Document
[ i l l Patent Number: 5,031,400
United States Patent [191
Boyd [45] Date of Patent: Jul. 16, 1991
1541 HIGH TEMPERATURE TURBINE ENGINE FOREIGN PATENT DOCUMENTS STRUCTURE 1284689 12/1968 Fed. Rep. of Germany ... 416/198 A [75] Inventor: Gary L. Boyd, Tempe, Ariz.
870124 3/1942 France ............................. 416/241 B
2402 1/1982 Japan .............................. 416/198A
[73] Assignee: Allied-Signal Inc., Morris Township,
57004 4/1983 Japan .............................. 416/198 A
N.J.
OTHER PUBLICATIONS [21] Appl. No.: 282,786 Stoddart, D. E., “Using Silicon Nitride for Gas Turbine [22] Filed: Dec. 9, 1988 Engines”, Gas Turbine International (Ju1.-Aug., 1972):16- 19.
[51] Int. ( 3 . 5 ................................................ F02C 7/32
Primary Examiner-Louis J. Casaregola [52] U.S. Cl. ............................ 60/39.320; 416/198 A; 416/241 B Assistant Examiner-Timothy S. Thorpe Attorney, Agent, or Firm-Terry L. Miller; James W.
[58] Field of Search ................ 464,436; 403/369, 378, 403/380; 416/198 R, 198 A, 170 R, 241 B; McFarland; Robert A. Walsh 60/39.36, 39.32 [571 ABSTRACT [561 References Cited A high temperature turbine engine includes a rotor portion having axially stacked adjacent ceramic rotor U.S. PATENT DOCUMENTS parts. A ceramic/ceramic joint structure transmits 2,660,399 11/1953 Robinson et a l . .............. 416/198 A torque between the rotor parts while maintaining coax- 2,743,080 9/1956 Feilden ........................... 416/198 A ial alignment and axially spaced mutually parallel rela- 3,070,348 12/1962 Vogel ............................. 416/198 A tion thereof despite thermal and centrifugal cycling.
3,680,979 8/1972 Hansen et al. .................. 416/198 A
3,941,506 3/1976 Robb et al. ..................... 416/198 A 4,123,19910/1978 Shimizu et al. ................. 416/241 B 12 Claims, 2 Drawing Sheets
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stacked and interconnected in torque transmitting rela- tion while preserving coaxial alignment and axially HIGH TEMPERATURE TURBINE ENGINE spaced parallelism of the disks despite thermal and cen- STRUCTURE trifugal cycling. Conventional metallic turbine struc- The U.S. Government has rights in the present inven- 5 tures employ a curvic coupling between adjacent tur- tion pursuant to Contract No. DEN3-167 issued and bine disks. With the development of ceramic materials funded by the Department of Energy (DOE), and ad- and application of these materials to turbine disks the ministered by the National Aeronautics and Space Ad- use of conventional curvic coupling structure was at- tempted. However the curvic coupling structure when ministration (NASA).
10 fabricated of ceramic material consistently failed be- TECHNICAL FIELD cause of fracturing of the ceramic curvic teeth. At- The present invention is in the field of high tempera- tempts to modify the conventional curvic structure to ture turbine engine structure. Particularly, the present allow fabrication with ceramic material were unsuc- invention is directed to structure of a high temperature cessful.
turbine engine composed of both metallic and ceramic 15 SUMMARY O F T H E INVENTION components.
