U.S. patent application number 15/387407 was filed with the patent office on 2017-07-20 for combustion chamber arrangement.
This patent application is currently assigned to ROLLS-ROYCE plc. The applicant listed for this patent is ROLLS-ROYCE plc. Invention is credited to Hua Wei HUANG, Carl L MULDAL, Luca TENTORIO.
Application Number | 20170205069 15/387407 |
Document ID | / |
Family ID | 55488010 |
Filed Date | 2017-07-20 |
United States Patent
Application |
20170205069 |
Kind Code |
A1 |
TENTORIO; Luca ; et
al. |
July 20, 2017 |
COMBUSTION CHAMBER ARRANGEMENT
Abstract
A combustion chamber arrangement including an outer annular wall
and an inner annular wall spaced from the outer annular wall. The
inner annular wall includes a plurality of tiles. At least one of
the tiles is secured to the outer annular wall by at least one stud
and a cooperating nut. Each stud includes a head and a threaded
portion extending from the head. The threaded portions extend
through an aperture in the tile and an aperture in the outer
annular wall. The head includes a plurality of spacers to space the
head from an inner surface of the tile. An associated washer either
has an aperture extending radially there-through or a slot
extending radially along one of the surfaces of the washer to
supply coolant over the stud or the space between the inner annular
wall and the outer annular wall is arranged to supply coolant over
the stud.
Inventors: |
TENTORIO; Luca; (Derby,
GB) ; HUANG; Hua Wei; (Derby, GB) ; MULDAL;
Carl L; (Derby, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROLLS-ROYCE plc |
London |
|
GB |
|
|
Assignee: |
ROLLS-ROYCE plc
London
GB
|
Family ID: |
55488010 |
Appl. No.: |
15/387407 |
Filed: |
December 21, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R 3/007 20130101;
F23R 3/002 20130101; F23R 3/60 20130101; F23R 3/16 20130101; F23R
3/005 20130101 |
International
Class: |
F23R 3/00 20060101
F23R003/00; F23R 3/16 20060101 F23R003/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2016 |
GB |
1600760.1 |
Claims
1. A combustion chamber arrangement comprising an outer annular
wall and an inner annular wall spaced from the outer annular wall,
the inner annular wall comprising a plurality of tiles, at least
one of the tiles being secured to the outer annular wall by at
least one stud and a cooperating nut, the at least one stud
comprising a head and a threaded portion extending from the head,
the threaded portion of the at least one stud extending through an
aperture in the at least one tile and an aperture in the outer
annular wall, wherein the head comprising a plurality of spacers to
space the head from an inner surface of the at least one tile, the
spacers being circumferentially spaced around the head of the stud,
the head, the threaded portion and the spacers of the at least one
stud being integral.
2. A combustion chamber as claimed in claim 1 wherein each tile is
secured to the outer annular wall by at least one stud and a
cooperating nut, the at least one stud of each tile comprising a
head and a threaded portion extending from the head, the threaded
portion of the at least one stud extending through an aperture in
the at least one tile and an aperture in the outer annular wall,
wherein the head of the at least one stud of each tile comprising a
plurality of spacers to space the head from the inner surface of
the respective tile, the spacers being circumferentially spaced
around the head of the stud of each tile, the head, the threaded
portion and the spacers of the at least one stud of each tile being
integral.
3. A combustion chamber as claimed in claim 2 wherein each tile has
a plurality of studs, each stud having a cooperating nut, each stud
comprising a head and a threaded portion extending from the head,
the threaded portion of each stud extending through a respective
aperture in the at least one tile and a respective aperture in the
outer annular wall, wherein the head of each stud comprising a
plurality of spacers to space the head from the inner surface of
the at least one tile the spacers being circumferentially spaced
around the head of each stud, the head, the threaded portion and
the spacers of each stud being integral.
4. A combustion chamber as claimed in claim 1 wherein the head of
the at least one stud locates in a corresponding recess in the tile
and the plurality of spacers space the head from the inner surface
of the recess of the tile.
5. A combustion chamber as claimed in claim 4 wherein the surface
of the head of the stud remote from the threaded portion is
arranged flush with the inner surface of the tile.
6. A combustion chamber as claimed in claim 4 wherein an outer
surface of the recess of the tile abuts an inner surface of the
outer annular wall.
7. A combustion chamber as claimed in claim 1 wherein the spacers
are cylindrical in cross-section or the spacers are rectangular in
cross-section.
8. A combustion chamber as claimed in claim 7 wherein two of the
sides of each rectangular cross-section spacers are arranged
parallel to corresponding sides of the other rectangular
cross-section spacers.
9. A combustion chamber as claimed in claim 1 wherein two of the
sides of each spacer extend radially with respect to the stud to
define a plurality of radially extending passages.
10. A combustion chamber arrangement comprising an outer annular
wall and an inner annular wall spaced from the outer annular wall,
the inner annular wall comprising a plurality of tiles, at least
one of the tiles being secured to the outer annular wall by at
least one stud and a cooperating nut, the at least one stud
comprising a head and a threaded portion extending from the head,
the threaded portion of the at least one stud extending through an
aperture in the at least one tile and an aperture in the outer
annular wall, wherein the head comprising a plurality of spacers to
space the head from an inner surface of the at least one tile, the
spacers being circumferentially spaced around the head of the stud,
the head, the threaded portion and the spacers of the at least one
stud being integral, there are five spacers, a second spacer is
angularly spaced apart from a first spacer by a first angle, a
third spacer is angularly spaced apart from the second spacer by a
second angle, a fourth spacer is angularly spaced apart from the
third spacer by a third angle, a fifth spacer is angularly spaced
apart from the fourth spacer by a fourth angle and the first spacer
is angularly spaced apart from the fifth spacer by a fifth
angle.
11. A combustion chamber as claimed in claim 10 wherein the first
angle is greater than the second angle, the second angle is less
than the third angle, the third angle is equal to the fourth angle,
the fifth angle is less than the fourth angle and the first angle
is greater than the fifth angle.
12. A combustion chamber as claimed in claim 10 wherein a middle of
the fourth spacer and a middle of the first angle are arranged
diametrically opposite each other.
13. A combustion chamber as claimed in claim 12 wherein the middle
of the fourth spacer and the middle of the first angle are arranged
parallel to the axis of the annular outer wall.
14. A combustion chamber as claimed in claim 12 wherein the middle
of the first angle is arranged axially upstream of the middle of
the fourth spacer.
15. A combustion chamber as claimed in claim 1 wherein the spacers
are arcuate in cross-section and each spacer comprises a convex
surface and a concave surface.
16. A combustion chamber arrangement comprising an outer annular
wall and an inner annular wall spaced from the outer annular wall,
the inner annular wall comprising a plurality of tiles, at least
one of the tiles being secured to the outer annular wall by at
least one stud and a cooperating nut, the at least one stud
comprising a head and a threaded portion extending from the head,
the threaded portion of the at least one stud extending through an
aperture in the at least one tile and an aperture in the outer
annular wall, wherein the head comprising a plurality of spacers to
space the head from an inner surface of the at least one tile, the
spacers being circumferentially spaced around the head of the stud,
the head, the threaded portion and the spacers of the at least one
stud being integral, there are six spacers, the spacers are arcuate
in cross-section and each spacer comprises a convex surface and a
concave surface, wherein a second spacer is angularly spaced apart
from a first spacer by a first angle, a third spacer is angularly
spaced apart from the second spacer by a second angle, a fourth
spacer is angularly spaced apart from the third spacer by a third
angle, a fifth spacer is angularly spaced apart from the fourth
spacer by a fourth angle, a sixth spacer is angularly spaced apart
from the fifth spacer by a fifth angle and the first spacer is
angularly spaced apart from the sixth spacer by a sixth angle.
