U.S. patent application number 13/259941 was filed with the patent office on 2012-03-29 for turbomachine having an annular combustion chamber.
This patent application is currently assigned to SNECMA. Invention is credited to Didier Hippolyte Hernandez, Romain Nicolas Lunel, Thomas Olivier Marie Noel.
Application Number | 20120073259 13/259941 |
Document ID | / |
Family ID | 41278564 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120073259 |
Kind Code |
A1 |
Hernandez; Didier Hippolyte ;
et al. |
March 29, 2012 |
TURBOMACHINE HAVING AN ANNULAR COMBUSTION CHAMBER
Abstract
A turbomachine including an annular combustion chamber, the
combustion chamber presenting a connection flange at its downstream
end for connection to an outer casing. The connection flange bears
axially against the outer casing and is blocked in an axial
direction by the upstream end of an inner casing of a high pressure
turbine.
Inventors: |
Hernandez; Didier Hippolyte;
(Quiers, FR) ; Lunel; Romain Nicolas; (Montereau
Sur Le Jard, FR) ; Noel; Thomas Olivier Marie;
(Vincennes, FR) |
Assignee: |
SNECMA
Paris
FR
|
Family ID: |
41278564 |
Appl. No.: |
13/259941 |
Filed: |
March 12, 2010 |
PCT Filed: |
March 12, 2010 |
PCT NO: |
PCT/FR2010/000210 |
371 Date: |
September 23, 2011 |
Current U.S.
Class: |
60/39.37 |
Current CPC
Class: |
F23R 3/60 20130101; Y02T
50/60 20130101; F23R 3/50 20130101; F01D 25/243 20130101; F01D
9/023 20130101; Y02T 50/671 20130101 |
Class at
Publication: |
60/39.37 |
International
Class: |
F23R 3/50 20060101
F23R003/50 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 7, 2009 |
FR |
09/01704 |
Claims
1-8. (canceled)
9. A turbomachine comprising: an annular combustion chamber, the
combustion chamber presenting a connection flange at its downstream
end for connection to an outer casing, wherein the connection
flange bears axially against the outer casing and is blocked in an
axial direction by the upstream end of an inner casing of a high
pressure turbine, the connection flange of the combustion chamber
and the upstream end of the inner casing of the turbine bearing
radially against the outer casing.
10. A turbomachine according to claim 9, wherein the upstream face
of the connection flange includes an annular setback having a
cylindrical face and a radial face that bear respectively against a
cylindrical face and a radial face of the inner annular surface of
the outer casing.
11. A turbomachine according to claim 9, wherein the upstream end
of the inner casing of the turbine has a cylindrical face bearing
radially against an inner cylindrical surface of the outer
casing.
12. A turbomachine according to claim 10, wherein the end of the
connection flange comprises a cylindrical portion that extends
axially between the radial face of the annular setback of the outer
casing and the upstream end of the inner casing of the turbine.
13. A turbomachine according to claim 12, wherein the combustion
chamber and the inner casing of the turbine are mounted inside the
outer casing from downstream, with radial clearance while cold
between the downstream end of the connection flange and the
upstream end of the inner casing of the turbine.
14. A turbomachine according to claim 9, wherein the outer casing
is continuous between an upstream flange situated at the upstream
end of the combustion chamber and a downstream flange situated at
the downstream end of the inner casing of the high pressure
turbine.
15. A turbomachine according to claim 9, wherein the connection
flange includes a bent portion that is elastically deformable in a
radial direction.
16. A turbomachine according to claim 9, wherein the inner casing
of the turbine is fastened at its downstream end to the outer
casing via a bolted connection.
Description
[0001] The present invention relates to attaching an annular
combustion chamber of a turbomachine such as a bypass turbojet for
an airplane.
[0002] Going from upstream to downstream, a turbomachine comprises
low and high pressure compression stages feeding an annular
combustion chamber from which the hot combustion gases drive outlet
high and low pressure turbines. The combustion chamber is attached
at its downstream end by means of radial connection flanges that
are bolted to corresponding radial flanges of inner and outer
casings of the combustion chamber. An inner casing of the high
pressure turbine is fastened by having its upstream end bolted to
the radial flange of the outer casing of the combustion chamber and
to the downstream radial flange of the combustion chamber.
[0003] Forming a radial flange in the outer casing gives rise to a
local discontinuity in the longitudinal extent of the casing,
thereby reducing its stiffness and thus limiting its lifetime.