In view of the deficiencies of the conventional tur- OF T H E INVENTION BACKGROUND bine engine art, and of the materials of construction and structural techniques available for making such engines, A long-recognized need in the turbine engine art has 20 it is a primary object for this invention to provide a been to attain higher operating temperatures in order to achieve a greater thermodynamic efficiency and an rotor structure for a turbine engine which includes axially stacked ceramic disk portions coupled in torque increased power output per unit of engine weight. Ide- ally, a turbine engine should operate with stoichiomet- transmitting corotational relation.
ric combustion in order to extract the greatest possible More particularly, it is an object for this invention to energy value from the fuel consumed. However, the 15 provide a turbine engine having a rotor member includ- temperatures resulting from stoichiometric and even ing axially stacked ceramic disk portions which cooper- near-stoichiometric combustion are beyond the endur- atively define a joint structure providing both torque ance capabilities of metallic turbine engine components. transmission and coaxial alignment between the ceramic Consequently, as the turbine engine art has progressed, disk portions.
an ever greater emphasis has been placed upon both Accordingly, the present invention provides a cera- 30 enhanced cooling techniques and the development of midceramic coupling structure comprising: a ceramic temperature and oxidation resistant metals for use in first member having a respective axially disposed first components of the engine which are exposed to the face circumscribing a rotational axis of said first mem- highest temperatures. That is, cooling techniques and ber, said first member defining on said first face a cir- high temperature metals have been developed for each 35 cumferentially arrayed first plurality of radially extend- of combustion chambers, turbine stator nozzles, and ing grooves, a ceramic second member having a respec- turbine blades. This quest has led to the development of tive axially disposed second face circumscribing a re- elaborate cooling schemes for all of these components spective rotational axis coaxial with the rotational axis as well as to classes of nickel-based “super alloy” metals of said first member and confronting said first face, said which may be cast using directionally solidified or sin- 40 second member defining on said second face a circum- gle crystal techniques. All in all, the quest for higher ferentially arrayed second plurality of radially extend- operating temperatures in a turbine engine fabricated of ing grooves matching circumferentially and in axial metallic components has led to a still increasing com- juxtaposition with said first plurality of grooves, a plu- plexity and expense in the making of the engine. rality of radially elongate ceramic members each one An alternative approach to the attainment of higher 45 received in a respective one of said first plurality of operating temperatures in a turbine engine has been grooves and in a matching one of said second plurality recognized. This approach involves the use of high- of grooves, and means for urging said first member and strength ceramic components in the engine. Ceramic said second member axially toward one another to trap components are better able than metals to withstand the said radially elongate ceramic members in said grooves, high temperature oxidizing environment of a turbine 50 whereby said first member and said second member are engine. However, the term “high strength” in connec- maintained both in coaxial and axially spaced parallel tion with ceramic structures must be viewed in context. relationship and in torque transmitting corotational While many ceramic materials exhibit superior high relation with one another.
temperature strength and oxidation resistance, ceramics An advantage of the present invention is that it pro- have historically been difficult to employ in turbine 55 vides a turbine engine with a rotor member having engines because of a comparatively low tensile fracture stacked ceramic disk portions which are coupled for strength and a low defect tolerance. Consequently, a torque transmitting corotation while also being retained long-recognized need has been for the development of concentrically to one another in axially spaced parallel hybrid ceramic/metallic structures which utilize the relation.
characteristics of each material to best advantage in The ceramidceramic joint structure of the present 60 order to allow combustion in a turbine engine to take invention provides both torque transmission and coaxial place closer to or at the stoichiometric level. alignment between axially adjacent ceramic structures An additional problem with the use of ceramics in a cooperatively defining the joint structure. Unlike con- turbine engine arises when the ceramic material is used ventional curvic or modified curvic joint structures to form a turbine disk structure. Particularly in an axial 65 when constructed of ceramic material, the present joint flow turbine having more than one turbine stages, the structure does not result in large tensile stress concen- plural disks defining the stages of the turbine are formed trations nor in notch tensile failures of the ceramic ma- as separate pieces. These disks then must be axially terial.
