented surface of the trench and a portion of the turbine blade tip are angularly disposed with respect to the outer flow path wall.
  • the object of the invention is to provide a fan or compressor of the type disclosed avoiding or reducing leakage around the blade tip without adversely affecting performance.
  • the blade tip does not penetrate along its full width into the trench when the operating speed causing penetration is obtained.
  • the tip aft portion first penetrates into the trench. This allows deeper penetration without causing too substantial turbulence and accordingly penetration is acceptable at low operation speeds to reduce or avoid leakage in the low speed operating range.
  • the angular contour is designed to effectuate a closure in the gap between the inner wall of the trench and the tip of the blad upon displacement of the compressor and/or fan blade arising out of the growth of the materials resulting from stable hand temperature operating conditions.
  • the invention in its preferred embodiment is illustrated for use in the lower temperature stations of a gas turbine engine and particularly in the compressor section where a soft material circumscribes the engine's inner diameter of the engine case and is abradable so as to be susceptible of being machined by the operation of the rotating blades.
  • a soft material circumscribes the engine's inner diameter of the engine case and is abradable so as to be susceptible of being machined by the operation of the rotating blades.
  • the blades at zero rotational speeds are spaced from the inner diameter of the rub strip and when accelerated to its highest operating speed, cut into the rub strip to define the trench.
  • the trench shape can be machined out prior to engine operation. What is considered the improvement by the teachings of this invention is the particular contour of the tips of the blades and its cooperating trench.
  • FIG. 1 A portion of a compression section 10 of an axial flow compressor of a gas turbine engine is illustrated in Fig. 1.
  • a flow path 16 for working medium gases extends axially through the compression section.
  • An outer wall 18 having an inwardly facing surface to 20 and an inner wall 22 having an outwardly facing surface 24 form the flow path.
  • a plurality of axially spaced rows of rotor blades as represented by the single blades 26 extend outwardly from the rotor 12 across the flow path into proximity with the outer wall.
  • Each blade has an unshrouded tip 28 and is contoured to an airfoil cross section. Accordingly, each blade has a pressure side and a suction side and, as illustrated, has an upstream edge 30 and a downstream edge 32.
  • Extending over the tips of each row of rotor blades is a stator seal land 34.
  • Each land has a circumferentially extending groove or trench 36 formed therein to a depth D at an inwardly facing surface 37 thereof paralleling the
  • a plurality of rows of stator vanes represented by the single vanes 38 are cantilevered inwardly from the stator 14 across the flow path 16 into proximity with the inner wall 22.
  • Each vane which in this illustration has an unshrouded tip 40, is contoured to an airfoil section. Accordingly, each vane has a pressure side and a suction side and, as illustrated, has an upstream edge 42 and a downstream edge 44.
  • Extending over the tips of each row of stator vanes is a rotor seal land 46. Each land has a circumferentially extending groove 48 formed therein.
  • the blade tips 28 are spaced from the inwardly facing surface 37.
  • the gap between tips and surface enables assembly of the components.
  • the rotor tips grow radially outward machining the groove 36 in the abradable material of the stator seal land 34.
  • the point of closes proximity of the blades to the bottom of the groove is referred to as the «pinch point» and normally occurs during a transient engine operating to a maximum speed or power condition.
  • the outer wall including the land moves both axially and radially relative to the blade tips to a position at which the blade tips 28 and inner surface 37 define a gap D.
  • Fig. 2 which is a prior art design is that the blade 50 penetration along its full width into the trench 54 toward the inwardly facing surface 52 as operating speed/increases causes a substantial pumping of air against the trench vertical wall 53 adjacent the blade trailing edge which creates turbulence.
  • the turbulence as shown by arrow A essentially becomes a blockage in the flow path of the gas engine's working medium and adversely affects performance.
  • the maximum depth of blade tip penetration must be controlled to avoid unreasonable turbulence losses at the maximum operating speed. At low speed operating the blade 50 will not penetrate into the trench 54 and leakage can readily occur between the flow path outer wall and the blade tip.
  • the full width of the blade works on the air and has the tendency of over pressurizing this air and hence, creates the undesirable turbulence.
  • the tip of the blade and the inwardly facing surface 37 of the trench 36 are contoured to be angularly disposed relative to the outer gas path wall 18. This is best seen in Fig. 3.
  • the trench 36 is formed to define the contour of the inwardly facing surface 37.
  • the depth of the trench 36 as measured from the inwardly facing surface 20 of the outer wall 18 increases toward the vertical side wall 39 of the tench 36 adjacent the blade trailing edge 32.
  • the axial extension of surface 37 relative to the flow path defined by surface 20 forms angle alpha a.
  • the tip 28 of the blade 26 slants from a given diameter at the leading edge 30 to a higher diameter at the trailing edge 32.
  • Fig. 4 exemplifies another configuration on how the tip can be contoured to combat the leakage problem alluded to in the above.
  • the tip of blade 70 is contoured in a sawtooth fashion providing a plurality of parallel channels 72.
  • the inner surface 74 is angularly disposed to the gas path wall providing similar benefits as was described above.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)

Claims (4)