17. A combustion chamber as claimed in claim 16 wherein the first
angle is greater than the second angle, the second angle is less
than the third angle, the third angle is less than the fourth
angle, the fifth angle is less than the fourth angle, the sixth
angle is less than the fifth angle and the first angle is greater
than the sixth angle.
18. A combustion chamber as claimed in claim 16 wherein a middle of
the first angle and a middle of the fourth angle are arranged
diametrically opposite each other.
19. A combustion chamber as claimed in claim 18 wherein the middle
of the first angle and the middle of the fourth angle are arranged
parallel to the axis of the annular outer wall.
20. A combustion chamber as claimed in claim 18 wherein the middle
of the first angle is arranged axially upstream of the middle of
the fourth angle.
21. A combustion chamber as claimed in claim 16 wherein the concave
surface of the first spacer faces the concave surface of the second
spacer, the convex surface of the second spacer faces the concave
surface of the third spacer, the convex surface of the third spacer
faces the convex surface of the fourth spacer, the concave surface
of the fourth spacer faces the concave surface of the fifth spacer,
the convex surface of the fifth spacer faces the convex surface of
the sixth spacer and the concave surface of the sixth spacer faces
the convex surface of the first spacer.
22. A combustion chamber as claimed in claim 1 wherein there is an
even number of spacers and two adjacent spacers at a first radial
side of the head being arranged further circumferentially apart
than two adjacent spacers at a second opposite radial side of the
head
23. A combustion chamber as claimed in claim 1 wherein there is an
odd number of spacers and the middle of a spacer at a first radial
side of the head and the middle of an angle between two adjacent
spacers at a second opposite radial side of the head being arranged
diametrically opposite each other.
24. A combustion chamber as claimed in claim 1 wherein the spacers
are equi-circumferentially spaced around the head of the stud.
25. A combustion chamber as claimed in claim 1 wherein the at least
one tile is manufactured by a method selected from the group
consisting of casting and additive layer manufacturing, the at
least one tile comprises a superalloy selected from the group
consisting of a nickel based superalloy, a cobalt based superalloy
and an iron based superalloy.
26. A combustion chamber as claimed in claim 1 wherein the at least
one stud is manufactured by additive layer manufacturing, the at
least one stud comprises a superalloy selected from the group
consisting of a nickel based superalloy, a cobalt based superalloy
and an iron based superalloy.
27. A combustion chamber as claimed in claim 1 wherein the at least
one stud comprises a different material to the at least one tile
and the at least one stud comprises a material with higher
temperature capability than the material of the tile.
Description
[0001] The present disclosure concerns a combustion chamber
arrangement and in particular to a dual wall combustion chamber
arrangement including an inner wall comprising a plurality of
tiles.
[0002] One known combustion chamber arrangement is a dual wall
combustion chamber arrangement including an outer annular wall and
an inner annular wall in which the inner annular wall comprises a
plurality of combustion chamber tiles. The combustion chamber tiles
have studs which are formed integrally with the combustion chamber
tile during the manufacturing process, e.g. casting. Each stud has
a threaded portion which extends through a corresponding aperture
in the outer annular wall and a corresponding washer and nut are
located on the stud to secure the tile to the outer annular wall.
The combustion chamber tiles of the inner annular wall protect the
outer annular wall from hot combustion gases.
[0003] The ends of the studs adjacent to each combustion chamber
tile are exposed to the hot combustion gases due to thermal
conduction from the inner surfaces of the combustion chamber
tile.
[0004] The studs of the combustion chamber tiles may be cooled by
directing coolant through impingement cooling apertures in the
outer wall at the base of the studs. The studs of the combustion
chamber tiles may also be cooled by providing effusion cooling
apertures through the combustion chamber tiles to provide a film of
coolant on the hot side of the combustion chamber tiles and on the
hot side of the combustion chamber tile adjacent and over the ends
of the studs.
[0005] If the combustion chamber tiles are manufactured by casting,
it is difficult to control the position of the integral studs on
the combustion chamber tiles. Furthermore, it is difficult to cool
the hot side of the combustion chamber tiles in the vicinity of the
studs due to the difficulty in laser drilling the effusion cooling
apertures. Laser drilling the effusion cooling apertures involves
drilling the apertures from the hot side of the combustion chamber
tile and thus the laser beam will strike and damage any structure
in the path of the laser beam at the cold side of the combustion
chamber tile. If a stud is struck by the laser beam it will damage
the stud and may cause the stud to fail in operation. Thus, this
may result in the use of different patterns of effusion cooling
apertures at different regions of the combustion chamber tiles,
e.g. the effusion cooling apertures are angled at different angles
in the different regions, rather than a single uniform pattern of
effusion cooling apertures in the combustion chamber tiles. In
order to avoid damage to the studs there is a zone around each stud
where no cooling apertures are laser drilled. If the combustion
chamber tiles are manufactured by additive layer manufacturing,
e.g. laser powder bed, then either a large number of combustion
chamber tiles may be built vertically in parallel at one time or a
much smaller number of combustion chamber tiles may be built
horizontally in parallel at one time. The former method maximises
the number of combustion chamber tiles produced at one time and
hence minimises the cost per combustion chamber tile but the studs
do not have acceptable quality. The latter method produces studs
with acceptable quality but the cost per combustion chamber tile is
much higher than the former method.
[0006] According to a first aspect of the present disclosure there
is provided a combustion chamber arrangement comprising an outer
annular wall and an inner annular wall spaced from the outer
annular wall, the inner annular wall comprising a plurality of
tiles, at least one of the tiles being secured to the outer annular
wall by at least one stud and a cooperating nut, the at least one
stud comprising a head and a threaded portion extending from the
head, the threaded portion of the at least one stud extending
through an aperture in the at least one tile and an aperture in the
outer annular wall, wherein the head comprising a plurality of
spacers to space the head from an inner surface of the at least one
tile, the spacers being circumferentially spaced around the head of
the stud, the head, the threaded portion and the spacers of the at
least one stud being integral.
[0007] The at least one tile may have a plurality of studs, each
stud having a cooperating nut, each stud comprising a head and a
threaded portion extending from the head, the threaded portion of
each stud extending through a respective aperture in the at least
one tile and a respective aperture in the outer annular wall,
wherein the head of each stud comprising a plurality of spacers to
space the head from the inner surface of the at least one tile, the
spacers being circumferentially spaced around the head of each
stud, the head, the threaded portion and the spacers of each stud
being integral.
[0008] Each tile may be secured to the outer annular wall by at
least one stud and a cooperating nut, the at least one stud of each
tile comprising a head and a threaded portion extending from the
head, the threaded portion of the at least one stud extending
through an aperture in the at least one tile and an aperture in the
outer annular wall, wherein the head of the at least one stud of
each tile comprising a plurality of spacers to space the head from
the inner surface of the respective tile, the spacers being
circumferentially spaced around the head of the stud of each tile,
the head, the threaded portion and the spacers of the at least one
stud of each tile being integral.