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28 is exposed to the exhaust chamber 54. Consequently, Additional objects and advantages of the present invention will appear from a reading of the following the flow path 18 leads once again through the regenera- detailed description of a single preferred embodiment of tor member 28, and to ambient via the outlet 16.
the invention taken in conjunction with the appended In order to complete this description of the engine 10, 5 it must be noted that in the combustor 30 fuel is added drawing figures.
to the pressurized air flowing from compressor rotor 22 DESCRIPT1oN OF THE to support combustion. This combustion results in a flow of high temperature pressurized combustion prod- FIG. 1 provides a fragmentary longitudinal view, ucts flowing downstream in the combustor 30, and in partly in cross section of a hybrid ceramic/metallic 10 flow path 18 subsequent to the combustor. Also, the turbine engine embodying the invention; rotor member 20 is journaled in housing 12 by a journal FIG. 2 depicts an enlarged fragmentary cross sec- bearing 56 disposed between the rotor portions 22 and tional view of a portion of the engine presented by FIG.
44. A metallic power output shaft portion 60 (only a 1 with parts thereof omitted for clarity of illustration: portion of which is visible in FIG. 1) of the rotor mem- FIG. 3 provides an exploded perspective view of a turbine rotor assembly portion of the turbine engine, 15 ber 20 extends outwardly of the housing 12.
Viewing now FIGS. 2 and 3 in conjunction, it will be with parts thereof omitted or broken away for clarity of seen that the hybrid ceramic/metallic rotor member 20 illustration; and includes not only the metallic compressor rotor portion FIG. 4 presents a fragmentary view taken along line 22, the ceramic turbine rotor portion 4 4 , and metallic 4-4 of FIG. 2.
20 power output shaft portion 60 (not visible in FIGS. 2 BEST MODE FOR CARRYING OUT T H E and 3), but also a plurality of torque transmitting and INVENTION concentricity retaining coupling structures each gener- FIG. 1 depicts a hybrid ceramic/metallic turbine ally referenced with the numeral 62, and a single axially engine 10. The engine 10 includes a housing 12 which extending metallic tie bolt member 64. The coupling defines an inlet 14, an outlet 16, and a tortuous flow path 25 structures 62 and tie bolt 64 are cooperative to unite the 18 communicating the inlet 14 with the outlet 16 for portions 22,44 and 60 to define the rotor member 20. In conveying a flow of fluid therebetween. A hybrid ce- other words, the coupling structures 62 transmit torque ramic/ metallic rotor member generally referenced between the portions of the rotor member 20 while with the numeral 20 is journaled in the housing 12 and maintaining coaxial concentricity and axially spaced cooperates therewith to bound the flow path 18. It will 30 mutual parallelism of the portions.
be seen that the rotor member 20 includes a compressor The ceramic turbine portion 4 4 includes three axially rotor portion 22, rotation of which inducts ambient air stacked individual generally disk-shaped ceramic parts 14, as indicated by arrow 24, and delivers this 66,68, and 70. At their outer periphery, each of the disk via inlet air pressurized to a flow path section 18' as indicated by parts 66,68,70, define plural respective integral and arrow 26. 35 circumferentially spaced apart radially outwardly ex- 18' leads axially through a tending turbine blade portions 72, 74, and 76. The disk The flow path section segment of somewhat less than 180" of a rotary annular part 70 also includes an axially elongate hub portion 78 regenerator member 28 which is received in the housing (viewing FIG. 1) which is circularly cylindrical in 12. Downstream of the regenerator 28, the flow path 18 transverse section and defines a journal surface for the leads through an axially extending combustion structure 40 bearing 56. Each of the disk parts 66, 68, and 70 define generally referenced with the numeral 30. The combus- a central through bore, generally referenced with the tor structure 30 is fabricated of ceramic material and numeral 80, and through which passes the tie bolt 64. A includes a ceramic outer liner 32 which is supported at head part 82 of the tie bolt bears upon the disk part 66 one end by an outer transition member 34. A ceramic while an opposite end of the tie bolt (not shown) thread- inner combustion liner 36 is coaxially disposed within 45 ably carries a nut (also not shown) bearing on the shaft the outer liner 32, and is supported at one end on a portion 60. As a result, the tie bolt 64 is loaded in tension ceramic transition duct member 38. The flow path 18 while the remainder of the rotor member 20 is loaded in leads axially toward the one end of the combustion liner compression.
