A hybrid ceramic/metallic fastener (bolt) includes a headed ceramic shank carrying a metallic end termination fitting. A conventional cap screw threadably engages the termination fitting to apply tensile force to the fastener

Boyd, Gary L.

A high temperature turbine engine includes a rotor portion having axially stacked adjacent ceramic rotor parts. A ceramic/ceramic joint structure transmits torque between the rotor parts while maintaining coaxial alignment and axially spaced mutually parallel relation thereof despite thermal and centrifugal cycling

NASA Technical Reports Server

High temperature turbine engine structure

A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member

United States Patent [191 
IIIIII 11111111 111 IIIII 11111 l111111l llll 11111111111111111111ll 
USGo5134842A 
[11] Patent Number: 5,134,842 
Boyd [45] Date of Patent: Aug. 4, 1992 
[54] HIGH TEMPERATURE TURBINE ENGINE 
[75] Inventor: Gary L. Boyd, Tempe, Ariz. 
[73] Assignee: Allied-Signal Inc., Moms Township, 
[21] Appl. No.: 610,499 
[22] Filed: Nov. 6, 1990 
STRUCTURE 
Moms County, N.J. 
Related U.S. Application Data 
[62] Division of Ser. No. 280,760, Dec. 6, 1988, Pat. No. 
5,011,353. 
[51] Iat. C l . 5  ................................................ FU2C 7/20 
[52] US. Cl. ................................... 60/39.31; 60/39.32 
[58] Field of Search ................. 60/39.31, 39.32, 39.75, 
60/753; 415/214.1 
~561 References Cited 
U.S. PATENT DOCUMENTS 
2,764,266 9/1956 Hawonh .......................... 415/214.1 
3,199,294 8/1965 Hagen ................................ 60/39.31 
3,263,424 8/1966 Birmann ............................. 60/39.31 
4,422,300 12/1983 Dierberger et al. .................. 60/753 
4,492,131 1/1985 Conolly ................................. 60/753 
4,934,138 6/1990 Boyd .................................. 60/39.75 
4,944,151 7/1990 Hovnanian ......................... W39.32 
FOREIGN PATENT DOCUMENTS 
55-107120 11/1980 Japan . 
58-178900 1/1984 Japan . 
962057 6/1964 United Kingdom . 
1312339 4/1973 United Kingdom . 
Primary Examiner-Richard A. Bertsch 
Assktant Examiner-Howard R. Richman 
Attorney, Agent, or Firm-Terry L. Miller; Jerry J. 
Holden; Robert A. Walsh 
1573 ABSTRACT 
A hybrid ceramic/metallic fastener (bolt) includes a 
headed ceramic shank carrying a metallic end termina- 
tion fitting. A conventional cap screw threadably en- 
gages the termination fitting to apply tensile force to the 
fastener. 
5 Claims, 2 Drawing Sheets 
https://ntrs.nasa.gov/search.jsp?R=20080004323 2019-08-30T02:19:01+00:00Z
U.S. Patent Aug. 4,1992 Sheet 1 of 2 5,134,842 
-76 
U.S. Patent Aug. 4,1992 Sheet 2 of 2 5,134,842 
5,134,842 
1 2 
structural techniques available for making such engines, 
it is a primary object for this invention to provide a 
hybrid ceramic/metallic fastener for use in a high tem- 
perature turbine engine. 
Particularly, it is an object of this invention to pro- 
vide a hybrid ceramic/metallic fastener wherein a ce- 
ramic portion may be disposed in a high temperature 
part of a turbine engine to retain and support another 
ceramic component, and to extend therefrom toward a 
This is a division of application Ser. NO. 07/280,760 10 lower temperature engine part. The metallic portion of 
the fastener cooperatively interengages with the ce- 
ramic portion and includes provision for engaging other 
engine structure, which may be metallic, in order to 
The present invention is in the field of high tempera- apply a 
ture turbine engine structure. Particularly, the present IS Still particularly it is an object for this invention 
invention is directed to structure of a high temperature to provide interengagement between an elongate 
turbine engine composed of both metallic and ceramic cer-c and an elongate both 
mutually subject to an axial tensile force. components. 