[0009] Each tile may have a plurality of studs, each stud having a
cooperating nut, each stud comprising a head and a threaded portion
extending from the head, the threaded portion of each stud
extending through a respective aperture in the at least one tile
and a respective aperture in the outer annular wall, wherein the
head of each stud comprising a plurality of spacers to space the
head from the inner surface of the at least one tile, the spacers
being circumferentially spaced around the head of each stud, the
head, the threaded portion and the spacers of each stud being
integral.
[0010] The head of the at least one stud or the head of each stud
may locate in a corresponding recess in the tile and the plurality
of spacers space the head from the inner surface of the recess of
the tile.
[0011] The surface of the head of the stud remote from the threaded
portion may be arranged flush with the inner surface of the
tile.
[0012] The outer surface of the recess of the tile may abut the
inner surface of the outer annular wall. The outer surface of the
recess of the tile may be spaced from the inner surface of the
outer annular wall.
[0013] The spacers may be cylindrical in cross-section or the
spacers may be rectangular in cross-section.
[0014] Two of the sides of each rectangular cross-section spacers
may be arranged parallel to corresponding sides of the other
rectangular cross-section spacers.
[0015] Two of the sides of each spacer may extend radially with
respect to the stud to define a plurality of radially extending
passages. There may be five spacers.
[0016] A second spacer may be angularly spaced apart from a first
spacer by a first angle, a third spacer may be angularly spaced
apart from the second spacer by a second angle, a fourth spacer may
be angularly spaced apart from the third spacer by a third angle, a
fifth spacer may be angularly spaced apart from the fourth spacer
by a fourth angle and the first spacer may be angularly spaced
apart from the fifth spacer by a fifth angle. The first angle may
be greater than the second angle, the second angle is less than the
third angle, the third angle is equal to the fourth angle, the
fifth angle is less than the fourth angle and the first angle is
greater than the fifth angle. The middle of the fourth spacer and
the middle of the first angle may be arranged diametrically
opposite each other. The middle of the fourth spacer and the middle
of the first angle may be arranged parallel to the axis of the
annular outer wall. The middle of the first angle may be arranged
axially upstream of the middle of the fourth spacer.
[0017] The spacers may be arcuate in cross-section and each spacer
comprises a convex surface and a concave surface. There may be six
spacers. A second spacer may be angularly spaced apart from a first
spacer by a first angle, a third spacer may be angularly spaced
apart from the second spacer by a second angle, a fourth spacer may
be angularly spaced apart from the third spacer by a third angle, a
fifth spacer may be angularly spaced apart from the fourth spacer
by a fourth angle, a sixth spacer may be angularly spaced apart
from the fifth spacer by a fifth angle and the first spacer may be
angularly spaced apart from the sixth spacer by a sixth angle. The
first angle may be greater than the second angle, the second angle
is less than the third angle, the third angle is less than the
fourth angle, the fifth angle is less than the fourth angle, the
sixth angle is less than the fifth angle and the first angle is
greater than the sixth angle. The middle of the first angle and the
middle of the fourth angle may be arranged diametrically opposite
each other. The middle of the first angle and the middle of the
fourth angle may be arranged parallel to the axis of the annular
outer wall. The middle of the first angle may be arranged axially
upstream of the middle of the fourth angle.
[0018] The concave surface of the first spacer may face the concave
surface of the second spacer, the convex surface of the second
spacer faces the concave surface of the third spacer, the convex
surface of the third spacer faces the convex surface of the fourth
spacer, the concave surface of the fourth spacer faces the concave
surface of the fifth spacer, the convex surface of the fifth spacer
faces the convex surface of the sixth spacer and the concave
surface of the sixth spacer faces the convex surface of the first
spacer.
[0019] There may be an even number of spacers and two adjacent
spacers at a first radial side of the head may be arranged further
circumferentially apart than two adjacent spacers at a second
opposite radial side of the head
[0020] There may be an odd number of spacers and the middle of a
spacer at a first radial side of the head and the middle of an
angle between two adjacent spacers at a second opposite radial side
of the head may be arranged diametrically opposite each other.
[0021] The spacers may be equi-circumferentially spaced around the
head of the stud. The at least one stud may have a fillet between
the head and threaded portion. The spacers do not overlap the
fillet. The spacers may be radially spaced from the fillet.
[0022] Each stud may have a cooperating washer, the washer having
at least one aperture extending radially there-through or the
washer having at least one slot extending radially along one of the
surfaces of the washer to supply coolant over the at least one
stud.
[0023] The at least one washer may comprise a plurality of slots
extending radially along an inner surface of the washer.
[0024] The at least one washer may comprise a plurality of slots
extending radially along an outer surface of the washer.
[0025] The at least one washer may comprise a plurality of slots
extending radially along an inner surface of the washer and a
plurality of slots extending radially along an outer surface of the
washer.
[0026] The tile may have at least one boss to space the tile from
the annular outer annular wall, the at least one aperture in the
tile extending through the at least one boss, and the boss having
at least one cooling aperture extending there-through to supply
coolant over the stud.
[0027] The at least one tile may have effusion cooling apertures
extending there-through from the outer surface to the inner surface
of the tile. The effusion cooling apertures may be arranged at an
acute angle to the inner surface of the at least one tile.
[0028] The effusion cooling apertures may be arranged at an angle
of 20.degree. to 90.degree. to the inner surface of the at least
one tile. The effusion cooling apertures may be arranged at an
angle of 20.degree. to 30.degree. to the inner surface of the at
least one tile.
[0029] The at least one tile may be manufactured by casting or
additive layer manufacturing, e.g. powder bed laser deposition,
direct laser deposition, selective laser sintering, selective laser
melting etc. The at least one tile may comprise a nickel based
superalloy, a cobalt based superalloy or an iron based
superalloy.
[0030] The at least one stud may be manufactured by additive layer
manufacturing, e.g. powder bed laser deposition, direct laser
deposition, selective laser sintering, selective laser melting etc.
The at least one stud may comprise a nickel based superalloy, a
cobalt based superalloy or an iron based superalloy.
[0031] The at least one stud may comprise a different material to
the at least one tile and the at least one stud comprises a
material with higher temperature capability than the material of
the tile. The at least one stud and the at least one tile may
comprises different superalloys. The at least one stud and the at
least one tile may comprises different nickel based
superalloys.
[0032] The combustion chamber may be an annular combustion chamber
or a tubular combustion chamber.
[0033] The combustion chamber may be a gas turbine engine
combustion chamber.
[0034] The skilled person will appreciate that except where
mutually exclusive, a feature described in relation to any one of
the above aspects of the invention may be applied mutatis mutandis
to any other aspect of the invention.
[0035] Embodiments of the invention will now be described by way of
example only, with reference to the Figures, in which:
[0036] FIG. 1 is partially cut away view of a turbofan gas turbine
engine having a combustion chamber arrangement according to the
present disclosure.
[0037] FIG. 2 is an enlarged cross-sectional view of a combustion
chamber arrangement according to the present disclosure.
[0038] FIG. 3 is a perspective view of a combustion chamber tile of
the combustion chamber arrangement shown in FIG. 2.
