U.S. patent application number 15/255536 was filed with the patent office on 2017-03-09 for assembly group with a combustion chamber shingle for a gas turbine.
The applicant listed for this patent is Rolls-Royce Deutschland Ltd & Co KG. Invention is credited to Carsten CLEMEN, Tobias MELLENTIEN, Igor SIKORSKI, Ivo SZARVASY.
Application Number | 20170067642 15/255536 |
Document ID | / |
Family ID | 58055339 |
Filed Date | 2017-03-09 |
United States Patent
Application |
20170067642 |
Kind Code |
A1 |
SZARVASY; Ivo ; et
al. |
March 9, 2017 |
ASSEMBLY GROUP WITH A COMBUSTION CHAMBER SHINGLE FOR A GAS
TURBINE
Abstract
An assembly group for a combustion chamber of a gas turbine
includes a combustion chamber shingle with a mounting element and a
bolt formed as a separate structural component for supporting the
combustion chamber shingle at a wall of the combustion chamber. The
mounting element has a reception area into which a bolt head of the
bolt is inserted transversely with respect to a longitudinal axis
of the bolt and anchored therein in a form-fit manner. At the
reception area, the mounting element forms an edge area that
protrudes substantially radially with respect to the longitudinal
axis of the bolt and that at least partially surrounds an edge of
the bolt head. The edge of the bolt head does not extend
exclusively in a plane that is perpendicular to the longitudinal
axis of the bolt.
Inventors: |
SZARVASY; Ivo; (Berlin,
DE) ; CLEMEN; Carsten; (Mittenwalde, DE) ;
MELLENTIEN; Tobias; (Berlin, DE) ; SIKORSKI;
Igor; (Berlin, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rolls-Royce Deutschland Ltd & Co KG |
Blankenfelde-Mahlow |
|
DE |
|
|
Family ID: |
58055339 |
Appl. No.: |
15/255536 |
Filed: |
September 2, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R 2900/00018
20130101; F23R 3/60 20130101; F23R 3/002 20130101 |
International
Class: |
F23R 3/60 20060101
F23R003/60; F23R 3/00 20060101 F23R003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 4, 2015 |
DE |
10 2015 217 034.9 |
Sep 8, 2015 |
DE |
10 2015 217 161.2 |
Claims
1. Assembly group for a combustion chamber of a gas turbine,
comprising: one combustion chamber shingle with a mounting element,
and at least one bolt formed as a separate structural component for
mounting the combustion chamber shingle at a combustion chamber
wall of the combustion chamber, wherein the mounting element has a
reception area into which a bolt head of the bolt is inserted
transversely with respect to a longitudinal axis of the bolt and
anchored therein in a form-fit manner, at the reception area, the
mounting element forms an edge area that protrudes substantially
radially with respect to the longitudinal axis of the bolt and
surrounds the edge of the bolt head at least partially, and at its
bottom side that is facing away from the combustion chamber
shingle, the bolt head that is inserted into the reception area
forms at least one contact surface for an abutting arrangement at
the combustion chamber wall and/or at least one contact surface for
an abutting arrangement at the edge area of the mounting element,
with the contact surface extending in a tilted manner with respect
to the longitudinal axis of the bolt.
2. Assembly group according to claim 1, wherein at least one first
edge section is formed at the edge of the bolt head, abutting at
the radially protruding edge area, and at least one second edge
section that is arranged at a distance to the first edge section is
formed at the edge of the bolt head, abutting at the combustion
chamber wall if the combustion chamber shingle is mounted thereat
according to the intended use.
3. Assembly group according to claim 2, wherein the edge area of
the mounting element is embodied so as to not extend along the
entire circumference of the longitudinal axis of the bolt and so as
to be open towards at least one side, and in that the second edge
section of the bolt head is present at this one side, so that the
second section is not surrounded by the radially protruding edge
area.
4. Assembly group according to claim 2, wherein the bolt head is
locally thickened at the second edge section in the axial direction
with respect to the longitudinal axis of the bolt.
5. Assembly group according to claim 4, wherein a locally thickened
section has an extension in the axial direction that is increased
by 15% and up to 100% as compared to adjoining sections of the bolt
head.
6. Assembly group according to claim 4, wherein a locally thickened
section of the bolt head extends along a circumference with a
length that corresponds to at most a 1/3 of the total circumference
of the bolt head.
7. Assembly group according to claim 1, wherein the bolt head is
conically shaped at an edge section that is surrounded by the
radially protruding edge area of the mounting element.
8. Assembly group according to claim 7, wherein a conically shaped
edge section of the bolt head becomes wider in the direction of a
front side that is defined by the bolt head.
9. Assembly group according to claim 1, wherein an edge section is
formed at the bolt head, which at least in one area extends so as
to be tilted at an angle (.alpha..sub.4) with respect to a
connection direction along which the bolt head is inserted into the
reception area of the mounting element of the combustion chamber
shingle.
10. Assembly group according to claim 9, wherein the radially
protruding edge area of the mounting element defines a channel for
inserting the bolt head that tapers off and extends along the
connection direction, wherein the taper degree of the channel
corresponds to the angle (.alpha..sub.4) at which the at least one
area of the edge section extends in manner tilted with respect to
the connection direction.
11. Assembly group according to claim 1, wherein an edge section
with a contact surface for abutting arrangement at the radially
protruding edge area of the mounting element is formed at the bolt
head, wherein the contact surface extends in a tilted manner with
respect to a first spatial direction and the longitudinal axis of
the bolt, as well as with respect to a second spatial direction
that is perpendicular to the first spatial direction.
12. Assembly group according to claim 1, wherein a conical
transitional area is formed between a bolt shaft of the bolt by
means of which the combustion chamber shingle is supported at the
combustion chamber wall and the bolt head.
13. Assembly group according to claim 12, wherein a lateral surface
of the transitional area is concavely arched and has a radius of
curvature that corresponds to the range of 1.0 to 3.5 times the
diameter of the bolt shaft.
14. Assembly group for a combustion chamber of a gas turbine,
comprising: one combustion chamber shingle with a mounting element
and at least one bolt that serves for mounting the combustion
chamber shingle at a combustion chamber wall of the combustion
chamber and that is formed as a separate structural component,
wherein the bolt has a bolt shaft by means of which the combustion
chamber shingle is supported at the combustion chamber wall,
characterized in that the mounting element has a reception area
into which a bolt head of the bolt is inserted transversely with
respect to a longitudinal axis of the bolt and anchored therein in
a form-fit manner, at the reception area, the mounting element
forms an edge area that is substantially radially protruding with
respect to the longitudinal axis of the bolt and that at least
partially surrounds the edge of the bolt head, the reception area
has a basal plane, above which the radially protruding edge area
extends, and the bolt head has a front side which is facing towards
a basal plane and at which a concave internal arching is provided
that is arranged centrally with respect to the bolt shaft, in
cross-section the concave internal arching has a radius of
curvature that corresponds to at least a sixth of a mean width of
the bolt head transversely with respect to the longitudinal axis of
the bolt, in cross-section the concave internal arching has a
radius of curvature that corresponds to at least half the diameter
of a bolt shaft of the bolt by which the combustion chamber shingle
is supported at the combustion chamber wall.
