U.S. patent application number 15/808162 was filed with the patent office on 2018-05-10 for combustion chamber of a gas turbine.
The applicant listed for this patent is Rolls-Royce Deutschland Ltd & Co KG. Invention is credited to Miklos GERENDAS.
Application Number | 20180128487 15/808162 |
Document ID | / |
Family ID | 60301838 |
Filed Date | 2018-05-10 |
United States Patent
Application |
20180128487 |
Kind Code |
A1 |
GERENDAS; Miklos |
May 10, 2018 |
COMBUSTION CHAMBER OF A GAS TURBINE
Abstract
A combustion chamber of a gas turbine, with at least one shingle
that including a plate-shaped shingle body that has a
circumferential shingle edge which is raised from the side that is
facing away from the combustion chamber interior space, and which
abuts against a combustion chamber wall in the mounted state of the
shingle, wherein the shingle body is provided with an arrangement
of effusion cooling holes, and the combustion chamber wall is
provided with an arrangement of impingement cooling holes in the
area of the shingle, wherein the arrangement of impingement cooling
holes has a lateral distance to the shingle edge that is between
1.5 and 2 times the distance of the surface of the combustion
chamber wall to the surface of the shingle body, and that the
distance of the arrangement of impingement cooling holes is between
1.1 and 3 times the lateral distance in the corner areas of the
shingle.
Inventors: |
GERENDAS; Miklos; (Am
Mellensee, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rolls-Royce Deutschland Ltd & Co KG |
Blankenfelde-Mahlow |
|
DE |
|
|
Family ID: |
60301838 |
Appl. No.: |
15/808162 |
Filed: |
November 9, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R 2900/03044
20130101; Y02T 50/675 20130101; F23R 3/04 20130101; F23R 2900/03041
20130101; Y02T 50/60 20130101; F23R 3/002 20130101 |
International
Class: |
F23R 3/04 20060101
F23R003/04; F23R 3/00 20060101 F23R003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 2016 |
DE |
10 2016 222 099.3 |
Claims
1. A chamber of a gas turbine, with at least one shingle that
comprises a plate-shaped shingle body having a circumferential
shingle edge which is raised from the side that is facing away from
the combustion chamber interior space, and which abuts against a
combustion chamber wall in the mounted state of the shingle,
wherein the shingle body is provided with an arrangement of
effusion cooling holes, and the combustion chamber wall is provided
with an arrangement of impingement cooling holes in the area of the
shingle, wherein the arrangement of impingement cooling holes has a
lateral distance to the shingle edge which is between 1.5 and 2
times the distance of the surface of the combustion chamber wall to
the surface of the shingle body, and in that the distance of the
arrangement of impingement cooling holes is between 1.1 and 3 of
the lateral distance in the corner areas of the shingle.
2. The combustion chamber according to claim 1, wherein the
distance in the corner areas is between 1.5 and 2.5 of the
distance.
3. The combustion chamber according to claim 1, wherein the corner
area of the arrangement of impingement cooling holes is embodied in
a linear manner.
4. The combustion chamber according to claim 1, wherein the corner
area of the arrangement of impingement cooling holes is embodied in
a rounded-off manner.
5. The combustion chamber according to claim 1, wherein the
arrangement of effusion cooling holes comprises the entire shingle
body.
6. The combustion chamber according to claim 5, wherein effusion
cooling holes are arranged inside the distance (A).
7. The combustion chamber according to claim 5, wherein the ratio
of the number of impingement cooling holes to the number of
effusion cooling holes is 1:1 to 1:3.
8. The combustion chamber according to claim 7, wherein
respectively at least one row of effusion cooling holes is arranged
inside the distance, wherein the number of rows of effusion cooling
holes inside the distance corresponds to the ratio of the number of
impingement cooling holes to the number of effusion cooling holes.
Description
[0001] The invention relates to a combustion chamber of a gas
turbine according to the features of the generic term of claim
1.
