U.S. patent application number 16/117062 was filed with the patent office on 2019-03-28 for nozzle comprising axial extension for a combustion chamber of an engine.
The applicant listed for this patent is Rolls-Royce Deutschland Ltd & Co KG. Invention is credited to Carsten CLEMEN, Ruud EGGELS, Benno WURM.
Application Number | 20190093896 16/117062 |
Document ID | / |
Family ID | 63683760 |
Filed Date | 2019-03-28 |
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United States Patent
Application |
20190093896 |
Kind Code |
A1 |
CLEMEN; Carsten ; et
al. |
March 28, 2019 |
NOZZLE COMPRISING AXIAL EXTENSION FOR A COMBUSTION CHAMBER OF AN
ENGINE
Abstract
The present invention relates to a nozzle for a combustion
chamber (3) of an engine (T) for providing a fuel-air mixture at a
nozzle exit opening of the nozzle (2). According to the invention,
an extension (5) for guiding the fuel-air mixture extending in the
axial direction with respect to a nozzle longitudinal axis (DM) is
provided at an air guide element (271b) of a radially outwardly
located air channel (27b) of the nozzle (2).
Inventors: |
CLEMEN; Carsten;
(Mittenwalde, DE) ; WURM; Benno; (Berlin, DE)
; EGGELS; Ruud; (Berlin, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rolls-Royce Deutschland Ltd & Co KG |
Blankenfelde-Mahlow |
|
DE |
|
|
Family ID: |
63683760 |
Appl. No.: |
16/117062 |
Filed: |
August 30, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F23R 2900/00012
20130101; F23R 3/286 20130101; F23R 3/14 20130101; F23D 11/38
20130101; F23R 3/30 20130101 |
International
Class: |
F23R 3/28 20060101
F23R003/28 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2017 |
DE |
10 2017 217 328.9 |
Claims
1. Nozzle for a combustion chamber (3) of an engine (T) for
providing a fuel-air mixture at a nozzle exit opening of the nozzle
(2), wherein the nozzle (2) comprises a nozzle main body (20) that
comprises the nozzle exit opening and that extends along a nozzle
longitudinal axis (DM), and the nozzle main body (20) further
comprises at least the following: at least one first, inner air
channel (26) for conveying air to the nozzle exit opening,
extending along the nozzle longitudinal axis (DM), at least one
fuel guiding channel (25) for conveying fuel to the nozzle exit
opening that is positioned radially further outside than the first
air channel (26) with respect to the nozzle longitudinal axis (DM),
and at least one further air channel (27b) that is positioned
radially further outside than the fuel guiding channel (25) with
respect to the nozzle longitudinal axis (DM), wherein an air guide
element (271b) for guiding air flowing from the at least one
further air channel (27b) is provided at an end of this at least
one further air channel (27b) that is positioned in the area of the
nozzle exit opening, characterized in that an extension (5) for
guiding the fuel-air mixture is provided at the air guide element
(271b) of the at least one further air channel (27b), extending in
the axial direction with respect to the nozzle longitudinal axis
(DM).
2. Nozzle according to claim 1, characterized in that the extension
(5) is embodied in a tubular manner.
3. Nozzle according to claim 1 or 2, characterized in that the
extension (5) extends in the axial direction with a length
(l.sub.5) that is less than 3.5. times a height (H) of the at least
one further air channel (27b) and/or of a swirling element (270b)
that is provided in the at least one further air channel (27b).
4. Nozzle according to any of the claims 1 to 3, characterized in
that the air guide element (271b) of the at least one further air
channel (27b) has a section at which an inner diameter (D1) of the
nozzle exit opening defined by the air guide element (271b) is
minimal, and the extension (5), as measured from a first reference
point (E1) at this section and the location of the minimal inner
diameter (D1), extends in the axial direction all the way to a
second reference point (E2) that is located at a distance (I) from
the first reference point (E1), which (a) is at least as large as a
height (H) of the at least one further air channel (27b) and/or of
a swirling element (270b) that is provided inside the at least one
further air channel (27b), and (b) corresponds to maximally 3.5
times this height (H).
5. Nozzle according to any of the preceding claims, characterized
in that a radially outwardly located lateral surface of the
extension (5) connects to a radially outwardly located lateral
surface of the air guide element (271b).
6. Nozzle according to claim 5, characterized in that the air guide
element (271b) and the extension (5) have substantially or exactly
the same outer diameter (D2).
7. Nozzle according to any of the preceding claims, characterized
in that an inner lateral surface of the extension (5) connects in
the axial direction to an inner lateral surface of the air guide
element (271b) of the at least one further air channel (27).
