US2641440A - Turbine blade with cooling means and carrier therefor - Google Patents

Description

s. B. WILLIAMS June `9, 1953 TURBINE BLADE WITH COOLING MEANS AND CARRIER THEREFOR 5 Sheets-Sheet 1 Filed Nov. 18, 1947 .mwmm/ NTOR.

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TUREINE BLADE WITH COOLING MEANS AND CARRIER THEREFOR Filed Novyls, 1947 5 sheets-sheet :s

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June 9, 1953 s. B. WILLIAMS 2,641,440

TURBINE BLADE WITH COOLING MEANS AND CARRIER THEREFOR Filed Nov. 18, 1947 5 Sheets-Sheet 4 IN V EN TOR. dama/ef .5. )/z/'ams.

Z- yWMM June 9, 1953 s. B. WILLIAMS v I 2,641,440

TURBINE BLADE WITH COOLING MEANS AND CARRIER THEREFOR Filed Nov. 18, 1947 5 Sheets-Sheet 5 INVENTOR. Sama/e] M/zZz'dm'. BY

Patented June 9, 1953 ITED STATES PATENT OFFICE 2,641,440 TURBINE BLADE WITHQOQLNG AND CARRIER THEREFOR Samuel B. Williams; lilirmingham,v Mich., assgo to Chrysler- Corporation, Highland Park, Mich., a corporation of Delaware Application November 1s, 1947,'seria1 No. 786,679

(C1. esse-sais) 12 Claims. 1

rlthis application relates to' a turbine blade having passages therein for cooling purposes and to a carrier for a plurality of such blades cone' structed so as to enable the cooling' passages to function.

In gas turbines, it is a problem to construct the blades in such a way that they will not be adversely affected bythe hot gases driving the turbine. I propose to construct the bladein such a way that it is provided with passages through which air will pass under centrifugal action and an existing pressure difference as Athe blades rotate. I also propose to construct the carrier in such a way that it has' passages for cooling air leading to the blades from intake openings rangement or mounting turbine blades in the carrier, whereby they are enabled to have movement with respect to the carrier.

A further object is to provide an improved method of producing a carrier for a turbine blade. Other objects will appear= from, the disclosure. In the drawingsi n Fig. l is a plan view of a. portion of one part of an improved carrier for turbine blades ofthe present invention, several of the latter being in place on the carrier part and shown in section; Fig. 2 is a plan view oi" a corresponding portion of the other part of the carrier;

Fig. 3 is a sectional View on lines 3-3' of Figure' l through the carrier and the turbine blades;

Fig. 4 is a sectional view showing the portion of Fig. 3 Within the circle 4;

Fig. 5 is a sectional view on rlines 5-5- of Figure 1 through a portion of the carrier;

Fig-6 is a. sectional view taken along the linel 6--6 of Fig. 3;

Fig. '7 is a plan View of a turbine blade taken from its convex side;

Fig. 8 is a sectional view taken along the line 8-8- of Fig. 7;

Fig. 9is' a sectionalfv'iew takenalong the line- Fig. loisa plan view of the turbine blade taken'y from its-concave side;

Fig'. l1 is a sectional view taken on Atheline l lle-,ll of Fig". l0;

Figure 12 is a plan View like Figure l, but drawnto an enlarged scale and showing the ex teriorsof' the nested blades;

Fig. 13 is a sectional view shovzing the structure on which the blade carrier is mounted; and

Fig.l 14 is a sectional View taken on theline lli-:M of Fig. 1'3`.

The reference character lll representsra concavo-convex turbine blade, as shownfin Fig. '7. This blade has a plurality of` passages il therein terminating in; the tip and in one edge thereof. The blade portion proper.- of the conventional streamline forni characterized by a rounds-disading edge and tapered trailing edge, is of substantially uniformywidth Athroughout its length, and adjacent the end thereof near a root portion l2 the passages ll combine with one another in twos to form passages i3'. Near the root portion lf2 the passages combine in pairs to form passagesv M, which finally combine into a single pas sage f5 extendingv through the root l2.