36, as indicated by arrow 18". Within the transition duct Viewing FIG. 3, it will be seen in greater detail that member 38 is disposed a ceramic axial flow turbine 50 each of the adjacent disk parts 66,68, and 70, as part of section, generally referenced with the numeral 40. The the coupling structures 62, define respective axially turbine section 40 includes a ceramic stator member 42 extending annular boss portions, generally referenced and a ceramic turbine rotor portion 44 cooperatively with the numeral 84. The boss portions 84 extend defining the flow path 18. toward one another, but stop short of mutual contact to Downstream of the turbine rotor portion 4 4 , the flow 5 5 define respective confronting axially disposed face sur- path 18 extends axially and radially outwardly between faces, each referenced with the numeral 86. Each of the a pair of spaced apart cooperative ceramic exhaust duct boss portions 84 also define four radially extending members, respectively referenced with the numerals semi-circular grooves 88. The grooves 88 are equally 46,48. A plurality of hybrid ceramic/metallic fastener circumferentially spaced apart and precisely match the members 50 (one of which is visible in FIG. 1) coopera- 60 circumferential spacing of the grooves 88 in the next tively engage the one exhaust duct member 46 and the axially adjacent and confronting boss portion 84. Thus, housing 12. A ceramic spacer member 52 received over the confronting grooves 88 are in axial alignment and 50 spaces apart the duct members disposed as cooperative pairs by the confronting bosses the fastener members 46,48. 84.
Subsequent to the exhaust duct members 46,48, the 65 Disposed in each pair of the matching semicircular flow path 18 leads to an exhaust chamber generally grooves 88 and between the confronting boss portions referenced with the numeral 54. A segment of some- 84 is one of four radially extending elongate and circu- what less than 180" of the ceramic regenerator member larly cylindrical ceramic pin members 90. Viewing
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FIG. 4, it will be seen that the pin members 90 axially said second member defining on said second face a space apart the boss portions 84. Such is the case be- circumferentially arrayed second plurality of radi- cause the grooves 86 are each slightly less than a full ally extending groves matching circumferentially semi-circle. Further, the radius 92 of each groove 88 is and in axial juxtaposition with said first plurality of slightly less than one-half the diameter of each pin 90. 5 grooves , As a result, each of the pin members 90 define four a plurality of radially elongate ceramic members each radially extending lines of contact 94,96,98 and 100 with one received in a respective one of said first plural- the adjacent boss portions 84. The lines of contact ity of grooves and in a matching one of said second 94-100 are disposed proximate to a transverse radial plurality of grooves, plane 102 equally spaced between the adjacent ceramic 10 means for urging said first member and said second member axially toward one another to trap said disk parts, and are adjacent a radially extending arcuate radially elongate ceramic members in said grooves, transition surface, or “round” 104 which blends the groove 88 to the face surface 86. whereby said first member and said second mem- Because the ceramic material from which the disk ber are maintained both in coaxial and axially parts 66-70, and pins 90 are fabricated, which may be 15 spaced parallel relationship and in torque transmit- ieaction bonded silicone nitride, has virtually no plastic ti’ng opirational relation with one another, deformation and experiences only very slight elastic wherein each of said plurality of radially elongate deformation under the compressive load provided by members is circularly cylindrical in cross section, tie bolt 64, the pin members 90 do not “bottom” in the wherein each of said first plurality of grooves and grooves 88. In other words, the pin members 90 define said second plurality of grooves is semi-circular in 20 an axial clearance 106 with the respective boss portion cross section, 84. The clearance 106 also extends circumferentially wherein each of said grooves define a respective with respect to the pin member 90 between the adjacent radius closely approximating but slightly less than line contacts 94-100 associated with each groove 88. one-half the diameter of the respective ceramic In view of the above, it is easily seen that the radially elongate member trapped therein. 25 coupling structure 62 is composed of features 84-106, 2. The invention of claim 1 wherein each of said and is preserved in torque transmitting relative position ceramic radially elongate members defines two circum- by the axial compressive load provided by the tie bolt ferentially spaced radially extending lines of contact 64. It should be noted that metallic compressor rotor with each of the ceramic first member and ceramic portion 22 and metallic power output shaft portion 60 30 second member also define a conventional curvic coupling therebe- 3. The invention of claim 2 wherein said radially tween so that torque from turbine portion 44 may be elongate ceramic members space axially apart said first delivered externally of the engine 10 via the shaft por- member and said second member.
