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Publication numberUS3856433 A
Publication typeGrant
Publication dateDec 24, 1974
Filing dateAug 2, 1973
Priority dateAug 2, 1973
Also published asCA1018067A, CA1018067A1
Publication numberUS 3856433 A, US 3856433A, US-A-3856433, US3856433 A, US3856433A
InventorsC Grondahl, J Eskesen
Original AssigneeGen Electric
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Liquid cooled turbine bucket with dovetailed attachment
US 3856433 A
Abstract
A liquid-cooled turbine bucket construction is described in which the airfoil bucket core, platform (with metering means) and root with dovetail configuration are integrally formed. The pressure and suction sides of each bucket are each provided with a liquid reservoir defined in part by metering means (e.g., a weir), grooves in the upper surface of the platform and face of the airfoil core and holes interconnecting these grooves with the underside of the platform adjacent the metering means.
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United States Patent [191 Grondahl et a].

[ Dec. 24, 1974 LIQUID COOLED TURBINE BUCKET WITH DOVETAILED ATTACHMENT [75] Inventors: Clayton M. Grondahl, Elnora; John H. Eskesen, Schenectady, both of NY.

[73] Assignee: General Electric Company,

Schenectady, NY.

[22] Filed: Aug. 2, 1973 [2]] Appl. No.: 384,990

[52] US. Cl 416/97, 416/96, 416/92 I [51] Int. Cl. F0ld 5/08, FOld 5/18 [58] Field of Search 416/92, 95, 96, 97

[56] References Cited UNITED STATES PATENTS 3,446,481 5/1969 Kydd 416/96 3,658,439 4/1972 Kydd.....

3,736,071 5/1973 Kydd 416/97 FOREIGN PATENTS OR APPLICATIONS 1,801,475 4/1970 Germany 416/95 Primary ExaminerEverette A. Powell, Jr.

Assistant ExaminerLouis J. Casaregola Attorney, Agent, or Firm- Leo I MaLossi; Joseph T. Cohen; Jerome C. Squillaro ABSTRACT A liquid-cooled turbine bucket construction is described in which the airfoil bucket core, platform (with metering means) and root with dovetail configuration are integrally formed. The pressure and suction sides of each bucket are each provided with a liquid reservoir defined in part by metering means (e.g., a weir), grooves in the upper surface of the platform and face of the airfoil core and holes interconnecting these grooves with the underside of the platform adjacent the metering means.

9 Claims, 3 Drawing Figures LIQUID COOLED TURBINE BUCKET WITH DOVETAILED ATTACHMENT BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION A liquid-cooled turbine bucket construction is described in which the airfoil bucket core, platform (with metering means) and root with dovetail configuration are integrally formed. The pressure and suction sides of each bucket are each provided with a liquid reservoir defined in part by metering means (e.g., a weir), grooves in the upper surface of the platform and face of the airfoil core and holes interconnecting these grooves with the underside of the platfon'n adjacent the metering means.

BRIEF DESCRIPTION OF THE DRAWING The exact nature of this invention as well as objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawings in which:

FIG. 1 is a view partially in section showing the side view in elevation of part of the dovetailed root, platform and airfoil and liquid coolant feed means in register therewith;

FIG. 2 is a view partially in section with the retainer/- feed ring and a cover plate cut away to show the integral formation in the platform of the reservoir, the longitudinally extending metering means, platform gutter, platform coolant channels and feed holes leading thereto and FIG. 3 is a view taken on line 33 of FIG. 2 with the airfoil skin removed in part to show the location and interconnection of the airfoil channels, the platform channels and feed conduits leading to the platform channels from the underside of the platform.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turbine bucket consists of skin 11, 11a (e.g., sheet metal) affixed, as by brazing, to the unitary root/- platform/airfoil core 12. Root portion 13 is formed in the conventional dovetail configuration by which bucket 10 is retained in slot 14 of wheel rim 16. Each groove 17 recessed in the surface of platform 18 is connected to a similar groove 19 recessed in the surface of airfoil portion 21 of unit 12. The cooling channels (preferably rectangular in shape) defined by skin 11a and grooves 17 are thus in communication on a one-toone basis with the cooling channels defined by skin 11 and grooves 19 and cooling liquid is conducted therethrough at a uniform distance from the exterior surface. At the radially outer ends thereof the rectangular cooling channels on the pressure side of bucket 10 are in flow communication with, and terminate at, manifold 22 recessed into airfoil portion 21. On the suction side of bucket 10 the cooling channels are in flow communication with, and terminate at, a similar manifold (not shown) recessed into airfoil portion 21. Near the trailing edge of bucket 10 a cross-over conduit (opening shown at 23) connects the manifold on the suction side with manifold 22.

Open-circuit cooling is accomplished by spraying cooling liquid (usually water) at low pressure in a generally radially outward direction from nozzles, such as nozzle 24 (one shown), mounted on each side of the rotor disk. The coolant is received in annular gutter 26 formed in ring member 27, one of which is mounted on each side of wheel rim 16. Ring member 27 in addition to conducting the function of coolant distribution to each bucket also retains the buckets l0 properly positioned in wheel rim 16 as more completely described in U.S. Pat. application Ser. No. 385,096 Wojcik, filed Aug. 2, 1973 and assigned to the assignee of the instant invention. The Wojcik application is incorporated by reference.

