US3848663A

US3848663A - Rotary regenerator for a gas turbine engine with resilient mounts for positioning the regenerator

Info

Publication number: US3848663A
Application number: US00417441A
Authority: US
Inventors: V Rao
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1973-11-19
Filing date: 1973-11-19
Publication date: 1974-11-19
Anticipated expiration: 1991-11-19
Also published as: DE2453258A1; GB1474710A; JPS5083613A; CA1017956A

Abstract

A rotary regenerator for use in a gas turbine engine comprising a ceramic core matrix and a circular rim surrounding the matrix as the regenerator rotates about its geometric axis, a ring gear carried by the rim for driving the regenerator, a resilient connection between the rim and the ring gear to establish a cushion for the ceramic core and means for resiliently mounting and positioning the regenerator core to establish proper sealing contact between the regenerator core and the regenerator seals as the latter sealingly engage the surface of the regenerator core.

Description

tates atet 11 1 ROTARY REGENERATOR FOR A GAS TURBINE ENGINE WITI-ll RESILIENT MOUNTS FOR POSITIONING THE REGENERATOR Inventor: V. Durga Nageswar Rao,

Woodhaven, Mich.

Assignee: Ford Motor Company, Dearborn,

Mich.

Filed: Nov. 19, 1973 Appl. No.: 417,441

US. Cl 165/8, 165/10, 74/443, 74/446, 64/27 NM Int. Cl. F2801 19/00 Field of Search 165/8, 10; 74/446, 443; 1 64/27 NM References Cited UNITED STATES PATENTS Chute 165/8 X Nov. 19, 1974 3,300,967 1/1967 Trapp 1. 165/8 x 3,789,917 2/1974 Jarry 165/8 FOREIGN PATENTS OR APPLICATIONS 1,206,246 9/1970 Great Britain 1. 165/8 Primary ExaminerAlbert W. Davis, Jr. Attorney, Agent, or Firm-Donald J. Harrington; Keith L. Zerschling [5 7] ABSTRACT A rotary regenerator for use in a gas turbine engine comprising a ceramic core matrix and a circular rim surrounding the matrix as the regenerator rotates about its geometric axis, a ring gear carried by the rim for driving the regenerator, a resilient connection between the rim and the ring gear to establish a cushion for the ceramic core and means for resiliently mounting and positioning the regenerator core to establish proper sealing contact between the regenerator core and the regenerator seals as the latter sealingly engage the surface of the regenerator core.

12 Claims, 17 Drawing Figures PATENIE WIQIBM 3,848,663

sum 20! e PATENTEL, rm 1 9 m4 saw u or a rm 1 91914 v SHEET 5 OF 6 PATENTLU [Ill Ill! ROTARY REGENERATOR FOR A GAS TURBINE ENGINE WITH RESILIENT MOUNTS FOR POSITIONING THE REGENERATOR GENERAL DESCRIPTION OF THE INVENTION This invention relates generally to rotary regenerators for use in gas turbine engines. Examples of rotary regenerators that are capable of embodying the improvement of my invention are shown in prior art US. Pat. Nos. 3,586,096, 3,496,933 and 3,525,384. Each of these prior art patents is owned by the assignee of this invention.

A regenerator in a gas turbine engine of the type disclosed in the aforesaid patents and in this disclosure is situated typically in a regenerator core chamber in the engine housing and is covered by a regenerator cover. The engine housing and the regenerator core chamber define gas flow passages which are intersected by the regenerator core. Compressed air from the gas turbine engine compressor passes through one gas passage and combustion gases on the downstream side of the engine power turbine pass through another passage. The core becomes heated by the turbine exhaust gases and heated core region, upon rotation of the regenerator, comes in contact with the relatively cool compressed intake air on the upstream side of the burner as the intake air passes through a different segment of the regenerator core. Gas seals capable of withstanding the operating temperatures encountered in the gas turbine engine are effective to seal and isolate one regenerator region at one operating pressure from another region at a different operating pressure. The seals are situated on the opposite sides of the regenerator core in sealing engagement with the core surfaces as the core revolves about its geometric axis. The regenerator core is driven by a pinion which meshes with the ring gear mounted on the rim of the ceramic regenerator core. One seal assembly is mounted on a seal surface formed on the engine housing adjacent one surface of the regenerator core and the other seal is mounted on the corresponding surface of the regenerator cover.