[0002] Specifically, the invention relates to a combustion chamber
of a gas turbine which is covered with shingles. At least one
shingle comprises a plate-shaped shingle body which has a
circumferential shingle edge. It extends from the cold side of the
shingle body that is facing away from the combustion chamber's
interior space to the combustion chamber wall and thus forms an
intermediate space between the shingle body and the combustion
chamber wall. Cooling air is introduced into this intermediate
space through impingement cooling holes, and is subsequently
discharged through effusion cooling holes of the shingle body
located at its surface. For this purpose, the shingle body is
provided with an arrangement of effusion cooling holes, which may
for example be embodied in a row-shaped manner or with another
arrangement with respect to each other. The impingement cooling
holes of the shingle wall are also embodied in a suitable
arrangement.
[0003] As for the state of the art, at first EP 0 576 435 B1 is
referred to. It shows a structure that is illustrated in FIG. 2.
Here, it is shown that a shingle 25 has a substantially
plate-shaped shingle body 29 that is delimited by a shingle edge
31. The shingle edge 31 extends from the shingle body 29 in the
direction towards the combustion chamber wall 32 to form an
intermediate space 35. The combustion chamber wall 32 is provided
with impingement cooling holes 34 to introduce cooling air into the
intermediate space 35. This cooling air flows out of the
intermediate space 35 through the effusion cooling holes 33 that
are formed in the shingle body 29. Due to the fact that the shingle
edge 31 cannot be arranged in a sealing manner at the combustion
chamber wall 32, there is always a leakage, which is illustrated as
leakage air 36. Thus, a part of the air volume that is supplied
through the impingement cooling holes 34 flows from the
intermediate space 35 unused as leakage air 36, and cannot be used
to flow through the effusion cooling holes 33.
[0004] FIG. 3 shows a similar structure, wherein the same parts are
indicated by the same reference signs. With regard to this,
reference is made to U.S. Pat. No. 5,598,697 A. Although this
construction differs from the constructional principles according
to the invention, it shows that either leakage air 36 flows out of
the intermediate space 35 and cannot be used for effusion cooling
holes 33, or a seal 38 has to be used.
[0005] The sealing of the impingement cooling cavity by means of an
additional seal is also known from EP2354660 (rigid seal),
EP1310735 (elastic seal), U.S. Pat. No. 7,140,185 (coating). Common
to all seal-based solutions are the higher costs resulting from the
manufacture of the seal, the greater mounting effort due to the
mounting of the seal, and the risk of the seal failing.
[0006] Thus, in the state of the art there is the problem that a
sealing of the intermediate space between the shingle and the
combustion chamber wall is not possible without additional effort,
or is only possible to a limited extent. This results in a leakage
air or leakage flow, as a result of which cooling air flows unused
from the intermediate space between the combustion chamber wall and
the shingle body, and is not available for cooling through the
effusion cooling holes.
[0007] Further, EP 1 351 022 B1 is quoted as the state of the
art.
[0008] The invention is based on the objective of creating a
combustion chamber of a gas turbine which ensures an effective use
of the cooling air in the area of the shingle, while at the same
time having a simple structure and a single, cost-effective
manufacturability.
[0009] According to the invention, the objective is achieved by a
combination of features of claim 1, with the subclaims showing
further advantageous embodiments of the invention.
[0010] Thus, it is provided according to the invention that the
arrangement of impingement cooling holes has a distance to the
shingle edge which lies between 1.5 to 2 times the distance of the
surface of the combustion chamber wall to the surface of the
shingle body, and that in the corner areas of the shingle the
distance of the arrangement of impingement cooling holes is between
1.1 and 3 times the above-mentioned distance.
[0011] The invention is based on the basic principle of designing
the inflow of cooling air into the intermediate space formed by the
shingle in such a manner that the supply of cooling air through the
impingement cooling holes occurs in the middle area of the shingle
body, i.e. up to a distance from the shingle edge. As the effusion
cooling holes extend across the entire surface of the shingle body,
the cooling air can be discharged through the sufficiently
dimensioned effusion cooling holes. This flow of air is caused by
the resulting pressure difference across the shingle. In a
completely sealed shingle edge, the air flows though all of the
effusion bore holes, without any dead bands of the flow being
formed. In a complete sealing, the pressure gradient in the
intermediate space causes only very small amounts of air to flow as
leakage air via the shingle edge. In total, there is thus little
reason why the cooling air flowing in through the impingement
cooling holes should enter as leakage air via the shingle edge.
