US2883151A - Turbine cooling system - Google Patents

Description

3 Sheets-Sheet 1 HVE. mm N ATTORNEY NVENTOR NamnLA Fe. @DUDA N. R. DOLIDA TURBINE COOLING SYSTEM April 21, 1959 Filed Jan. 26, 1954 April 21, 1959 N. R. DOLIDA TURBINE COOLING SYSTEM 3 Sheets-Sheet 2 Filed Jan. 26, 1954 28 INVENTOR NIHULAEI Fl. DDLIDA @lfm ATTORNEY 3 sheets-sheet 5 Filed Jan. 26, 1954 lE-E INVVENToR NlEHULAE R. DDI-l DA ATTORNEY Patented Apr. 21, 1959 United States Patent l@ffice TURBINECOOLING SYSTEM Nicholas R. Dolida, Flushing, N.Y., assigner to Curtiss- Wright Corporation, a corporation of Delaware Application January 26, 1954, Serial No. 406,283 s claims. (ci. ass- 39.151

This invention relates to turbine apparatus and is particularly directed to a gas turbine construction having means for liquid cooling the turbine.

The power output and thermal efciencyof -a gas turbine engine can 'be increased by increasing the temperature of its turbine motive fluid. In general, however, any such increase is limited by the maximum permissiable operating temperature of the turbine blades andthe turbine rotor disc. An object of the present invention comprises the provision of `a novel turbine lapparatushaving means for liquid cooling the turbine rotor blades and/or turbine disc without requiring the transfer of the cooling liquid across relatively moving parts. A still further object of the invention comprises the provision of a novel liquid cooled turbine construction in which liquid sealed within the turbine rotor is circulated through the turbine rotor disc -and/or the turbine rotor -blades in response to the centrifugal forces acting on said liquid and in which a cooling medium is passed through a. stationary member in heat exchange relation with said sealed rotor liquid. i

Other objects of the invention will become apparent upon reading the annexed detailed description in connection with the drawing in which:

Fig. 1 is a partial axial sectional view through a twostage turbine embodying the invention;

Fig. 2 is a sectional view taken along line 2-2 of Fig. l;

Fig. 3 is a schematic development taken along line 3 3 of Fig. l;

Fig. 4 is an enlarged sectional view of the peripheral bladed portion of one of the turbine rotor stages, showing one blade partially in section;

Fig. 5 is a developed view taken along line `5--5 of Fig. 4;

. Fig. 6 is an enlarged View of a portion of Fig. l;

Fig. 7 is a view taken along line 7 7 of Fig. 6;

Fig. 8 is a view similar to a portion of Fig. 6 but illustrating a modified construction;

,i Fig. 9 is a view illustrating the `addition of check valves to certain of the rotor passages; and

Fig. 10 is a view similar to Fig. 4 but of a modied rblade construction.

Referring to the drawing, reference numeral 1t) designates the two-stage rotor of a gas turbine engine having a rst stage rotor disc 12 yand 1a second-stage rotor disc 14 with each of said stages being fdrivably `connected to a stub shaft 16, said shaft extending into and through the rotor discs to form a 'hub for said discs. The turbine stub shaft 16 is splined to the turbine shaft 18 fand the turbine rotor is supported by a bearing 20 disposed about the turbine shaft 18, said bearing being mounted in a lixed support member schematically indicated at 22.

. yA plurality of circumferentially-spaced` blades 24 are secured to and extend radially outwardly from the periphery 'of the turbine rotor disc 112 as illustrated in Figs.` 4 and. 5. i A. similar, pluralityofblades (not illustrated) ex- 2 tend radially outwardly from the periphery of the turbine' rotor disc 14. The turbine motive fluid ilows axially, between the turbine rotor blades and coacts with said blades to drive the turbine rotor. In a conventional gas turbine engine, the turbine rotor drives an air compressor which in turn supplies compressed air to the turbine combustion .chamber and the hot gases discharging from said chamber constitute the turbine motive lluid. The gas turbine engine and rotor structure so far described is conventional.