The seal assemblies are comprised of a seal diaphragm that is loaded with the forces due to the differential gas pressures passing through the regenerator. The regenerator chamber defined by the engine housing and the regenerator cover has dimensions that are fixed, and the clearance for the regenerator seals therefore is fixed. The axis of rotation and the clearance for the seals are controlled by balancing the gas loads on the diaphragm seal elements. It is desirable to balance the gas loading as much as possible so that the loads on the seal elements are maintained at optimum levels and are distributed uniformly over the seal surface.

The improvements of my invention make it possible to achieve a better balance for the sealing forces. This results in a reduced seal wear rate and excessive local loads on the seal are avoided. The axis of rotation of the regenerator core is fixed thereby avoiding variations in the seal loads as the regenerator core rotates. Failure of the diaphragm seal elements after continued operation of the regenerator core are reduced in frequency.

The ring gear is mounted on the regenerator rim by a resilient attachment ring thereby providing a cushion which maintains the regenerator core in a fixed axial position and distributes seal loads more uniformly. It also avoids excessive localized loading due to misalignment of the regenerator. The resilient connection also provides a damping action for the regenerator which prevents shock loading of the ceramic core.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. 1 shows an adjustable resilient mounting means for a rotary regenerator in a gas turbine engine.

FIG. 2 is a view similar to FIG. 1 showing an alternate mounting means for a regenerator having a split ring gear.

FIG. 3 is a view similar to FIG. 1 showing a second alternate construction of the resilient mounting means for a regenerator with a split ring gear.

FIG. 4 is a view of an alternate regenerator mounting for a regenerator rim similar to the rim shown in FIG. 1.

FIG. 5. shows a detail of a mounting spring used to establish a yieldable driving connection between a regenerator ring gear and a regenerator core rim.

FIGS. 6 and 6A show, respectively, the locking grooves in either end of the mounting spring shown in FIG. 5. I

FIG. 7 shows the mounting spring ends of FIGS. 6 and 6A together with the locking element that joins the two ends together. 7

FIG. 8 is a plan view of the connection shown in FIG. 7.

FIG. 9 is a partial assembly view showing the mounting spring of FIG. 5 assembled between the ring gear and the regenerator core rim.

FIG. 10 is a view similar to FIG. 9 showing a ring gear, a drive flange and ring clip on the mounting spring.

FIG. 11 is a view similar to FIG. 5, but which includes also an illustration of resilient cushions between the regenerator rim and the rim contacting forces of the mounting spring.

FIG. 12 is a cross sectional view taken along the plane of section line 12l2 of FIG. 11.

FIG. 13 is a cross sectional view taken along the plane of section line l313 of FIG. 11.

FIGS. 14 and 15 show two other embodiments similar to the embodiment of FIGS. 11 through 13.

PARTICULAR DESCRIPTION OF THE INVENTION In FIG. 1, reference character 10 designates a ceramic regenerator core with asteel rim 12. A ring gear mounting material, preferably made of a high temperature elastomer, is situated between the rim l2 and the ring gear 14. Ring gear 14 includes teeth 16 which mesh with a drive pinion not shown. The regenerator core 10 is adapted to rotate about its geometric axis 18 as the ring gear 14 is driven. The regenerator seals are situated in sealing engagement with both axial sides 20 and 22 of the regenerator core although they are not illustrated in the drawings.

A portion of the engine housing is shown at 24 and a portion of a regenerator cover is shown at 26. The housing portion 24 and the cover portion 26 are provided with aligned openings 28 and 30 respectively, for receiving adjusting bolt 32. Bolt 32 includes a head 34 which is located near the interior of the regenerator cavity in the engine housing and a threaded portion 36 on which is positioned an adjusting nut 38. A hollow shaft 40 surrounds the bolt 32. A first compression spring 42 is situated between the regenerator cover portion 26 and the left hand end of the hollow shaft 40. A second compression spring is situated between the right hand end of the hollow shaft 40 and a spacer 44 slidably situated within the opening 28. The spacer 44 surrounds the stem of the bolt 40 and engages the nut 38.

The hollow shaft is formed with a pair of stems 46 and 48. A bearing wheel 50 is joumaled on the stem 46 and is held fast by suitable fastening means such as clips 52 and 54. A wear resistant, low friction sleeve 56 surrounds the bearing wheel 50. It engages the adjacent side 58 of the ring gear 14. A second bearing wheel 60 is journaled on the stem 48 and, like the wheel 50, it includes a low friction sleeve 62 which engages the adjacent side 64 of the ring gear 14. The sleeves 56 and 62 may be formed of Teflon or some other similar low friction material. The distance between the stem may be fixed and the diameter of the bearings may be varied to suit the width of the ring gear that is chosen. The ring gear is guided between the two bearing wheels and rotates between them.