15. Assembly group according to claim 14, wherein in cross-section
the internal arching is delimited by two convex bulges that
protrude in the direction of the basal plane.
16. Gas turbine engine with a combustion chamber that comprises at
least one assembly group according to claim 1.
Description
[0001] This application claims priority to German Patent
Application No. DE102015217034.9 filed Sep. 4, 2015 and German
Patent Application No. DE102015217161.2 filed Sep. 8, 2015, the
entirety of both applications are incorporated by reference
herein.
DESCRIPTION
[0002] The invention relates to an assembly group for a combustion
chamber of a gas turbine according to the generic term of claim
1.
[0003] For the purpose of cooling, combustion chambers of a gas
turbine, in particular of a gas turbine engine, have so-called
combustion chamber shingles. These combustion chamber shingles are
regularly provided for cladding a fire tube of the combustion
chamber. Here, air for cooling down as well as for leaning the
combustion and thus for reducing NOx emissions can be conducted
into the combustion chamber through the combustion chamber shingle.
For this purpose, the combustion chamber shingle has at least one
mixed air hole. In addition, it is also provided to furnish a
combustion chamber shingle with multiple, often up to several
thousands, so-called effusion cooling holes via which the
combustion chamber shingle is cooled against the high temperatures
that are present inside the combustion. As for that, generic
assembly groups are known for example from EP 0 972 992 B1 or DE
102 14 570 A1.
[0004] In practice, the individual combustion chamber shingles are
fixated at a combustion chamber wall through bolts that are formed
at them. The bolt of a combustion chamber shingle, which is thus
formed as a stud bolt, is then fixated at the combustion chamber
wall by means of a nut. In such embodiments, losses of preload due
to creeping are often observed in the stud bolt. What is more, in a
bolt that is formed integrally with the combustion chamber shingle,
a sufficient cooling of the shingle at the location of the bolt is
not easily possible. Moreover, if the combustion chamber shingle is
mounted at the combustion chamber wall via an integrated bolt, it
is hard to accommodate possible different requirements regarding
the thermal conductivity and strength and thus the manufacturing
material of the bolt and the combustion chamber shingle itself.
[0005] Thus, the invention is based on the objective to improve an
assembly group for a combustion chamber of a gas turbine with at
least one combustion chamber shingle that is to be mounted at a
combustion chamber wall of the combustion chamber in this respect
and to remedy or at least reduce the previously mentioned
disadvantages.
[0006] This objective is achieved through an assembly group of
claim 1 as well as through an assembly group of claim 14.
[0007] According to a first aspect of the invention, the assembly
group, apart from a combustion chamber shingle and a mounting
element that is formed thereat preferably integrally, also has a
separate bolt for mounting the combustion chamber shingle at the
combustion chamber wall of the gas turbine combustion chamber. The
mounting element of the combustion chamber shingle has a reception
area into which a bolt head of the bolt is inserted transversely to
a longitudinal axis of the bolt and is anchored at the same in a
form-fit manner. For the purpose of anchoring the bolt head in a
form-fit manner, the mounting element forms an edge area that
protrudes radially with respect to the longitudinal axis of the
bolt at the reception area and that at least partially surrounds an
edge of the bolt head. According to the invention it is now further
provided that, at its bottom side that faces away from the
combustion chamber shingle, the bolt head forms at least one
contact surface for an abutting arrangement at the combustion
chamber wall and/or at least one contact surface for an abutting
arrangement at the edge area of the mounting element, extending so
as to be tilted with respect to the longitudinal axis of the
bolt.
[0008] Consequently, according to the first aspect of the
invention, the invention is based on the basic principle that a
bolt provided for mounting the combustion chamber shingle can be
inserted via its bolt head in the reception area at the combustion
chamber shingle and is then anchored in the same in a form-fit
manner. Here, in particular the edge of the bolt head, which is
surrounded by an edge area of the reception area at the combustion
chamber shingle, is geometrically designed in such a manner that a
defined planar abutting arrangement of the bolt head at the
radially protruding edge area and/or directly at the combustion
chamber wall is achieved when the combustion chamber shingle is
mounted at the combustion chamber wall by means of the bolt
according to the intended use. Hence, the bottom side of the bolt
head has no flat, plate-shaped form, but rather differs from the
same in such a manner that [0009] a section of the bolt head can
come into an abutting arrangement at the combustion chamber wall
when the combustion chamber shingle is mounted at the combustion
chamber wall, and/or [0010] a section of the bolt head abuts the
radially protruding edge area of the mounting element along a
contact surface that extends in a tilted manner with respect to the
longitudinal axis of the bolt.
[0011] Thus, it has been shown that undesired bending moments and
transverse forces in the bolt and in particular at the bolt head
can be avoided if the bottom side of the bolt head is formed in
such a manner that it is not uniformly plane and that it is not
only arranged in a plate plane that extends perpendicularly to the
longitudinal axis of the bolt, but if instead sections with contact
surfaces are provided thereat that are tilted with respect to the
longitudinal axis of the bolt and/or protrude in an elevated manner
at the bottom side of the bolt head. While, thanks to the
configuration of the bolt as a separated structural component, an
improved cooling of the bolt can be achieved and the manufacturing
material for the combustion chamber shingle can be selected by and
large independently of the manufacturing material of the bolt, an
optimized form-fit anchoring of the bolt at the reception area of
the combustion chamber shingle as well as a longer service life of
the bolt is achieved through the bolt head geometry that is
provided according to the invention.
[0012] In an exemplary embodiment, formed at the edge of the bolt
head are at least one first edge section, abutting the radially
protruding edge area via a first contact surface, and at least one
second edge section that is arranged at a distance to the first
edge section and that abuts the combustion chamber wall via a
second contact surface if the combustion chamber shingle is mounted
at the combustion chamber wall according to the intended use. In
this way, if the bolt is fixated at the combustion chamber wall,
the bolt head can be supported directly against the combustion
chamber wall as well as against the edge area of the mounting
element that is formed at the combustion chamber shingle, wherein
the edge area is also supported directly against the combustion
chamber wall and for this purpose abuts the combustion chamber wall
preferably in a planar manner.