[0012] In the constructions of double-wall combustion chambers as
they are already known from the state of the art, the shingle is
usually bolted onto the combustion chamber wall without any seals.
Such seals would be elaborate and cost-intensive. In addition,
thermal expansions and contractions always lead to minor gap
formation. In addition, manufacturing tolerances also exclude a
completely sealed abutment of the shingle edge at the combustion
chamber wall. Further, it should be noted that the geometry of
combustion chambers of gas turbines is very complex and does not
always allow for a complete sealing of the shingle edge. In this
context, it is to be understood that the person skilled in the art
knows what is to be understood by the term "gas turbine", namely an
aircraft gas turbine or a stationary gas turbine. The invention can
be used with both. Thus, the solution according to the invention
makes it possible to use substantially the entire volume of cooling
air for the purpose of cooling the shingles, namely, on the one
hand, for cooling the cold surface of the shingle that is facing
away from the combustion chamber interior space by means of
impingement cooling and, on the other hand, for film cooling by
means of the air that is discharged through the effusion cooling
holes. Since what results according to the invention is a
considerable or complete reduction of the leakage flow, the present
invention results in a considerable increase of the efficiency of
the shingle cooling.
[0013] Thus, it is provided according to the invention that the
impingement cooling holes are not formed up to the shingle edge,
but that the arrangement of impingement cooling holes is chosen in
such a manner that each impingement cooling hole has a distance
from each shingle edge through which a leakage may occur. This
distance is chosen in such a manner that it is defined based on the
free jet length of the impingement cooling jet. The free jet length
is the path length between the exit site of the cooling air from
the impingement cooling hole and impingement site on the cold
surface of the shingle body that is facing away from the combustion
chamber's interior space. The volume of the intermediate space
between the combustion chamber wall and the shingle body is also
defined based on this free jet length. According to the invention,
the distance of the impingement cooling holes from the shingle edge
is dimensioned in such a manner that it corresponds to at least 1.5
times the free jet length of the impingement cooling jet. The
distance can be up to 2 times the free jet length, with this value
being a preferred value. Thus, by defining the distance it is thus
ensured that a sufficient number an effusion holes is present
between the edge area of the arrangement with impingement cooling
holes or of the field which is formed by the impingement cooling
holes and the shingle edge. The cooling air which is discharged
through the edge-side impingement cooling holes and wants to move
in the direction towards the shingle edge thus impinges on a
sufficient number of effusion holes and can be discharged through
them. Thus, any discharge of this air flow in the form of leakage
air is avoided.
[0014] Combustion chamber shingles are usually formed in a
rectangular, more seldom in an triangular or diamond-shaped,
manner. The result is a corner area of the shingle edges in the two
neighboring edge areas, which meet in the corner area and in which
no impingement cooling holes are present, meet. To ensure that a
sufficient outflow of the impingement cooling air through the
effusion cooling holes is ensured also in the corner areas, it must
be considered that, according to the invention, the edge distances
between the shingle edge and the arrangement of impingement cooling
holes are linearly added. According to the invention, a bevel or
rounding is formed here in the arrangement of the impingement
cooling holes. According to the invention, in an advantageous
embodiment this beveled or rounded area is defined by a factor that
can be referred to as the overlay constant. This overlay constant
has a value of 1.1 to 3, preferably of 1.5 to 2.5, ideally of 2.
The distance in the corner area is enlarged by the factor of the
overlay constant to ensure that the intermediate space between the
shingle body and the combustion chamber wall is passed by the flow
to the desired extent.
[0015] Thus, according to the invention a smaller projected surface
results for the arrangement of impingement cooling holes than for
the arrangement of effusion cooling holes. The arrangement of
impingement cooling holes is thus shifted away from the shingle
edge, and is set at a distance to the same. To ensure a reliable
through-flow of cooling air as well as the generation of a suitable
pressure gradient in this embodiment, it is possible according to
the invention to respectively form the impingement cooling holes
with an enlarged diameter as compared to the embodiment according
to the state of the art, in which the arrangement of impingement
cooling holes extends across the entire surface of the shingle. As
an alternative, it is also possible to provide a larger number of
impingement cooling holes as compared to the state of the art in
order to supply the cooling air volume. Here, the impingement
cooling holes can be set closer to each other in the area of the
arrangement of impingement cooling holes to avoid any impingement
cooling holes located close to the edge within the distance to the
shingle edge.
