US2920865A

US2920865A - Bladed stator or rotor constructions with means to supply a fluid internally of the blades

Info

Publication number: US2920865A
Application number: US388303A
Authority: US
Inventors: Lombard Adrian Albert
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1952-10-31
Filing date: 1953-10-26
Publication date: 1960-01-12
Anticipated expiration: 1977-01-12
Also published as: GB743680A; FR1105247A; DE1035341B; US2788053A; CH325000A; NL88170C; FR1090193A; CH318289A

Description

Jan. 12, 1960 A. A. LOMBARD 2,920,865

BLADED STATOR OR ROTOR CONSTRUCTIONS WITH MEANS TO SUPPLY A FLUID INTERNALLY 0F Filed on. 2631953 THE BLADES 5 Sheets-Sheet l Jan. 12, 1960 A. A. LOMBARD 2,920,865

BLADED STATOR 0 ROTOR CONSTRUCTIONS WITH MEANS TO SUPPLY A FLUID INTERNALLY OF THE BLADES Filed Oct. 26, 1953 5 Sheets-Sheet 2 Jan. 12, 1960 A. A. LOMBARD BLADED STATOR OR ROTOR CONSTRUCTIONS WITH MEA TO SUPPLY A FLUID INTERNALLY OF THE BLADES Filed Oct. 26, 1953 3 Sheets-Sheet 3 United States Patent BLADEDSTATOR OR ROTOR CONSTRUCTIONS WITH MEANS TO. SUPPLY A FLUID IN'IZER- NALLY OF THE BLADES Claims priority,,application Great Britain October 31-, 1952 8= Claims. (Cl. 253-39-15) Thisv invention relates; to-bladed stator and rotor constructions for fluid machines, for instance, for axial flow turbines or compressors, which constructions employ blades supported in a, drum or disc structure by attachment portions on the-blades, which attachment portions have shoulders engaging correspondinglyw shouldered slots in the disc or drum, and which attachment portionsaiford between them tunnels extending across the drum or disc and suitable to convey aflow of fluid between the blade attachment portions. Such a bladed construction will be referred tohereinafter as a bladed construction of the kind specified.

Itv is known to. supply. a.fluid, suchas compressed: air, to theinteriors of bladesfor thepurpose of cooling or beating them during operationv of the fluid machine of which they form part and this invention is further concernedwith bladed constructionsof the kind specified in,

which the blades have-internalpassagesto convey a heating or coolingfluid.

According to.the..present invention, a bladed constructionof the kind specified comprises a. plurality of blades each having at least an inlet lengthwise passage therein.

and a deliverylengthwise-passage therein, which, passages are interconnected at their. ends remote fromtheiattachment. portionof. the blade, and,which passages, extend through the attachment portion to open into-thetunnels on opposite sides of thev attachment portion, each blade being arranged so that its v inlet passage opens into the same tunnel as the inlet, passage of the next adjacentblade on one side of it andsothat its delivery passage opens into the sametunnel. as-thedelivery, passage of the .next

adjacent blade on the other. side of it,.and.blanking means,

toclose-ofl atleast thetcorresponding ends of alternate tunnels andthe opposite endsof the remaining tunnels.

, With the arrangement ofthis invention, the said alternate tunnels-formed between blades of a row of blades may be employedv to convey asupplyof a fluid, say, com-..

In one preferred construction as applied to a bladed 1' rotor construction with the blades-supportedat theperiphery ofaav rotor structure, the tunnels into which the inlet passages: opten, are blanked-E fromthe downstream side of the blade attachment portions, and: a pressure fluid which-is conveniently compressed-air issupplied on the upstream side ofthe: blade: attachmentaportions, and therpressurefluidflows fromthis space: into the tunnels andithen through the inlet and: delivery passages in the blades; into the. remaining tunnels which are blanked-off from-the upstream side of the. blade attachmentportions: so. that thefipressure fluid exhausting from the bladesflows intotheispace on. the downstream side of the bladerattachmentportions;