[0013] The edge area of the mounting element is preferably formed
in such a manner that it does not run around the entire
longitudinal axis of the bolt so that the bolt head can be inserted
into the reception area transversely to the longitudinal axis of
the bolt. Consequently, the edge area is open towards at least one
side. The second edge section of the bolt head, which forms the
second contact surface for an abutting arrangement at the
combustion chamber wall, is preferably present at this one open
side, so that the second section is not surrounded by the radially
protruding edge area, and projects into a recess that is defined by
the edge area. By virtue of the fact that the preferably axially
protruding edge section that comprises the second contact surface
projects into a recess of the edge area at the mounting element of
the combustion chamber shingle, an anti-rotation device for the
bolt head can also be provided. Here, the edge section meshes in a
form-fit manner into the recess, namely in such a way that any
twisting of the bolt head in relation to the edge area is blocked.
If a nut is screwed onto a bolt shaft of the bolt in order to
fixate the combustion chamber shingle at the combustion chamber
wall, the bolt is thus secured against any contortion.
[0014] In an exemplary embodiment, the bolt head is locally
thickened at the at least one second edge section in the axial
direction as viewed with respect to the longitudinal axis of the
bolt.
[0015] A locally thickened section has an extension that is larger
by at least 15% compared to adjoining sections of the bolt head. In
one embodiment variant, the extension is approximately twice as
large in the axial direction as the extension of adjoining sections
of the bolt head or of a mean extension of the usually disc-shaped
or plate-shaped bolt head. In other words, a wall thickness of the
bolt head is increased at the locally thickened section by at least
15% as compared to a mean wall thickness of the bolt head in order
to achieve a defined abutting arrangement of this locally thickened
section at the combustion chamber wall and, where necessary, a
sufficiently loadable securing against any contortion of the bolt
during the further mounting of the combustion chamber shingle in
the combustion chamber. In one embodiment variant, the height of
the locally thickened section is increased by approximately the
wall thickness of the edge area of the reception area as compared
to adjoining bolt head sections.
[0016] In order to thicken the bolt head in a defined manner only
in a local area, the locally thickened section of the bolt head
extends along a circumference of the bolt head with a length that
corresponds to at most a 1/3, preferably at most a 1/4 of the total
circumference of the bolt head.
[0017] Alternatively or additionally, the bolt head can be formed
in a conical manner in at least one edge section that is surrounded
by the edge area of the mounting element. Due to the conical
extension of the edge section, a contact surface is defined that is
tilted with respect to the longitudinal axis of the bolt. What is
understood here by a contact surface that is tilted with respect to
the longitudinal axis of the bolt is a surface that extends at an
angle of more or less than 90.degree. to a longitudinal axis of the
bolt and thus obliquely to the longitudinal axis of the bolt.
[0018] In one embodiment variant, a conically shaped edge section
of the bolt head becomes wider in the direction of a front side
that is defined by the bolt head and that is located opposite the
bottom side. Hence, such a conical edge section tapers off with
respect to an axial direction along which a bolt shaft for fixating
the combustion chamber shingle at the combustion chamber wall
connects to the bolt head.
[0019] It has been shown in experiments and simulations that when
it comes to the loads that occur at the bolt during operation, a
configuration of the bolt head can be advantageous in which the
bolt head is formed so as to be asymmetrical with respect to the
longitudinal axis of the bolt. Here, the bolt head may for example
have a base area that is formed by a rectangular surface and a
semicircular surface connecting to the same, as viewed along the
longitudinal axis of the bolt.
[0020] In one embodiment variant, an edge section is formed at the
bolt head, with that edge section or at least its contact surface
extending at least in one area so as to be tilted by an angle with
respect to a connection direction along which the bolt head is
inserted into the reception area of the mounting element of the
combustion chamber shingle. Through the edge section that extends
in a tilted manner with respect to the connection direction at
least in one area and that is for example conically shaped for this
purpose, the insertion of the bolt head into the reception area can
be facilitated, for example. Further, it can be ensured through
such a configuration of the edge section that the inserted bolt
head is locked inside the reception area if it has been inserted
according to the intended use.
[0021] Particularly for this purpose it can additionally be
provided that the radially protruding edge area of the mounting
element defines a channel for inserting the bolt head, with this
channel tapering off and extending along the connection direction.
At that, the taper degree of the channel can correspond to an angle
at which the at least one area of the edge section extends in a
tilted manner with respect to the connection direction. Thus, a
clearance between the edge section and the edge area at the channel
is reduced and a predefined alignment of the bolt head is ensured
inside the reception area through the tapering channel at the
mounting element and the obliquely extending area of the edge
section at the bolt head. Furthermore, it has been shown that
transverse forces acting on the bolt head during fixation of the
combustion chamber shingle at the combustion chamber wall can be
reduced in particular through designing the edge section of the
bolt head so that it extends in a manner tilted with respect to the
connection direction.
[0022] For reducing bending moments and transverse forces that
occur at the bolt head, it can further be provided either
alternatively or additionally that an edge section with a contact
surface for abutting arrangement at the radially protruding edge
area of the mounting element is formed at the bolt head, wherein
this contact surface extends in a tilted manner with respect to a
first spatial direction and to the longitudinal axis of the bolt as
well as with respect to a second spatial direction that is
perpendicular to the first spatial direction. In this way, the
contact surface can for example extend so as to be tilted with
respect to all three spatial directions that are perpendicular to
one another. Such a configuration has proven to be advantageous in
particular in combination with a bolt head that is shaped conically
at its edge. Here, a first conically shaped edge section may for
example be provided in a front part of the bolt head that is
located in the connection direction, wherein this front part may
for example have a semicircular base area with an edge that is
convexly arched in the connection direction. In that case, the edge
section with the contact surface that extends in a tilted manner is
provided at a second, rear part of the bolt head and is inserted
into the tapering channel of the mounting element, so that the
tilted contact surface of the bolt head edge abuts in a planar
manner to an inner surface of the channel that extends in a tilted
manner due to the taper. In this way, a compensation for transverse
forces and bending moments is achieved during mounting of the bolt
at the combustion chamber wall, which are introduced via the front
part of the bolt head and its form-fit mesh into the reception area
of the mounting element.
[0023] A preferably conically shaped transitional area is provided
for reducing a notch effect in the area of the transition between a
bolt shaft of the bolt, via which the combustion chamber shingle is
held at the combustion chamber wall, and the bolt head. The
transition between the bolt shaft, which for example supports an
external thread of the (thread) bolt, thus occurs along the
longitudinal axis of the bolt via a conically shaped section of the
bolt that consequently becomes wider in the direction of the bolt
head.