8. Nozzle according to any of the preceding claims, characterized
in that the extension (5) has at least two sections (50, 51)
succeeding each other in the axial direction and having different
inner diameters.
9. Nozzle according to any of the preceding claims, characterized
in that an inner diameter is enlarged continuously or with at least
one step in the axial direction at least at a section of the
extension (5).
10. Nozzle according to claim 9, characterized in that the at least
one section of the extension (5) has an inner lateral surface that
extends so as to be oriented radially outwards with regard to the
nozzle longitudinal axis (DM) and/or that is concavely curved.
11. Nozzle according to any of the claims 1 to 7, characterized in
that the extension (5) has an inner diameter that is constant in
the axial direction.
12. Nozzle according to any of the preceding claims 1 to 10,
characterized in that the extension (5) widens at least at one end
that is located in the axial direction.
13. Combustion chamber assembly group, with a burner seal (4) that
has a bearing section (41) having a passage opening and extending
along the nozzle longitudinal axis (DM), and a nozzle (2) according
to any of the claims 1 to 12 that is positioned in the passage
opening of the bearing section (41).
14. Combustion chamber assembly group according to claim 13,
characterized in that the extension (5) of the nozzle (2) projects
beyond the bearing section (41) in the axial direction.
15. Combustion chamber assembly group according to claim 13 or 14,
characterized in that the burner seal (4) is formed without flow
guiding elements (40).
16. Engine with at least one nozzle according to any of the claims
1 to 12 or a combustion chamber assembly group according to any of
the claims 13 to 15.
Description
[0001] The invention relates to a nozzle for a combustion chamber
of an engine for providing a fuel-air mixture at a nozzle exit
opening of the nozzle.
[0002] An (injection) nozzle for a combustion chamber of an engine,
in particular for an annular chamber of a gas turbine engine,
comprises a nozzle main body that has a nozzle exit opening and
that, in addition to a fuel guiding channel for conveying fuel to
the nozzle exit opening, has multiple (at least two) air guiding
channels for conveying air intermixed with fuel to the nozzle exit
opening. A nozzle usually also serves for swirling the supplied
air, which, intermixed which the supplied fuel, is subsequently
conveyed into the combustion chamber at the nozzle exit opening of
the nozzle. For example, multiple nozzles may be grouped together
in a nozzle assembly group that comprises multiple nozzles arranged
next to each other, usually along a circular line, for introducing
fuel into the combustion chamber.
[0003] In nozzles with multiple air guiding channels and at least
one fuel guiding channel as they are known from the state of the
art, for example from U.S. Pat. No. 9,423,137 B2, it is provided
that a first air channel extends along a nozzle longitudinal axis
of the nozzle main body and a fuel guiding channel is positioned
radially further outwards than the first air channel with respect
to the nozzle longitudinal axis. In that case, it is additionally
provided that at least one further air channel is positioned
radially further outwards than the fuel guiding channel with
respect to the nozzle longitudinal axis. Here, one end of the fuel
guiding channel at which the fuel form the fuel guiding channel
flows out in the direction of the air from the first air guiding
channel is typically located--with respect to the nozzle
longitudinal axis and in the direction of the nozzle exit
opening--in front of the end of the second air channel from which
the air then flows out in the direction of a mixture of air from
the first air channel and fuel from the fuel guiding channel. What
is further provided in the state of the art and for example also
provided in U.S. Pat. No. 9,423,137 B2 is to provide such a nozzle
with a third air channel, with its end, which may also be displaced
radially outwards, following the end of the second air channel in
the axial direction.
[0004] The nozzle is positioned at the combustion chamber via a
burner seal that seals the nozzle towards the combustion space of
the combustion chamber. Here, the burner seal is usually floatingly
mounted at a head plate of the combustion chamber to compensate for
radial and axial movements between the nozzle and the combustion
chamber and to ensure a reliable sealing effect in different
operating states.
[0005] For guiding the fuel-air mixture provided by the nozzle, the
burner seal often has a flow guiding element at the combustion
space side. However, due to the axial displaceability of the nozzle
relative to the burner seal and its flow guiding element, here the
aerodynamic conditions vary depending on the operational state of
the engine. Also, a radial distance between the nozzle and the
burner seal, which has to be provided due to the construction,
renders it more difficult to achieve an exactly predefined guidance
of the fuel-air mixture via the flow guiding element of the burner
seal. Both above-mentioned aspects influence the development of
undesired soot emissions.
[0006] Against this background, there is the objective to provide a
combustion chamber assembly group that is improved in this regard
and that comprises a nozzle for providing a fuel-air mixture.
[0007] This objective is achieved through a nozzle of claim 1.