[0039] FIG. 4 is a cross-sectional view of a threaded stud of the
combustion chamber arrangement shown in FIG. 2.
[0040] FIG. 5 is a perspective view of a threaded stud of the
combustion chamber arrangement shown in FIG. 2.
[0041] FIG. 6 is an enlarged cross-sectional view through a
threaded stud of the assembled combustion chamber arrangement
according to the present disclosure.
[0042] FIG. 7 is an enlarged cross-sectional view through an
alternative threaded stud of the assembled combustion chamber
arrangement according to the present disclosure.
[0043] FIG. 8 is an enlarged cross-sectional view through a further
threaded stud of the assembled combustion chamber arrangement
according to the present disclosure.
[0044] FIG. 9 is a cross-sectional view in the direction of arrows
AA-AA in FIG. 9.
[0045] FIG. 10 is an enlarged cross-sectional view through another
threaded stud of the assembled combustion chamber arrangement
according to the present disclosure.
[0046] FIG. 11 is an enlarged cross-sectional view through another
threaded stud of the assembled combustion chamber arrangement
according to the present disclosure.
[0047] FIG. 12 is a cross-sectional view in the direction of arrows
CC-CC in FIG. 11.
[0048] FIG. 13 is a plan view of an arrangement of the spacers on a
threaded stud used in FIG. 6, FIG. 7, FIG. 10 or FIG. 11.
[0049] FIG. 14 is a plan view of an alternative arrangement of the
spacers on a threaded stud used in FIG. 6, FIG. 7, FIG. 10 or FIG.
11.
[0050] FIG. 15 is a plan view of an arrangement of the spacers on a
threaded stud used in FIG. 6, FIG. 7, FIG. 10 or FIG. 11.
[0051] FIG. 16 is a plan view of an alternative arrangement of the
spacers on a threaded stud used in FIG. 6, FIG. 7, FIG. 10 or FIG.
11.
[0052] FIG. 17 is a plan view of an alternative arrangement of the
spacers on a threaded stud used in FIG. 6, FIG. 7, FIG. 10 or FIG.
11.
[0053] With reference to FIG. 1, a gas turbine engine is generally
indicated at 10, having a principal and rotational axis X-X. The
engine 10 comprises, in axial flow series, an air intake 11, a
propulsive fan 12, an intermediate pressure compressor 13, a
high-pressure compressor 14, combustion equipment 15, a
high-pressure turbine 16, an intermediate pressure turbine 17, a
low-pressure turbine 18 and an exhaust nozzle 19. A fan nacelle 24
generally surrounds the fan 12 and defines the intake 11 and a fan
duct 23. The fan nacelle 24 is secured to the core engine by fan
outlet guide vanes 25.
[0054] The gas turbine engine 10 works in the conventional manner
so that air entering the intake 11 is compressed by the fan 12 to
produce two air flows: a first air flow into the intermediate
pressure compressor 13 and a second air flow which passes through
the bypass duct 23 to provide propulsive thrust. The intermediate
pressure compressor 13 compresses the air flow directed into it
before delivering that air to the high pressure compressor 14 where
further compression takes place.
[0055] The compressed air exhausted from the high-pressure
compressor 14 is directed into the combustion equipment 15 where it
is mixed with fuel and the mixture combusted. The resultant hot
combustion products then expand through, and thereby drive the
high, intermediate and low-pressure turbines 16, 17, 18 before
being exhausted through the nozzle 19 to provide additional
propulsive thrust. The high 16, intermediate 17 and low 18 pressure
turbines drive respectively the high pressure compressor 14, the
intermediate pressure compressor 13 and the fan 12, each by
suitable interconnecting shaft 20, 21 and 22 respectively.
[0056] The combustion chamber 15, as shown more clearly in FIG. 2,
is an annular combustion chamber and comprises a radially inner
annular wall structure 40, a radially outer annular wall structure
42 and an upstream end wall structure 44. The radially inner
annular wall structure 40 comprises a first annular wall 46 and a
second annular wall 48. The radially outer annular wall structure
42 comprises a third annular wall 50 and a fourth annular wall 52.
The second annular wall 48 is spaced radially from and is arranged
radially around the first annular wall 46 and the first annular
wall 46 supports the second annular wall 48. The fourth annular
wall 52 is spaced radially from and is arranged radially within the
third annular wall 50 and the third annular wall 50 supports the
fourth annular wall 52. The upstream end of the first annular wall
46 is secured to the upstream end wall structure 44 and the
upstream end of the third annular wall 50 is secured to the
upstream end wall structure 44. The upstream end wall structure 44
has a plurality of circumferentially spaced apertures 54 and each
aperture 54 has a respective one of a plurality of fuel injectors
56 located therein. The fuel injectors 56 are arranged to supply
fuel into the annular combustion chamber 15 during operation of the
gas turbine engine 10.
[0057] The second annular wall 48 comprises a plurality of rows of
combustion chamber tiles 48A and 48B and the fourth annular wall 52
comprises a plurality of rows of combustion chamber tiles 52A and
52B. The combustion chamber tiles 48A and 48B are secured onto the
first annular wall 46 by threaded studs, washers and nuts and the
combustion chamber tiles 52A and 52B are secured onto the third
annular wall 50 by threaded studs, washers and nuts.
[0058] Each of the combustion chamber tiles 48A, 48B, 52A and 52B
has a first surface 41 and a second surface 43, as shown in FIG. 3.
The first surface 41 of each combustion chamber tile 48A, 48B, 52A,
52B is an outer surface facing the respective outer annular wall 46
and 50 and the second surface 43 of each combustion chamber tile
48A, 48B, 52A, 52B is an inner surface facing away from the
respective outer annular wall 46 and 50.
[0059] The combustion chamber tiles 48A, 48B, 52A and 52B are for
annular combustion chamber wall 40 and 42 and each combustion
chamber tile 48A, 48B, 52A and 52B has effusion cooling apertures
58, as shown in FIG. 3. The effusion cooling apertures 58 extend
through the combustion chamber tiles 48A, 48B, 52A, 52B from the
first surface 41 to the second surface 43. The effusion cooling
apertures 58 are arranged in axially spaced rows and the effusion
cooling apertures 58 in each row are circumferentially spaced
apart. The effusion cooling apertures 58 in each row are offset
circumferentially from the effusion cooling apertures 58 in each
adjacent row. The effusion cooling apertures 58 are arranged at an
acute angle to the second surface 43 of the combustion chamber
tiles 48A, 48B, 52A, 52B. The effusion cooling apertures 58 may be
arranged at an angle of 20.degree. to 90.degree. to the second
surface 43 of the combustion chamber tiles 48A, 48B, 52A, 52B. The
effusion cooling apertures 58 are arranged for example at an angle
of 20.degree. to 30.degree. to the second surface 43 of the
combustion chamber tiles 48A, 48B, 52A, 52B.
[0060] In addition the first annular wall 46 and the third annular
wall 50 are provided with a plurality of impingement cooling
apertures 60 which are arranged to direct coolant, e.g. air, onto
the first surface 41 of the tiles 48A, 48B, 52A and 52B, as shown
in FIG. 6. The impingement cooling apertures 60 are generally
arranged to extend perpendicularly through the first annular wall
46 and the third annular wall 50. The impingement cooling apertures
60 are generally arranged in rows in which the impingement cooling
apertures 60 are circumferentially spaced and the impingement
cooling apertures 60 in axially adjacent rows are circumferentially
staggered.