[0024] It has been shown in this context that a configuration of
the lateral surface of a correspondingly concavely arched
transitional area with a radius of curvature in the range of 1.0 to
3.5 times the diameter of the bolt shaft is particularly
advantageous for the long life fatigue strength of the bolt when it
is used in a combustion chamber of a gas turbine engine.
[0025] For the purpose of solving the task at hand, it is provided
according to another aspect of the invention that the bolt head
that is held in a form-fit manner at the reception area of the
combustion chamber shingle has a front side which is facing towards
a basal plane of the reception area and at which a concave internal
arching is provided that is arranged centrally with respect to a
bolt shaft of the bolt. The configuration of the bolt head with a
concave internal arching at its front side can of course be readily
combined with a configuration of the bolt head according to the
first aspect of the invention.
[0026] Through the concave internal arching, a recess is formed at
the front side of the bolt head that is offset with respect to the
basal plane of the reception area. Together with the basal plane,
this recess defines a central air chamber in the area of the
connection of the combustion chamber shingle to the bolt. Via this
air chamber between the bolt head and the surface of the combustion
chamber shingle in particular an improved cooling of the bolt
and/or of the combustion chamber shingle by means of a cooling air
flow can be achieved. Through the concave internal arching, a
volume for cooling air is made available that is increased as
compared to the volume of a cooling air gap as it would be defined
by a planar front side of the bolt head and a planar basal plane of
the reception area.
[0027] In the cross-section, the central concave internal arching
can have a radius of curvature which corresponds to at least one
sixth of a mean width of the bolt head in transverse direction to
the longitudinal axis of the bolt. In this manner, it is achieved
that the internal arching and the air chamber that is defined by it
take up a substantial part of the front side of the bolt head. It
can also be provided that the concave internal arching has a radius
of curvature in cross-section that corresponds to at least half of
the diameter of a bolt shaft of the bolt by which the combustion
chamber shingle is held at the combustion chamber wall. Here, the
concave internal arching is in particular preferably provided in
extension of the bolt shaft at the front side of the bolt head, and
is thus located below the bolt shaft in the mounted state of the
combustion chamber shingle according to the intended use.
[0028] In one embodiment variant, the internal arching is delimited
in cross-section by two convex bulges that protrude in the
direction of the basal plane. By means of the convex bulges, a
reduction of the tensions in the transitional area from the bolt
shaft to the bolt head is achieved. Here, the two convex bulges
that can be seen in cross-section can be formed by a collar or rim
that circumferentially extends at the front side and protrudes in
an elevated manner. In this case, such a protruding collar may
extend in a circular-ring-shaped manner at the front side of the
bolt head, for example.
[0029] Besides, it can be provided that the combustion chamber
shingle, in particular the mounting element, is provided with at
least one opening for a cooling air flow. Here, the at least one
opening can be provided at a basal plane of the reception area
and/or at a side wall of the reception area for the bolt head that
is protruding therefrom. In a further development that is based
hereon, multiple effusion cooling holes may for example be provided
at the mounting element, in particular in the area of the basal
plane.
[0030] Alternatively or additionally, the bolt can be formed with
at least one passage opening or passage channel for the supply of
cooling air to the bolt head and/or the combustion chamber shingle.
Here, a passage opening or passage channel is formed at a bolt
shaft and/or the bolt head in a preferably centric manner with
respect to the longitudinal axis of the bolt.
[0031] The bolt may be manufactured as a pressed part or by means
of metal powder injection molding or an additive manufacturing
method such as selective laser sintering, direct laser
depositioning, or by using laser deposition welding. The same
principally also applies to the mounting element of the combustion
chamber shingle as well as to the combustion chamber shingle
itself.
[0032] Although the assembly group according to the invention can
be used in gas turbines with a combustion chamber of any design, in
a preferred variant the use in a gas turbine engine is provided.
Here, the assembly group with the combustion chamber shingle and
the bolt for bearing the combustion chamber shingle can in
particular be used in a fire tube of a combustion chamber.
[0033] Other advantages and features of the invention will become
apparent in the following description of exemplary embodiments by
referring to the Figures.
[0034] Herein:
[0035] FIG. 1 shows a schematic sectional rendering of a gas
turbine engine in which an assembly group according to the
invention is used;
[0036] FIG. 2 shows a schematic sectional rendering of a combustion
chamber of the gas turbine engine of FIG. 1;
[0037] FIG. 3 shows, by sections, a top view of a combustion
chamber shingle that is used inside a fire tube of the combustion
chamber of FIG. 2;
[0038] FIGS. 4A and 4B schematically show sectional renderings for
illustrating fixations of the combustion chamber shingle to a
combustion chamber wall for the fire tube as they are known in the
state of the art;
[0039] FIG. 5A shows a sectional rendering of a bolt of a first
embodiment variant of an assembly group according to the invention
for mounting a combustion chamber shingle;
[0040] FIG. 5B shows a perspective view of a mounting element of a
combustion chamber shingle of the first exemplary embodiment of an
assembly group according to the invention, which forms a reception
area for a bolt head of the bolt of FIG. 5A;
[0041] FIG. 6A shows, by sections, a sectional rendering of a bolt
of a second embodiment variant of an assembly group according to
the invention, which has a bolt head that is conically shaped at
its edges;
[0042] FIG. 6B shows a sectional rendering of the mounting element
for the bolt head of FIG. 6A;
[0043] FIGS. 6C to 6E show different renderings of the bolt
according to the second embodiment variant;
[0044] FIG. 6F shows, by sections and in a perspective view, the
mounting element of FIG. 6B with a view into the internal space of
the reception area.
[0045] FIG. 1 shows a schematic sectional rendering of a gas
turbine engine T, which, among other parts, has a combustion
chamber section 15 with a combustion chamber that comprises an
assembly group that is designed according to the invention.
Otherwise, the gas turbine engine T is embodied in a per se known
manner and comprises, among other parts, an air inlet 11, a fan 12
that rotates inside an engine housing, a medium-pressure compressor
13 and a high-pressure compressor 14, which are arranged behind
each other along an engine axis 1. Connecting to the high-pressure
compressor 14 is the combustion chamber section 15, followed by a
high-pressure turbine 16, a medium-pressure turbine 17 and a
low-pressure turbine 18 along the engine axis 1. From the
low-pressure turbine 18, exhaust gas flows outward via an exhaust
nozzle 19 at the end of the gas turbine engine T.