60. Because the lines of contact 94-100 lie closely 4. The invention of claim 3 wherein said lines of tion adjacent to the transverse plane 102, and the pin mem- 35 contact are disposed as closely as practicable to a trans- bers 90 do not bottom in the grooves 88, the adjacent verse radial plane equidistantly between said first mem- ber and said second member.
disk parts are coupled for torque transmission therebe- 5. The invention of claim 4 wherein said radially tween entirely without circumferential slack or lost motion therebetween. Also, the disk parts 66-70 are elongate ceramic members are everywhere radially 40 spaced from both said first member and said second jointed coaxially and in mutually parallel axially spaced relationship. The pin members 90 are clamped between member with the exception of said lines of contact.
the confronting bosses 84 by the compressive force 6. The invention of claim 5 wherein each of said first 64. This clamping force is suffi- member and said second member define an axially ex- provided by tie bolt ciently high that the pin members cannot escape radi- tending central bores, said urging means including an ally from the grooves 88. Also, because the radius 92 is 45 elongate tensile member disposed in said central bore and providing a reactive compressive load to said first as large as practicable, and nearly as large as one-half the diameter of pins 90, concentrations of tensile stresses and second member urging the latter toward one an- and notch sensitivity of the ceramic material is avoided other.
by the present invention 7 . The invention of claim 1 wherein each of said While the present invention has been depicted and 50 ceramic first member and said ceramic second member described by reference to a single preferred embodi- define respective axially extending boss portions, said ment of the invention, such reference does not imply boss portions defining said respective first face and any limitation upon the invention, and no such limita- second face.
tion is to be inferred. The invention is intended to be 8. A method of coupling a prior of axially adjacent 55 ceramic rotor members in axially spaced parallel and limited only by the spirit and scope of the appended claims which provide additional definition of the inven- coaxial torque transmitting relationship, said method tion. including the steps of: What is claimed is: defining one each of said pair of rotor members an 1. A ceramic/ceramic coupling structure comprising: axially disposed face circumscribing the rotational a ceramic first member having a respective axially 60 axis thereof; disposed first face circumscribing a rotational axis forming on each of said pair of faces a respective of said first member, said first member defining on plurality of circumferentially spaced apart radially said first face a circumferentially arrayed first plu- extending grooves which are positionally matching rality of radially extending grooves, one face to the other; a ceramic second member having a respective axially axially juxtaposing said pair of rotor members to 65 disposed second face circumscribing a respective confront said pair of faces with one another, and rotational axis coaxial with the rotational axis of pairing said respective pluralities of grooves with said first member and confronting said first face, one another;
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mate to but less than one-half said determined di- disposing in each pair of said pluralities of grooves radially elongate ceramic elements; ameter.
10. The method Of claim 9 wherein said step of urging during said pair of rotor members axially toward one said pair of rotor members axially toward one another another to trap said ceramic elements in said paired 5 includes the steps of forming a central axially extending grooves therebetween; bore in each one of said pair of rotor members, dispos- spacing apart said pair of faces with said ceramic ing an elongate tensile member in said bore, applying a said to main- tensile force to said tensile member, and reacting said Of tain coaxia1 an axially spaced parallel tensile force on said pair of rotor members, thereby to said rotor members; 10 urge the latter axially together.