Coolant received in gutters 26, is directed through feed holes 28, each of which is in flow communication with a reservoir 29 extending in a direction parallel to the axis of rotation of the turbine disk. The openings into the feed holes 28 from gutters 26 are equally spaced around the circumference of gutters 26 to insure equal distribution of coolant to the buckets via these feed holes.

While coolant is spread out as a thin film in gutters 26, it accumulates to fill each reservoir 29 (the ends thereof being closed by means of a pair of cover plates 31). As liquid coolant continues to reach each reservoir 29, the excess discharges over the crest of weir 32 along the length thereof and is thereby metered. Preferably the crest of weir 32 is arcuate (convex toward the axis of rotation) in cross-section and is a portion of a cylinder in configuration in order to accommodate slight differences in the disposition of the buckets 10 relative to each other. Although the distance of the crest of any given weir from the axis of rotation may vary slightly from that of another weir, the cylindrical configuration of the weir crest curving toward the root must be accurately machined so that each element of each such cylindrical surface extends parallel to the elements forming the cylindrical convex ridges of the dovetailed configuration. In this manner each element of the crest surface can be set parallel to the axis of rotation (the axis of the shaft on which the rotor is mounted). This machining accuracy is required in order to insure that liquid coolant passes uniformly over the full length of the weir crest.

Coolant that has traversed the weir crest 32 continues in the generally radial direction to enter longitudinally extending platform gutter 33 as a film-like distribution, passing thereafter through the cooling channel feed holes 34. Thus, one each of reservoir 29, weir 32 and gutter 33 constitute a set, one such set being formed in the underside of platform 18 on each side of root portion 13.- Most of the channel feed holes 34 are in flow communication with grooves 17 on a one-toone basis, although a few of these holes 34 connect directly with grooves 19. In any event, the coolant passes from holes 34 to manifold 22 (and the suction manifold, not shown) viabucket cooling channels.

As the coolant traverses the surfaces of the platform and of the airfoil, these elements are kept cool. Some portion of the cooling liquid, depending upon the rate of flow, is converted to the gaseous or vapor state as it absorbs heat. The vapor or gas and any remaining liquid coolant exit from the manifold 22 via opening 36, preferably to enter a collection slot (not shown) formed in the casing for the eventual recirculation or disposal of the ejected fluid.

Although the cooling channels have been illustrated herein extending spanwise of the turbine bucket, the instant invention is equally applicable to bucket constructions in which the cooling channels are disposed in a convoluted or spiral configuration.

What we claim as new and desire to secure by by Letters Patent of the United States is:

1. Turbine bucket construction comprising in combination:

a. integrally formed airfoil-shaped core, platform and root portions, said root portion having a dovetailed configuration,

b. a first group of cooling grooves recessed into the upper surface of said platform portion,

c. a second group of cooling grooves recessed into the pressure and suction faces of the airfoil-shaped core, each of the cooling grooves in said first group being connected to a separate cooling groove in said second group,

(1. skin material disposed over said upper surface of said platform portion and over said pressure and suction faces thereby covering said first and second groups of cooling grooves,

e. a pair of longitudinally-extending recesses formed in the underside of said platform portion one of said recesses extending along each side of, in the same direction as, and adjacent to said dovetailed configuration, a pair of longitudinally-extending gutters formed in the underside of said platform portion, one of said gutters extending parallel to and adjacent each of said recesses,

f. a pair of longitudinally-extending projections formed along the underside of said platform portion, each of said projections separating one recess and one gutter, each of said projections having a crest, said crest being arcuate in cross-section and presenting a convex cylindrical surface, the elements of the cylindrical surfaces of both crests being parallel to the elements of the cylindrical convex ridges of said dovetailed configuration and g. a plurality of holes passing through said platform portion placing said first group of cooling grooves in flow communication with the underside of said platform portion adjacent each of said projections on the side thereof away from the recess adjacent thereto.

2. The turbine bucket as recited in claim 1 wherein the crest of the longitudinally extending projection is in the form of an arc of a circle in cross-section.

3. The turbine bucket as recited in claim 1 wherein the far ends of each of the recesses formed in the underside of the platform portion are closed off by a pair of plate-like members.

4. The turbine bucket as recited in claim 1 wherein the pair of recesses and the pair of projections are located between the pair of gutters.

5. The turbine bucket as recited in claim 1 wherein each groove of the second group of cooling grooves terminates in one of two interconnected manifolds located near the tip of said bucket.