[0046] The medium-pressure compressor 13 and the high-pressure
compressor 14 of a compressor unit of the gas turbine engine T
respectively comprise multiple stages, of which each has an
arrangement of fixed stationary guide vanes 20 that extend in the
circumferential direction. These guide vanes 20 are often also
referred to as stator blades, and they protrude radial inward from
a core 21 into a ring-shaped flow channel of the compressors 13 and
14. Further, the compressors 13 and 14 have multiple compressor
rotor blades 22 that protrude radially outward from a rotatable
compressor drum or compressor disc 26. This compressor drum or
compressor disc 26 is coupled to a turbine rotor hub 27 of a
turbine unit that is formed by the high-pressure turbine 16, the
medium-pressure turbine 17 and the low-pressure turbine 18.
Connecting to the compressor stages of the gas turbine engine T
with the medium-pressure compressor 13 and the high-pressure
compressor 14, is the combustion chamber section 15 in which the
driving energy for driving the turbine stages of the turbines 16,
17 and 18 is generated. Stationary guide vanes 23 are also
respectively provided in turbines 16, 17 and 18. They protrude
radially inward at the core 21 into a ring-shaped flow channel of
the turbines 16, 17 and 18. Further, radially outwardly protruding
turbine rotor blades 24 are provided at the turbine rotor hub
27.
[0047] During operation, the compressor drum or compressor disc 26
including the compressor rotor blades 22 that are attached thereat
as well as the turbine rotor hub 27 including the turbine rotor
blades 24 attached thereat rotate round the engine axis 1. Via a
shaft 25, a torque that is thus generated at the turbine rotor
blades 24 is transferred to the fan 12 in order to drive it and to
suction in an air flow into the gas turbine engine 1 along an entry
direction A. At that, the sucked-in air is divided in a known
manner into a primary air flow and a secondary air flow, in
particular in order to obtain the greater part of the total thrust
from the secondary air flow. The secondary air flow is conducted
externally past the core 21 inside of which the compressor 13 and
14, the combustion chamber section 15 as well as the turbines 16,
17 and 18 are arranged. A that, the secondary air flow is conducted
past the core 21 along the engine axis 1 inside a bypass channel
10. By contrast, the primary air flow is conducted to the
compressors 13 and 14 and subsequently into the combustion chamber
of the combustion chamber section 15.
[0048] In the sectional rendering of FIG. 2, a configuration of a
combustion chamber 3 of this combustion chamber section 15 is
shown. Here, the combustion chamber 3 comprises, among other parts,
a fuel nozzle 29 that is supported inside a combustion chamber
head. Via the fuel nozzle 29, fuel is injected into a fire tube 300
of the combustion chamber 3 that defines the combustion space of
the combustion chamber 3. This fire tube 300 is accommodated inside
a cavity that is defined by a combustion chamber exterior housing
30 and a combustion chamber interior housing 31 of the combustion
chamber 3. The exhaust gases of the mixture that is ignited inside
the combustion space of the fire tube 300 reach the high-pressure
turbine 16 via a turbine inlet guide vane row 33, so that the
turbine stages are set into rotation. The combustion space of the
fire tube 300 is delimited by a combustion chamber wall 32 of the
combustion chamber 3, at which combustion chamber shingles 34 are
internally arranged. Thus, the combustion chamber wall 32 encloses
the combustion space of the combustion chamber 3 and supports the
combustion chamber shingles 34 by which the combustion chamber wall
32 is clad so as to facilitate additional cooling and to withstand
the high temperatures that are present inside the combustion
space.
[0049] Here, the combustion chamber shingles 34 are respectively
supported at the combustion chamber wall 32 by one or multiple
bolts 4. Here, each bolt 4 extend through an opening at the
combustion chamber wall 32 and is fixated at the combustion chamber
wall 32 by means of one nut 6, respectively. Cooling of the
respective combustion chamber shingle 34 is facilitated through
multiple effusion cooling holes 340 that are provided at the
combustion chamber shingle 34 according to FIG. 3. In addition, a
combustion chamber shingle 34 can have at least one admixing hole
35 via which air can flow into the combustion space from an
exterior space that surrounds the fire tube 300. Here, the air that
flows through an admixing hole 35 serves for cooling down and/or
the leaning the combustion.
[0050] At that, the exterior space that surrounds the fire tube
300, for example in the form of an annular channel, forms an air
supply 36 for the admixing holes 35 and the effusion cooling holes
340. Air that flows into the combustion chamber 3 along an inflow
direction Z is divided in the area of the fuel nozzle 29 through a
cup-shaped section into a primary air flow for the combustion space
of the fire tube 300 and a secondary air flow for the exterior
space including the air supply 36 that surrounds the fire tube 300.
Here, the air usually flows into the combustion chamber 3 via a
diffusor (not shown in FIG. 2).
[0051] So far, the fixation of the combustion chamber shingle 34 at
the combustion chamber outside wall 32 has been regularly carried
out by means of bolts 4 that are formed integrally with a
combustion chamber shingle 34, as is illustrated in an exemplary
manner in a sectional rendering in FIGS. 4A and 4B. Here, a bolt
shaft 40 of a bolt 4 that is formed at the inner side of the
combustion chamber shingle 34 has a thread 42 at its top end. With
the bolt shaft 40 extending through an opening in the combustion
chamber wall 32 and being screwed on from the outside onto a nut 6,
the combustion chamber shingle 34 is mounted at the combustion
chamber wall 32 according to the intended use, so that it is
internally supported against the combustion chamber wall 32 through
a support 341 of the combustion chamber shingle 34.
[0052] The manufacture of a combustion chamber shingle 34 is
usually carried out particularly by means of casting and applying a
ceramic coating, or through an additive manufacturing method, such
as for example selective laser sintering, direct laser
depositioning, or by means of electron beam weld cladding. However,
a bolt 4 that is formed integrally at the combustion chamber
shingle 34 renders particularly manufacture by means of additive
manufacturing methods more difficult. Moreover, problems due to
creeping of the material are often observed during operation, which
can lead to a failure of the bolt 4 and thus to a loss of the
combustion chamber shingle 34. The solution according to the
invention provides a remedy for this problem, with exemplary
embodiments of the invention being described in the following in
more detail by referring to FIGS. 5A to 5B and 6A to 6F.