In: another preferred construction as appliedato; a "bladedirotor construction, the tunnelsinto which the inlet passages open, are blanked-oh at each end, and the tun- 2,920,865 Patented Jan. 12, 1960 blades form a, complete annular shroud, a shouldered rootfixingportion by whichthe bladeis engaged with-the rotor disc or, drum, and a. circumterentially-narrow, axially-extensive stem which joins the platform to the root fixing, portion, so-that spaces of substantial dimen sions a form d between the p rsv o a j t em and these spacesare, conveniently. used as the tunnels,

Two embodiments f this, invention will now be described asappliedto turbinerotor constructions, the description making reference to,the accompanying drawings, in which Figure 1 is a form, of blade suitable for use in the turbine constructions,

Figure 2 is ,a. sectionlonthe line 2 2 of Figure 1,

Figure 3 is a view corresponding to part of. Figure 1 showing the root end of a blade such as-is assembled next to the bladeofqFigure 1,

Figure 4, is a section ontheline 44 of Figure 1, drawn Ito-alarger scale,

Figured be View similar to Figure 4 of a modified type of. blade, I Figure6 is a perspective, view. of p art of one turbine rotor constructionusing the blade-S illustratedin Figures 1. to 4, the View being from the upstream side of the rotor,

Figure-J is an axial view on part of the turbine rotor of u ei mm he-downs te my d i Figure 8 is. an axial, view of the upstream side of a second on truction,

Figure 9 isa sectionon the line 9-9- of Figure 8, and

Figure. 1.0, is a. section. on th 1ine.10.10 of Figure 9.

In,t efirstembgdim ti i s Q 4 nd d the invention applied tothe' ro'tor, of an axialrflow turbine of, a, gas=turbine engine, which rotor comprises a. rotor disc. sarryi e t s Pe ip ery. wine f individual bla elements each of which comprises a vane portion 11 pon hicht e orki uid,- ft e e mp n es sra ial r nner endan at ac m n P r ion,

In this construction the attachment portion comprises (Figuresl to4) three essential parts, abladeplatforrn 12 from which the vane 11 of'the-blade projects, a root fixing portion 13 for retainingthe blade in position on the rotor disc, structure, which root fixing portion (13) has a number of outwardly-facing shoulders 13a in its cir cumfierentiallyedirected. faces and which engages in a slot having. complementary shoulders and cut in a thickened periphery 10a or" the rotor disc 10, and a stem portion 14 which is. in.,,the form of a circumferentially-narrow, axially-.extensiyeweb so. as to have a pair of circumferentiallyrfacing surfaces 14a and which thus has a gen- .erally narrower cross section than either the platform 12 or the root fixing portion 13 and interconnects; these parts. The platforms 12 of a ringof blades co-operate in circumferential abutment to form a substantially complete annular shroud for the inner ends of the vanes 11 ofthe. ring of blades, and the.

root attachmentportions

12,, 13,14 -form withthe portions 15 of the rotor disc 10 between the slots a, series of duct passages (16.), referred to hereinafter as tunnel-like spaces 16, which extend axially;- across. the periphery of the disc from theupstream side of the disc to the downstream side.

The vane portion 11 of each blade in the ring of blades is formed with three lengthwise passages 17, 1 8; 19,

.a pair of narrow webs 20 which extend across the thickness of the vane portion from the convex surface thereof to the concave surface thereof and these webs 20 are partly removed to form a chamber as indicated at '22 in Figures 4 and 5 adjacent the tip of the blade, so

that the three

passages

17, 18, 19 are interconnected adjacent the tip of the blade. The blade is provided with an outer shroud portion 21 which may conveniently be formed as indicated in Figure 4 in one piece with the vane 11 or as indicated in Figure 5 separately from the vane 11 of the blade and brazed in position at the tip to close-off the passages in a manner preventing leakage from them while permitting fluid to flow between them. In the former case the shroud portion 21 may The