The hollow shaft may be adjusted in a direction parallel to the axis 18 by suitably adjusting the nut 38. This nut may be located externally thereby permitting adjustment without the necessity for disassembling the regenerator system. The compression of the springs is changed upon adjustment of the nut 38. Accordingly, the position of the regenerator core is controlled by the external adjustment. Several of the adjusting mechanisms illustrated in FIG. 1 may be provided at angularly spaced positions around the regenerator core 10. Suitable adjustments in each of them may be made to prevent misalignment of the regenerator core and to establish the proper clearances. Even wear due to loss of clearance and excess leakage due to excessive clearance can be avoided by suitable adjusting the appropriate adjusting mechanism at any one or more of the angularly positions.

The embodiment of FIG. 2 is somewhat similar to the embodiment of FIG. 1, but it includes only a single bearing roller. The elements of the FIG. 2 construction that have counterpart elements in the FIG. 1 construction have been identified by the same reference numerals although prime notations have been added. The mode of operation of the FIG. 2 construction is the same as that described with reference to FIG. 1.

The stem 46', which extends from the hollow sleeve shaft 40 carries a bearing roller 66. A low friction sleeve of Teflon or some similar bearing material surrounds the bearing roller 66 as indicated at 68. The roller 66 is positioned within a peripheral groove 70 formed in ring gear 72, which is joined to regenerator rim 12 by resilient ring gear mounting material 74.

The diameter of the bearing roller 66 is selected to fit the width of the peripheral groove 70 in the ring gear. Adjustments of the nut 38 cause the stem 46 to shift in one axial direction or another thereby appropriately positioning the ring gear and controlling the direction of the axis of rotation of the regenerator.

The FIG. 3 construction has features that are common to the FIGS. 1 and 2 constructions. It includes, for example, an adjusting bolt 32'. A compression spring 40' is situated between a roller 74 which corresponds to roller 66 of the FIG. 2 embodiment. Roller 74 is journaled on a collar 76 which surrounds the bolt 32'. Spring 40' and spring 42 on the opposite side of the roller engage the sides of the collar 76. A low friction material is applied to the outer periphery of the roller 74 and to each axial side thereof, as indicated at 78, 80 and 82. The periphery of roller 74 engages the peripheral groove 84 formed in ring gear 86 of the regenerator indicated generally by reference character 10.

In FIG. 4 is shown another embodiment that employs two rollers similar to the rollers shown in FIG. 1. The elements of the FIG. 4 construction that have counterpart elements of the FIG. 1 construction have been indicated by similar reference characters although double prime notations are added. The carrier for the rollers of the FIG. 4 construction differ from the carrier stems 46 and 48 of the FIG. 1 construction by their bifurcated ends. The carrier for roller 60", for example, includes a fork member 84 having two

legs

86 and 88 which are joined by pin 90. The roller 60 is joumaled on the pin 90, and periphery 68" engages the side of ring gear 14". The roller 50- is similarly carried by fork 92. Each fork 84 and 92 is carried by a shaft that corresponds to the hollow sleeve shaft 40 of the FIG. 1 construction.

FIG. 5 shows a peripheral spring that surrounds the hub of a heat exchanger of the type described with reference to FIGS. 1-4. The spring is circular and the ends are formed with projections of lateral grooves 94. The opposite end is formed with projections or lateral grooves 96. The spring which is designated by reference character 98 is provided with shaped

bends

100 and 102 in alternating relationship. The spring itself. which is more appropriately termed a mounting ring for the ring gear, may be formed of high strength alloy by a hot forming process. The shape of the mounting ring in the fabricated condition prior to assembly is shown in FIG. 5. The shape of the mounting ring after assembly about the regenerator rim 104 and within the ring gear 106 is shown in FIG. 9. The ends may be joined together by a linking element 108 which is formed with axially extending projections 110 which register with the grooves formed in the ends of the mounting ring strip, thereby locking the two ends together in a continuous ring.