[0016] In the following, the invention is explained based on the
exemplary embodiments in connection with the drawing. Herein:
[0017] FIG. 1 shows a schematic rendering of a gas turbine engine
according to the present invention,
[0018] FIG. 2 shows a rendering of the state of the art,
[0019] FIG. 3 shows a rendering of the state of the art,
[0020] FIG. 4 shows a schematic side view of a first exemplary
embodiment of the invention,
[0021] FIG. 5 shows a rendering of a further exemplary embodiment
of the invention, which is analogous to FIG. 4,
[0022] FIG. 6 shows a simplified rendering, which is analogous to
FIG. 5, including a rendering of possible leakage flows,
[0023] FIG. 7 shows a top view of a first exemplary embodiment of
the corner design, and
[0024] FIG. 8 shows a view of a further exemplary embodiment, which
is analogous to FIG. 7.
[0025] The gas turbine engine 10 according to FIG. 1 represents a
general example of a turbomachine in which the invention may be
used. The engine 10 is configured in a conventional manner and
comprises, arranged successively in flow direction, an air intake
11, a fan 12 that rotates inside a housing, a medium-pressure
compressor 13, a high-pressure compressor 14, a combustion chamber
15, a high-pressure turbine 16, a medium-pressure turbine 17, and a
low-pressure turbine 18 as well as an exhaust nozzle 19, which are
all arranged around a central engine axis 1.
[0026] The medium-pressure compressor 13 and the high-pressure
compressor 114 respectively comprise multiple stages, of which each
has an arrangement of fixedly arranged stationary guide vanes 20
that extends in the circumferential direction, with the stationary
guide vanes 20 being generally referred to as stator vanes and
projecting radially inward from the core engine shroud 21 through
the compressors 13, 14 into a ring-shaped flow channel. Further,
the compressors have an arrangement of compressor rotor blades 22
that project radially outward from a rotatable drum or disc 26, and
are coupled to hubs 27 of the high-pressure turbine 16 or the
medium-pressure turbine 17.
[0027] The turbine sections 16, 17, 18 have similar stages,
comprising an arrangement of stationary guide vanes 23 projecting
radially inward from the housing 21 through the turbines 16, 17, 18
into the ring-shaped flow channel, and a subsequent arrangement of
turbine blades/vanes 24 projecting outwards from the rotatable hub
27. During operation, the compressor drum or compressor disc 26 and
the blades 22 arranged thereon as well as the turbine rotor hub 27
and the turbine rotor blades/vanes 24 arranged thereon rotate
around the engine central axis 1.
[0028] FIGS. 4 to 6 respectively show simplified sectional views in
a sectional plane that comprises the central axis of a combustion
chamber 15, which is not shown. Here, a combustion chamber wall 32
provided with an arrangement of impingement cooling holes 34 is
shown in a schematic manner. With a view to simplifying the
rendering, the impingement cooling holes 34 as well as the effusion
cooling holes 33, which will be described in the following, are
shown only by the flow direction in the form of a flow arrow.
[0029] Shingles 25 are arranged at a side of the combustion chamber
wall 32 that is facing towards the combustion chamber interior
space 30, being for example screwed on, as it is shown in FIG. 2.
The shingles have a plate-shaped, substantially flat shingle body
29 that is provided with effusion cooling holes 33. At the edge
area of the shingle body 29, a circumferential shingle edge 31 is
formed, abutting the combustion chamber wall 32. The height of the
shingle edge 31 defines the volume of an intermediate space 35 into
which the impingement cooling air flows and is subsequently
discharged through the effusion cooling holes 33. The height of the
intermediate spaces 35, and thus the volume of the intermediate
space 35, is defined by the free jet length L of the impingement
cooling air or of the impingement cooling jet that is shown in
FIGS. 4 and 5.
[0030] As shown in FIGS. 4 to 6, the arrangement of impingement
cooling holes 34 is arranged at a distance A from the shingle edge
31. The effusion cooling holes 33 are distributed about the entire
surface of the shingle body 29.