1. Axial-FanNerdichter für ein Gasturbinentriebwerk, das Betriebszustände mit hoher und niedriger Drehzahl sowie einen Stator (14) und einen Rotor (12), der in dem Stator (14) drehbar gelagert ist, wobei ein Arbeitsmediumströmungsweg (16) zwischen einer nach innen weisenden Oberfläche (20) einer äußeren Wand (18) des Stators (14) und einer nach außen weisenden Oberfläche (24) des Rotors (12) gebildet ist, wobei der Rotor (12) mehrere sich radial erstreckende Schaufeln (26) trägt, die jeweils eine Spitze (28), eine Vorderkante (30) und eine Hinterkante (32) haben, wobei ein sich in Umfangsrichtung erstreckender Graben (36) in der nach innen weisenden Oberfläche (20) der Statoraußenwand (18) gebildet ist, wobei die Schaufelspitzen (28) in den Graben (36) eindringen und wobei der Graben eine nach innen gerichtete Oberfläche und eine vertikale Seitenwand (39) benachbart zu den Hinterkanten (32) der Schaufeln (26) hat, wobei die nach innen weisende Oberfläche des Grabens (36) zu der Kontur der Schaufelspitzen (28) parallel ist, dadurch gekennzeichnet, daß die Schaufelspitzen (28) und die nach innen weisende Oberfläche (37) des Grabens (36) relativ zu der nach innen weisenden Oberfläche der Statoraußenwand (18) abgewinkelt angeordnet und relativ zu der FanNerdichter-Mittellinie geneigt sind, wobei die Tiefe des Grabens (36), gemessen von der nach innen weisenden Oberfläche (20) der Statoraußenwand (20) aus, zu der vertikalen Seitenwand (39) des Grabens (36) hin zunimmt, wodurch ein Hinterkantenteil jeder Schaufelspitze (28) sich in den Graben (36) erstrecken kann, wenn der FanNerdichter (10) in dem Betriebszustand mit niedriger Drehzahl ist.
2. FanNerdichter nach Anspruch 1, dadurch gekennzeichnet, daß die Spitze (28) jeder Schaufel (26) ab einem bestimmten Durchmesser an der Vorderkante (30) bis zu dem höheren Durchmesser an der Hinterkante (32) geneigt ist.
3. FanNerdichter nach Anspruch 2, dadurch gekennzeichnet, daß der Stator (14) eine besondere Richtung des axialen Wachstums hat und daß die Richtung der Neigung in der Richtung des axialen Wachstums ist, um den Spalt zwischen den Spitzen (28) der Schaufeln (26) und der nach innen weisenden Oberfläche (37) des Grabens (36) bei axialem Wachstum des Stators (14) zu minimieren.
4. Fan/Verdichter nach Anspruch 1, gekennzeichnet durch ein abschleifbares Material (34), mit welchem die Außenwand (18) benachbart zu den Spitzen (28) der Schaufeln (26) verkleidet ist, wobei der Graben (36) in das abschleifbare Material (34) spanabhebend eingearbeitet wird, indem der FanNerdichter auf den Betriebszustand mit hoher Drehzahl beschleunigt wird, wodurch sich die Schaufeln (26) radial ausdehnen.
EP86630032A 1985-03-11 1986-03-06 Einrichtung um die Blattspitzenverluste bei Kompressoren zu vermindern Expired - Lifetime EP0194957B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US71027085A 1985-03-11 1985-03-11
US710270 1985-03-11

Publications (3)

Publication Number Publication Date
EP0194957A2 EP0194957A2 (de) 1986-09-17
EP0194957A3 EP0194957A3 (en) 1987-06-03
EP0194957B1 true EP0194957B1 (de) 1990-01-31

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP86630032A Expired - Lifetime EP0194957B1 (de) 1985-03-11 1986-03-06 Einrichtung um die Blattspitzenverluste bei Kompressoren zu vermindern

Country Status (3)

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EP (1) EP0194957B1 (de)
JP (1) JPS61207802A (de)
DE (2) DE194957T1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6363726A (ja) * 1986-09-05 1988-03-22 Nippon Shokubai Kagaku Kogyo Co Ltd 表面処理用組成物
DE59202211D1 (de) * 1991-08-08 1995-06-22 Asea Brown Boveri Deckblatt für axialdurchströmte Turbine.
EP0536575B1 (de) * 1991-10-08 1995-04-05 Asea Brown Boveri Ag Deckband für axialdurchströmte Turbine
DE19738671B4 (de) * 1997-09-04 2007-03-01 Alstom Dichtungsanordnung
EP1840332A1 (de) * 2006-03-27 2007-10-03 Siemens Aktiengesellschaft Schaufel einer thermischen Strömungsmaschine sowie thermische Strömungsmaschine
WO2014189564A2 (en) * 2013-03-06 2014-11-27 United Technologies Corporation Pretrenched rotor for gas turbine engine

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH221391A (de) * 1939-04-06 1942-05-31 Maschf Augsburg Nuernberg Ag Spaltabdichtungseinrichtung an den Köpfen der Beschaufelung von Strömungsmaschinen, insbesondere Dampfturbinen.
GB882015A (en) * 1957-04-18 1961-11-08 English Electric Co Ltd Improvements in and relating to high speed axial flow compressors
DE1057137B (de) * 1958-03-07 1959-05-14 Maschf Augsburg Nuernberg Ag Schaufelspaltdichtung bei Kreiselradmaschinen mit deckband- oder deckenscheibenlosenLaufraedern
FR1348186A (fr) * 1963-02-19 1964-01-04 Hélice carénée
CH414681A (de) * 1964-11-24 1966-06-15 Bbc Brown Boveri & Cie Strömungsmaschine
US3575523A (en) * 1968-12-05 1971-04-20 Us Navy Labyrinth seal for axial flow fluid machines
GB2034435A (en) * 1978-10-24 1980-06-04 Gerry U Fluid rotary power conversion means
US4645417A (en) * 1984-02-06 1987-02-24 General Electric Company Compressor casing recess

Also Published As

Publication number Publication date
EP0194957A3 (en) 1987-06-03
JPS61207802A (ja) 1986-09-16
DE194957T1 (de) 1987-03-19
EP0194957A2 (de) 1986-09-17
DE3668661D1 (de) 1990-03-08

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