FIG. 10 shows a mounting ring, a ring gear and a rim in similar relationships. The ring gear may be provided with a drive flange guide or projection 112 and the mounting ring is formed with a projection 114 which is folded around the flange 112 thereby locking the mounting ring to the ring gear. The curvature of the shaped bends 100 and 102 and the thickness of mounting ring are determined by the amount of stress necessary to provide adequate deflection, to absorb the thermal expansion of the ring gear and to provide adequate friction between the ring gear and the heat exchanger rim to prevent slippage. The ring gear, the mounting ring and the rim may be assembled in a suitable assembly fixture which will permit the sliding of the ring gear over the ring into position and which will permit the mounting ring to be pressed within the annular opening that is available between the ring gear and the regenerator um. I

In the embodiment of FIGS. 11, 12 and 13, there is shown, in addition to the mounting ring and the formed bends, a so-called cushion 116 which is secured to one side of formed bends 102. One side of the formed bends is between the regenerator rim and the mounting ring. The rim, which is shown at 118, is formed with a peripheral groove 120 which receives a mounting ring 98. The cushion material preferably is a glass fiber rein- '5 forced cellulose rubber or the like. Shock forces are absorbed by the cushion material to complement the cushioning action of the mounting ring itself and also to resist axial shifting movement of the regenerator core during the operation so that the proper seal loading of the adjusting mechanism of FIGS. 1 through 4 may be maintained.

The embodiment of FIG. 14 shows a regenerator construction similar to FIGS. 11 through 13, but the cushion material 124, which is a polymer, is reinforced with windings, such as woven glass fibers or carbon fibers or a metal wire. The fibers or the metal wire are coated with a primer for establishing a bond between the reinforcement and the polymer. The reinforcement wire or fibers are identified in FIG. 14 by reference character 122. Other elements of the construction of FIG. 14 are identified by the same reference characters used in FIGS. 11 through 13 for corresponding elements, but prime notations are added. i

The embodiment of FIG. 15 includes a spring metal reinforcement 122'. Like the reinforcementof FIG. 14, reinforcement 122' is wrapped around the periphery of the core and the polymer is poured and formed around it. The other elements of the FIG. 15 construction that are common to the FIG. 14 construction are identified by similar reference characters, but double prime notations are added.

Having thus described a preferred embodiment of my invention what I claim and desire to secure by United States Letters Patent is:

l. A regenerator assembly for a gas turbine engine comprising a rotary regenerator core mounted within a gas turbine engine, said assembly comprising a ceramic matrix adapted to conduct a counterflow of hot and cool gases under differential pressures, a matrix rim surrounding the regenerator matrix, a ring gear surrounding the rim, a means for yieldably mounting the ring gear concentrically around the rim, an adjustable member situated adjacent the ring gear and mounted on portions of said housing for shifting movement in a direction generally parallel to the axis of rotation of said regenerator matrix, bearing means carried by the adjustable member for positioning said rim relative to said adjustable member, means for yieldably maintaining said adjustable member in its adjusted position whereby the axial position of said regenerator matrix with respect to the engine housing and-the direction of the axis of rotation of said matrix may be controlled.

2. The combination as set forth in claim 1 wherein: said adjustable member comprises a sleeve, an adjusting bolt disposed within said sleeve, means for yieldably positioning said sleeve on said bolt whereby relative displacement of said sleeve with respect to said bolt is opposed by a spring force, means for adjusting the position of said bolt with respect to said sleeve to establish a relative adjustment therebetween and said bearing means comprises at least one bearing carried by said sleeve in rolling engagement with said ring gear thereby imparting to said ring gear a supporting force that locates the axial disposition of said regenerator with respect to said housing.

3. The combination of claim 2 wherein said sleeve carries two bearing rollers, one roller being situated on either axial side of said ring gear in rolling engagement therewith.

4. The combination as set forth in claim 2 wherein: said ring gear comprises a peripheral groove, a roller situated in said groove, the peripheral margin of said roller being adapted to engage the axial side of said groove, said roller being carried by said sleeve shaft for rotation about an axis that is transverse of the axis of rotation of said regenerator.

5. The combination as set forth in claim 1 whereas: said rim has a peripheral spring ring positioned about its periphery, said spring frictionally engaging the outer surface of said rim and the inner surface of the surrounding ring gear whereby the latter is frictionally and yieldably connected to said rim, said spring being in the form of a strip having alternately formed sections that apply radial forces to said rim and to said ring gear to establish a frictional driving connection therebetween.

6. The combination as set forth in claim 2 wherein: said rim has a peripheral spring ring positioned about its periphery, said spring frictionally engaging the outer surface of said rim and the inner surface of the surrounding ring gear whereby the latter is frictionally and yieldably connected to said n'm, said spring being in the form of a strip having alternately formed sections that apply radial forces to said rim and to said ring gear to establish a frictional driving connection therebetween.