[0031] FIG. 4 shows an exemplary embodiment in which the ratio of
the number of impingement cooling holes to the effusion cooling
holes is 1:1. According to the invention, the distance A is chosen
in such a manner in this exemplary embodiment that a row of
effusion cooling holes is located between the edge of the next
impingement cooling hole 34 and the shingle edge 31, as shown in
the right-hand half of FIG. 4.
[0032] In the exemplary embodiment shown in FIG. 5, the ratio of
impingement cooling holes to the effusion cooling holes is 1:2.
Consequently, two rows of effusion cooling holes 33 are provided in
the distance area A between the shingle edge 31 and the arrangement
of impingement cooling holes 34.
[0033] If a ratio of impingement cooling holes to effusion cooling
holes is 1:3, three rows of effusion holes would be present in the
distance area A. This embodiment is not shown.
[0034] FIG. 6 shows a rendering that is analogous to FIG. 5 and
from which it can be seen that, in the most unfavorable case, only
a very small leakage air flow 36 would flow via the shingle edge 31
from the intermediate space 35 should the shingle edge 31 be sealed
very insufficiently against the combustion chamber wall 32.
[0035] FIGS. 7 and 8 respectively show a simplified top view of the
embodiment according to the invention in a schematic rendering.
Here, in particular the shingle edge 31 is shown, which provides a
seating surface of the shingle, as shown in FIGS. 4 to 6. A field
of impingement cooling holes is indicated by the reference sign 37,
without describing the individual impingement cooling holes and
their arrangement. They can be arranged in a suitable manner, with
the particular arrangement of impingement cooling holes not playing
a decisive role for the invention. Rather, what is important here
is that a distance A, in which no impingement cooling holes and
thus no impingement perforation is present, results between the
side of the shingle edge 31 that is facing towards the arrangement
of impingement cooling holes 34. FIGS. 7 and 8 show the inner side
of the shingle edge 31 as edge R1 or R2. Further, FIGS. 7 and 8
respectively show the distance A between the edge R1 or R2 and a
boundary G of the field 37 of the impingement cooling holes.
[0036] As shown in FIG. 7, the distances A add up at the edges of
the field 37 according to the invention, resulting in a beveling of
the field 37. Thus, the edge distances A add up in such a manner in
the edges of the shingle 25, that a value A results if a distance
from the first edge R1 of the seating surface of the shingle edge
31 of the shingle 25. A value A also results from the second edge
R2 of the seating surface of the shingle edge 31 of the shingle.
Thus, the field 37 of the impingement cooling holes (impingement
cooling pattern) ends along a line L1 that is parallel to the edge
R1, and at a distance along a line L2 that is parallel to the edge
R2. In this manner, the distance A is defined. The boundary of the
field 37 of the impingement cooling holes is indicated by G as a
dashed line. In the corners, the field 37 of the impingement
cooling pattern has a distance of C.times.A on the line L1 along
the edge R1. Analogously, a distance of C.times.A results regarding
the edge R2 and the line of the boundary G of the impingement
cooling pattern. The factor C is defined as an overlay constant,
and generally lies between 1.1 and 3, preferably between 1.5 and
2.5, ideally 2. With C=1 (state of the art), the impingement
perforation along the line L1 would reach to the edge R2 up to the
intersection with line L2. FIG. 7 shows an ideal state with a
distance of 2.times.A from the impingement cooling perforation
along the line L1 to the edge R2. As shown in FIG. 7, the result is
additional corner area in the shape of an equilateral triangle,
with no impingement cooling holes being provided therein.
[0037] FIG. 8 shows a variant in which the field 37 of the
impingement cooling holes is rounded off in the corner area, so
that the boundary G extends in the form of a circular arc in this
location.
[0038] According to the invention, the openings for the impingement
cooling are thus placed at a distance A from the edge of the
shingle in order to avoid any edge leakages from an
impingement-effusion-cooled shingle, so that effusion cooling holes
can be arranged between the impingement cooling opening that is
closest to the edge and the inner side of the edge of the shingle
so as to ensure an outflow of cooling air from the impingement
cooling holes through the effusion cooling holes, and to avoid any
edge leakage. The distance from the edge of the shingle, in which
no impingement cooling holes are provided, is at least 2 times the
free path length of the impingement cooling jet within the
intermediate space formed by the shingle.
* * * * *