The first-stage turbine rotor disc 12 has ya plurality of circumferentially-spaced pairs of radially extending passages 26 and 28, said passages extending radially outwardly through the rotor hub 16 'and disc 12 to the periphery of ,said disc. Four -such pairs of passages spaced 90 apart are illustrated. The second-stage turbine rotor disc 14 `has a similar plurality of circumferentia1lyspaced pairs of passages 30 and 32 staggered 45 degrees from ,the passages of the rst-stage rotor disc 12, as shown in Figs. Zand 3.

Each rotor passage 26 terminates at its radially outer end at the periphery of the rst stage rotor disc 12 in an annulus 34 formed by la ring 36 secured on one side of said rotor adjacent to its periphery. Likewise each rotor passage 28 terminates lat its radially outer end in an annulus 38 formed by a ring 40 secured to the other side of the rotor disc 12 at `the periphery of said disc. Also each blade 24 secured to the periphery of the rotor disc 12 has passages `42, 44 and 46 extending longi` tudinally therethrough toward the radially outer end of the blade, each passage 42 being disposed adjacent to the center of its blade and each passage 44 and 46 being disposed adjacent to an edge of its blade. Each blade passage 42 communicates with the rotor annulus 34 through a passage 48 in the rotor disc 12, there being one such passage 48 for each blade 24. Similarly each blade passage 44 and 46 communicates with the `rotor annulus 38 through passages 50 and 52 in the rotor disc 12, there being one set lof rotor disc passages 50 and 52 for each blade 24. Also each `blade 24 has a passage 47 adjacent to its radially outer end interconnecting the` blade passages 42, 44 and 46.

' 38, 48, 50 and 52 connecting its ber 60 has ribs 64 extending laxially along its outer sur-` face |and engaging the inner surface of the bore through the rotor hub 16, said ribs forming passages 66 therebe" tween. rIlhe tubular member 62 extends axially beyond the ends of the member 60 and rings 68 and 70vare se" if cured between the member 62 and the rotor hub 16 to enclose the space therebetween. The rings 68 and 70 are axially spaced from the ends` of the member 60 so that the annular space between the member `60 land the bore of the rotor hub 16 isfin communication with the annu- -lar space between the members 60 and 62 :around the ends of the member 60.` The annular space between the' membersV 60 and 62 is partitioned by fins 72 extending axially `along the outer surface of the member 62 and radially toward the member 60. The end rings 68 and L 70 and tubular members 60 :and 62 'are `secured tol mit gether, as by brazing, to form a unitary structure which can readily be inserted within the rotor hub 16.

The end ring 70 has aplurality ofwradiall'y extending` ears 74 which are secured to the hub 16 as by screws-75 (shown in Fig. 7) whereby the 4.unitary structure of tubular members 60 .and 624 and the end . rings 68 and 70 are rotatable as a unit with the turbine rotor. The end ring 68 has a plurality of openings 76 therethrough and an annular bellows construction 78 is connected to the ringL 63`acrosssaid openings. In addition, a spring4 80 is disposed in compression between a plate 82 connected across the end of the bellows 78' and .a plate 84, said latter plate bearing against' a shoulder 86 within the'rotorhub 1'6.

As illustrated the number' of ribs 64' is equal to the numberof pairs' of rotor disc passages 26 and 28 plus the number of pairs of' rotor disc passages 30 and 32" andthe ribs'v 64"are` so spaced circumferentially that'each inter-rib passage 66 is in alinement with one of s'aid pairs of rotordis'c passages. Also, tliorse'intenrib passages 66' aline/d with` al pair of rotor discl passages 26` and 28 have partitions-94th'ereacross'between` its associated pair' off said rotor disc passages. The alternate interLrib' passagesv 66` are each alinedwith a pair of rotor disc passages 30 and 32 and each' said alternate passage has a partitionr 96 lbetween its associated rotor disc passages.

Thev passages'within the rotor hub"1f6 formed= by the annular members 60 and 62' togetherwith-the rotor disc passages 26, 23,30, 32, 34, 38, 43, 50 and 52 andthe rotor4` blade passages 42, 44, 46 and 47 are filled with a suitable liquid as for example water. For filling said passages, a combination valve and' ller member 100 andV a combination valve and vent member 102 are provided. In order to'fll said passages, the members` 100 and 102'are unscrewed ay limited extent from theirclosed positions illustratediin Fig. 1 and` then the liquidi under pressure is supplied through the member 160 to' ll saidrotor passages with liquid While the gas in said passagesescapes through the ventIv member 102i After said rotor passages are lled with liquid the members- 1'00and 102 are screwedv down against their valve seatsl to their positions illustrated thereby sealingsaid' liquid' Within the rotor. The spring 80` functions to keep the liquid within the rotor underpressure and the annular; space 104 within the bellows 78 functions as an expan-v sion chamber for said liquid.