8. The combination as set forth in claim 4 wherein: said rim has a peripheral spring ring positioned about its periphery, said spring frictionally engaging the outer surface of said rim and the inner surface of the surrounding ring gear whereby the latter is frictionally and yieldablyconnectedto said rim, said spring being in the form of a strip having alternately formed sections that apply radial forces to said rim and to said ring gear to establish a frictional driving connection therebetween.

9. The combination as set forth in claim 5 wherein: a yieldable heat resisting cushion is located between said spring and said regenerator rim whereby forces distributed between said ring gear and said rim are cushioned thereby avoiding undesirable shock loads and maintaining the adjusted position established by adjusting said adjustable member.

10. The combination as set forth in claim 6 wherein: a yieldable heat resisting cushion is located between said spring and said regenerator rim whereby forces distributed between said ring gear and said rim are cushioned thereby avoiding undesirable shock loads and maintaining the adjusted position established by adjusting said adjustable member.

11. The combination as set forth in claim 7 wherein: a yieldable heat resisting cushion is located between said spring and said regenerator rim whereby forces distributed between said ring gear and said rim are cushioned thereby avoiding undesirable shock loads distributed between said ring gear and said rim are cushioned thereby avoiding undesirable shock loads and maintaining the adjusted position established by adjusting said adjustable member.

UNITED STATES PATENT OFFICE r CERTIFICATE OF CORRECTION PATENT NO. 3 ,8u8,66 DATED 7: November 19, 197A INVENTOR(S) V- Dur'ga Nageswar' Rao It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: I

Column l line 2 1, canc el "hub" and substitute -1"im--,

Signed and sealed this 1st day of July 1.975.

(SEAL) Attest C. ILXRSHALL DANN Commissioner of Patents and Trademarks RUTH C. I-IA5ON Attesting Officer

Claims

1. A regenerator assembly for a gas turbine engine comprising a rotary regenerator core mounted within a gas turbine engine, said assembly comprising a ceramic matrix adapted to conduct a counterflow of hot and cool gases under differential pressures, a matrix rim surrounding the regenerator matrix, a ring gear surrounding the rim, a means for yieldably mounting the ring gear concentrically around the rim, an adjustable member situated adjacent the ring gear and mounted on portions of said housing for shifting movement in a direction generally parallel to the axis of rotation of said regenerator matrix, bearing means carried by the adjustable member for positioning said rim relative to said adjustable member, means for yieldably maintaining said adjustable member in its adjusted position whereby the axial position of said regenerator matrix with respect to the engine housing and the direction of the axis of rotation of said matrix may be controlled.

6. The combination as set forth in claim 2 wherein: said rim has a peripheral spring ring positioned about its periphery, said spring frictionally engaging the outer surface of said rim and the inner surface of the surrounding ring gear whereby the latter is frictionally and yieldably connected to said rim, said spring being in the form of a strip having alternately formed sections that apply radial forces to said rim and to said ring gear to establish a frictional driving connection therebetween.

7. The combination as set forth in claim 3 wherein: said rim has a peripheral spring ring positioned about its periphery, said spring frictionally engaging the outer surface of said rim and the inner surface of the surrounding ring gear whereby the latter is frictionally and yieldably connected to said rim, said spring being in the form of a strip having alternately formed sections that apply radial forces to said rim and to said ring gear to establish a frictional driving connection therebetween.

8. The combination as set forth in claim 4 wherein: said rim has a peripheral spring ring posItioned about its periphery, said spring frictionally engaging the outer surface of said rim and the inner surface of the surrounding ring gear whereby the latter is frictionally and yieldably connected to said rim, said spring being in the form of a strip having alternately formed sections that apply radial forces to said rim and to said ring gear to establish a frictional driving connection therebetween.

11. The combination as set forth in claim 7 wherein: a yieldable heat resisting cushion is located between said spring and said regenerator rim whereby forces distributed between said ring gear and said rim are cushioned thereby avoiding undesirable shock loads and maintaining the adjusted position established by adjusting said adjustable member.

12. The combination as set forth in claim 8 wherein: a yieldable heat resisting cushion is located between said spring and said regenerator rim whereby forces distributed between said ring gear and said rim are cushioned thereby avoiding undesirable shock loads and maintaining the adjusted position established by adjusting said adjustable member.