Further to the above, the present invention provides 
2o a high temperature hybrid ceramic/metallic fastener 
comprising an elongate ceramic portion having at one 
end thereof a head part of comparatively larger dime- 
HIGH TEMPERATURE TURBINE ENGINE 
STRUCI'URE 
The United States government has rights in the pres- 5 
mt invention pursuant to Contract NO. DEN 3-167, 
issued and funded by the Department of Energy 
(DOE), and administered by the National Aeronautics 
and Space Administration (NASA). 
filed Dec. 6, 1988, now U.S. Pat. No. 5,011,353. 
TECHNICAL FIELD 
stress to the fastener. 
BACKGROUND OF THE INVENTION 
A long-recognized need in the turbine engine art has 
been to attain higher operating temperatures in order to 
achieve both a greater thermodynamic efficiency and 
an increased power Output per unit Of engine weight' ter, an integra] elongate shank part of comparatively smaller diameter extending axially from said head part Ideally, a turbine engine should operate with stoichio- 25 to an end termination portion thereof; a metallic end metric combustion in order to extract the greatest possi- fitting defining an axially extending thread defining ble energy value from the fuel consumed. However, the feature; said end fitting and said shank portion defining temperatures resulting from stoichiometric and even 
near-stoichiometric combustion are the endur- cooperating means for intersecuring one to the other to 
ance capabilities of metallic turbine engine components. 30 sustain an directed force. 
Consequently, as the turbine engine art has progressed, An advantage Of the represent invention resides in the 
an ever greater emphasis has been placed upon both provision of a hybrid ceramic/metallic mechanical fas- 
enhanced cooling techniques and the development of tener wherein the beneficial characteristics of each ma- 
temperature and oxidation resistant metals for use in terial are 
components of the engine which are exposed to the 35 
highest temperatures. That is, cooling techniques and from the provision of a turbine engine wherein ceramic 
high temperature metals have been developed for each parts having high resistance 
of combustion chambers, turbine stator nozzles, and may to comPOnents by means 
M i n e  blades. This quest has led to the development of of the hybrid ~ r - c / m e ~ 1 i c  fastener. m t  the 
elaborate cooling schemes for all of these components 40 ceramic components dong with the cerarhic 
well as to classes of nickel-based "super alloy" metals portion of the hybrid fastener may be exposed to high 
which may be Cast using directionally solidified or sin- temperatures while metallic structures exposed to corn- 
gle crystal techniques. All in all, the quest for higher ParativelY cooler structures are employed to support 
operating temperatures in a turbine engine fabricated of the ceramic components- The metallic portion of the 
metallic components has led to a still increasing com- 45 hybrid fastener advantageously cooperates with the 
plexity and expense in the making of the engine. metallic support structure of the engine to provide a 
An alternative approach to the attainment of higher tensile force in the hybrid fastener. 
operating temperatures in a turbine engine has been Additional objects and advantages of the Present 
recognized. This approach involves the of high- invention Will appear from a reading Of the following 
strength ceramic components in the engine. Ceramic 50 detailed description of a single preferred embodiment of 
components are better able t h a  metals to withstand the the invention taken in conjunction with the appended 
high temperature oxidizing environment of a turbine drawing figures. 
to best advantage. 
Another advantage Of the present invention 
BRIEF DESCRIPTION OF THE DRAWINGS en3ne. However, the term-"high- strength" in connec- tion with ceramic structures must be viewed in context. 