longitudinal passages

17, 18, 19 have

extensions

17a, 18a, 19a respectively through the platform 12 of the blade, and the extensions of the passages in the leading and trailing edges of the vane portion open at their inner ends through one circumferentially-facing surface 14a of the stem 14 and the extension 19a of the mid chord passage 19 opens to the other circumferentiallyfacing surface 14a of the stem 14. The blades are divided into two sets, one of which sets comprises blades each having their root attachment portions as shown in Figure 1 and having its leading and trailing

edge passage extensions

17a, 18a opening to the right of the stem 4 (as viewed axially from the upstream side of the rotor),

and the other of which sets comprises blades having their root attachment portions as shown in Figure 3 and I having their leading and trailing

edge passage extensions

17a, 18a opening to the left ofthe stem 14. The blades are assembled in the disc 10 so that the blades of the I two sets alternate with one another and thus each blade 'has its

extensions

17a, 18a of the leading and trailing

edge passages

17, 18 opening into the same tunnel-like space 16 as the corresponding extensions of the next ad acent blade on one side, and has its extensions 19a of the mid chord passage 19 opening into the same tunnel-like space as the corresponding extension 19a of V the mid-chord passage 19 of the blade next adjacent it on its opposite side.

Blanking means is provided to blank-off one end of each tunnel-like space 16. The blanking means is arranged so that the tunnel-like spaces 16 are left open alternately to the upstream side and the downstream side 'of the turbine disc .10, the tunnel-like spaces 16 into which the

extensions

17a, 18a of the leading and

trailmg edge passages

17, 18 open, communicating with the upstream side of the turbine disc 10, and the other tunnel- 'like spaces 16 opening to the downstream side of the turbine disc so that the mid chord passages 19 communicate with the downstream side of the turbine disc 10.

The blanking means may comprise a series of plates fitted on to the rim 10a of the disc 10 and bearing against the end surfaces of the stems 14.

Referring to Figure 6, the blanking means for the upstream surface is illustrated as comprising a number of plates 24 with cutaway portions opposite the tunnels 16 which are to be left uncovered, and having flanges along their outer edges to engage with undercut channels 25 in the upstream edges of the blade platforms 12 and having along the radially inner edges flanges 26 to rest on a ledge-like projection 27 from the disc periphery to locate the plate radially. The upstream end of each jecting from it and when the plates 24 are in position the lower edges of the cutaway portions engage behind the hooked features 28...

The blanking means for the downstream surface is shown (Figure 7) ,as comprising a number of individual blanking plates 30 which engage by their radially outer edges in slots 31 (seen in Figures 1, 3 and 6) in the downstream edges of the blade platforms 12 and which engage by lateral lugs 32 behind hooked features 33 projecting from the downstream end of the root fixing portions 13 and by deformable tabs 34 at their radially inner ends in a shallow annular channel 35 cut in the periphery 10a of the disc 10.

Pressure air is supplied to the rotor disc 10 on its upstream side and the pressure air flows into the tunnellike spaces 16 which are open to the upstream side of the disc 10 and thence into and along the

lengthwise inlet passages

17, 18 in the leading and trailing edges of the blades to the tips thereof, into and along the mid chord lengthwise delivery passages 19 back to the root attachment ends of the blades, into the tunnel-like spaces 16 which communicate with the downstream side of the disc and thence into the working fluid annulus of the turbine.

The pressure air supplied to the upstream side of the disc 10 may be sealing air as is usually employed for preventing leakage of working fluid radially inwards between the upstream edges of the blade platforms 12 and the adjacent stationary structure (not shown). Usually theupstream edges of the platforms 12 and the adjacent stationary structure are formed to provide a labyrinth seal at this point and the pressure air is suppliedto the space between the upstream side of the turbine disc 10 and the stationary structure from the compressor of the gas-turbine engine.

-It will be appreciated the compressed air is at its coolest 'in flowing along the leading and trailing

edge passages

17, 18 and so has its greatest cooling effect where it is most needed.

In a second embodiment (Figures 8-10) which is also applied to cooling the blades of a turbine rotor of a gas-turbine engine, similar blades are employed as those described in connection with the first embodiment.