[0053] What both variants of FIGS. 5A to 5B and 6A to 6F have in
common is that the bolt 4 is formed as a separate structural
component and is inserted into a reception area 50 of a mounting
element 5 at the combustion chamber shingle 34 and is anchored
therein in a form-fit manner. Here, the bolt 4 respectively forms a
disc-shaped bolt head 41 that can be inserted into the reception
area 50 at the combustion chamber shingle 34 along a connection
direction V, that extends transverse to a longitudinal axis of the
bolt M. For this purpose, the reception area 50 of the mounting
element 5 that is formed in one piece at the combustion chamber
shingle 34 is formed in a pouch-shaped manner and is open towards a
transverse side, so that the bolt head 41 of a bolt 4 can be
inserted into it along the connection direction V and can be
supported in a form-fit manner inside the reception area 50. Here,
in order to secure the bolt head 41 at the reception area 50 in a
form-fit manner, the mounting element 5 forms substantially
radially protruding, web-shaped edge areas 51, surrounding the bolt
head 41 that is inserted into the reception area 50 at the edge
side.
[0054] In the exemplary embodiment of FIGS. 5A and 5B, the bolt
head 41 is formed in a disc-shaped manner and so as to be
asymmetrical with respect to the longitudinal axis of the bolt M.
The bolt head 41 has a semicircular base area at a front part, as
viewed in the connection direction V, while a rear part of the bolt
head 41, at which the bolt shaft 40 protrudes, has a rectangular
base area.
[0055] At its rear part, the disc-shaped bolt head 41 is provided
with a superstructure 46, which defines a local thickening of an
edge section of the bolt head 41 at a bottom side of the bolt head
41. Through this superstructure 46, a wall thickness of the bolt
head 41 is locally increased and namely in an area in which the
edge of the bolt head 41 is not surrounded by the radially
protruding edge area 51 of the mounting element 5 and can
internally abut at the edge area 51 via (first) contact surfaces.
Thus, the superstructure 46 is provided at a rear part of the bolt
head 41 with respect to the connection direction V, which is
present at the open side of the pouch-shaped reception area 50 if
the bolt 4 is inserted therein according to the intended use. Here,
the height of the superstructures 46 is dimensioned in such a
manner that the superstructure 46 is flush with the edge area 51 of
the mounting element 5 and thus the bolt head 41 can directly abut
at the combustion chamber wall 32 via a (second) contact surface
460 if the nut 6 is screwed onto the bolt shaft 40 in order to
fixate the combustion chamber shingle 34 at the combustion chamber
wall 32. Thus, on the one hand, the bolt head 41 can directly
locally abut at the combustion chamber wall 32 via the
superstructure 46 and, on the other hand, can be supported at the
edge area 51 of the mounting element 5 in the present case along
more than 60%, e.g. approximately 70% to 80%, of its total
circumference. In the present case, the superstructure 46 has
approximately the same thickness as the edge area 51.
[0056] If mounted at the combustion chamber wall 32 according to
the intended use, the edge area 51, which is U-shaped in top view,
as well as the superstructure 46 respectively abut in a planar
manner at the combustion chamber wall 32. In this manner, it is
avoided that the bolt head 41 is too tightly wound inside the
reception area 50 as the nut 6 is being tightened, and that it
becomes subject to undesired bending moments in the course of the
mounting process, which ultimately lead to a failure of the bolt 4
during operation of the gas turbine engine T. Through the
superstructure 46 at the bolt head 41, the bolt 4 is further also
secured against any twisting relative to the mounting element 5, if
the bolt head 41 is inserted into the reception area 50. For this
purpose, the superstructure 46 is embodied with such a width that
is surrounded by the radially protruding edge areas 51 of the
mounting element 5 that are located transversely opposite with
respect to the longitudinal axis of the bolt M. Consequently, the
superstructure 46 abuts the edge area 51 or at least comes into an
abutting arrangement with the same at opposite positions
transversely to the longitudinal axis of the bolt M in order to
block any twisting of the bolt 4 around the longitudinal axis of
the bolt M. In this manner, the bolt 4 remains in a defined
position relative to the combustion chamber shingle 34 if it is
mounted at the combustion chamber wall 32 and the nut 6 is screwed
to the bolt shaft 40. Thus, an anti-rotation device is integrally
formed at the bolt head 41 through the superstructure 46.
[0057] Further, the reception area 50 has a basal plane 500 above
which the edge area 51 of the mounting element 5, which is
protruding substantially in the radial direction and extending
partially along the circumference of the longitudinal axis of the
bolt M, extends. This basal plane 500 at the surface of the
combustion chamber shingle 34 is faced by a front side 410 of the
bolt head 41 when the bolt head 41 is inserted into the reception
area 50 according to the intended use. In order to provide an air
chamber with a comparatively large volume for the through-flow of
cooling air between the front side 410 and the basal plane 500, the
front side 410 is not embodied in a planar manner, but rather has a
concave internal arching 43 that is preferably arranged centrally
with respect to the bolt shaft 40. The concave internal arching 42
has an inner radius that substantially corresponds to the radius of
the circular cylindrical bolt shaft 40.
[0058] The concave internal arching 43 is rimmed by a collar that
is formed in the manner of a circular-ring and protrudes in an
elevated manner at the front side 410. Extending from this collar
at the front side 410 of the bolt head 41, two convex bulges 44,
which are arranged at a distance from each other in the transverse
direction with respect to the longitudinal axis of the bolt M, can
be seen in the sectional rendering of FIG. 5A. The collar that
surrounds the concave internal arching 43 is thus formed in a
bead-like manner. Connecting to this collar in the radial direction
or transverse direction is respectively one outer edge 45 of the
bolt head 41. In this way, the bead-like collar surrounding the
concave internal arching 43 is arranged at a distance to the
outermost edge 45 of the bolt head 41 in the radial direction.
Through the bead-shaped collar at the front side of the bolt head
41 tensions occurring in a transitional area 411 between the bolt
shaft 40 and the bolt head 41 are reduced. Here, the thickness of
the collar is dimensioned in such a way that a gap for cooling air
still remains between this collar and the basal plane 500 if the
bolt head 41 is inserted into the reception area 50 according to
the intended use and the combustion chamber shingle 34 is mounted
according to the intended use.
[0059] Further, a recess 501 is provided at a side wall of the
reception area 50 that is protruding in the axial direction for the
purpose of providing a cooling air flow to the combustion chamber
shingle 34. Via the recess 501, a cooling air flow can be guided to
an external side of the combustion chamber shingle 34 that is
facing away from the combustion space. This cooling air flow can
for example be guided to the mounting element 5 through a passage
channel (not shown in FIG. 5A) that is formed inside the bolt shaft
40 (cf. also FIG. 6D).
