JPS6048617B2 - Bearing cooling method and device in gas turbine engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for cooling and thermally insulating bearings located close to the combustion zone of a gas turbine engine.

Components located within or near the gas turbine engine area must be thermally insulated for continued operation.

This invention relates to a method for cooling a bearing of a compressor gas turbine, and the bearing has a turbine structure (i.e., split shaft type).
Because of this, it is located close to the area in the turbine where combustion occurs. Bearings in this area have traditionally been cooled by directing cooling air from an intermediate stage of the compressor to the bearings to be cooled. A problem that has arisen in the past has been the excessive heating of the cooling air during passage through the combustor area, resulting in poor bearing cooling due to inadequate or insufficient air flow over the bearing surfaces. be. Cooling air is directed to the compressor shaft to cool the bearings located in the hot area,
Many of the problems associated with shafts with flow channels are avoided by this invention.

Any cooling air directed into the area of the bearing in question must be removed therefrom by suitable equipment, and the removal of such cooling air shall be carried out with as little disturbance to the operation of the machine as possible. It should be noted that The present invention relates to a method for cooling bearings located in the compressor section of a gas turbine.

Cooling of the bearing is important because of its location close to the combustion stage of the turbine. The bearing is configured to allow cooling air to pass therethrough and, in particular, includes a pair of annular spaces through which the cooling air is moved to remove heat from the surface of the bearing.
A coaxial tube arrangement effectively directs air into the heat exchange space within the bearing, and the same tube arrangement directs the heated air away from the bearing through the cylindrical space between the outer and inner tubes. lead.

Since the tube system must pass through a very hot part of the turbine, i.e. the combustion stage, a coaxial air arrangement is advantageous in that the inner tubes, which carry cooler air to the bearings, are diverted from the heat of the combustion zone by the outer tubes. It works most effectively because it insulates effectively. Excess heat gained by the outer tube is carried away to the atmosphere, so that minimal excess heat taken up by the coaxial outer tube is transferred to the inner tube. This tends to have a minimized effect on turbine operation. In the following, the invention will be explained with reference to the drawings.

In FIG. 1, a ``dual shaft'' or ``split shaft'' turbine 10 is shown having an output shaft 12 and a compressor shaft 14. The output shaft 12 is supported by bearings 16 and 18, and the compressor shaft 14 is supported by bearings 20 and 22. Power for driving the compressor portion of the compressor turbine is provided by vanes 24 . A power vane 26 is provided to drive the output shaft 12 to provide power to the load. Since the operation of turbine equipment is well understood by those skilled in the art, only a brief description of the turbine will be provided.

Air is supplied to intake chamber 30 and then directed to compression stage 32 where it is compressed.

When the air passes through the final blade of the compression stage, it is between 6.5 and 7k9
A pressure of Ic71f (90-100 psi) is reached. The compressed air is then led through the outlet 34 o into the combustion chamber 36 of the turbine. Turbine fuel is in basket 38
The compressed air enters the inlet 37 of the basket 38 and enters the passage 4 of the basket 38.
0, where it is mixed with atomized fuel and then combusted. The hot combustion gases pass through the basket exit log 42 and through a set of guide vanes 44 . The gas then passes through the power vanes 24 to drive the compressor section, and the gas is then discharged into another set of fixed vanes 46. It will be seen that a set of movable wings 48 are shown cooperating with fixed wings 46.

The movable J wing 48 includes an actuator 50 that allows the small angle movable wing to pivot to change the direction of gas passing through the movable wing. The redirected hot gases then pass through vanes 26, which drive output shaft 12 to provide output power from the turbine. The hot discharge gas then passes through the discharge differential user 52 and into the discharge chamber 53 where it is conducted to the atmosphere or passes through a heat exchanger for regeneration. Before proceeding further, it may be convenient to describe some of the mechanical components associated with bearing 20 according to the present invention.

The bearing 20 is of the Kingsbury (trademark) type and includes a number of bearing buds 2 that match the bearing surface of the shaft 14.
0'.

The bearing pads 20' are mounted within the bearing housing member 60 so as to transmit supporting forces to the housing member 60 at points 62' (FIG. 3), one of which is shown. 1
A pair of bearing retaining rings 64 are attached to the butt 20' with dowels 66.
is provided to hold it in its proper position.

Oil grooves 68 are provided in housing member 60 for lubrication. Housing member 60 is secured within bearing case 70 by dowels or any other suitable locking member.

The bearing case 70 includes a pair of annular members 72 integrally formed.
, 74. Attached to the annular members 72, 74 are labyrinth closures 76, 78 in closely spaced relationship with the shaft 14. The bearing case 70 has an internal air passage 80 that includes a pair of annular spaces 8
2,84. The outer portion of the integrally formed bearing case 70, designated by reference numeral 86 for convenience, is cylindrical and has a pair of annular portions 88 and 90 integrally formed. The annular portions 88 and 90 are labyrinth type sealing devices 92
, 94 are attached. The outer part 86 has a bolt 91 (
The two parts 86, 89, which are fixed and bolted to the lower part 8.9 (FIG. 3), are fixed to the outer case 100 by any suitable device. Outer case 100 is also made in half for manufacturing and assembly reasons and is mechanically connected to member 102 by bolt 101' and to member 110 by bolt 103 to secure bearing 20 in place. In addition to stating that the outer portion 86 of the bearing case 70 should be held firmly in place by the outer case 100 that is attached, it is important to mention the mechanical hardware that holds the outer portion 86. It is. Bearing case 70
The outer portion 86 of the bolt 8 includes an aperture 120 that allows the bolt 8 to
It communicates with an opening in a hollow flange 122 attached to the outer portion 86 at 7 .