A stationary hollow member 110 extends into the rotor hub in contact with the rotor tubular member 62',` said' member comprising a hollow shaft-'like member 110; having a plurality of circumferentially-spaced fins 112 extending axially along the member V1310 and radiallyy outwardly` therefrom and'also comprising a sleeve member 114'tted over and extending axially beyond the ns112. A plug 116y is 'tted within the sleeve member 114 adjacent to the inner'endof'said member but spacedI from the. adjacentend.Y ofthe shaft-like member 110 so that the bore through the memberv 110 is in communica` tionrwith the nned space'ab'out said member around the inner end ofsaid member;

Ay pump. 120 is connected, by means schematically indicated at 122, to they outer'end ofthefshaft-like member-110 for` supplying azrelatively cool liquid thereto.A The outer end of the sleeve member 114 has an outlet conduit connection 124 for outflow of said cooling'fluidVA They outer' surface of the-i sleevemembery 114' is dis-` posed "adjacent tothe innersurfaceof the' rotor tubular member 62 for good heat transfer'therebetween: Withf this construction, if the liquid circulated through ther stationary member 110 is sufficiently cool, saidrliquid' will-remove heat from" theliquid ini the rotor hub. The" heat transfer path from the v-liquiduin the rotor hub to said cooling liquid'is through the. rotor hub fins 72 and thefwallof the rotorhubmember 62' to thev wall ofthe stationary sleeve member114' and its-associated'nsslZ-r to the cooling' liquid. Thusthe stator structure 110, 11.2,- 114` and 116- and `the? adjacentlrotor structure' con-` stltutes. a heat exchange structurexutilizing a liquidY cool`` ing medium for extracting heat from the rotor liquid. Preferably the portions of said stator structure passage outside the turbine rotor are shielded by heat insulating material as indicated at 126. Any suitable cooling medium may be used. For example, liquid fuel supplied to the combustion chamber of the gas turbine engine may be circulated through: said stator heat exchange structure on its way to saidV combustion chamber.

The fins 72 and` 112l increase the efficiency of the heat transfer between the rotor liquid and the cooling medium.- Said fins may be slotted to break up any boundary layer` of liquid which might form therealong' to decrease the heat transfer through said fins` l'n' addition, for good heat transfer, the walls of the rotor and stationary members 62 and 11'4 respectively should be quite thin and the clearance between said walls should be as small as possible without the presence of excessive friction therebetween. Thus the clearance between said rotor and stator members preferably is of the order of magnitude ofthe clearances found in plain bearings. Also theheat transfer between the rotor liquid andthe cooling medium is increased by increasing the length of'cont'act' ofthe rotor and stator' members 62 and 114. Preferably the length of contact of' said members 62 and 1142 is at least'4 several times the diameter of their contacting surfaces'. Also lubricating oil or other material' with lubricating' properties preferablyis disposed or passed between' the" rotor `and stator members' 62 and 114 at assemblyto serve both as a lubricant between their relatively movable' walls and as a medium for heat transfer between` said walls.