[0060] Further, the bolt 4 of the embodiment variant of FIGS. 5A
and 5B (as well as the bolt 4 of the variant of FIGS. 6A to 6F) is
optimized in the area of the transition between the bolt shaft 40
and the bolt head 41, so that no increased risk of failure due to a
possible notch effect is present in this area. Thus, a conically
shaped transitional area 411 is provided between the bolt shaft 40
and the bolt head 41. This conical transitional area 410 has a
concave arching with a radius of curvature R40. In the present
case, this radius of curvature R40 substantially corresponds to the
radius of the circular cylindrical bolt shaft 40. However, the
shape-optimized transitional area 410 may have a contour that
deviates from the shape of a circular ring.
[0061] In the further exemplary embodiment according to the FIGS.
6A to 6F, a design of the bolt head 41 as well as of the reception
area 50 at the combustion chamber shingle 34 has been chosen that
differs from the variant of the FIGS. 5A and 5B. As can in
particular be seen from the sectional renderings of the bolt head
41 and the mounting element 5 in the FIGS. 6A and 6B, in this case
the edge of the bolt head 41, which is surrounded in a form-fit
manner inside the reception area 50 by the edge area 51 of the
mounting element 5, has a conical shape. Accordingly, the edge of
the bolt head 41 continuously becomes wider in the direction of its
front side 41 or tapers off in the direction of the bolt shaft 40.
Correspondingly, the edge area 51 of the mounting element 5 forms
conically extending contact surfaces for an abutting arrangement of
the edge of the bolt head 41 that is surrounded by it. Thus, the
edges of the bolt head 41 that are provided for the form-fit
anchoring of the bolt 4 at the mounting element 5 form contact
surfaces that do not only extend in a flat plane that is
perpendicular to the longitudinal axis of the bolt M. Rather, the
contact surfaces of the bolt head 41 that are provided for the
abutting arrangement at the edge area 51 of the mounting element 5
are formed so as to be tilted with respect to the longitudinal axis
of the bolt M, and namely so as to be tilted in the direction of
the basal plane 500 of the reception area 50.
[0062] Further, as compared to the embodiment variant of FIGS. 5A
and 5B, the bolt head 41 has an enlarged concave internal arching
43 at its front side 410 that is facing towards the basal plane
500. Thus, here the internal arching 43 spans almost the entire
width of the bolt head 41 in the cross-section. For example, a
radius of curvature R43 of the concave internal arching is more
than twice as large as the radius of the circular cylindrical bolt
shaft 40. In this manner, a comparatively narrow support 41 is
achieved at the basal plane 500 of the reception area 50 in
combination with the conical configuration of the edge of the bolt
head 41. In addition, in this way the bolt head 41 is aligned
inside the reception area 50 already during insertion, so that the
bolt head 41 abuts at the edge area 51 of the mounting element 5 in
a planar manner in particular after the combustion chamber shingle
34 has been mounted at the combustion chamber wall 32. In this
manner, a self-centering of the bolt head 41 inside the reception
area 50 is achieved by means of the conical design of the edge of
the bolt head 41 if the bolt head 41 is inserted into the reception
area 50 along the connection direction V and thus transversely to
the longitudinal axis of the bolt.
[0063] For optimizing the force path and for reducing undesired
transverse forces and bending moments, the shape of the reception
area 50 and of the edge area 51 of the mounting element 5 are also
embodied in an alternative manner. Thus, the edge area has concave
and convex areas that transition into each other and have
approximately corresponding radiuses r.sub.a, r.sub.i. Further, the
substantially radially protruding edge areas 51 of the mounting
element 5 have a wall thickness d1, d2 that changes starting from
the basal plane 500. Here, a wall thickness d2 of the edge area 51
is increased in the area of the abutting arrangement of the conical
edge of the bolt head 41 as compared to a wall thickness d1 in an
area that is located near the basal planes 500, so that a higher
strength is ensured.
[0064] As can in particular be seen from FIGS. 6D and 6E, in the
shown exemplary embodiment the bolt head 41 is formed with a base
area that is formed by a rectangular shape with a semicircle
connecting thereto. Here, the semicircle with a radius Ra is
present at a front side of the bolt head 41 in the connection
direction V, which is completely surrounded by the edge area 51 of
the mounting element 5 if the bolt head 41 is inserted into the
pouch-shaped reception area 50 according to the intended use. The
radius Ra of the front semicircle of the base area corresponds to
half the width b of the rectangular shape. Here, the end of the
bolt head 41 that is defined by the semicircular base area and is
located in the connection direction V is embodied in an overhanging
manner with respect to the rear end with the rectangular base area
by means of an off-set arrangement of the center point of the front
semicircle with respect to the longitudinal axis of the bolt M in
connection direction V. Further, the length a of the rectangular
shape that extends along the connection direction V is smaller than
its width b and the radius Ra of the semicircle.
[0065] The individual parts of the base area of the bolt head 41
define different edge sections 41a and 41b that are surrounded by
the edge area 51 of the mounting element 5 when the bolt head 41 is
inserted and internally abut at the edge area 51 via the contact
surfaces 412 when the combustion chamber shingle 34 is mounted at
the combustion chamber wall 32. While a first edge section 41a is
formed along a circle line at the front side of the bolt head 41,
the edge sections 41b with the length a extend along the connection
direction V. Thanks to the asymmetric configuration of the bolt
head 41 with respect to the longitudinal axis of the bolt M that is
thus created, the bolt head 41 that is inserted into the reception
area 50 is secured against any twisting around the longitudinal
axis of the bolt M if the nut 6 is screwed on.
[0066] In the present case, the two edge sections 41b of the bolt
head 41, which extend along the connection direction V, are
respectively divided into two partial areas 41ba and 41bb. The
partial area 41bb is located between the partial area 41ba and the
front edge section 41a. This partial area 41bb is formed conically
and so as to become wider towards the front side of the bolt head
41. In addition, the rear partial area 41ba, as viewed in the
connection direction V, is tilted with respect to the connection
direction V by an angle .alpha..sub.4. Thus, in the partial area
41ba, the edge section 41b forms a contact surface 412 for abutting
arrangement at the substantially radially protruding edge area 51
of the mounting element 5, with the contact surface 412 extending
in a tilted manner with respect to a first spatial direction x that
coincides with the connection direction V and the longitudinal axis
of the bolt M, as well as extending in a tilted manner with respect
to a second spatial direction y that is perpendicular to the first
spatial direction x and the connection direction V. This complex
design of the edge section 41b at the partial area 41ba, which is
illustrated particularly with a view to FIG. 6C, at least partially
compensates the conical shape at the front side of the bolt head 41
in order to reduce transverse forces that are acting on the bolt
head 41 as a result of the fixation at the combustion chamber wall
32.