The passage lli is formed in the metal itself, whieh 'rn/ay becast Stellite. The passages ll, i3, and 'M originate in the' cast blank from. which the turbine blade all may be formed. The aforesaid* depend reinforcing flanges I8', la anual. `The purpose of the portion. ilV of the various blades is to form one side of the gas-now channel between blades'. The root l2l ofthe blade hasc'urved sur: faces 24 at each side'oi a lnarrow neck Eicon nectin'g the` blade portion proper with the root.-

Tl'i'e; surfaces 2ll have radii of curvature shorterv than those of rsurfaces in; theY carrier about to be described. with which they engage in such away as! to allow limited angular movement of each' blade with respect to the carrier.

Fig. 4.shows" the blade" llll held byits root por-` tion l2.-in cboperatingmembers 2'3 and 2'lform-l g ingarearrier` 25.- Thev carrier. members maybe 3 formed of a stainless steel having a compositie such as 16% chromium, 25% nickel, 6% molybdenum, and the balance iron. The neck portion 22 of the blade fits within suitably shaped portions 26 of carrier members 23 and 24, which portions form shoulders having curved surfaces 2163 engaging the curved surfaces 2l on the blade roots l2. The surfaces 25a yform the outer sides of grooves 2lib in the carrier member receiving the blade roots l2.

As Shown in Fig. 12, the blade surfaces 2l have a smaller radius of curvature than the carrier surfaces 26EL have, and thereby some rolling movement of the blades with respect to the carrier is permitted.

As shown in Figs. 4 and 12, a dowel pin 21 fits in an unnumbered opening in the carrier member 24 `and into grooves 28 in an adjacent pair of blade roots to retain the blades against peripheral movement with respect to the carrier '25. every turbine blade I 8 receives a dowel pin 21 but only at every fourth or fifth blade around the carrier are adjacent pairs `of blade roots tted with dowel pins in the manner described, this being suflicient to prevent undesirable peripheral movement of the blade. The carrier members 23 and 24 are held together by a plurality of bolts 29, one of which is shown in detail in Fig. 4. This bolt has a portion 38 having -a righthand thread engaging the carrier member 23, a slot 3| in the portion 38 to be engaged by a suitable tool such as a Screw driver, a portion 32 having a left-hand thread engaging the carrier member 24, and an intermediate smooth portion 33 joining the threaded portions and 32. As shown in Figs. l and 5, the carrier member 24 has integrally formed on an inner surface 34, a plurality of lands 35, 35, and 31. lThe land 35 is relatively long, extending almost from the outer periphery of the carrier 24 almost to an opening 38 of the hub portion of the carrier member 24. The bolts 29 extend through the lands 35 and -alternate lands 35. The land 35 is somewhat shorter than the land 35, terminating a greater distance from the hub opening 38, and the land 31 is still shorter in length, terminating a still greater distance from the hub opening. The long lands 35 have the greatest angular spacing, being separated by four short lands 31, and three intermediate lands 35 spacing the short lands 31 from one another. Lands 35, 36, and 31 are grooved and receive, respectively, silver soldering wires 40, 4l, and 42 of lengths suited to the lands. The soldering wire in the groove in land 35 extends outwardly only to the bolt 29. As indicated in Fig. 5 for land 35, each land carries a coating or -plating 43 of nickel. The carrier member 23 mating with the carrier member 24 has on an inner surface 44, lands 45, 46, and 41, mating respectively with lands 35, 36, and 31, in the mannerv shown for the lands 35 and in Fig. 5. The lands in the carrier member 23 correspond in width and length to the lands with which vthey mate in carrier member 24 and differ therefrom in having no groove for soldering Wire. However, each land in the carrier member 23 has a nickel coating 48, which is spaced a very small amount from the nickel coating 43 on the mating land, except that the nickel coatings on the portions of the land-s 35 and 45 beyond the bolts 29 are in direct contact with one another.

After the carrier members 23 and 24 have been assembled and fastenedy together by the bolts 29, they are heated to a brazing or soldering temper- NOt 4 ature for a sufficient time to cause the soldering wires 48, 4|, and 42 to be drawn into the slight spaces between the nickel platings 43 and 48 on the lands and bonded` therewith by alloying through diffusion.