[0061] Each combustion chamber tile 52A, 48A is shown more clearly
in FIG. 3, and comprises a rail 62 which extends around the
periphery of the tile 52A, 48A and extends from the first surface
41 of the tile 52A, 48A towards the third annular wall 50 or first
annular wall 46 respectively. The rail 62 spaces the tile 52A, 48A
from the third annular wall 50 or first annular wall 46
respectively. The rail 62 comprises axially spaced
circumferentially extending rail portions 62A and 62B and
circumferentially spaced axially extending portions 62C and 62D
which extend between and are secured to the rail portions 62A and
62B. Each combustion chamber tile 52A, 48A also has at least one
mounting aperture 64 extending there-through from the first surface
41 to the second surface 43 of the combustion chamber tile 52A, 48A
and in this arrangement there is a plurality of mounting apertures
64, for example four. Each combustion chamber tile 52A, 48A also
has at least one boss 63 which extends from the first surface 41 of
the tile 52A, 48A towards the third annular wall 50 or the first
annular 46 respectively. Each mounting aperture 64 extends radially
through a corresponding one of the bosses 63. The outer surface of
each boss 63 of the combustion chamber tile 48A, 48B, 52A, 52B
abuts the inner surface of the outer annular wall 46 or 52
respectively.
[0062] In the combustion chamber arrangement according to the
present disclosure as shown in FIGS. 3 to 6 each of the combustion
chamber tiles 52A, 52B is secured to the third annular wall 50,
e.g. an outer annular wall, by at least one stud 66, a cooperating
washer 76 and a cooperating nut 78 and in this arrangement there is
a plurality of studs 66, a plurality of washers 76 and a plurality
of nuts 78, e.g. four studs 66, four washers 76 and four nuts 78.
Each stud 66 comprises a head 68 and a threaded portion 70
extending from the head 68, as shown in FIGS. 4 and 5. The threaded
portion 70 of each stud 66 extends through, e.g. radially through,
a corresponding mounting aperture 64 in the respective combustion
chamber tile 52A, 52B and an aligned mounting aperture 80 in the
third annular wall 50. The head 68 of each stud 66 comprises a
plurality of spacers 72 to space the head 68 from the second,
inner, surface 43 of the associate combustion chamber tile 52A, 52B
and each washer 76 has at least one aperture extending radially
there-through or at least one slot extending radially along one of
the surfaces 75, 77 of the washer 76, e.g. the surface 75
contacting the third annular wall 50 or the surface 77 contacting
the nut 78. In this example each washer 76 has a plurality of slots
82 extending radially along the surface 75 of the washer 76
contacting the third annular wall 50. Each stud 66 has a
corresponding washer 76 placed around the threaded portion 70 of
the stud 66 and a corresponding nut 78 threaded onto the threaded
portion 70 of the stud 66 and each stud 66 and respective nut 78
are tightened to secure the combustion chamber tile 48A, 48B, 52A,
52B onto the first wall 46 or third wall 50 respectively. Each stud
66 has a fillet 74 where the threaded portion 70 merges into the
head 68.
[0063] Similarly, each of the combustion chamber tiles 48A, 48B is
secured to the first annular wall 46, e.g. an outer annular wall,
by at least one stud 66, a cooperating washer 76 and a cooperating
nut 78 and in this arrangement there is a plurality of studs 66, a
plurality of washers 76 and a plurality of nuts 78, e.g. four studs
66, four washers 76 and four nuts 78. Each stud 66 comprises a head
68 and a threaded portion 70 extending from the head 68. The
threaded portion 70 of each stud 66 extends through, e.g. radially
through, a corresponding mounting aperture 64 in the respective
combustion chamber tile 48A, 48B and an aligned mounting aperture
80 in the third annular wall 50. The head 68 of each stud 66
comprises a plurality of spacers 72 to space the head 68 from the
second, inner, surface 43 of the associate combustion chamber tile
48A, 48B and each washer 76 has at least one aperture extending
radially there-through or at least one slot extending radially
along one of the surfaces 75, 77 of the washer 76, e.g. the surface
75 contacting the third annular wall 50 or the surface 77
contacting the nut 78. In this example each washer 76 has a
plurality of slots 82 extending radially along the surface 75 of
the washer 76 contacting the third annular wall 50. Each stud 66
has a corresponding washer 76 placed around the threaded portion 70
of the stud 66 and a corresponding nut 78 threaded onto the
threaded portion of the stud 66.
[0064] It is to be noticed that in FIGS. 3 to 6 that the spacers 72
are circumferentially spaced around the head 68 of each stud 66 and
in particular the spacers 72 are equi-circumferentially spaced
around the head 68 of each stud 66. The spacers 72 are cylindrical
and circular in cross-section. The spacers 72 do not overlap the
fillet 74 of each stud 66 to avoid undesirable stress
concentrations and damage to the stud and in this example the
spacers 72 are radially spaced from the fillet 74 of each stud
66.
[0065] In operation hot combustion gases produced in the combustion
chamber flow generally in the direction of arrow A within the
annular combustion chamber 15. A coolant, for example air, flows in
the direction of arrow B over the outer surfaces of the first
annular wall 46 and the third annular wall 50. Some of the coolant,
air, flows C through the impingement cooling apertures 60 to
provide impingement cooling of the first surfaces 41 of the
combustion chamber tiles 48A, 48B, 52A and 52B and then through the
effusion cooling apertures 58 to provide a film of coolant on the
second surfaces 43 of the combustion chamber tiles 48A, 48B, 52A
and 52B. Further portions of the coolant flows E through the slots
82 along the surfaces 75 of the washers 76 and then turns to flow F
radially through the mounting apertures 80 in the first and third
annular walls 46 and 50 and then through the mounting apertures 64
in the bosses 63 and the main body of the combustion chamber tiles
48A, 48B, 52A and 52B. The coolant flows radially with respect to
the annular combustion chamber 15 over the surface of the threaded
portion 70 of each stud 66, then over the fillet 74 of each stud 66
and then is directed to flow over a cold surface 67 of the head 68
of each stud 66 and through the space between the head 68 of each
stud 66 and the second, inner, surface 43 of the associated
combustion chamber tile 48A, 48B, 52A and 52B and also between the
spacers 72. Thus, the coolant cools the threaded portion 70, the
spacers 72, the fillet 74 and the head 68 of each stud 66. The flow
of coolant G may help form a cooling film of coolant on the second
surface 43 of the combustion chamber tile 48A, 48B, 52A and 52B and
over the surface of the head 68 of the stud 66. Some of the coolant
flowing from effusion cooling apertures 58 over the second, inner,
surface 43 of the combustion chamber tile 48A, 48B, 52A and 52B
upstream of the stud 66 may flow over the cold surface 67 of the
head 68 and in the space between the head 68 of each stud 66 and
the second, inner, surface 43 of the associated combustion chamber
tile 48A, 48B, 52A and 52B and also between the spacers 72 and
around the fillet 74 and some of the coolant flowing from effusion
cooling apertures 58 over the second, inner, surface 43 of the
combustion chamber tile 48A, 48B, 52A and 52B upstream of the stud
66 may flow over the hot surface 69 of the head 68 of the stud 66.