During'gas turbine operation, the' leading andY trailing edges of the turbine rotor blades 24 run hotter' than' the intermediate portions of the blades. Hence the liquid' within the central passage 42 of each blade runs cooler and therefore morev dense than the liquid in the other' blade passages 444 and 46; Accordingly during rotor operation the centrifugal forces on' the liquid within' the' rotor blades acts as a centrifugal pump topumpli'quid' radially outwardly through each blade passage 42 and then `across its associated blade passage 47 and radially: inwardly through its associated blade passages 44 andE 46. The inner end of each blade passage 42 is' con nected to the rotor disc passages 26-through the annulus 34 and the inner ends of the blade passages 44 and 46 are connected to the rotor disc passages 28 through the" annulus 38. In addition, the radially inner ends of each pair of rotor disc passages 26 and 28 areseparat'edr by apartition 94 but are in communication with' each other around the ends of the rotor hub'tubular member` 60. Accordingly the passages of each rotor blade 24'A form part of a loop' passageway for said blade around which, during gas turbine operation, the turbine rotor' liquid is pumped, the directionl of the liquid? circulation being' indicated by the arrows in Figs. 1, 3 and 4. Ina similar manner the rotor liquid circulates through the passages 30 and 32 of the rotor disc 1'4I and through its-- associatedV blade passages during gas turbine operation. As the rotor liquid flows axially along the rotor hubs' through the passages between the rotor ns 72 heat isv transferred, as previously described, to the cooling fluid-A flowing in the opposite direction through the passages between the stationary member iins 1121 In this way heat is continually removed from the relatively warm"l rotor 'liquid' returning to theA rotor" hub as' said Warrr'i rotor liquid flows along the inner surface of the rotor" hub so thaty relatively cool rotor liquid is returned toS the central rotor blade passages 42. Therefore, the' dif-v ferential between the liquid temperature in said rotor" Gate-type-valve means 128 may beY provided in" each 's offr the passages 28- andV 32 for regulating the rate of cir--y culation o'f'the rotor liquid coolant therethrough. Als@ thesmnerk surfac`eof the hollow Shaft'like member? 1105 mman-a assaut maybe coated 'with aheat insulating material to minimize any heat transfer through the walls of said member. Likewise the outer surface of the rotor tubular member 60 may be similarly coated with heat insulating material. With the rotor passages completely lilled with liquid some boiling of the liquid may take place along the hot Walls of the rotor blade passages. A limited amount of such boiling is desirable because additional heat is removed from said blade walls as heat transfer takes place as a result of local boiling along said walls. i As illustrated in Fig. 3 the ribs 64 separate the liquid circulating through the passages of the rotor disc 12 from that circulating through the passages of the `rotor disc 14 in order that the relatively warm rotor liquid returning radially inwardly through the rotol passages 28 does not intermingle with the relatively cool liquid approaching the passages 30 of the rotor disc 14. With this construction the loop passageways through the rotor disc 12 are inparallel with the loop passageways through the rotor disc 14. However, since the blades of the second stage rotor disc 14 normally run considerably cooler than the blades of the rst stage rotor disc 12 the second stage rotor disc is not in need of cooling to the same extent as the iirst stage rotor disc.

'If a leak should occur in the liquid coolant passages of the turbine rotor during turbine operation, for example because of a turbine rotor blade failure, the turbine will q'uickly lose all or substantially all its liquid coolant. Under these conditions if operation of the turbine is continued at normal or full power excessive turbine blade temperatures will result. To prevent this means may be provided for energizing a signal circuit to warn the operator whenever the liquid coolant passages within the turbine rotor are not completely illed. For this purpose the end plate or plug 116 of the shaft-like stator member 110 may have a switch or contact 130 mounted thereon for engagement bythe central portion 132 of thebellows end plate 82 for closing a warning or control circuit 134 when the passages of the turbine rotor are not completely full. With this arrangement, if a leak should occur in the liquid coolant passages of the turbine rotor, the spring 80 will force the bellows end plate 82 to the right (Figs. 1 and 6) to engage the switch or contact 130` to complete the warning signal or control circuit 134. Upon receiving a warning signal the operator can reduce the fuel ow to a safe value or the control circuit 134, when energized, can automatically limit the fuel ilow to a low safe value.

In addition to the function of the spring 80 for closing the circuit 134 when a leak occurs in the passages of the rotor coolant system, the spring 80 normally maintins the liquid coolant in the turbine rotor under pressure. This raises the boiling temperature of said liquid coolant and increases the efiiciency of the heat exchange system. In addition to or in lieu of the spring 80 the output pressure of the gas turbine power plant compressor may be used to pressurize the liquid coolant in the turbine rotor. Such an arrangement is shown in Fig. 8.

The structure of Fig. 8 is like that of Figs. 1-7 except the spring 80 has been replaced by a bellows 140. The left side (Fig. 8) of the bellows 140 is exposed to the output pressure of the turbine compressor (not illustrated) thereby forcing the bellows 140 against the bellows 78 to pressurize the liquid within the rotor passages.