In Fig. 5 the melted soldering wire drawn between the nickel coatings 43 and 48 is'indicated by the reference character 43. Likewise, the nickel coatings 43 and 48 will have alloyed by diffusion to some extent with the lands, either during the brazing process because of its length, or during a previous heat treatment, lor during a subsequent heat treatment. As indicated in Fig. 3, the inner end of each land 45 on the carrier member 23 is increased in thickness to lform a projection 58, and the inner end of the mating land 35 on the carrier member 24 is reduced in thickness, as indicated at 5l, so as to receive the projection 50 on the land 45. Thus indexing of the carrier members 23 and 24 is facilitated.

The mating lands on the carrier members 23 and 24 by being bonded together form radial passages for cooling air leading from the hub openings 38 to the root portions l2 of the blades I0, lets the air pass out through the passages Il, I3', I4, and i5 therein, cooling the blades. 'I'he carrier member 23 is -mounted on a flanged ring 52 which is in turn mounted on a rib 53 on a bolt 54 somewhat spaced from one end. Nearer the end of the bolt is an enlarged threaded portion 55 provided with a plurality of slots 56. The end of the bolt 54 has a polygonal shape 51. A nut 58 engaging the threaded portion 55 acts through the ring 52 to press the carrier 25 against the end of the casing 59. Between the ring 52 and the nut 58 is a washer y68 having a plurality of tangs 55a fitting in the grooves 55 in the threaded portion of the bolt and tangs 5l fitting in grooves 62 in the nut 58. Thus the nut 58 is locked against rotational movement on the bolt 54. The left end of the bolt 54, as viewed in Fig. 13, carries outwardly extending spokes 63, which engage a shoulder 64 formed in the casing 59 and cooperate with the nut 58 to hold the carrier 25 against the end of the casing 55. A retaining ring 65 tting in a groove in the casing engages the spokes `B3 on the bolt 54 to hold the bolt against accidental displacement when the nut 58 is loosened. The casing 59 is mounted for rotation in a bearing 66. Air reaches the central opening 38 in the carrier 23 from the left end of the casing 59 through the spaces between the spokes I63 on the bolt 54.

As seen in Fig. 4, the, root portion I2 of each blade I8 rests in the groove 25h in each carrier member. Each of these grooves has a small groove having a surface 51*1 extending approximately 45 to the radial plane of the carrier 25. In each small groove there is a circular sealing ring 61 which extends about the particular carrier member to which it is positioned and engages the angled surface 61a and the end of each blade root I2 to provide sealing of each blade to this region. Centrifugal force due to rotation of the carrier 25 causes sealing rings 61 to` be pressed radialy outwards to insure proper sealing. Betweeen adjacent edges of the roots l 2 of adjacent blades lil, there are relatively short, straight seals 68 moved outwardly under centrifugal action to provide sealing between the blades. This is shown in Figure 12. The ring seals 61 and the rod-like seals 68, being round in cross-section, offer no opposition to the previously Idescribed rocking movement of the blade with respect to the carrier 25- made possible by the difference in radii of curvature between the surfaces ZI-on the blade roots I2 and the surfaces 26 on the carrier members 2 3' and 24.A

As seen in Fig. 6,- theedge ofV the shelf-like portion Il of one blade It is shaped to conform to the adjacent side of the next turbine blade Hl, with a small amount of clearance therebetween permitting the aforementioned rocking movement of blade on carrier.

I claim:

l. An assembly comprising a row of circumferentially aligned successive turbine bladesseach having an enlarged root provided with curved shoulder surfaces curving in the direction of the ciroumferentiall'y aligned blades on both sides, and a carrier formed of mating parts embracing the root portions and including grooves receiving the root portions of the blades, the grooves having circumferentially curved surfaces formed according to a cylindrical path of revolution and engaged by the curved surfaces of the blade roots, the radius of curvature of the blade-root curved surfaces being smaller than that of the carrierpart-groove curved surfaces to provide for angular rolling movement of the blades with respect to the carrier and in the plane of the latter due to rocking of the aforesaid root curved surfaces on the aforesaid carrier curved surfaces.