This provides additional cooling of the stud 66.
[0066] The boss, or each boss, 63 of the combustion chamber tiles
52A, 48A may be replaced by a plurality of pillars arranged
circumferentially around the respective mounting aperture 64 to
transfer clamping loads rather than the boss 63. This would also
allow coolant to flow between the pillars and then through the
respective mounting aperture 64 to cool the stud 66. In this
eventuality it may be possible to provide a conventional washer or
a washer with the radial slots or radial apertures.
[0067] Another combustion chamber arrangement according to the
present disclosure is shown in FIG. 7 and it is substantially the
same as that described with reference to FIGS. 3 to 6 and like
parts are denoted by like numerals. The combustion chamber
arrangement in FIG. 7 differs in that each combustion chamber tile
48A, 48B, 52A, 52B has at least one boss 84 extending from the
first surface 41 toward the first annular wall 46 or third annular
wall 50 respectively and in this example and in this arrangement
there is a plurality of bosses 84, for example four. Each
combustion chamber tile 48A, 48B, 52A, 52B also has at least one
recess 86 in the second surface 43 aligned with a boss 84 and in
this arrangement there is a plurality of recesses 86, for example
four, each one of which is aligned with a corresponding one of the
bosses 84. Each boss 84 has an outer surface 88 parallel to and
spaced from the first, outer, surface 41 and each recess 86 has an
inner surface 90 parallel to and spaced from the second, inner,
surface 43 of the combustion chamber tile 48A, 48B, 52A, 52B. Each
combustion chamber tile 48A, 48B, 52A, 52B also has at least one
mounting aperture 64 extending through the at least one boss 84
from the outer surface 88 of the boss 84 to the inner surface 90 of
the recess 86 of the combustion chamber tile 48A, 48B, 52A, 52B and
in this arrangement there is a plurality of mounting apertures 64,
for example four, one extending through each boss 84 from the outer
surface 88 of the boss 84 to the inner surface 90 of the
corresponding recess 86 of the combustion chamber tile 48A, 48B,
52A, 52B. The outer surface 88 of each boss 84 of the combustion
chamber tile 48A, 48B, 52A, 52B abuts the inner surface of the
outer annular wall 46 or 52 respectively.
[0068] The head 68 of each stud 66 locates in a corresponding
recess 86 in the combustion chamber tile 48A, 48B, 52A, 52B and the
plurality of spacers 72 on the head 68 of each stud 66 space the
head 68 from the inner surface 90 of the respective recess 86 of
the combustion chamber tile 48A, 48B, 52A, 52B.
[0069] In this example the surface of the head 68 of each stud 66
remote from the threaded portion 70 is arranged flush with the
inner surface 43 of the combustion chamber tile 48A, 48B, 52A, 52B.
However, the surface of the head 68 of each stud 66 remote from the
threaded portion 70 may be arranged so that it is not flush with
the inner surface 43 of the combustion chamber tile 48A, 48B, 52A,
52B. The surface of the head 68 of each stud 66 remote from the
threaded portion 70 may be arranged so that it is spaced back from
the inner surface 43 of the combustion chamber tile 48A, 48B, 52A,
52B so that it is positioned between the inner surface 90 of the
recess 86 and the inner surface 43 of the combustion chamber tile
48A, 48B, 52A, 52B. The head 68 of each stud 66 and the
corresponding recess 86 have matching shapes but the head 68 of the
stud 66 has slightly smaller dimensions than the recess 86 so that
there is a gap between the head 68 of the stud 66 and the recess
86. For example each head 68 may be circular in cross-section and
the recess 86 is circular in cross-section. Each boss 84 may have a
shape to match the shape of the corresponding recess 68. For
example the recess 86 may be circular in cross-section and the boss
84 may be circular in cross-section. However, the boss 84 may have
a different shape to the corresponding recess 86, for example the
boss may be rectangular or square and the recess may be circular in
cross-section.
[0070] In operation hot combustion gases produced in the combustion
chamber flow generally in the direction of arrow A within the
annular combustion chamber 15. A coolant, for example air, flows in
the direction of arrow B over the outer surfaces of the first
annular wall 46 and the third annular wall 50. Some of the coolant,
air, flows C through the impingement cooling apertures 60 to
provide impingement cooling of the first surfaces 41 of the
combustion chamber tiles 48A, 48B, 52A and 52B and then through the
effusion cooling apertures 58 to provide a film of coolant on the
second surfaces 43 of the combustion chamber tiles 48A, 48B, 52A
and 52B. Further portions of the coolant flows E through the slots
82 along the surfaces 75 of the washers 76 and then turns to flow F
radially through the mounting apertures 80 in the first and third
annular walls 46 and 50 and then through the mounting apertures 64
in the bosses 84 of the combustion chamber tiles 48A, 48B, 52A and
52B. The coolant flows radially with respect to the annular
combustion chamber 15 over the surface of the threaded portion 70
of each stud 66, then over the fillet 74 of each stud 66 and then
is directed to flow G over the head 68 of each stud 66 and through
the space between the head 68 of each stud 66 and the inner surface
90 of the recess 86 of the associated combustion chamber tile 48A,
48B, 52A and 52B and also between the spacers 72. Thus, the coolant
cools the threaded portion 70, the spacers 72, the fillet 74 and
the head 68 of each stud 66. The coolant then turns to flow H
radially with respect to the annular combustion chamber 15 through
the gap between the periphery of the head 68 of the stud 66 and the
side of the recess 86 and into the annular combustion chamber 15.
The flow of coolant H may help form a cooling film of coolant on
the second surface 43 of the combustion chamber tile 48A, 48B, 52A
and 52B and over the surface of the head 68 of the stud 66.
[0071] A further combustion chamber arrangement according to the
present disclosure is shown in FIGS. 8 and 9, but this does not
show the stud. This arrangement is similar to that shown in FIG. 7,
but differs in that a plurality of cooling apertures 92 extend
through an upstream sidewall 84A of the at least one boss 84,
preferably each boss 84, to the corresponding recess 86. The
cooling apertures 92 provide further coolant, air, into each recess
86 which supplements the coolant, air, flowing through the mounting
apertures 80 in the first and third annular walls 46 and 50 and
then through the mounting apertures 64 in the bosses 84 of the
combustion chamber tiles 48A, 48B, 52A and 52B. These cooling
apertures 92 may be formed by drilling, e.g. laser drilling, or
during/by the additive layer manufacturing process. Alternatively,
the washers 76 may be conventional washers and all the coolant,
air, is supplied through the cooling apertures 92. FIG. 9 also
shows an arrangement of spacers 72 on the head 68 of a stud 66,
which may be used in any of the embodiments of the present
disclosure. The spacers 72 are circular in cross-section. The
spacers 72 do not overlap the fillet 74 of the stud 66 and in this
example the spacers 72 are spaced radially from the fillet 74 and
the periphery of the stud 66. In this example there are four
spacers 72. The head 68 of the stud 66D has a part circular
peripheral edge portion 71A and a flat peripheral edge portion 71B.
The flat peripheral edge portion 71B is arranged to cooperate with
a similar flat sidewall of the recess 86 to prevent rotation of the
stud 66 during tightening of the stud 66 and associated nut 78. In
this example the flat sidewall is the upstream sidewall 84A of the
recess 86.