6. In a gas turbine wherein a turbine disk is mounted on a shaft rotatably supported in a casing, said turbine disk extending substantially perpendicular to the axis of said shaft and having turbine buckets mounted on the outer rim thereof, means located radially inward of said bucket adjacent said turbine disk for supplying liquid coolant to said buckets to enter open-circuit distribution paths comprising cooling channels and a manifold system in each of said buckets, the improvement comprising:

a. each of said buckets having integrally formed airfoil-shaped core, platform and root portions, said root portion having a dovetailed configuration fitting into a matching slot in said outer rim,

b. the platform portion of each bucket having a pair of longitudinally-extending recesses formed in the underside thereof, one of said recesses extending along each side of, in the same direction as and adjacent said dovetailed configuration, a pair of longitudinally-extending gutters formed in the underside of said platform portion, one of said gutters extending parallel to and adjacent each of said recesses,

c. a pair of longitudinally extending projections formed along the underside of said platform portion, each of said projections separating one recess and one gutter, each of said projections having a crest, said crest being arcuate in cross-section and presenting a convex cylinder surface, the elements of the cylindrical surfaces of both crests being parallel to the elements of the cylindrical convex ridges of said dovetailed configuration and d. in each of said buckets a plurality of first cooling grooves recessed into the upper surface'of the platform portion, said cooling grooves being connected to a plurality of second cooling grooves recessed into the pressure and suction faces of the airfoil shaped core, said second cooling grooves in turn being connected to a manifold system adapted to discharge coolant from said bucket,

e. skin material disposed over the upper surface of the platform portion and over the pressure and suction faces of each of said buckets thereby covering said first and second cooling grooves and said manifold system except for the exit therefrom,

f. a plurality of holes passing through said platform portion placing said first cooling grooves in flow communication with said pair of gutters and g. said means for supplying liquid coolant being in flow communication with each of said longitudinally extending recesses,

whereby once any given recess has become full of coolant, as additional coolant enters said recess the excess coolant flows over the adjacent crest along the length thereof and passes through said holes, said first and second cooling grooves and said manifold for exit from said bucket.

7. The turbine bucket as recited in claim 6 wherein the pair of recesses and the pair of projections are located between the pair of gutters.

8. The improvement recited in claim 6 wherein the far ends of each of the recesses formed in the underside of the platform portion are closed off by a pair of platelike members.

3,856,433 6 9. The improvement recited in claim 6 wherein in a grooves on the pressure side of said bucket and the secgiven bucket the holes passing through the platform 0nd set in flow communication with cooling grooves on portion to the underside thereof are divided into two the suction side of said bucket. sets, one set in flow communication with cooling

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3446481 *Mar 24, 1967May 27, 1969Gen ElectricLiquid cooled turbine rotor
US3658439 *Nov 27, 1970Apr 25, 1972Gen ElectricMetering of liquid coolant in open-circuit liquid-cooled gas turbines
US3736071 *Nov 27, 1970May 29, 1973Gen ElectricBucket tip/collection slot combination for open-circuit liquid-cooled gas turbines
DE1801475A1 *Oct 5, 1968Apr 30, 1970Daimler Benz AgTurbinenschaufel
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3936227 *Jan 23, 1975Feb 3, 1976General Electric CompanyCombined coolant feed and dovetailed bucket retainer ring
US4017210 *Feb 19, 1976Apr 12, 1977General Electric CompanyLiquid-cooled turbine bucket with integral distribution and metering system
US4090810 *Mar 23, 1977May 23, 1978General Electric CompanyLiquid-cooled turbine bucket with enhanced heat transfer performance
US4142831 *Jun 15, 1977Mar 6, 1979General Electric CompanyLiquid-cooled turbine bucket with enhanced heat transfer performance
US4156582 *Dec 13, 1976May 29, 1979General Electric CompanyLiquid cooled gas turbine buckets
US4185369 *Mar 22, 1978Jan 29, 1980General Electric CompanyMethod of manufacture of cooled turbine or compressor buckets
US4212587 *May 30, 1978Jul 15, 1980General Electric CompanyCooling system for a gas turbine using V-shaped notch weirs
US4242045 *Jun 1, 1979Dec 30, 1980General Electric CompanyTrap seal for open circuit liquid cooled turbines
US4259037 *May 18, 1978Mar 31, 1981General Electric CompanyLiquid cooled gas turbine buckets
US4338780 *Nov 29, 1978Jul 13, 1982Hitachi, Ltd.Method of cooling a gas turbine blade and apparatus therefor
US4350473 *Feb 22, 1980Sep 21, 1982General Electric CompanyLiquid cooled counter flow turbine bucket
US5003766 *May 8, 1989Apr 2, 1991Paul Marius AGas turbine engine
US5122033 *Nov 16, 1990Jun 16, 1992Paul Marius ATurbine blade unit
US5177954 *Jun 26, 1990Jan 12, 1993Paul Marius AGas turbine engine with cooled turbine blades
US5387431 *Mar 5, 1992Feb 7, 1995Fuisz Technologies Ltd.Saccharide-based matrix
DE2920284A1 *May 18, 1979Dec 6, 1979Gen ElectricKuehlsystem fuer eine gasturbine
Classifications
U.S. Classification416/97.00R, 416/96.00R, 416/92
International ClassificationF01D5/08, F01D5/18, F02C7/16
Cooperative ClassificationF01D5/081, F05D2240/81, F01D5/185
European ClassificationF01D5/08C, F01D5/18D
Legal Events
DateCodeEventDescription
Feb 14, 1984PAPatent available for license or sale