US2554368A

US2554368A - Turbine rotor cooling

Info

Publication number: US2554368A
Application number: US550887A
Authority: US
Inventors: Walter A Ledwith
Original assignee: United Aircraft Corp
Current assignee: Raytheon Technologies Corp
Priority date: 1944-08-23
Filing date: 1944-08-23
Publication date: 1951-05-22
Anticipated expiration: 1968-05-22

Description

May 22, 1951 Filed Aug. 23, 1944 W. A. LEDWITH TURBINE ROTOR COOLING UN D01 2 Sheets-Sheet 1 FIG.

INVENTOR May 22, 1951 w. A. LEDWITH TURBINE ROTOR COOLING 2 Sheets-Sheet 2 Filed Aug. 23, 1944 m: om.

mm mm \vm mm N0 m0 #9 ww INVENTOR Patented May 2 2, 1 951 TURBINE ROTOR COOLING Walter A. Ledwith, Hartford, Conn., assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application August 23, 1944, Serial No. 550,887

9 Claims.

This invention relates to internally cooling the rotor of a turbine.

Cooling chambers have been placed in turbine rotors adjacent to the supporting bearings to limit heat transfer to the bearings. Since one end of the turbine rotor is generally connected to the mechanism driven by the turbine, circulation of cooling fluid into the turbine rotor at this end is diflicult. If the coolant is pumped into the rotor through collector rings an extremely high pressure is required to force the coolant into the rotor against the centrifugal force resulting from the high rotational speed. An object of this invention is to overcome these objections by circulating the coolant through chambers adjacent both ends of the turbine rotor from a single coolant inlet at one end of the rotor.

In turbines driven by hot gases, circulation of coolant through the power section of the rotor has been avoided because the high temperature of the power section may produce undesirable changes in the coolant. A feature of this invention resides in directing coolant through the power section of the rotor without direct contact with its hottest parts.

A feaure of this invention is the proportioning of the coolant between the chambers in the rotor to assure adequate cooling in both chambers.

Another feature is the circulation of coolant through substantially the entire length of the turbine rotor so that coolant admitted at one end will circulate through a chamber adjacent the other end.

Other objects and advantages will be apparent from the specification and claims and from the accompanying drawing which illustrates an embodiment of the invention.

Fig. 1 is a sectional view through the turbine.

Fig. 2 is a sectional view on a larger scale through the central part of the turbine rotor.

The turbine shown includes a casing built up of rings I2, I 6, l6 and [8 supported by radial pins 29 in a housing 22. These pins which are all in substantially the same plane and which constitute the support for the casing within the housing engage bores at bosses 24 in one ring it of the casing. Rotor 26 within the casing has a number of rows of blades 28 alternating with the rows of nozzles 30 in the casing.

Housing 22 has a head 34 which forms a part of the housing and supports a bearing sleeve 36 for the front end of rotor 26. At the other end of the turbine, the housing 22 supports a mounting 38 within which is a bearing 4i! of the shaft. The mounting has a number of legs 42 engaging radial pins 44 in the housing.

Rotor 26 is made up of a number of discs 46, 48, 5E8 and 52, each of which is substantially a constant stress disc, and shaft forming

end elements

54 and 56. The discs and the end elements are all held together by a central bolt 58. The ends of the bolt are positioned within the

end elements

54 and 56 and are connected to the end elements by threaded

rings

60 and 62. Each of the

rings

60 and 62 has inner and outer threads engaging respectively with coopcrating threads on the bolt and on the end elements. On one of the rings the inner and outer threads may differ in pitch so that as the ring is screwed into place, a substantial tension may be applied to the bolt.

Since the casing is built up of casing rings bolted together and since the rotor is built up of discs, it is apparent that the turbine is adapted for endwise assembly. To assist in aligning the discs, each disc may have projecting annular flanges on opposite sides having interengaging elements preferably in the form of face splines cooperating with similar elements on the adjoining disc. Similarly, the inner ends of the

shaft elements

54 and 56 may have face splines cooperating with splineson the end discs.

Gas enters the first stage nozzles of the turbine through an inlet scroll ill which is bolted on or otherwise attached to the end of casing Iii. Gas from the turbine discharges through a duct 12 connected to the end casing ring and surrounding the rear bearing mounting.

Coolant is admitted to the rearward end of the rotor through a tube 14 mounted in one of the projecting legs 42 of the bearing mounting 38 and connecting with a passage 56 in bearing 40. A cap 18 on the bearing mounting has a connecting passage by which coolant from passage 16 is guided to a tube 82 extending through a cap 84 on the .end of the central bolt. Coolant enters at the axis of the rotor and does not have to be pumped against centrifugal forces.

The bolt has radial passages $6 adjacent its rearward end which communicate with a chamber 88 within the rotor permitting coolant to flow through this chamber and discharge through one or more grooves 98 in the end element 56. Similarly, at the forward end of the bolt radial passages 92 permit coolant to flow through a chamber 94 Within the end element passage in the rotor packing I04 in end element 56 may be held in.

place by sleeves I05 and I98 which'may be"integral with

sleeves

60 and 62. respectively. These sleeves have passages :I'lfi and H2 toipermit a flow of coolant from inside to outside :of the sleeve.

In order that the coolant as it'passes through the power section of the turbine rotor {shall snot be overheated a tube I I4 is placed within the hollow bolt and is held in spaced relation to the inner surface of the bolt by projectingribs l-IB on the tube. At opposite ends of the tube the joint between the tube and bolt is made tight by seals or packing H8 which may be held in place by rings [28 on the ends of the tube. This packing assists in holding the tube in spaced relation to the bolt. A part of the coolant entering the rearward end of the turbine rotor flows through the tube to reach the passages 92 at the forward end of the rotor. is smaller than the inlet tube 82 to provide for The dimension of passage 86 .proportioning the distribution of the coolant between the two cooling chambers. It will be understood that the tube may be omitted if .it .is found that the bolt does not become too hot during turbine operation.