While many ceramic materials exhibit superior high 55 
temperature strength and oxidation resistance, ceramics 
have historically been difficult to employ in turbine 
engines because of a cooparatively low tensile fracture 
strength and a low defect tolerance. Consequently, a 
long-recognized need has been for the development of 60 1; 
hybrid ceramic/metallic structures which utilize the 
characteristics of each material to best advantage in 
order to allow combustion in a turbine engine to take 
place closer to or at the stoichiometric level. 
SUMMARY OF THE INVENTION 
In view of the deficiencies of the conventional tur- 
bine engine art, and of the materials of construction and 
FIG. 1 provides a longitudinal view, partly in cross 
section of a hybrid ceramic/metallic turbine enghe 
embodying the invention; 
FIG. 2 depicts an enlarged fragmentary cross sec- 
tional view of a portion of the engine presented by FIG. 
FIG. 3 provides an exploded perspective view of a 
hybrid ceramic/metallic fastener embodying the pres- 
ent invention; 
FIG. 4 depicts a part of the hybrid ceramic/metallic 
FIG. 5 presents an exploded longitudinal view, partly 
in cross section, of a hybrid ceramic/metallic fastener 
embodying the invention. 
65 fastener in perspective view; and 
5.134,842 
3 
BEST MODE FOR CARRYING OUT THE 
INVENTION 
FIG. 1 depicts a hybrid ceramic metallic turbine 
engine 10. The engine 10 includes a housing 12 which 
defines an inlet 14, an outlet 16, and a tortuous flow path 
18 communicating the inlet 14 with the outlet 16 for 
conveying a flow of fluid therebetween. A hybrid cera- 
midmetallic rotor member generally referenced with 
the numeral 20 is journaled in the housing 12 and coop- 
erates therewith to bound the flow path 18. It will be 
seen that the rotor member 20 includes a compressor 
rotor portion 22, rotation of which inducts ambient air 
via inlet 14, as indicated by arrow 24, and delivers this 
air pressurized to a flow path section 18' as indicated by 
arrow 26. 
The flow path section 18  leads axially through a 
segment of somewhat less than 180' of a rotary annular 
regenerator member 28 which is received in the housing 
12. Downstream of the regenerator 28, the flow path 18 
leads through an axially extending combustion structure 
generally referenced with the numeral 30. The combus- 
tor structure 30 is fabricated of ceramic material and 
includes a ceramic outer liner 32 which is supported at 
one end by a generally cone-shaped outer transition 
member 34. A ceramic inner combustion liner 36 is 
coaxially disposed within the outer liner 32, and is sup- 
ported at one end on a ceramic transition duct member 
38. The flow path 18 leads axially toward the one end of 
the combustion liner 36, as indicated by arrow 18". 
Within the transition duct member 38, a ceramic turbine 
back shroud member 40 and a ceramic turbine stator 
member 42 cooperatively define the flow path 18, and 
lead the latter radially inwardly to a ceramic turbine 
rotor portion 44 of the rotor member 20. 
Downstream of the turbine rotor portion 44, the flow 
path 18 extends axially and radially outwardly between 
a pair of spaced apart cooperative ceramic exhaust duct 
members, respectively referenced with the numerals 
46,48. A plurality of hybrid ceramic/metallic fastener 
members 50 (one of which is visible in FIG. 1) coopera- 
tively engage the one exhaust duct member 46 and the 
housing 12. A ceramic spacer member 52 received over 
the fastener members 50 spaces apart the duct members 
46,48. 
Subsequent to the exhaust duct members 46,48, the 
flow path 18 leads to an exhaust chamber generally 
referenced with the numeral 54. A segment of some- 
what less than 180' of the ceramic regenerator member 
28 is exposed to the exhaust chamber 54. Consequently, 
the flow path 18 leads once again through the regenera- 
tor member 28, and to ambient via the outlet 16. 