[0072] Another combustion chamber arrangement according to the
present disclosure is shown in FIG. 10. This arrangement is similar
to that shown in FIGS. 8 and 9, but differs in that the downstream
sidewall 84B of the or each boss 84, recess 86, is angled to enable
the coolant to flow onto the inner surface 43 of the combustion
chamber tiles 48A, 48B, 52A and 52B. The upstream sidewall 84A is
flat to prevent rotation of the bolt 66. Again the, or each, washer
76 may or may not have radial apertures or radial slots for the
flow of coolant, air.
[0073] An additional combustion chamber arrangement according to
the present disclosure is shown in FIGS. 11 and 12. This
arrangement is similar to that shown in FIGS. 8 and 9, but differs
in that the or each boss 84, recess 86, is cylindrical and the
cooling apertures 92 are circumferentially spaced with respect to
the axis of the mounting aperture 64 and the head 68 of the stud 66
is circular. Again the, or each, washer 76 may or may not have
radial apertures or radial slots for the flow of coolant, air.
[0074] FIG. 13 shows one arrangement of the spacers 72 on the head
68 of a stud 66A, which may be used in any of the embodiments of
the present disclosure. In this type of stud 66A two of the sides
of each spacer 72 extend radially with respect to the stud 66A to
define a plurality radially extending passages 73A, 73B, 73C, 73D
and 73E. In this arrangement there are five spacers 72A, 72B, 72C,
72D and 72E. A second spacer 72B is angularly spaced apart from a
first spacer 72A by a first angle .alpha.1, a third spacer 72C is
angularly spaced apart from the second spacer 72B by a second angle
.alpha.2, a fourth spacer 72D is angularly spaced apart from the
third spacer 72C by a third angle .alpha.3, a fifth spacer 72E is
angularly spaced apart from the fourth spacer 72D by a fourth angle
.alpha.4 and the first spacer 72A is angularly spaced apart from
the fifth spacer 72E by a fifth angle .alpha.5. The first angle
.alpha.1 is greater than the second angle .alpha.2, the second
angle .alpha.2 is less than the third angle .alpha.3, the third
angle .alpha.3 is equal to the fourth angle .alpha.4, the fifth
angle .alpha.5 is less than the fourth angle .alpha.4 and the first
angle .alpha.1 is greater than the fifth angle .alpha.5. The first
angle .alpha.1 is greater than the third angle .alpha.3. In this
particular example the first angle is about 90.degree., the second
angle is about 25.degree., the third angle is about 35.degree., the
fourth angle is about 35.degree. and the fifth angle is about
25.degree.. It is also to be noted that the middle of the fourth
spacer 72D and the middle of the first angle .alpha.1 are arranged
diametrically opposite each other. The middle of the fourth spacer
72D and the middle of the first angle .alpha.1 are arranged
parallel to the axis of the annular outer wall 46 or 50. The middle
of the first angle .alpha.1 is arranged axially upstream of the
middle of the fourth spacer 72D.
[0075] Again it is to be noted that the spacers 72 are
circumferentially spaced around the head 68 of the stud 66A and in
particular the spacers 72 are not equi-circumferentially spaced
around the head 68 of the stud 66A. The spacers 72 do not overlap
the fillet 74 of the stud 66A and in this example the spacers 72
extend radially from the fillet 74 to the periphery of the stud
66A.
[0076] FIG. 14 shows one arrangement of the spacers 72 on the head
68 of a stud 66B, which may be used in any of the embodiments of
the present disclosure. In this type of stud 66B the spacers 72 are
arcuate in cross-section and each spacer 72 comprises a concave
surface and a concave surface. In this arrangement there are six
spacers 72F, 72G, 72H, 72I, 72J and 72K. A second spacer 72G is
angularly spaced apart from a first spacer 72F by a first angle
.alpha.6, a third spacer 72H is angularly spaced apart from the
second spacer 72G by a second angle .alpha.7, a fourth spacer 721
is angularly spaced apart from the third spacer 72H by a third
angle .alpha.8, a fifth spacer 72J is angularly spaced apart from
the fourth spacer 72I by a fourth angle .alpha.9, a sixth spacer
72K is angularly spaced apart from the fifth spacer 72J by a fifth
angle .alpha.10 and the first spacer 72F is angularly spaced apart
from the sixth spacer 72K by a sixth angle .alpha.11. The first
angle .alpha.6 is greater than the second angle .alpha.7, the
second angle .alpha.7 is less than the third angle .alpha.8, the
third angle .alpha.8 is less than the fourth angle .alpha.9, the
fifth angle .alpha.10 is less than the fourth angle .alpha.9, the
sixth angle .alpha.11 is less than the fifth angle .alpha.10 and
the first angle .alpha.6 is greater than the sixth angle .alpha.11.
The first angle .alpha.6 is about 50.degree., the second angle
.alpha.7 is about 20.degree., the third angle .alpha.8 is about
45.degree., the fourth angle .alpha.9 is about 55.degree., the
fifth angle .alpha.10 is about 45.degree. and the sixth angle
.alpha.11 is about 20.degree.. The middle of the first angle
.alpha.6 and the middle of the fourth angle .alpha.9 are arranged
diametrically opposite each other. The middle of the first angle
.alpha.6 and the middle of the fourth angle .alpha.9 are arranged
parallel to the axis of the annular outer wall 46 or 50. The middle
of the first angle .alpha.6 is arranged axially upstream of the
middle of the fourth angle .alpha.9.
[0077] The concave surface of the first spacer 72F faces the
concave surface of the second spacer 72G, the convex surface of the
second spacer 72G faces the concave surface of the third spacer
72H, the convex surface of the third spacer 72H faces the convex
surface of the fourth spacer 72I, the concave surface of the fourth
spacer 72I faces the concave surface of the fifth spacer 72J, the
convex surface of the fifth spacer 72J faces the convex surface of
the sixth spacer 72K and the concave surface of the sixth spacer
72K faces the convex surface of the first spacer 72F.
[0078] Again it is to be noted that the spacers 72 are
circumferentially spaced around the head 68 of the stud 66B and in
particular the spacers 72 are not equi-circumferentially spaced
around the head 68 of the stud 66A. The spacers 72 do not overlap
the fillet 74 of the stud 66A and in this example the spacers 72
extend radially from the fillet 74 to the periphery of the stud
66A.
[0079] FIG. 15 shows the arrangement of the spacers 72 on the head
68 of a stud 66, which may be used in any of the embodiments of the
present disclosure. The spacers 72 are circumferentially spaced
around the head 68 of the stud 66 and in particular the spacers 72
are equi-circumferentially spaced around the head 68 of the stud
66. The spacers 72 do not overlap the fillet 74 of the stud 66 and
in this example the spacers 72 are spaced radially from the fillet
74 and the periphery of the stud 66. The spacers 72 are cylindrical
and circular in cross-section. In this example there are six
spacers 72.
[0080] FIG. 16 shows a further arrangement of spacers 72 on the
head 68 of a stud 66C, which may be used in any of the embodiments
of the present disclosure. The spacers 72 are rectangular, or
square, in cross-section. The spacers 72 do not overlap the fillet
74 of the stud 66C and in this example the spacers 72 are spaced
radially from the fillet 74 and the periphery of the stud 66C. Two
of the sides of each rectangular cross-section spacer 72 are
arranged parallel to corresponding sides of the other rectangular
cross-section spacers 72. In this example there are four spacers
72.