2. The assembly specified in claim l in which every two adjacent blades in the row define an intervening gas flow channel, there being a shelflike gas ow channel portion between every two said adjacent blades projecting from a pan, ci one of the blades radially outward of the carrier toward the other blade and terminating in spaced adjacency complementally thereto to form the radially inner side of the gas flow channel between blades and at the same time to limit relative movement of the blade with respect to the carrier.

3. An assembly comprising a plurality of turbine blades having enlarged roots disposed in a row defining an annular path, a carrier composed of mating parts having grooves adjacent the periphery engaging the turbine roots, the grooves having portions on either lateral side of the annular path extending beyond the ends of the turbine roots at acute angles thereto, and sealing rings defining circular paths transversely aligne able with the annular row of blade roots so as to register axially with the ends of the latter and being positioned in the said angled groove portions for being urged outwards under centrifugal force due to rotation of the assembly so asto press against the groove portions of the carrier andthe blade root ends.

4. An assembly comprising a plurality of turbine blades having enlarged roots, a, carrier composed of mating parts having grooves adjacent the periphery engaging the blade roots, each blade root increasing in Width when considered in a radial direction about the carrier from the inner end of the blade to an intermediate region of the blade root radially outward of the end so as to form `with an adjacent blade a groove, and a plurality of rod-like seals positioned in the grooves and urged into the grooves radially outwards under centrifugal force due to rotation of the carrier to seal the adjacent edges of the turbine blades.

5. An assembly comprising a plurality of turbine blades having enlarged roots at their' inner ends, a carrier composed of mating parts having grooves adjacent the periphery engaging the turbine blade roots, the grooves having portions beyond the ends of the turbine roots at acute angles thereto,v sealing rings disposed between. said groove portions of the blade roots urged outwards underl centrifugal` force due to rotation of the assembly so as to press against the groove portions of the carrier and the blade root` ends,`each blade root increasing in width when considered in a radial direction about the carrier from the inner end of the blade to an intermediate region of the blade root radially outward of the end so as to form with an adjacent blade a groove, and a plurality of rod-like seals positioned in the grooves and urged into the grooves radially outwards under centrifugal force due to rotation of the carrier to seal the adjacent edges of the turbine blades.

6. The assembly specified in claim 5, the blades having passages for air cooling extending from the roots, the carrier parts having cooperating portions forming passages for air cooling communicating with the blade roots.

'7. An assembly comprising a row of circumferenti-ally` aligned successive turbine blades each having an enlarged root at the blade end provided with curvedy shoulder surfaces curving in the direction of the circumferentiaily aligned blades on both sides, a carrier composed of mating parts having grooves adjacent the periphery engaging the turbine roots, the grooves having oircum ferentially curved surfaces formed according to a cylindrical path of revolution and engaged by the curved surfaces of the blade roots, the radius of curvature of the blade-root curved surfaces being smaller than that of the carrierpartgroove curved surfaces to provide for angular rolling movement of the blades with respect to the carrier and in the plane of the latter due to rocking of the aforesaid root curved surfaces on the aforesaid carrier curved surfaces, the grooves having portions beyond the ends of the turbine roots at acute angles thereto, sealing rings in the groove portions urged outwards under centrifugal force due to rotation of the assembly so as to press against the groove portions of the carrier and the blade root ends, each blade root increasing in width when considered in a radial direction about the carrier from the inner end of the blade to an intermediate region of the blade root radially outward of the end so as to form with an adjacent blade a groove, and a pluralityk of rod-like seals positioned in the grooves and urged radially outwards under centrifugal force due to rotation of the carrier to seal the adjacent edges of the turbine blades, the sealing rings and the rod-like seals being of round cross section so as to offer no opposition to the aforesaid angular movement of the blades with respect to the carrier.'