said ceramic elements to transmit torque between said 11. A rotor member for a combustion turbine engine pair of rotor members; and including a compressor inducting ambient air and deliv- further including the step of limiting contact between ering the air pressurized to a combustor, means for said ceramic elements and said rotor members to mixing fuel with the pressurized air in said combustor to essentially line contact. 15 support combustion producing a flow of high tempera- 9. A method of coupling a pair of axially adjacent ture pressurized combustion products, and a turbine expanding said combustion products toward ambient, ceramic rotor members in axially spaced parallel and said rotor member comprising a ceramic first turbine coaxial torque transmitting relationship, said method rotor portion and an axially adjacent ceramic second including the steps of: defining On each of said pair of rotor members an 20 turbine rotor portion, said rotor portions each defining axially disposed face circumscribing the rotational a respective axially extending central bore, a metallic tensile member disposed in said central bore and provid- axis thereof; ing tensile force to the remainder of said rotor member, forming on each of said pair of faces a respective said rotor member including means for reacting said plurality of circumferentially spaced apart radially 25 tensile force to compressively bias said rotor portions extending grooves which are positionally matching toward one another, and said rotor portions defining one face to the other; integral cooperating coupling means dependent upon juxtaposing said pair Of rotor members to said compressive bias for coaxial and axially spaced confront said Pair of faces with one and parallel alignment of said rotor portions while coupling Pairing said respective Pluralities of grooves with 30 the latter for torque transmitting corotation, wherein one another; said coupling means includes each of said rotor portions disposing in each pair of said pluralities of grooves defining a respective annular axially disposed force radially elongate ceramic elements; circumscribing said respective central bores and said faces confronting one another in axially spaced relation, during said pair of rotor members axially toward one another to trap said ceramic elements in said paired 35 each of said annular faces defining a respective circum- grooves therebetween; ferentially spaced plurality of radially extending grooves, each groove on each annular face aligning spacing apart said pair of faces with said ceramic axially with a groove on the other annular face to define employing said elements to main- elements, groove pairs, a plurality Of tain coaxial and axially spaced parallel alignment of 40 ceramic elements each disposed in a respective one of said rotor members; said groove pairs and axially spacing apart said rotor employing said ceramic elements to transmit torque portions, each one of said plurality of ceramic elements between said pair of rotor members; defines only radially extending line contact with each of the step Of limiting contact between said said rotor portions, said ceramic elements and said rotor ceramic elements and said rotor members to essen- 45 otherwise being spaced from one another.
tially line contact; and 12. The invention of claim 11 wherein each of said further including the steps of forming each of said radially extending grooves is of semi-circular shape Plurality of ceramic dements to a circularly CYlin- defining a radius less than but closely approximating drical shape having a determined diameter, and one-half the diameter of the circularly cylindrical ce- forming each of said plurality of grooves to a semi- 50 ramic element received therein.
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circular shape defining a radius closely approxi- 5 5
UNITED STATES PATENT AND TRADEMARK OFFICE
CERTIFICATE OF CORRECTION
P A T E N T NO. : 5 ? 031,400
DATED : 7/16/91
I N V E N T O R ( S ) : Gary L. Boyd
It is certified that error appears in the above-identified patent and that said Letters Patent is hereby corrected as shown below: Column 6: C l a i m 6 Line 3, Delete "bores", i n s e r t "bore".
Claim 8 Line 1, Delete lfpriort', i n s e r t "pair".
Column 7: Claim 8 Line 18, Delete "during", i n s e r t '"urging".
C l a i m 8 Line 23, Delete "an", i n s e r t "and".
C l a i m 8 Line 25, i n s e r t "employing" before "said ceramic elements".
C l a i m 9 Line 3 4 , Delete "duringt', i n s e r t "urging".
Column 8: C l a i m 11 Line 4 2 , i n s e r t T'wherein'' between and "each one".
Signed and Sealed this
Third Day of November, 1992
Attest: DOUGLAS B. COMER Acting Commissioner o f Patents and Trademarks Attesting OfJicer