[0067] Further, a channel corresponding to the geometry of the
partial area 41ba is formed at the edge area 51 of the mounting
element 5. This channel tapers off reversely to the connection
direction V, or becomes wider in the connection direction V, and
thus ensures a defined planar abutting arrangement at the edge area
51 of the contact surface 412 of the partial area 41ba which
extends transversely in two respects if the bolt head 41 is
inserted into the reception area 50. For the purpose of configuring
the channel that tapers off reversely to the connection direction
V, the edge area 51 has areas 51a, 51b that are protruding in a
web-like manner and have a wall thickness that continuously
diminishes along the connection direction V from a maximum value d3
to a minimum value d4. Due to the continuously changing wall
thickness, the rear section of the channel, as viewed in the
connection direction V, extends at an angle .alpha..sub.5 with
respect to the connection direction V, wherein this angle
.alpha..sub.5 substantially corresponds to the angle .alpha..sub.4
at the rear partial area 41ba of the bolt head 41. Thus, those
areas of the edge area 51 that connect to each other along the
connection direction V and protrude in a web-like manner on the one
hand have a changing wall thickness in a rear part for defining the
expanding channel and for surrounding of the back or rear edge
section 41b of the bolt head 41, and on the other hand have a
constant wall thickness d4 in a front part for surrounding the
front edge section 41a of the bolt head 41.
[0068] In this way, by virtue of the interaction of the edge area
51 and the channel which is defined by it and into which an edge of
the bolt head 41 is inserted, namely with the edge section 41b of
the bolt head 41 that forms contact surfaces 412 that are oriented
differently with respect to the connection direction V, not only a
centering of the bolt head 41 inside the reception area 50 during
insertion of the bolt head 41 is achieved, but in this way also a
defined alignment of the bolt head 41 in the axial direction and a
defined abutting arrangement at an inner side of the edge area 51
of the mounting element 5, which is not completely circumferential,
is obtained if the combustion chamber shingle 34 is fixedly
attached at the combustion chamber wall 32 by means of the bolt
4.
[0069] Although this is not shown in 6A to 6F, here, too, it can be
provided in a further development that the bolt head 41 has a local
thickening at an area of its edge that is located in the rear with
respect to the connection direction V, so as to further reduce a
bending moment that occurs during mounting and to provide
additional securing against any contortion of the bolt 4 during the
attachment of the nut 6.
[0070] Further, alternatively or additionally also a bolt washer
with a conical contact surface can be provided for the recovery of
lost bolt pretension due to creeping. Such a bolt washer is fit
onto the bolt shaft 40 and is arranged between the nut 6 and the
combustion chamber wall 32 after the combustion chamber shingle 34
has been fixated.
[0071] As is indicated in an exemplary manner in FIG. 6D, the bolt
shaft can have a passage channel 400 for cooling air that is
arranged centrally inside the bolt shaft. Via this passage channel
400, the cooling air can then flow via the bolt shaft 400 into the
air chamber that is defined with the concave internal arching 43d
and thus in particular to the bolt head 41 and the combustion
chamber shingle 34. Alternatively or additionally, the pouch-shaped
reception area 50 can have cooling air openings at its side
walls.
[0072] Particularly the bolt 4, which can be inserted into the
respective reception area 50 of the combustion chamber shingle 34
as a separate structural component, can be manufactured by means of
selective laser sintering, direct laser depositioning, by means of
electron beam weld cladding, as a pressed part or through metal
powder injection molding. The same principally also applies to the
mounting element 5 of the combustion chamber shingle 34 as well as
to the combustion chamber shingle 34 itself. Thanks to the at least
two-part superstructure, it is possible to manufacture the bolt 4
and the combustion chamber shingle 34 separately from each other.
In this way, it is also possible to choose independently of each
other the materials for the combustion chamber shingle 34 on the
one hand and the bolt 4 that is used to mount the combustion
chamber shingle 34 at the combustion chamber wall 32 on the other
hand. Particularly by embodying the bolt head 41 with the geometry
according to the invention, the form-fit connection between the
bolt head 41 and the combustion chamber shingle 34 is optimized in
a targeted manner, so that for example undesired bending moments
and transverse forces acting onto the bolt head 41 during the
fixation of the combustion chamber shingle 34 at the combustion
chamber wall 32 can be considerably reduced or even completely
avoided as compared to solutions known to date. Here, it is of
course possible to fixate the combustion chamber shingle 34 at the
combustion chamber wall 32 by means of multiple (at least two)
separate bolts 4, for which purpose it would have multiple mounting
elements 5 that, where necessary, can also be oriented differently
with respect to each other.
PARTS LIST
[0073] 1 engine axis [0074] 10 bypass channel [0075] 11 air inlet
[0076] 12 fan [0077] 13 medium-pressure compressor [0078] 14
high-pressure compressor [0079] 15 combustion chamber section
[0080] 16 high-pressure turbine [0081] 17 medium-pressure turbine
[0082] 18 low-pressure turbine [0083] 19 exhaust nozzle [0084] 20
guide vane [0085] 21 core [0086] 22 compressor rotor blade [0087]
23 guide vane [0088] 24 turbine blade [0089] 25 shaft [0090] 26
compressor drum or compressor disc [0091] 27 turbine rotor hub
[0092] 28 outlet cone [0093] 29 fuel nozzle [0094] 3 combustion
chamber [0095] 30 combustion chamber exterior housing [0096] 300
fire tube [0097] 31 combustion chamber interior housing [0098] 32
combustion chamber wall [0099] 33 turbine inlet guide vane row
[0100] 34 combustion chamber shingle [0101] 340 effusion cooling
hole [0102] 341 support [0103] 35 admixing hole [0104] 36 air
supply [0105] 4 bolt [0106] 40 bolt shaft [0107] 400 passage
channel [0108] 41 bolt head [0109] 410 front side [0110] 411
transitional area [0111] 412 contact surface [0112] 41a, 41b edge
section [0113] 41ba, 41bb partial area [0114] 42 thread [0115] 43
internal arching [0116] 44 bulge [0117] 45 outer edge [0118] 46
superstructure (locally thickened edge section) [0119] 460 contact
surface [0120] 5 mounting element [0121] 50 reception area [0122]
500 basal plane [0123] 501 recess [0124] 51 edge area [0125] 51a,
51b area protruding in a web-like manner [0126] 6 nut [0127] A
entry direction [0128] a, b length [0129] d1, d2, d3, d4 wall
thickness [0130] M longitudinal axis of the bolt [0131] R40, R41,
R43 radius of curvature [0132] Ra radius [0133] r.sub.a, r.sub.i
radius [0134] T gas turbine engine [0135] V connection direction
[0136] Z inflow direction [0137] .alpha..sub.4, .alpha..sub.5
angle
* * * * *