Furthermore, the flanges of the outer casing, of the combustion
chamber, and of the inner casing of the turbine, together with the
bolts, constitute a non-negligible fraction of the weight, and of
the manufacturing cost of the combustion chamber, of the outer
casing, and of the inner casing of the high pressure turbine.
[0004] An object of the present invention is to provide a
turbomachine that avoids the above-mentioned drawbacks of the prior
art in a manner that is simple, effective, and inexpensive.
[0005] To this end, the invention provides a turbomachine having an
annular combustion chamber, the combustion chamber presenting a
connection flange at its downstream end for connection to an outer
casing, the turbomachine being characterized in that the connection
flange bears axially against the outer casing and is blocked in an
axial direction by the upstream end of an inner casing of a high
pressure turbine, the connection flange of the combustion chamber
and the upstream end of the inner casing of the turbine bearing
radially against the outer casing.
[0006] The attachment of the combustion chamber no longer requires
a radial flange to be formed on the outer casing of the combustion
chamber, thereby enabling longitudinal continuity of the casing to
be re-established and increasing its lifetime. The traction forces
to which the outer casing is subjected are also better distributed
over its entire axial extent between its upstream and downstream
ends.
[0007] This type of attachment also gives rise to a local reduction
in the diameter of the outer casing and no longer requires bolts,
thereby leading to a reduction in the weight of the turbomachine,
and in the manufacturing costs of the combustion chamber, of the
outer casing, and of the outer casing of the high pressure
turbine.
[0008] The connection flange of the combustion chamber and the
upstream end of the inner casing of the turbine bearing radially
against the outer casing enables both the combustion chamber and
the inner casing of the turbine to be centered.
[0009] In an embodiment of the invention, the upstream face of the
connection flange includes an annular setback having a cylindrical
face and a radial face that bear respectively against a cylindrical
face and a radial face of the inner annular surface of the outer
casing.
[0010] The upstream end of the inner casing of the turbine may have
a cylindrical face bearing radially against an inner cylindrical
surface of the outer casing.
[0011] Preferably, the end of the connection flange comprises a
cylindrical portion that extends axially between the radial face of
the annular setback of the outer casing and the upstream end of the
inner casing of the turbine.
[0012] The combustion chamber and the inner casing of the turbine
are mounted inside the outer casing from downstream, and axial
clearance while cold is provided between the downstream end of the
connection flange and the upstream end of the inner casing of the
turbine.
[0013] While the turbomachine is in operation, the turbine casing
expands and presses against the downstream end of the cylindrical
portion of the connection flange, thereby limiting vibration.
[0014] The outer casing is made integrally with an outer casing of
the high pressure turbine, and it extends continuously between an
upstream flange situated at the upstream end of the combustion
chamber and a downstream flange situated level with the downstream
end of the inner casing of the high pressure turbine, the
downstream end of the inner casing of the high pressure turbine
being bolted to the downstream flange of the outer casing.
[0015] The connection flange of the combustion chamber
advantageously comprises a bent portion that is elastically
deformable in a radial direction, thereby enabling the radial
expansion of the combustion chamber relative to the radial
expansion of the outer casing to be absorbed in operation so as to
limit the radial forces that are applied to the outer casing while
the turbomachine is in operation.
[0016] The invention can be better understood and other details,
advantages, and characteristics of the invention appear on reading
the following description made by way of non-limiting example and
with reference to the accompanying drawings, in which:
[0017] FIG. 1 is a diagrammatic axial section view of a prior art
annular combustion chamber of a turbomachine;
[0018] FIG. 2 is a diagrammatic axial section view of the
attachment of a combustion chamber to an external casing in
accordance with the invention; and
[0019] FIG. 3 is a view on a larger scale of a portion of FIG.
2.
[0020] Reference is made initially to FIG. 1, which is a diagram of
a prior art annular combustion chamber 10 of a turbomachine such as
an airplane turbojet. The combustion chamber 10 comprises two walls
forming coaxial surfaces of revolution, namely an inner and outer
chamber walls 12 and 14 that are connected together at their
upstream end by an annular chamber end wall 16 and that include at
their downstream ends flanges 18 and 20 that extend inwards and
outwards, respectively, and that are fastened to radial flanges 22
and 24 respectively of inner and outer casings 26 and 28.
[0021] Upstream of its radial flange 24, the outer casing 28
carries fuel feed means 30 that pass through the casing 28 and that
lead to the upstream end of the combustion chamber between the
inner and outer walls 12 and 14. A spark plug 32 for igniting the
fuel in the chamber passes through the outer casing 28 and the
outer chamber wall 14.