[0081] FIG. 17 shows a further arrangement of spacers 72 on the
head 68 of a stud 66E, which may be used in any of the embodiments
of the present disclosure. The spacers 72 are circular in
cross-section. The spacers 72 do not overlap the fillet 74 of the
stud 66 and in this example the spacers 72 are spaced radially from
the fillet 74 and the periphery of the stud 66. In this example
there are six spacers 72. The spacers 72 are equi-circumferentially
spaced around the head 68 of the stud 66E. The head 68 of the stud
66E has a polygonal edge 71C and in this example is a hexagonal
edge. The polygonal edge 71C is arranged to cooperate with a
similar polygonal shaped recess 86 to prevent rotation of the stud
66E during tightening of the stud 66E and associated nut 78 or
alternatively if the head 68 of the stud 66E does not locate in a
recess 86 then a spanner may be used to locate on the head 68. The
studs 66A, 66B, 66 and 66C shown in FIGS. 11 to 13 respectively may
also have a head 68 provided with a polygonal edge 71C and in this
example is a hexagonal edge.
[0082] The head of the or each stud may be circular and have an
Allen key socket to enable tightening of the stud and nut using an
Allen Key and a spanner. Alternatively, the head of the stud may be
polygonal, e.g. hexagonal, to enable tightening of the stud and nut
using respective spanners or to enable the correspondingly shaped
recess to prevent rotation of the stud and to enable tightening of
the stud and nut using a spanner. In a further possibility, the
head of the stud has one or more flat sides to cooperate with one
or more flat sides of a correspondingly recess to enable tightening
of the stud and nut using a spanner.
[0083] The head of the or each stud may have an even number of
spacers and two adjacent spacers at a first radial side of the head
may be arranged further circumferentially apart than two adjacent
spacers at a second opposite radial side of the head.
[0084] The head of the or each stud may have an odd number of
spacers and the middle of a spacer at a first radial side of the
head and the middle of an angle between two adjacent spacers at a
second opposite radial side of the head may be arranged
diametrically opposite each other.
[0085] The spacers may be circumferentially spaced around the head
of the, or each, stud. The spacers may be equi-circumferentially
spaced around the head of the, or each, stud. The spacers are
circumferentially spaced around the head of the, or each, stud with
respect to the centre, or longitudinal axis, of the threaded
portion of the, or each, stud, as clearly shown in the figures.
[0086] The spacers may not overlap the fillet. The spacers may be
radially spaced from the fillet.
[0087] The at least one washer may comprise a plurality of slots
extending radially along an inner surface of the washer. The at
least one washer may comprise a plurality of slots extending
radially along an outer surface of the washer. The at least one
washer may comprise a plurality of slots extending radially along
an inner surface of the washer and a plurality of slots extending
radially along an outer surface of the washer.
[0088] The at least one tile may be manufactured by casting or
additive layer manufacturing, e.g. powder bed laser deposition,
direct laser deposition, selective laser sintering etc. The at
least one tile may comprise a nickel based superalloy, a cobalt
based superalloy or an iron based superalloy. The effusion cooling
apertures are formed in the cast combustion chamber tiles by
drilling, for example laser drilling. The effusion cooling
apertures in the additive layer manufactured combustion chamber
tiles may be formed during/by the additive layer manufacturing
process or the effusion cooling aperture may be formed in the
additive layer manufactured combustion chamber tiles by drilling,
e.g. laser drilling.
[0089] The at least one stud may be manufactured by additive layer
manufacturing, e.g. powder bed laser deposition, direct laser
deposition, selective laser sintering etc. or other suitable
manufacturing technique. The at least one stud may comprise a
nickel based superalloy, a cobalt based superalloy or an iron based
superalloy. The head, the threaded portion and the spacers of each
stud are integral, e.g. a single piece or a monolithic piece.
[0090] The at least one tile may have a plurality of studs, each
stud having a cooperating washer and a cooperating nut, each stud
comprising a head and a threaded portion extending from the head,
the threaded portion of each stud extending through a respective
aperture in the at least one tile and a respective aperture in the
outer annular wall, wherein the head of each stud comprising a
plurality of spacers to space the head from the inner surface of
the at least one tile and each washer having at least one aperture
extending radially there-through or at least one slot extending
radially along one of the surfaces of the washer.
[0091] Each tile may be secured to the outer annular wall by at
least one stud, a cooperating washer and a cooperating nut, the at
least one stud of each tile comprising a head and a threaded
portion extending from the head, the threaded portion of the at
least one stud extending through an aperture in the at least one
tile and an aperture in the outer annular wall, wherein the head of
the at least one stud of each tile comprising a plurality of
spacers to space the head from the inner surface of the respective
tile and the associated washer for each tile having at least one
aperture extending radially there-through or at least one slot
extending radially along one of the surfaces of the washer.
[0092] Each tile may have a plurality of studs, each stud having a
cooperating washer and a cooperating nut, each stud comprising a
head and a threaded portion extending from the head, the threaded
portion of each stud extending through a respective aperture in the
at least one tile and a respective aperture in the outer annular
wall, wherein the head of each stud comprising a plurality of
spacers to space the head from the inner surface of the at least
one tile and each washer having at least one aperture extending
radially there-through or at least one slot extending radially
along one of the surfaces of the washer.
[0093] The combustion chamber may be an annular combustion chamber
or a tubular combustion chamber.
[0094] The combustion chamber may be a gas turbine engine
combustion chamber.
[0095] An advantage of the present disclosure is that, because the
studs are not integral with the combustion chamber tiles, it is
possible to more easily provide a uniform pattern of effusion
cooling apertures throughout the whole, or a major part of the
combustion chamber tiles by drilling, e.g. laser drilling or EDM
drilling, the cast combustion chamber tiles, e.g. the drilling
machine does not have to be set to different drilling angles. It
also reduced the cost of drilling the effusion cooling apertures.
It also improves the cooling effectiveness of the effusion cooling
provided by the uniform pattern of effusion cooling apertures.
Another advantage of the present disclosure is that, because the
studs are not integral with the combustion chamber tiles, it
enables the combustion chamber tiles to be built vertically by
additive layer manufacturing in a laser powder bed at minimised
cost. A further advantage is that if one or more studs are damaged
on a combustion chamber tile it is easier and cheaper to replace a
damaged stud, or replace damaged studs, compared to the
conventional requirement to replace the entire combustion chamber
tile. Additionally, the studs may be made from a different material
to the combustion chamber tile, e.g. the studs may be made from a
material, e.g. superalloy, which has a higher temperature
capability than the combustion chamber tile, for example different
superalloys, e.g. different nickel based superalloys.
[0096] It may also be possible to provide one or more conventional
integral studs on one or more combustion chamber tiles.
[0097] It will be understood that the invention is not limited to
the embodiments above-described and various modifications and
improvements can be made without departing from the concepts
described herein. Except where mutually exclusive, any of the
features may be employed separately or in combination with any
other features and the disclosure extends to and includes all
combinations and sub-combinations of one or more features described
herein.
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