US2847185A - Hollow blading with means to supply fluid thereinto for turbines or compressors - Google Patents

Description

1953 J. A. PETRIE ET AL ,8

HOLLOW BLADING WITH MEANS TO SUPPLY FLUID THEREINTO FOR TURBINES OR COMPRESSORS Filed March 29, 19,54

3 Sheets-Sheet 1 1953 J. A. PETRIE ET AL 2,

HOLLOW BLADING WITH MEANS TO SUPPLY FL THEREINTO FOR TURBINES OR COMPRESSOR Filed March 29, 1954 3 Sheets-Sheet 2 Allg- 1953 J. A. PETRIE ET 2,847,185

HOLLOW BLADING WITH MEANS TO SUPP FLUID THEREINTO FOR TURBINES OR COMPRESSORS Filed March 29, 1954 5 Sheets-Sheet 3 ire thee

HOLLOW BLADING WETH IVIEANS TO SUPPLY FLUID THEREINTO FOR TURBINES OR COM- PRESSORS James Alexander Petrie, Littleover, Derby, and Charles William Robey, Kings Newton, Derby, England, as signers to Rolls-Royce Limited, Derby, England, a British company This inventionrelates to hollow blading for turbines or compressors, that is blading which has a cavity extending therein or a bore extending therethrough for the greater part at least of the spanwise length of the blading.

Such blading is employed when it is desired to pass a fluid through the blade, say for cooling purposes, and such blading may be either rotor blading or stator blading. The cavity or bore often has a cross section which is similar to but is scaled down from the full section of the blading so that the blading wall is of substantially uniform thickness.

This invention has for an object to provide an improved form of hollow blading element whereby the fluid, say the coolant, is delivered to flow in a desired path through the cavity or bore.

According to the present invention, a hollow blading element has fluid-delivery manifold means extending through the cavity or bore substantially from end to end thereof and with a clearance from the wall of the cavity or bore, said manifold means having an inlet'thereto at least at one end of the blading element and having an outlet or outlets to within the cavity or bore provided at a selected location relative to the wall of the cavity or bore, there being also outlets from the cavity or bore. If desired, there may be provided a pair of manifold passages which extend one from each end of the blading element to adjacent its spanwise mid-length, and the manifold passages may be afforded by separate members or in a single manifold piece.

Preferably, the outlet or outlets from the manifold means are disposed so that the fluid flows from the manifold first to contact the wall of the cavity or bore adjacent the leading edge of the blading element.

The manifold means in one preferred arrangement comprises a tube, conveniently of similar but scaled-down areofoil cross-section to the blading element, which is closed at one end and open at the other end, there being flange means between the open end of the tube and the adjacent end of the cavity or bore whereby the cavity or bore is closed at said adjacent end. Outlets are provided along the tube adjacent the leading edge of the blading element which itself is provided with outlets along its trailing edge.

Some embodiments of hollow blading of this invention will now be described with reference to the accompanying drawings, in which- Figure l is an axial section through part of a nozzleguide-vane assembly of a gas turbine, which assembly comprises one form of hollow blading,

Figure 2 is a perspective view of a blading element as shown in Figure 1, parts being broken away,

Figure 3 is a section 33 of Figure 1,

Figure 4 is a section on the line 4--4 of Figure 3,

Figures 5 and 6 show steps in the manufacture of the blading element of Figures 1 to 4,

Figure 7 is a view corresponding to Figure 1 showing a second embodiment of blading element, and

Figure 8 is a section on the line 8-8 of Figure 7.

Referring first to Figures 1 to 4, the form of turbine shown comprises a rotor disc 10 having rotor blades 11 at its periphery, and a stator structure comprising an outer casing 12 supporting a shroud 13 for the rotor blading 11 and a nozzle-guide-vane assembly 14 through which hot gases pass from a combustion chamber 15 on to the rotor blading. The stator structure also comprises an inner structure 16. The turbine also comprises an exhaust unit 17 of which only the inlet end is shown.

The nozzle-guide-vane assembly 14 is of the kind having blading elements through which cooling air is fed in operation to prevent over-heating of the blading elements.

Each blading element comprises an outer sheet-metal shell 18 of aerofoil section, and a pair of manifold members 19, 20 of similar section, of which the manifold member 19 extends from the outer end of the blading element to adjacent the mid length of the blading element and the manifold member 20 extends from the inner end of the blading element also to adjacent the mid length. The ends of the shell 18 are flanged over as indicated at 21 into contact with the outer ends of the manifold members 19, 20 and the manifold members are welded in place to the flanged portions 21. The flanged portions 21 also serve to close the inner and outer ends of the shell 18.

The shell 18 has outlets 22 adjacent its trailing edge and one manner of forming a shell 18 with such outlets will be described below.

As will best be seen from Figure 4, the manifold members 19, 20 are open at their outer ends and are closed at the inner ends, which are adjacent one another. Each manifold member is formed with a pair of oppositelydirected blisters 23 which assist to locate the member relative to the shell 18 and is cut away as at 24 along its leading edge to provide a slot-like outlet therefrom.