[0022] The outer casing 28 is made integrally with an outer casing
of a high pressure turbine 34 arranged at the outlet from the
combustion chamber 10, with a nozzle 36 and a rotor blade 38 of the
turbine being shown. The nozzle 36 is carried at its radially outer
end by an inner casing 40 carrying means for actively controlling
the clearance at the tips of the rotor blades in the high pressure
turbine. The upstream end of this inner casing has a radial flange
42 for fastening to the radial flange 24 of the outer casing 28,
the outer flange 20 of the combustion chamber being interposed
between said two flanges.
[0023] The outer flange 20 of the combustion chamber 10 and the
flange 42 of the inner casing 40 of the high pressure turbine 34
are fastened to the radial flange 24 of the outer casing 28 by
means of bolts 44 that are regularly distributed around the axis 46
of the turbomachine.
[0024] Incorporating a radial flange 24 in the outer casing 28
leads to a discontinuity being formed in the longitudinal extent of
the outer casing 28, thereby inducing a reduction in its lifetime.
Furthermore, this connection configuration by means of bolted
radial flanges has a non-negligible influence on the weight and the
manufacturing cost of the combustion chamber 10, of the outer
casing 28, and of the inner casing 40 of the high pressure turbine
34.
[0025] The invention shown in FIGS. 2 and 3 provides a solution to
those problems by eliminating the radial flange 24 of the outer
casing 28 together with the bolts 44, and by connecting the
combustion chamber 45 to the outer casing 46 via an elastically
deformable connection flange 48 that bears axially and regularly
against the outer casing 46.
[0026] The radially outer end of the flange 48 comprises a
cylindrical portion 50 that is connected at its upstream end to an
annular setback defined by a radial face 52 and a cylindrical face
54. The flange 48 includes a bent portion 56 that is elastically
deformable in a radial direction and that connects the radially
outer end of the flange 48 to the downstream end of the outer
chamber wall 14. This bent portion 56 has a V-shape with its apex
pointing upstream and enabling differential expansion between the
outer casing 46 and the combustion chamber 45 to be
compensated.
[0027] In the particular embodiment shown in FIG. 2, the outer
casing 46 is formed by a wall of section that flares upstream and
downstream from a substantially cylindrical middle portion 58 that
includes an annular rib 60 projecting from its cylindrical inside
face. The annular rib has a downstream face 61 and an inner
cylindrical face 63. The upstream and downstream ends of the outer
casing 46 have radial flanges 70 and 68 for fastening by bolts to
casings of the high pressure compressor and of the low pressure
turbine, respectively.
[0028] The combustion chamber 45 is mounted in the outer casing 46
from downstream. The radial face 52 of the annular setback of the
flange 48 comes to bear axially against the downstream face 61 of
the annular rib 60 of the outer casing 46, thereby enabling the
combustion chamber to be positioned axially relative to the outer
casing. The cylindrical face 54 of the annular setback of the
flange 48 comes to bear radially against the cylindrical face 63 of
the rib 60 and serves to center the combustion chamber 45 in the
outer casing 46.
[0029] The upstream end of the inner casing 62 of the high pressure
turbine has a cylindrical outer face 64 that comes to bear radially
against the cylindrical inner face of the outer casing 46 and that
enables the downstream end of the cylindrical portion 50 of the
flange 48 to be blocked in an axial direction. The radial thrust of
the inner casing 62 against the outer casing enables it to be
centered in the outer casing 46.
[0030] The inner casing 62 of the high pressure turbine includes a
radial flange 66 at its downstream end for fastening by means of
bolts to the radial flange 68 of the downstream end of the outer
casing 46.
[0031] In operation, the annular rib 60 of the outer casing 46 and
the upstream end of the inner casing 62 of the high pressure
turbine serve to block the connection flange 48 of the combustion
chamber 45 in an axial direction against the outer casing 46.
[0032] By eliminating the outer radial flange, the invention makes
it possible to reduce the weight of the outer casing 46 by about
8%.
[0033] Radial clearance may be provided on assembly between the
downstream end of the cylindrical portion of the connection flange
48 and the upstream end of the inner casing 62 in such a manner as
to avoid stressing the connection flange 48 of the combustion
chamber when cold.
[0034] In operation, the upstream end of the inner casing 62 comes
to bear against the downstream end of the connection flange 48,
thereby limiting the vibration of the flange 48.
[0035] The connection of the combustion chamber 45 as described
above is not limited to a substantially axial combustion chamber 45
as shown in FIGS. 2 and 3, and is applicable to any type of
combustion chamber such as a diverging combustion chamber 10 as
shown in FIG. 1, or a combustion chamber that converges
downstream.
* * * * *