In this construction, however, the tunnel-like spaces 16..between the stems 14 into which the

passage extensions

17a, 18a of the leading and trailing

edge passages

17, 18 open, are blanked off from both the upstream and downstream sides of the disc 10 and are connected by passages through the disc periphery 10a to a space 40 radially inwards of the disc periphery 10a, which space 40 is within an annular axial flange 41 formed on the disc inwards of its periphery 10a and within annular stationary structure 43. This flange 41 is formed externally as the rotating member of a labyrinth seal to cooperate with stationary sealing members 42 carried by the stationary structure 43 located radially inwards of the labyrinth seal formed between the upstream edges of the blade platforms and the adjacent stationary structure 52.

The spaces 16 into which open the leading and trailing

edge passages

17, 18, are connected with the space 40 by means of an annular channel 44 cut in the periphery of the turbine disc 10 and extending radially outwards to theportions 15 of the rotor disc between the bladeslots and by drillings 45 leading from the space 40 through the disc 10 to the radially inner end of the channel 44. Air is prevented from flowing from the channel 44 into the spaces 16 into which open the mid chord passages 19 by means of blanking plates 46. The plates 46 thus occupy and fill the parts of channel 44 where it divides alternate shouldered portions 15 and each plate 46 has serrated edges to coincide with the shoulder on the portion 15 and to co-operate with the shoulders on'the adjacent root fixing portions 13. Each plate 46 also has'a tsaapeaneae 46a overlying the portion 15 to prevent it falling tothebottom of the channelz44 in assembly. The plates 46 are placed imposition prior to mounting the blades inf the; disc periphery;

Referring particularly to Figure 8, the upstream ends of all the tunnels 16 are blanked otfby blanking plates 47 which either co-operate with the roots:- of three blades or with the roots of four blades. Each blanking plate 47 has at its radially outer edge a short axial flange 48 to engage in undercut grooves in the platforms 12 of the blades with which it co-operates, has apertures 49 therein which engage over hooked features 50 projecting from the ends of the portions 15 between the blade slots and has tabs 51 at its radially inner edge which can be engaged in an axially-facing shallow channel 51a cut in the disc periphery. Those plates 47 which co-operate with four blade roots are partly cut away adjacent their mid circumferential dimension so that they need only interlock with a pair of hooked features 50.

The blanking plates 30 for the downstream ends of the tunnels 16 which are in communication with the

passage extensions

17a, 18a may be formed as shown in Figure 7 or in any other convenient way. The downstream ends of the remaining tunnels 16, i.e. those into which passage extensions 19a open, are uncovered.

In use pressure sealing air is fed to space 53 between the disc and the stationary structure 52 to prevent inward leakage of the working fluid at the upstream edges of the blade platforms 12, and it will thus be appreciated that since the space 40 bounded by the axial flange 41 is separated from the working fluid passage of the turbine through two labyrinth seals, and since the pressure between the labyrinth seals in maintained high for sealing purposes, the pressure within this space 40 can be maintained at an even higher value.

As in the previous construction the pressure air may be abstracted from the compressor of the gas-turbine engine.

I claim:

1. A bladed construction of the axial flow kind comprising a rotor disc structure, a plurality of blades, the blades having at their radially inner ends integral blade attachment portions; the blade attachment portion of each blade element comprising a shouldered root-fixing portion engaging a corresponding shouldered slot in the rotor disc whereby the blade is retained in position on the rotor disc structure, a blade platform spaced radially from the root-fixing portion, the blade extending from the platform, said blade platforms together forming a substantially complete annular shroud, and a circumferentially-narrow axially-extending stem joining said platform to said root-fixing portion, whereby in the assembly of said blades on the rotor disc structure axiallyextending spaces of substantial circumferential dimensions are formed between the pairs of adjacent stems,

said axially-extending spaces forming duct passages; each blade having at least a lengthwise inlet passage therein and a lengthwise delivery passage therein, each blade having its inlet and delivery passages interconnected at their ends remote from the attachment portion of the blade, the inlet and delivery passages extending into the stem and opening through opposite sides thereof into the duct passages on each side of the attachment portion respectively, and each blade being arranged with its inlet passage opening into the same duct passage as the inlet passage of the next adjacent blade on one side of it whereby a cooling fluid supply to the blade and said adjacent blade on said one side can be effected through said duct passage, and with its delivery passage opening into the same duct passage as the delivery passage of the next adjacent blade on the other side of it whereby said latter duct passage forms an exhaust passage for cooling fluid from said blade and from said next adjacent blade on the other side.