Although the invention has been described in connection with a built-up turbine rotor it is applicable as well to a solid rotor of the type shown in the co-pending application of Ledwith,

Serial No. 486,620, filed May 11, 1943, now Patent No. 2,415,104. The turbine rotor in either event constitutes a rotating shaft, access to one end of which is diflicult. Coolant is circulated through I a chamber adjacent one end of the shaft or rotor by causing it to flow through an axial passage in the rotor from the opposite end to which coolant maybe admitted centrally of the shaft axis.

It is 'to be understood that the invention is ,not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. In a turbine, a rotor having a power section with at least one row of blades extending therefrom, axially spaced chambers adjacent opposite ends of the rotors, and lmeans for directing fluid to all of the chambers from one end of the rotor, said means including an axial extending through the power section and interconnecting the chambers,

a conduit for the fluid within and spaced from the walls of said passage and interconnecting the chambers, and sealing means around the conduit to keep the fluid out of the space surrounding the conduit.

2. In a turbine, a rotor having a power section with at least one row of blades, spaced chambers located at opposite ends of the rotor, spaced bearings for the rotor located adjacent to said chambers, and means for directing fluid to both of the chambers from one end of the rotor, said means including an axial passage in the rotor extending through the power section and interconnecting the chambers, a conduit for the fluid Within and spaced from the walls of said passage and interconnecting the chambers, and sealing means around the conduit to keep the fluid out of the space surrounding the conduit.

3. In -a turbine, a rotor having a power section with at least one row .of blades and a shaft extension at each end of the power section, each shaft extension having a chamber therein, a bearing surrounding each shaft extension and located adjacent to the chamber in each of said "shaftextensionsgmeans for directing coolant to .bothichambers :from one end of the rotor, said means "including .a passage in said rotor extending between and interconnecting said chambers, and "a conduit within and spaced from the walls of the passage and through which the coolant flows out of contact with the walls of the passage, and passages extending through each shaft extension and communicating with the adjacent chamber through which the coolant in the chambers may be discharged from the rotor.

4. .In a turbine, a rotor having a power section with at least one row of blades and a shaft extension at. each end of .the power section, each shaft extension having a chamber therein, a bearing surrounding each shaft extension and located adjacent to the chamber in each of said shaft extensions, means for directing coolant -to both chambers from one end of the rotor, said means including a passage in said .rotor extending between and interconnecting said chambers, a conduit within and spaced from the walls of the passage between the chambers through which the coolant flows, and sealing means around the conduit to keep the fluid out of the spacesurrounding the conduit.

5. In a turbine, a .rotor having .a power section and a shaft extension. at each end-of the power section, each shaft extension having a chamber therein, a bearing adjacent each chamher and surrounding each shaft extension, means for directing coolant to one of the chambers through the adjacent end of the rotor, a passage in said rotor connecting the chambers and a conduit within and spaced from 'the walls of the passage for flow of coolant from said one chamber to the other chamber without contacting the passage walls, and passages in the rotor adjacent each end and communicating with each of said chambers for the escape of coolant therefrom.

6. In a shaft, a chamber adjacent one rendfa passage from said chamber to the other end of the shaft, means for directing fluid through said passage to said chamber, said means including a tube within and spaced from the walls of the passage, sealing .means around the tube to keep fluid out of the space surrounding the tube, and a discharge passage extending radially of the shaft adjacent to said chamber for the escape of fluid.

7. In a shaft, a chamber adjacent one end, a passage from said chamber to. the other end of the shaft, a bearing surrounding said shaft adjacent to the chamber, and .means for directing fluid from said other end of the shaft to .said chamber including a tube within and spaced from the walls of the passage, sealing means around the tube to keep fluid out of the space surrounding the tube, and a discharge passage extending radially of the shaft adjacent to said chamber for the escape of fluid.

8. In a turbine rotor, a chamber adjacent one end, a passage through said rotor from said chamber to the other end, a bearing surrounding said rotor adjacent to said chamber, and means for directing coolant to said chamber from said other end of the rotor, said means including a tube within and spaced from the walls of the passage and extending from said chamher to said other end of the rotor, sealing means around the tube to keep fluid out of the space surrounding the tube, and a discharge passage extending radially of the rotor adjacent to said chamber for the escape of fluid.

9. In a turbine rotor, chamber adjacent one end, a passage through said rotor fromsaid chamber to the other end, a bearing surrounding said rotor adjacent to said chamber, and means for directing coolant to said chamber from said other end of the rotor, said means including a tube within and spaced from the walls of the passage and extending from said chamber to said other end of the rotor, sealing means around the tube to keep fluid out of the space surrounding the tube, said tube tapering toward said one end of the rotor, and a discharge passage extending radially of the rotor adjacent to said chamber for the escape of fluid.

WALTER A. LEDWITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,421,087 Johnson June 27, 1922 1,653,217 Koch Dem-'20, 1927 10 1,820,725 Bailey Aug. 25', 1931 1,828,782 Morton Oct. 27, 1931 1,938,688 Brook Dec. 12, 1933 2,073,605 Belluzo Mar. 16, 1937 2,241,782 Jendrassik May 13', 1941 2,339,779 Holzwarth Jan. 25, 1944 2,369,795 Planiol Feb. 20, 1945 2,461,239 Schuster Feb. 8, 1949 FOREIGN PATENTS 20 Number Country Date 381,899 Great Britain Oct. 13, 1932 506,479 Great Britain May 30, 1939 567,576 Germany Jan. 5, 1933