In order to complete this description of the engine 10, 
it must be noted that in the combustor 30 fuel is added 
5 
10 
15 
20 
25 
30 
35 
40 
45 
50 
to the pressurized air flowing from compressor rotor 22 55 
to support combustion. This combustion results in a 
flow of high temperature pressurized combustion prod- 
ucts flowing downstream in the combustor 30, and in 
flow path 18 subsequent to the combustor. Also, the 
rotor member 20 is journaled in housing 12 by a journal 60 
bearing 56 disposed between the rotor portions 22 and 
44, and a rolling element bearing (not visible in the 
Figures) disposed adjacent a metallic power output 
shaft portion 60 (only a portion of which is visible in 
FIG. 1) of the rotor member 20. 
Viewing now FIGS. 2 through 5 in conjunction, it 
will be seen that engine housing 12 includes a metallic 
outer support structure portion, generally referenced 
65 
4 
with the numeral 62. Disposed within the support struc- 
ture 62, and spaced axially and radially therefrom to 
cooperatively define therewith a compressor diffuser 
portion 18"' of flow path 18, is a metallic inner support 
structure 64. Nested within the metallic support struc-. 
tures 62 and 64 is a ceramic cup-like heat shield member 
66, and the ceramic exhaust duct members 46,48. The 
exhaust duct member 46 is spaced away from member 
48 by a ceramic spacer 52 received over a hybrid cera- 
mic/metallic fastener 50, as mentioned above. The duct 
member 48, heat shield 66 and inner metallic support 
structure 64 are stacked together. The inner support 
structure 64 is spaced from outer structure 62 by a me- 
tallic spacer member 68 received over the fastener 52. 
Three of the spacers 52 equally cucumferentially dis- 
posed are employed to support and locate members 46, 
48,64,50 and 68 in the housing 12, all with reference to 
the outer support structure 62. 
The hybrid ceramic/metallic fastener 50 includes a 
ceramic part generally referenced with the numeral 70, 
a metallic end fitting 72, a metallic sleeve portion 74, 
and a conventional metallic cap screw 76. The ceramic 
part 70 includes a head part 78 of comparatively larger 
diameter and an elongate shank part 80 of compara- 
tively smaller diameter extending from the head part 78 
to terminate in a shank end termination portion 82. 
Defined upon the end portion 82 and spaced from an 
end surface 84 thereof are a pair of transversely extend- 
ing diametrically opposite grooves or flats 86,88. A pair 
of flats 90,92 extend respectively from the pair of 
grooves 86,88, to the end 84 of the shank 80. As a result 
of the grooves 86,88, and flats 90,92, it can be seen that 
the shank 80 terminates in end portion 82 having a flat- 
tened tang 94 carrying a flattened bulbular enlargement 
96. 
The metallic end fitting 72 is received upon the end 
portion 82 of the shank 80. The fitting 72 includes an 
axially elongate annular portion 98 having a thread- 
defining bore 100 extending axially therethrough. Ex- 
tending axially from the annular portion 98 is a pair of 
confrontingly disposed generally J-shaped tongues 
102,104. These tongues 102,104 cooperatively define a 
necked transverse slot 106 having a reduced-width neck 
108. The metallic end fitting 72 is received transversely 
onto the end portion 82 of shank 80 so that these two are 
axially aligned one with the other. That is, the tang 94 
is received in neck 108 while the bulbular enlargement 
96 is received in the remainder of slot 106. Thereafter, 
the sleeve portion 74 is passed axially over the end 
fitting 72 in order to block the slot 106 and capture end 
portion 82 therein. Sleeve portion 74 is welded to end 
fitting 72 to permanently trap the shank 80 and end 
portion 82 thereof in the end fitting 72. The conven- 
tional cap screw 76 threadably engages the end fitting at 
bore 100 to impose a tensile force on the fastener 50. 