2: A Blades dense-nation as claimed in elaim 1; comprising also blanking means mounted onthe rotordisc structure and extending. over at: least; the corresponding ends of -alternate duct passages to. close. them. and over the opposite ends of the remaining duct passages to close these opposite ends. v

3". A bladdjconstruction as claimed in claim 2, having the blanking means mounted on the-rotor disc structurew and; extending over the: ends: of: the-Iduetpassages into whichthe said inlet passages open-,1, to elose offthe ends of said duct passages on the downstream side of the rotor disc structure, in combination with means supplying cooling fluid to the upstream side of the rotor disc structure.

4. A bladed construction as claimed in claim 1 comprising also blanking means mounted on the rotor disc structure and extending over the ends of all the duct passages to one side of the rotor disc structure to close them and on the opposite side of the rotor disc structure extending over the ends of the duct passages in communication with the inlet passages to close them, and means to supply cooling fluid to the duct passages in communication with the inlet passages comprising a radially-extending annular channel cut in the periphery of the rotor disc structure to open to each of the duct passages and blanking members located in the channel to prevent delivery of pressure fluid from the channel into those duct passages into which the blade delivery passages open.

5. A bladed construction as claimed in claim 4, comprising an axial flange on the rotor disc structure, and fixed structure co-operating with said flange encircling a space, and drillings through the rotor disc structure from the space to the bottom of said channel.

6. A bladed construction of the axial flow kind comprising a rotor disc structure, a plurality of blades, the blades having at their radially-inner ends integral blade attachment portions; the blade attachment portion of each blade comprising a shouldered root-fixing portion engaging a correspondingly-shouldered slot in the rotor disc whereby the blade is retained in position on the rotor disc structure, a blade platform spaced radially from the root-fixing portion, the blade extending from the platform, said blade platforms together forming a substantially complete annular shroud, and a circumferentially-narrow axially-extending stem joining said platform to said root-fixing portion, whereby in the assembly of said blades on the rotor disc structure axially-extending spaces of substantial circumferential dimensions are formed between the pairs of adjacent stems to aflord axially-extending duct passages; each blade having at least a lengthwise inlet passage therein and a lengthwise delivery passage therein, each blade having its inlet and delivery passages interconnected at their ends remote from the attachment portion of the blade, the inlet and delivery passages extending into the stem and opening on opposite sides thereof thereby to communicate with the duct passages on each side of the attachment portion respectively, and each blade being arranged with its inlet passage opening into the same duct passage as the inlet passage of the next adjacent blade on one side of it whereby a cooling fluid supply to the blade and to said next adjacent blade on said one side can be eflected through said duct passage, and with its delivery passage opening into the same duct passage as the delivery passage of the next adjacent blade on the other side of it whereby said latter duct passage forms an exhaust passage for cooling fluid from said blade and from said next adjacent blade on said other side.

7. A bladed construction as claimed in claim 6, comprising also blanking means mounted on the rotor disc structure and extending over at least the corresponding ends of alternate duct passages to close them and ex mewtending over the opposite ends of the remaining duct passages to close them. I I

8. A bladed construction as claimed in claim 7, having the blanking means-mounted on the rotor disc structure and extending over the duct passages into which the said inlet passages open, to close ofl? the ends of said duct passages on the downstream side of the rotor disc structure, in combination with means supplying cooling fluid to the upstream side of the rotor disc structure.

1 References Cited inthe file of this patent UNITED STATES PATENTS Noack July 10, 1934 Holzwarth Jan. 25, 1944 Schmitt Aug. 11, 1953 Ledinegg Ian. 26, 1954 Bruckmann Jan. 29, 1957 FOREIGN PATENTS Great Britain Jan. 17, 1947