It will be seen that with the arrangement described cooling air enters each shell 18 through the manifold members 19, 20 by flowing through the manifold members from their outer ends to the slots 24, and thus first contacts the shell adjacent its leading edge. The air flows rearwardly between the shell 18 and the walls of the manifold members 19, 2t) and out from the shell it; through the outlets 22.

In this way the cooling air flows first over those portions of the blading elements most requiring cooling. Further, provision of two tubular manifold members as above described projecting to adjacent the mid length of the shell of the blading element ensures that there is a greater flow of coolant adjacent the mid portion of the blading element (which requires greater cooling) than the end portions.

Use of two tubular manifold members 19, 20 as abovedescribed additionally permits relative thermal expansion between the shell 18 of the blading elements and the tubular manifold members. It will be appreciated that in operation the shell 18 of the blading element will be hot relative to the tubular manifold members 19, 2% thus giving rise to relative thermal expansion.

In this construction, each blading element is supported individually by being provided with end platforms 125, 26 which in turn are mounted in the stator structure.

The inner platform 25 has a flanged socket 27 wherein the end of the shell 18 is welded, an inwardly-projecting dog 28 which engages between castellations 29 on a ring 30 forming part of the inner stator structure 16, and a hooked projection 31 which co-operates with axial projections 32 on the ring 39 to retain the blading elements radially.

The number of castellations 2-9 is greater than the 3 number of dogs 28 so as to leave gaps for the passage of air from the space 33 around the combustion chamber to between the ring 36 and platforms and thus to the inlets of the manifold members 20.

Each platform 26 has a flanged socket 34 for the outer end of its associated blading element and flanges 35, 36 along its upstream and-downstream'edges respectively. The flange has a central dog 37 to engage a corresponding notch 38 in an inwardly-directed flange 39 on the outer casing 12, and the flange 36 has a central dog 46 to engage a notch 41 in a second inwardly-directed flange 42. The flange 39 is formed with a ring of holes 4-3 which permit the passage of air from space 44 outside the combustion chamber 15 to between the flanges 39, 42 and thus to the inlets to the manifold members 19.

Referring now to Figures 5 and 6, there is shown a blading element as just described in ditferent stages of manufacture. Each blading element is formed from sheet metal, and comprises a roughly rectangular piece of the metal sheet 4-5 which is folded so that a pair of opposite edges 4-6 meet, these edges being joined together and the whole being shaped so that the joined edges form the trailing edge of the blading element and so that the fold forms the rounded leading edge 47. Prior to folding the sheet metal piece, channels 48 are machined in that surface of the sheet 45 which will form the wall of the bore of the blading element after folding, these channels extending from the edges 46 which are to be joined, for a short distance towards one another. The channels 48 in one edge are arranged to register with those in the other edge, when the sheet metal piece has been folded so as to form the outlets 22.

The tubular manifold members which are of substantially the same aerofoil section as the blading element but substantially scaled down so that the tubular member is clear of the wall of the bore running through the blading element, are secured in position by welding them to one leaf of the metal sheet 45 prior to final folding, the flanged portions 21 being cut away as at 49 to fit around the manifold members.

Referring now to Figures 7 and 8, there is illustrated a second noZZle-guide-vane arrangement.

In this construction, each blading element has a shell 18 of a form similar to that described above with outlets 22 at its trailing edge. The manifold means in this case comprises a single tubular member 50 which is open at each end and projects at each end from the closed end of the shell 18. The central portion of the tube 50 is pinched together as indicated at 51 and the leading edge is cut away as at 52 over the central portion of the leading edge; there is thus formed a pair of passages 53 each having an inletadjacent a corresponding end of the shell 18, and an outlet adjacent the mid-length of the shell 18 facing the leading edge thereof.

In this case, the radially-inner ends of the blading elements are fitted into an annular structure formed by sheet metal parts 54, 55, 56, the upstream edges of the parts 54, 55 being brought together to form a flange 57 to engage an annular groove in a disc 58 welded to a part of the inner stator structure 16.

The radially-inner passages 53 of the manifold members 50 are fed with cooling air from space 33 through holes 59 in the disc 58 and annular distribution space 60.

The radially-outer ends of the shells 18 also fit into an annular structure which in this case affords a distribution space for feeding the radially-outer passages 53. The blading elements are fitted in an annular member 61 to which is secured the edge portions of a second annular member 62. The member 62 has locating projections 63 to co-operate with a notched ring 64 secured in the outer casing 65, and has a ring of holes 66 in it to permit cooling air to flow into the space between it and the member 61 from the space 46.

The invention is not limited in its application to blad ing elements formed by folding sheet metal pieces but is equally applicable to cast hollow blades or hollow blades of other constructions, for example, hollow blades formed by a number of pieces welded or brazed together.