In order to insure that circulation of the liquid coolant in the rotor starts in the right direction, that is in the direction indicated by the arrows in Fig. l, suitable check valves may be added to the turbine rotor passages 26 and 30. Such a modification is illustrated in Fig. 9. 'Ihe parts of Fig. 9 have been designated by the same reference numerals as the corresponding parts of Fig. 1 but with a subscript a added thereto.

Fig. 9 illustrates the rst stage turbine rotor disc 12a with one of its liquid coolant passages 26a. At the radially inner end periphery of said disc the passage` 26afis enlarged to receive a check valve housing structure having a ball-type check valve 152 urged radially inwardly against a valve seat by a spring 154. The spring 154 is designed to hold its valve 152 in its closed position against centrifugal force until` some low turbine speed is attained. As the check valve 152 opens, if llow of the liquid coolant starts in the wrong direction said valve will immediately close. Hence ow of the liquid coolant can only start in the direction indicated. Once started in the right direction the liquid coolant tlow will continue in this direction even though the check valves are subsequently held in their open positions by the centritugal force thereon when the turbine reaches its normal operating speed.

As best seen in Fig. 4 the outer ends of the passages 42, 44 and 46 of each blade are interconnected by their blade passage 47 to provide for circulation 'of the rotor liquid from one rotor blade passage to another blade passage. It is not essential, however, that the outer ends of the blade passages be interconnected. Fig. l0 illustrates a modification in which each rotor blade also has a dead-end passage. Except for this additional passage and its connection to the rotor disc passages the modiiication of Fig. l0 is like that of Figs. l-7. Hence for ease of understanding the parts of Fig. lOl have been designated by the same reference numerals but with a subscript b added thereto as the corresponding parts of Figs. 1-7.

lIn the modification of Fig. 10 each blade 24h, in addition to the passages 42h, 44b, 46b and 47b, has a relatively short dead-end passage adjacent to its trailing edge. The inner end of each blade dead-end passage 160 is connected to the rotor annulus 34b through a rotor disc passage 162. Circulation of liquid also takes place in such a dead-end passage because the liquid along its center runs cooler than that along its walls. Hence liquid circulates in each dead-end passage 160 in the manner indicated in Fig. l0. In addition, as indicated in Fig. l0, liquid also circulates through the other rotor blade passages 4211, 44h, 4Gb and 47b in a manner similar to the circulation through the corresponding passages of The addition of a dead-end passage 160 to each rotor blade has the disadvantage that the hot liquid returning along the walls of said passage to the annulus 34b raises the temperature of the liquid insaid annulus thereby increasing the temperature of the liquid supplied to each blade passage 42b. However, because the trailing edge of a rotor blade is quite thin, particularly at its outer end, it is difficult to place the relatively long liquid` passage 46b suiiiciently close to its blade trailing edge to adequately cool said edge. Hence the addition of the dead-end passage 160 to each rotor blade helps to cool the trailing edge of said blade.

While I have described my invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various iclhanges and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to cover all such modifications.

I claim as my invention:

l. A turbine rotor having a plurality of circumferentially-spaced blades extending radially from the rotor and also having means forming `a loop passageway rotatable with said rotor, said loop passageway forming means including a movable wall portion; liquid sealed within said passageway for cooling said rotor; and means cooperable with said movable wall portion for urging said movable wall portion in a direction to pressurize said liquid.

2. Turbine apparatus comprising a turbine rotor having passage means for circulation of liquid therethrough for cooling said rotor, said passage means including a wallpor-tion` movable to vary tfhey volume ofr saidv passage means; means cooperable withL said movable walll portion for applying a force thereto in avl direction to reduce the volume' of said passage meansy for pressurizing liquid therein; a stator structure lia-vinglpassagemeans disposed adjacent to atleast a'l portion of said* rotor passage means for heat exchange therebetwee'ng'and2 meansfor circulating a cooling liquid throughL saidf stator passageV means for extracting heat from said'frot'oi liquid.

