A variable geometry device is provided for use with the compressor outlet of a turbine engine. The turbine engine includes a support housing, a compressor contained within the support housing and having a compressed air outlet and in which a pair of spaced walls define an annular and radially extending diffuser passageway. The inner end of the diffuser passageway is open to the compressed outlet while the outer end of the diffuser passageway is open to the combustion chamber for the turbine engine. A plurality of circumferentially spaced diffuser vanes are mounted to one of the diffuser walls and protrude across the diffuser passageway. An annular recessed channel is formed around the opposite diffuser wall and an annular ring is mounted within the channel. A motor is operatively connected to this ring and, upon actuation, displaces the ring transversely across the diffuser passageway to variably restrict the diffuser passageway. In addition, the ring includes a plurality of slots which register with the diffuser vanes so that the vane geometry remains the same despite axial displacement of the ring

Lenz, Herman N.

Rogo, Casimir

NASA Technical Reports Server

United States Patent E191 
Rogo et al. 
[ i i ]  Patent Number: 4,544,325 
[451 Date of Patenk Oct. I. 1985 
[54] VARIABLE GEOMETRY DEVICE FOR 
TURBINE COMPRESSOR OUTLET 
[75] Inventors: Casimir Rogo, Mt. Clemens; Herman 
N. Lenz, Lambertville, both of Mich. 
[73] Assignee: Teledyne Industries, Inc., Los 
Angeles, Calif. 
[21] Appl. No.: 199,475 
[22] Filed: Oct. 22, 1980 
[51] Int. c1.4 ....................... FOlB 25/02; F04D 15/00 
[52] U.S. c1. ...................................... 415/150; 415/46; 
[58] Field of Search ................... 415/46, 47, 148, 150, 
415/211 
415/211 
~561 References Cited 
U.S. PATENT DOCUMENTS 
2,739,782 3/1956 White . 
2,763,426 9/1956 Erwin . 
2,996,996 8/1961 Jassniker ............................. 415/150 
3,365,120 1/1968 Jassniker . 
3,406,740 10/1968 Samerdyke . 
3,478,955 11/1969 Kunderman . 
3,489,391 1/1970 Kanger et al. ...................... 415/157 
3,829,237 8/1974 Chestnutt ............................ 4I5/181 
3,887,295 6/1975 Yu ....................................... 415/116 
3,975,911 8/1976 Morgulis et al. . 
3,994,620 11/1976 Spraker, Jr. et al. . 
4,149,826 4/1979 Torstenfelt .......................... 415/127 
FOREIGN PATENT DOCUMENTS 
1208697 2/1960 France ................................ 415/150 
Prinaiy Examiner-Philip R. Coe 
Assistant Examiner-Timothy F. Simone 
Attorney, Agent, or Firm-Gifford, VanOphem, 
Sheridan, Sprinkle & Nabozny 
[571 ABSTRACT 
A variable geometry device is provided for use with the 
compressor outlet of a turbine engine. The turbine en- 
gine includes a support housing, a compressor con- 
tained within the support housing and having a com- 
pressed air outlet and in which a pair of spaced walls 
define an annular and radially extending diffuser pas- 
sageway. The inner end of the diffuser passageway is 
open to the compressed outlet while the outer end of 
the diffuser passageway is open to the combustion 
chamber for the turbine engine. A plurality of circum- 
ferentially spaced diffuser vanes are mounted to one of 
the diffuser walls and protrude across the diffuser pas- 
sageway. An annular recessed channel is formed around 
the opposite diffuser wall and an annular ring is 
mounted within the channel. A motor is operatively 
connected to this ring and, upon actuation, displaces the 
ring transversely across the diffuser passageway to vari- 
ably restrict the diffuser passageway. In addition, the 
ring includes a plurality of slots which register with the 
diffuser vanes so that the vane geometry remains the 
same despite axial displacement of the ring. 
6 Claims, 3 Drawing Figures 
https://ntrs.nasa.gov/search.jsp?R=20080005901 2019-08-30T02:59:41+00:00Z
U.S. Patent oct. 1,1985 Sheet I of2 4,544,325 
U.S. Patent oct. 1,1985 Sheet 2 of 2 4,544,325 
Fig-2 
f f ig -3  
1 
4,544,325 
VARIABLE GEOMETRY DEVICE FOR TURBINE 
COMPRESSOR OUTLET 
The invention described herein was made in the per- 
formance of work under NASA Contract No. NAS 
3-23163 and is subject to the provisions of Section 305 
of the National Aeronautics and Space Act of 1958 (72 
Stat. 435; 42 U.S.C. 2457). 