8. An assembly comprising a plurality of turbine blades eaoh having an enlarged root and passages for cooling extending from the root and terminating in a tip and an edge, and a carrier for the blades comprising a pair of axially alignable complementary parts having opposed grooved peripheral portions engaging the blade roots and central hub openings adapted to register with one another when said parts are axially aligned, said parts being provided with surfaces extending between the central openings and the grooved peripheral portions in facing spacedrelationship and each incorporating radially extending lands raised therefrom, the radially extending raised lands on at least one of said parts being grooved to define solder chambers and mating with the raised lands on the other part and being bonded thereto with solder from said solder chambers, thereby cooperating with the facing surfaces to form radial passages for air forced by centrifugal action from the central openings and through the blades for cooling purposes.

9. The assembly specified in claim 8 in which the solder used is of the silver Wire type and in which the carrier parts contain nickel and chromium, the lands on the facing surfaces of the carrier parts being joined to one another through nickel bonded to the lands and through the silver solder bonded to the nickel, the carrier additionally including bolts at certain lands and joining the complementary parts.

10. The assembly specified in claim 8, some mating pairs of lands on the carrier parts terminating near the registering openings in the carrier, other mating pairs of lands between the aforesaid pairs of lands terminating farther from the registering openings, and still other lands between said other mating pairs terminating still farther from the registering openings.

11. A cooled turbine blade comprising lengthwise a neck, a root, and a blade having a tip edge, a relatively thin edge and a relatively thick edge, said neck being remote from said tip edge and merging with the root at laterally extending shoulders on the latter between the lateral sides of the same, the root having a base portion of substantially rectangular section presenting said shoulder surfaces and extending longitudinally therefrom to an end of the base portion, and a convex crown on said end of the base portion comprising a portion of a, cylindrical surface extending to and merging with the said lateral sides of the base portion, and flanks disposed transversely to said convex crown extending from one said lateral side to the other, said shoulder being formed with arcuate convex surfaces transversely disposed to said convex crown and being of a predeterminedly limited radius of curvature, said blade proper being passaged longitudinally and further comprising a shelf-like portion disposed between the thick and thin edges of the blade and being normal thereto, and flanges depending from the sides of the shelf-like portion in the direction of the root and presenting opposed and outwardly facing parallel plane surfaces one adjacent each of said thick and thin edges.

12. A cooled turbineblade comprising length- 8 wise a neck, a root, and a blade having a tip edge, a relatively thin edge anda relatively thick edge, said neck being remote from said tip edge and merging with the root at laterally extending shoulder surfaces on the latter between the lateral sides of the same, the root having a base portion of substantially rectangular section presenting said shoulders and extending longitudinally therefrom to an end of the base portion, and a convex crown on said end of the base portion comprising a portion of a cylindrical surface eX- tending to and merging with the said lateral sides of the base portion, and flanks disposed transversely to said convex crown extending from one said lateral side to the other, said shoulders being formed with arcuate convex surfaces transversely disposed to said convex crown and being of a predeterminedly limited radius of curvature.

SAMUEL B. WILLIAMS.

yReferences Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,325,208 Rice Dec. 16, 1919 1,366,119 Darling Jan. 18, 1921 1,603,966 Lorenzen Oct. 19, 1926 1,657,192 Belluzzo Jan. 24, 1928 1,891,948 Rice Dec. 27, 1932 2,038,670 Noack Apr. 28, 1936 2,149,510 Carrieus Mar. 7, 1939 2,220,420 Meyer Nov. 5, 1940 2,297,446 Zellbeck Sept. 29, 1942 2,401,826 Halford June 11, 1946 2,407,164 Kimball Sept. 3, 1946 2,436,087 Benson Feb. 17, 1948 2,473,899 Murphy June 21, 1949 2,489,683 Stalker Nov. 29, 1949 FOREIGN PATENTS Number Country Date 55 Great Britain Jan. 1, 1901 143,471 Switzerland Jan. 16, 1931 302,953 Great Britain Dec. 21, 1928 319,622 Great Britain Dec. 18, 1930 391,880 Germany July 29, 1924 516,781 Great Britain Jan. 11, 1940 557,860 Germany Aug. 29, 1932 878,999 France Nov. 2, 1942

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