3. Turbine apparatus comprising aA turbine rotor' hav'- ing a hub portion, a plurality of7 circumferentially-spaced bladesl extending radially front the rotor periphery andz passage means rotatable with said rotor, said rotor pas-I sage means including a rotor hub portion disposedv adja cent to the rotor hub and other portions extending into said rotor blades and interconnected With said hub portion of the rotor passage means;y liquidi sealed within'isaid passage means for cooling said Blades;y astator structure having passage means with a wall portion* disposed adjacent to and being axially coextens'ivewith at least ai part of said rotor hub portion of the rot'or passage means for heat exchange therebetween; `and' means for circulating a cooling liquid through saidV statorl passage means".I

4. Turbine apparatus comprising a turbine rotor having an annular hub, a plurality of circumferentially-- spaced blades extending radially' from the" rotor periphery and passage means rotatable with saidi rotor, said rotor passage means `including a rotor hub portion disposedI adjacent to and extending axially along the inner surface-` ofl said rotor hub and'V other portions extending into said rotor blades and interconnectedr with saidY hub portion of the rotor passagemeans; liquid'sealed within said rotor passages means for cooling saidz blades-g aA stator structure' extending into said rotor hubl and having passage meanswith a wall portion disposed adiacen't to and? extending" axially along said rotor hub portion ofthev rotor' passage means for heat exchange therebetween;y andE meansfor circulating a cooling liquid throughY said: stator' passagey means. p

5. Turbine apparatus as recitedin claim 4 and including a iiexibl'el diaphragm secured to the rotor hub andv forming a wall closing one axial end of the hub portion of the rotor passage means and said apparatus lalsoy in cluding means cooperable with said exible diaphragm for applying a force thereto for pressurizing the liquid within said rotor passage means.

6. Turbine apparatus comprising a turbine rotor hav-- ing an annular hub, a plurality of circumferentiallyspaced blades extending radially from the periphery of said rotor and also having liquid passage means rotatable therewith; liquid sealed within said rotor passage means for cooling said blades; said rotor passage means includ- 8. ing' a rotor hub portion disposed around and4 extending axially alongy the inner surface" ofsaidv annularl rotor hub, iirst and second radially' extendingJ passages within" each rotor blade, passage means connecting the radiali inner" end of each blade iiirst' passagewith one axial end of the rotor hub portion of said rotor passage means; and other passage' means connecting the radially inner end of each blade second passage with the other axial end' of the* rotor hub portion of said rotorpassage means, the. outer ends of the trst andf second'y passages of each1 bladejbeing connected to complete al loop* passagewayy for saidl blade andthe first and-second passages of each blade being s'o disposed' therein that during turbine operationl said'l blade' rst passage is at a cooler portion of ther bladeA s'othat; the liquid within each blade iirst' passage is at a= lower temperature, and therefore at a1 higher density,- than zu liquid in the second passage of said blade whereby'the;v centrifugal forces on the liquidf causes the. liquid to circulate through each blade in adirectionI radially out-v wardly through its rst passage; a stator'structure' having? a cylindrical portion extending into said annular rotor: hub portion and having passage means disposed withi'nf and extending axially along saidcylindrical' portion adjacent to the rotor hub portion of said rotor' passage means; .andi means for circulating a cooling' medium` through said stator structure passage-meansl in heat' exchange relation," withi the rotor'liqui'd.` v 7". Apparatus as recited'vv in claimJ 6 andf includinglaf flexible diaphragmy secured to said roto'rhl'l'b` and forming a wall closing one axial' end of the rotor hub@ portion of the rotor passage means and said apparatu'sl'alsoif inA cluding means cooperable with said llexiblediapliragmt for applying a force thereto for pressurizing. the liquidi l with said rotor passage means.

8. Apparatus as recited in claim 6 in which the axial length of the portion of said stator structure' cylindrical portion within said rotor hub portion is at least twice its diameter.

References Cited in thek tile of this patent UNITED STATES PATENTS `2,149,510 Darrieus Mar. 7, 19395 2,369,795 Planiol n Feb. 20, 1945 2,650,060 Stalker ,a Aug. 2'5, 1951i'4 FOREIGN PATENTS 195,736 Switzerland July 16, 1938 229,933 Switzerland Feb. 16', 1944 478,970 France n Nov;.2, 1915 623,841 Great Britain May 24, 1949 666,159 Great Britain a Feb. 6,. 1952

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