Viewing FIGS. 3,4 and 5 in particular, it will be seen 
that the end fitting 72 also defines a pair of axially ex- 
tending diametrically opposite external flats 110,112. In 
order to isolate the ceramic part 70 from torque im- 
posed upon the end fitting 72 when the cap screw 76 is 
tightened during assembly of the fastener, the outer 
support structure 62 defines a through hole 114 nonro- 
tatably receiving the end fitting 72. In other words, the 
hole 114 includes a pair of axially extending flats 
116,118 engaging flats 110,112 of the fitting 72. When 
the cap screw 76 is torqued, this torque is reacted by the 
outer support structure 62, and the ceramic part 70 is 
exposed only to tensile stress without torque. 
5,134,842 
5 6 
Returning to FIG. 2, it will be seen that the metallic gaging said metallic support structure, said fastener 
cap screw 76 engages metallic support structure 62, including means for cooperatively providing a tensile 
while the head portion 78 engages the ceramic exhaust force between said ceramic portion and said metallic 
duct 46. An advantage of the fastener 50 is the high portion to retain said ceramic member and metallic 
resistance to axial heat conduction offered by the ce- 5 support structure in cooperative association, and torque 
ramie Part 70. That is, even though head portion 78, and isolation means for preventing torque applied to said 
part of the shank 80 adjacent to head portion 78, are metallic portion from being applied to said ceramic 
exposed to temperatures as high as about 2500' F. 1370" portion of said fastener member. 
C.), the length and relatively low heat conduc- 2. The invention of claim 1 wherein said fastener 
tivity of the shank 80 allow metallic material to be em- 10 includes said portion defining at one end 
ployed at end fitting 72. thereof a head part of comparatively larger diameter 
While the present invention has been depicted and engaging ceramic member, an elongate integral described by reference to a single preferred embodi- part extending axially from said head 
ment of the invention, such reference does not imply part through &d bore of said ceramic member, said 
any limitation upon the invention, and no such limita- 15 shank part in an end termination part; a 
tion is to be inferred. The invention is intended to be metallic end fitting received upon said end termination 
part, said metallic end fitting and said end termination limited only by the spirit and scope of the appended claims, which provide additional definition of the inven- part defining coacting means for sustaining transmission tion. 
3. The invention of claim 2 wherein said coacting 
said end termination part defining an 
at the distal end thereof, said end fitting defining a trans- 
2o of tensile force therebetween. What is claimed is: 
1. A combustion turbine engine comprising an inlet, 
an outlet, and a flow path communicating a flow of fluid 
pressor inducting a flow of ambient air via inlet and 
therebetween, said engine including a rotatable corn- extending tang a eniargement 
delivering this air pressurized to a combustor, means 25 versely extending and in transverse 
delivering a flow of fuel to said combustor to support view matching said tang and enlargement, said end 
combustion in said pressurized air to produce a flow of fitting being received transverseb upon a i d  end termi- 
opening 
high temperature combustion and a turbine nation part in substantial axial alignment with said shank 
expanding said combustion products for discharge into part- 
ambient air via said outlet to derive mechanical power 30 4. The invention of claim 3 wherein said tensile force 
therefrom driving said compressor, said engine includ- Providing means includes said end fining defining a 
ing a ceramic member at or downstream of said corn- thread-defining feature, and a metallic member thread- 
bustor, said ceramic member being immersed in or in ably engaging said ihrad-defining feature and also 
part bounding said flow path so as to be exposed to said engaging said metallic Support structure to &Pose said 
high temperature combustion products, and a metallic 35 tensile force upon said fastener. 
support structure for supporting said ceramic member, 5. The invention of claim 4 wherein said torque kola- 
m h  of said ceramic member and &d support structure tion means includes said end fitting and said metallic 
&fining a respective axially aligning bore, a hybrid support structure defining nonrotatiod d y  rela- 
cenmic/metallic fastener member received in said re- tively movable cooperating means for isolating said 
spective bores of said ceramic member and support 40 ceramic portion from torque transmitted between said 
structure and having a ceramic portion engaging said metallic member and said thread-defining feature. 
ceramic member and a respective metallic portion en- * * * * *  
45 
50 
55 
60 
65 


High temperature turbine engine structure

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