BACKGROUND OF THE INVENTION 
I. Field of the Invention 
The present invention relates generally to variable 
geometry devices employed in turbine engines and, 
more particularly, to such a device for use in the dif- 
fuser passageway between the turbine engine compres- 
sor outlet and the combustion chamber. 
11. Description of the Prior Art 
A conventional turbine engine includes a support 
housing, a compressor having an outlet rotatably 
mounted within the support housing and a diffuser pas- 
sageway which fluidly connects the compressor outlet 
to a combustion chamber also contained within the 
support housing. In many previously known turbine 
engines, the diffuser passageway is generally annular in 
shape having its inner end open to the compressor outlet 
so that the air flow through the diffuser passageway is 
generally radially outward. In addition, many of the 
previously known turbine engines include diffuser 
vanes extending across the diffuser passageway to aero- 
dynamically control the flow of compressed air from 
the compressor and to the combustion chamber. 
Many turbine engine applications require that the 
turbine engine be operated over a broad range of oper- 
ating conditions. These different operating conditions in 
turn entail different air flow and pressure delivery re- 
quirements. Moreover, it is desirable to maintain high 
turbine engine performance, and thus turbine engine 
efficiency, at all of the operating conditions which, in 
turn, avoids surge, cavitation and other engine instabili- 
ties. 
One previously known method of broadening the 
flow capacity characteristics in the diffuser passageway 
is to use variable geometry engine components. In the 
case of centrifugal compressors, the desired variable 
geometry for the diffuser assembly is typically accom- 
plished by varying the angle of the diffuser vanes in the 
diffuser passageway. 
The previously known pivoted diffuser vanes, how- 
ever, have not proven wholly satisfactory in use to vary 
the diffuser geometry. One disadvantage of this method 
results from the leakage losses which occur in the dif- 
fuser assembly around the pivoted diffuser vanes and 
into the support housing. These clearance losses are 
further amplified due to the large openings in the dif- 
fuser walls which are required to compensate for ther- 
mal distortion and thermal expansion. 
A still further disadvantage of the use of pivoted 
diffuser vanes to vary the aerodynamic geometry of the 
diffuser Dassagewav is that it is difficult to accuratelv 
pivot all-of thi  diffuser vanes to the same angle due tb 
mechanical back-lash and mechanical play. Unwanted 
and undesired turbulences result when the diffuser 
vanes are positioned at different angles. 
65 
SUMMARY OF THE PRESENT INVENTION 
The present invention provides a variable geometry 
device for use in the diffuser passageway of the turbine 
5 
10 
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60 
2 
engine which overcomes the disadvantages of the previ- 
ously known variable geometry devices. 
In brief, in the present invention two spaced walls in 
the support housing form an annular diffuser passage- 
way having its inner end open to the compressor outlet. 
The outer end of the diffuser passageway is fluidly 
connected to the combustion chamber for the turbine 
engine. In addition, a plurality of circumferentially 
spaced diffuser vanes are secured to one support hous- 
ing wall and extend transversely or axially across the 
diffuser passageway. 
An aimular channel is formed around the entire cir- 
cumfery of the other diffuser wall. Thereafter, a ring is 
mounted within this channel and moving means are 
attached to the ring for moving the ring between a 
retracted and extended position. 
In its retracted position, the ring is nested within the 
channel so that one face of the ring is substantially flush 
with the wall of the diffuser passageway. Conversely, in 
its extended position, the ring protrudes into and re- 
stricts the diffuser passageway. 
In the preferred form of the invention, the ring has a 
plurality of circumferentially spaced slots so that one 
slot registers with and receives one diffuser vane 
therein. 'Thus, the diffuser vane geometry remains fixed 
regardless of the position of the ring. 