We claim:

1. A hollow blading element for use in a turbine or compressor having an outer wall defining a cavity extending substantially over the length of the blading element and fluid delivery manifold means extending within the cavity substantially from end to end thereof and with a clearance from said outer wall, said manifold means including a first wall part defining a first tubular passage having an inlet opening through one end of the blading element and extending from said one end lengthwise of the blading element to a closed end adjacent the mid length of the blading element, said manifold means further including asecond wall part defining a second tubular passage having an inlet opening through the opposite end of the blading element and extending from said opposite end lengthwise of the blading element to a closed end adjacent the mid length of the blading element, and said manifold means further having first outlet means from said first and second passages extending over a substantial length of said manifold means to distribute fluid into the clearance Space between the outer wall and said manifold means, and second outlet means from said clearance space through said outer wall to externally of the blading element.

2. A hollow blading element as claimed in claim 1, wherein said manifold means comprises a single manifold piece in the form of a tubular member extending through the whole length of the blading element and pinched together at its mid-length so as to afford said closed ends of said first and second passages which extend respectively from the ends of the blading element to adjacent the mid-length of the blading element and said first outlet means extending lengthwise of said passages along a substantial part thereof.

3. A hollow blading element as claimed in claim I, wherein the first outlet means are disposed to face the leading edge of the blading element so that the fluid flowing into the clearance space first contacts the outer wall adjacent the leading edge of the blading element, and said second outlet means are disposed adjacent the trailing edge of the blading element.

4. A hollow blading element as claimed in claim 1, wherein said outer wall comprises a sheet-metal shell formed from sheet metal bent on itself to bring a pair of edges together, said edges being provided with registering channels to aflford the outlets from the cavity of the blading element.

5. A hollow blading element as claimed in claim 4, comprising also flange means adjacent the end of the hollow blading element fitting around the manifold means and closing the ends of the cavity of the hollow blading element.

6. A hollow blading element for use in a turbine or compressor having an outer wall defining a cavity extending substantially over the length of the blading ment and fiuid delivery manifold means extending within the cavity substantially from end to end thereof and with a clearance from said outer wall, said manifold means comprising a pair of tubular members, each affording manifold passage, one of the tubular members extending from one end of the blading element to adjacent its mid-length and the other of the tubular members er tending from adjacent the opposite end of the blading: element to adjacent its mid-length, and each of said tubular members being open at its end adjacent the respective end of the blading 't'ent and closed at its opposite end, each of said tubular members having first outlet means therefrom extending lengthwise over a substantial part thereof to distribute fluid into the clearance space between the outer wall and the said manifold means, and second outlet means from said space through said outer wall to externally of the blading element.

7. A turbine nozzle guide vane assembly comprising a plurality of hollow blading elements, each said blading element having an outer wall defining a cavity extending substantially over the length of the blading element, and fluid-delivery manifold means comprising a pair of tubular members, each aflording a manifold passage, one of the tubular members extending from one end of the blading element to adjacent its mid length and the other of the tubular members extending from adjacent the opposite end of the blading element to adjacent its mid length, each of said tubular members having an inlet thereto at its end adjacent the respective end of the blading element and being closed at its opposite end, each tubular member having a clearance from said outer wall, and each of said tubular members having first outlet means extending lengthwise over a substantial part thereof, and each said blading element having second outlet means from said clearance space to externally of the blading element, said second outlet means being spaced chordwise of the blading element from the first outlet means whereby fluid flows from said first outlet means to said second outlet means in a direction generally chordwise of the blading element; outer annular support structure having said blading elements engaged therein by their outer ends and including means aflording a first annular fluid passage therein, the tubular members having inlets at the outer ends of the blading ele ments being in communication through said inlets with said first annular fluid passage, and inner annular support structure having said blading elements engaged therein by their inner ends and including means atfording a second annular fluid passage therein, the tubular members having their inlets at the inner ends of the blading elements being in communication through said inlets with said second annular fluid passage.

8. A turbine nozzle guide vane assembly comprising an outer annular support structure including means affording a first annular fluid passage therein; an inner annular support structure radially within and spaced from said outer annular support structure, said inner annular support structure including means affording a second annular fluid passage therein; a plurality of blading elements extending between and having their outer and inner ends engaged with said outer annular support structure and said inner annular support structure reelement, the inlets adjacent the outer ends of the blading elements being in communication with said first annular fluid passage and the inlets at the inner ends of the blading elements being in communication with the second annular fluid passage, first outlet means extending lengthwise of said passages along a substantial part thereof whereby fluid flowing from the manifold means through said first outlet means is distributed over a substantial length of said clearance space, and second outlet means from said clearance space to externally of the blading element, said second outlet means being spaced chordwise of the blading element from said first outlet means whereby fluid flows in said clearance space from said first outlet means in a direction generallychordwise of the blading element to said second outlet means.

References Cited in the file of this patent UNITED STATES PATENTS

Images