A tube 124 is sealed and fitted into flange 122. Outer case 100 similarly includes an opening 126 that communicates with an opening in hollow flange 128 .

Bolts 10,1 secure the flange 128 to the outer case 100. Tube 130 is sealed to flange 128
The tube 130 is mounted concentrically and coaxially with the tube 124 . The method for cooling the bearing 20 is as follows.

A device is provided in the housing 200 for removing a portion of the compressed air from the intermediate stage of the compressor. A suitable outlet hole 202 supplies compressed air to the housing 200. A suitable conduit housing 200 is provided between the inlet tube 124 to direct compressed air from the housing to the flange 122.
Compressed air enters the passage 80 through the openings 12 and into the annular spaces 2, 84. A portion of the compressed air enters the bearing arrangement through labyrinth-type closures 76, 78 and exits the bearing through an oil discharge tube (not shown). Most of the compressed air in the annular spaces 82, 84 enters the spaces 93, 95 through labyrinth-type closures 92, 94. Air from the annular space 93 passes through a group of holes 97 to the collection space 9
9, the air in space 95 is directed directly into space 99, from where it enters flange 128 and is conducted through tube 130 to the atmosphere or to a suitable heat sink device. It can be easily seen that the compressed air introduced into the bearing via tube 124 is now largely surrounded by the bearing cases 70, 86 to present a thermal barrier into the bearing 20.

Coaxial inner tube 124 and outer tube 130 in concentric relationship
It will be seen that this provides additional advantages.

Because of the need to direct cooling air through the combustion chamber 36, the outer tube 130 is exposed to very high temperatures. The coaxial arrangement of the tubes allows tube 130 and the cooling air passing therethrough to act as an insulator for tube 124. This is the inner tube 124
is meant to bring cooler air into the bearing case 70 than if the outer tube 130 were not in a coaxial relationship therewith. A coaxial tube arrangement also means that both the inlet and outlet tubes are in the same location, and instead of using two separate tubes, one for the inlet and the other for the outlet, the solution saves extra space due to this arrangement. The mechanical structure of the turbine is simplified since it requires space and creates undue complexity.

Although other methods are known for thermally insulating bearings that have to operate in high-temperature areas, the method according to the invention is superior in its performance and is relatively simple in mechanical construction. Believable.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a part of a gas turbine engine to which the present invention can be applied, Fig. 2 is a partial sectional view of a compressor bearing, and Fig. 3 is a line taken along the line in Fig. 2. cross-sectional view along
FIG. 4 is a partially cutaway perspective view of the compressor bearing according to the present invention. 10... Turbine, 12... Output shaft, 14... Compressor shaft, 16, 18, 20, 22... Bearing, 24...
・Power wing, 26... Wing, 30... Intake chamber, 32...
・Compression stage, 3F 4...Outlet, 36...Combustion chamber, 3
8... Basket, 37... Entrance, 40... Passage, 42... Basket exit, 44... Guide wing, 46
...Fixed wing, 48... Movable wing, 50... Actuator,
52...Discharge differential user, 20'...Bearing pad,
6? ...bearing housing member, 62...point, 64
... Bearing retaining ring, 66 ... Dowel, 68 ... Oil groove, 70 ... Bearing case, 72, 74 ... Annular member,
76, 78, 92, 94... Labyrinth type sealing device,
80... Air passage, 82, 84... Annular space, 8
6... Bearing case outer part, 88, 90... Annular part,
91, 101, 103... Bolt, 100... Outer case, 120... Opening, 122... Flange, 1
24...Inner tube, 126...Opening, 128...Flange, 130...Outer tube, 200 Housing.

Claims (1)

[Scope of Claims] 1. Compressed air is taken from the intermediate stage of the compressor section of the engine, and the compressed air is passed through the turbine outer case to the bearing casing 70.
compressed air is circulated through a pair of annular spaces 82, 84 in the bearing casing 70 where the air is heated and superheated. The heated air is collected from the annular spaces 82, 84 into the central collection space 99, and the heated air is passed from the central collection space 99 through the passage between the inner and outer tubes of the pair of coaxial tubes 124, 130. A method of cooling bearings in a gas turbine engine, consisting of removing the exterior of the turbine to its original position. 2 A set of bearing pads 20 that support the turbine shaft 14 are mounted inside, and the following pair of separate flow paths 80, 82, 84 are provided.
; a bearing casing 70 having 93, 95, 97 therein; and an annular space 82, 8 within this bearing casing 70;
a first flow path 80, 82 for distributing cooling air to 4;
84 and a second flow path 93, 95, 97 for collecting heated air through the annular spaces 82, 84, and between the annular spaces 82, 84 and the second flow paths 93, 95, 97. venting devices 92, 94 for allowing heated air to pass through to second channels 93, 95, 97, the first channels 80, 82, 84 of the pair of channels being connected to the inner tube 124 and a pair of coaxial tubes 124, 130 such that the second channels 93, 95, 97 communicate with the space between the outer tube 130 and the inner tube 124 of the coaxial tubes 124, 130. Bearing cooling system of gas turbine engine connected to.