BRIEF DESCRIPTION OF THE DRAWING 
A better understanding of the present invention will 
be had upon reference to the following detailed descrip- 
tion when read in conjunction with the accompanying 
drawing wherein like reference characters refer to like 
parts throughout the several views, and in which: 
FIG. 1 is a fragmentary sectional view illustrating a 
preferred embodiment of the variable geometry device 
of the present invention; 
FIG. 2 is a fragmentary sectional view taken substan- 
tially along line 2-2 in FIG. 1; and 
FIG. 3 is a fragmentary sectional view taken substan- 
tially along line 3-3 in FIG. 1. 
DE,TAILED DESCRIPTION OF A PREFERRED 
EMBODIMEN1' OF THE PRESENT INVENTION 
With reference first to FIG. 1, a portion of a turbine 
engine 10 is thereshown and comprises a support hous- 
ing 12 in which an air compressor means 14 is rotatably 
mounted. The air compressor means 14 also includes a 
final stage 16 open to a compressed air outlet 18. 
The support housing 12 includes a first annular dif- 
fuser wall 20 and a second annular diffuser wall 22 
which, together, form an annular diffuser passageway 
24 within the support housing 12. The inner end 26 of 
the diffuser passageway 24 is open to and registers with 
the compressor outlet 18 while the outer end 28 of the 
diffuser passageway 24 is open to a combustion cham- 
ber (not shown). Thus, in the well known fashion, the 
diffusor passageway 24 fluidly connects the compressor 
outlet 18 with the combustion chamber of the turbine 
engine 10. 
With reference now to FIGS. 1 and 3, a plurality of 
circumferentially spaced diffuser vanes 30 are secured 
to the diffuser wall 20 and extend entirely axially across 
the diffuser passageway 24. These diffuser vanes 30 are 
of a fixed geometry and aerodynamically shape the air 
flow from the compressor outlet 18 and to the combus- 
tion chamber. 
Still referring to FIGS. 1 and 3, an annular recessed 
channel 32 having a generally rectangular cross sec- 
4,544,325 
3 4 
tional shape is formed around the entire circumfery of wardly toward the diffuser side wall 22. Thus, with the 
the diffuser wall 22. A ring 34 having a front face 36 is ring 34 in its extended position, both the inner radial and 
then positioned within the channel 32 so that the ring 34 outer radial ends of the ring 34 taper toward and meet 
also extends entirely around the diffuser passageway 24. the diffuser side wall 22. The tapered portions 70 and 72 
The ring 34 is of a rigid construction and is preferably 5 of the ring 34 are designed to minimize air turbulence 
formed by casting. In addition, the ring 34 has a plural- through the diffuser passageway 24 when the ring 34 is 
ity of circumferentially spaced slots 36 (FIG. 3) formed in its extended position. 
through it so that one slot 36 registers with and receives From the foregoing, it can be seen that the present 
one diffuser vane 30 therein. invention provides a novel construction for varying the 
With reference now to FIGS. P and 2, a plurality ol' 10 aerodynamic geometry of the diffuser passageway in a 
circumferentially spaced pins 38 are secured at one end turbine engine without varying the geometry or angle 
40 to the ring 34 and each pin extends axially outwardly of the diffuser vanes. Moreover, the device of the pres- 
through an opening 42 in the base of the channel 3%. ent invention is compact in construction and virtually 
The pin 38 furthermore include an externally threaded fail safe in. operation. 
portion 44 along their length and the pins 38 can be 15 A still further advantage of the present invention is 
either integrally formed with the ring 34 or separately that leakage losses, a major disadvantage of the previ- 
fabricated and secured to the ring 34. In addition, the ously known pivotal diffuser vane constructions, is 
pins 38 are free to axially slide in the opening 42 and, in virtually entirely eliminated. Any leakage through the 
doing so, axially displace the ring 34 transversely acsoss ring slots 36 is simply returned to the diffuser air flow 
the diffuser passageway 24. 
In order to control the axial position of the pin 38, Having described our invention, however, many 
and thus of the ring 34, an internally threaded pinion 46 modifications thereto will become apparent to those 
is threadably attached to the threaded portion 44 of skilled in the art to which it pertains without deviation 
each pin 38. Each pinion 46 is axially constrained with from the spirit of the invention as defined by the scope 
respect to the support housing 12 by a retainer 48 so that 25 of the appended claims. 
rotation of the pinion 46 axially displaces the pin 38 and We claim: 
the ring 34 due to the threaded connection between 1. A compressor assembly for a turbine engine com- 
each pinion 46 and its associated pin 38. 
A gear ring 50 is rotatably mounted to the support a support housing, 
housing 12 by a ball bearing assembly 52 so that the gear 30 a compressor means contained within the support 
ring 50 rotates concentrically around the compressor housing and having a compressed air outlet; 
assembly 14. The teeth 54 of the gear ring 50 mesh with said support housing having a pair of spaced diffuser 
the inner radial ends of the pinions 46. walls which form an annular diffuser passageway 
With reference still to FIGS. 1 and 2, a motor 60 is having its inner end open to said compressed air 
contained within the support housing 12 and includes an 35 outlet, 
output shaft 62 on which a drive gear 64 is secured. 'The said diffuser passageway having an annular recessed 
drive gear 64, in turn, is in mesh with one of the pinions channel formed along one diffuser wall, 
46. The motor 60 is a reversible motor and is of any a ring mounted in said channel, 
conventional construction, such as an electric or hy- means for moving said ring transversely across said 
draulic motor. 40 passageway between a retracted position in which 
With reference now particularly to FIG. 1, in opera- said ring is nested within said channel and an ex- 
tion, rotation of the drive gear 64 by the motor 60 rotat- tended position in which one side of said ring pro- 
ably drives one of the pinions 46. This, in turn, rotates trudes into and restricts said diffuser passageway, 
the gear ring 50 on its ball bearing assembly 52 in depen- a plurality of circumferentially spaced pins secured to 
dence upon the direction of rotation of the motor 60. 45 and extending axially outwardly from the other 
Since the gear ring 50 is in mesh with each of the pin- side of said ring and through an opening in said 
ions 46, all of the pinions 46 rotate in unison with each channel, each pin having an external threaded por- 
other. tion along its length and 
The rotation of the pinions 46 axially displaces the wherein said moving means comprises a 
pins 38 with their attached ring 34 due to the threaded 50 plurality of internally threaded pinions, one pinion 
engagement between each pinion 46 and its associated threadably engaging each pin, 
pin 38. Thus, the ring 34 moves transversely across the means for restraining said pinions against axial 
diffuser passageway 24 between a retracted position, movement, 
shown in solid line in FIG. 1, and an extended position, a gear ring rotatably mounted to said housing coax- 
shown in phantom line in FIG. 1. In its retracted posi- 55 ially with said ring, said gear ring being in mesh 
tion, the ring 34 is nested within the channel 32 so that with said pinions, 
its front face 36 is substantially flush with the diffuser a drive gear in mesh with one of said pinions, and 
wall 22. Conversely, with the ring 34 in its extended motor means for rotatably driving said drive gear. 
position, the ring 34 restricts the diffuser passageway 24 2. The invention as defined in claim 1 and further 
without altering the geometry of the diffuser vanes 30 60 comprising a plurality of circumferentially spaced vanes 
due to the sliding engagement of the vanes 30 in the ring secured to the other diffuser wall and protruding into 
slots 36. said diffuser passageway and wherein said ring includes 
The provision of the circumferentially spaced pins 38 a plurality of slots which register with and slidably 
prevents the ring from tilting and ensures that all por- receive said vanes. 
tions of the ring protrude into the diffuser passageway 65 3. The invention as defined in claim 2 wherein said 
24 by the same amount. vanes extend entirely transversely across said diffuser 
As is shown in FIG. I, both the inner radial end '70 passageway and into said slots when said ring is in its 
and outer radial end 72 of the ring 34 are tapered in- retracted position. 
20 and ultimately to the combustion chamber. 
prising: 
5 
4,544,325 
6 
4. The invention as defined in claim 1 wherein the and outer radial ends of said ring which tapers from said 
center of said one side of said ring is substantially flush one dng side and toward said one diffuser 
6. The invention as defined in claim 5 wherein the 
inner and outer radial ends of said one side of said dng with said one diffuser wall when said ring is in its re- 
tracted position. 
5. The invention as defined in claim 4 wherein said 
ring includes a tapered portion adjacent both the inner 
5 substantially register with said one diffuser wall when 
said ring is in said extended position. * * * * *  
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25 
30 
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60 
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Variable geometry device for turbine compressor outlet

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