[0008] What is proposed according to the invention is a nozzle for
a combustion chamber of an engine for providing a fuel-air mixture
at a nozzle exit opening of the nozzle, wherein the nozzle
comprises the nozzle main body that comprises the nozzle exit
opening and that extends along a nozzle longitudinal axis. Here,
the nozzle main body further comprises at least the following:
[0009] at least one first, inner air channel for conveying air to
the nozzle exit opening, extending along the nozzle longitudinal
axis, [0010] at least one fuel guiding channel for conveying fuel
to the nozzle exit opening that is positioned radially further
outwards as compared to the first air channel with respect to the
nozzle longitudinal axis, and [0011] at least one further air
channel positioned radially further outwards compared to the fuel
guiding channel with respect to the nozzle longitudinal axis,
wherein an air guide element for guiding air that flows from the at
least one further air channel is provided at an end of this at
least one further air channel that is positioned in the area of the
nozzle exit opening.
[0012] Now an extension for guiding the fuel-air mixture extending
in the axial direction with respect to the nozzle longitudinal axis
is provided at the air guide element of the at least one further
air channel. Here, the axial direction along which the extension
extends is oriented towards a combustion space of the combustion
chamber when the combustion chamber assembly group comprising the
nozzle is arranged at a combustion chamber according to the
intended use. Thus, the axial extension is located inside the
combustion space and extends in the flow direction of the fuel-air
mixture to be provided if the nozzle is arranged at the combustion
chamber according to the intended use.
[0013] In a nozzle according to the invention, it is thus provided
that the nozzle main body is formed with an extension for guiding
the fuel-air mixture that is provided at the nozzle exit opening in
the area of the air guide element of the at least one further (in
the case of multiple air guiding channels of the radially
outermost) air channel. Thus, the axial extension is configured and
provided for guiding the created mixture of the fuel from the fuel
guiding channel and the air from the first, inner air channel as
well as the at least one further air channel. While thus the air
guide element of the at least one further air channel is configured
and provided for guiding air from the at least one further air
channel, in particular for deflecting the flowing and usually
swirled air with a radially inwardly oriented directional
component, the axial extension is configured and provided for
guiding the created fuel-air mixture. In this way, a mixture
guidance is integrated in the nozzle, whereby any flow elements at
the combustion-space side can be omitted at a burner seal via which
the nozzle is positioned at the combustion chamber. In this way,
the burner seal can be limited to its sealing function, and can be
embodied without aerodynamic elements that influence the flow. By
integrating the mixture guidance at the nozzle itself, any axial
displacement of the nozzle and the burner seal relative to each
other occurring as a result of operation does not have any negative
influences on the guidance of the fuel-air mixture.
[0014] In an exemplary embodiment, the extension is formed in a
tubular manner. In that case, the extension may for example be
embodied in the kind of a tube piece at the combustion-space side
end of the nozzle main body. In particular, the extension can be
formed or molded at the nozzle main body as a tubular end
piece.
[0015] In an exemplary embodiment it is provided that the extension
extends in the axial direction with a length that is less than 3.5
times a height of the at least one further air channel and/or that
is less than 3.5. times a height of a swirling element provided in
the at least one further air channel. In this embodiment variant,
given a height H of the at least one further air channel or of the
swirling element, the following thus applies to a length l.sub.5
with which the extension extends in the axial direction:
l.sub.5.ltoreq.3.5 H. A corresponding geometric correlation between
the length of the axial extension and the height of the at least
one further air channel and/or of a swirling element provided in
this air channel has proven to be advantageous for influencing the
flow.
[0016] Alternatively or additionally, it can be provided that the
air guide element of the at least one further air channel has a
section (which is hollow and is passed by air from the air channel
during operation of the engine) at which an inner diameter defined
by the air guide element and thus the cross-sectional surface of
the nozzle exit opening which is passable by a flow is minimal, and
the extension--measured from a first reference point at this
section and at the location of the minimal inner diameter--extends
in the axial direction up to a second reference point that is
located at a certain distance from the first reference point. Here,
it may for example be provided that the distance between the first
reference point and the second reference point that is measured
along the nozzle longitudinal axis [0017] (a) is at least as great
as a height of the at least one further air channel and/or a height
of a swirling element that is provided inside the at least one
further air channel, and [0018] (b) maximally corresponds to 3.5
times this height.
[0019] As for the distance I between the first reference point at
the minimal inner diameter of the air guide element and the second
reference point that is located downstream thereto, the following
correspondingly applies for a height H of the at least one further
air channel or of the swirling element provided therein:
H.ltoreq.I.ltoreq.3.5 H.
[0020] In one embodiment variant, a radially outwardly located
lateral surface of the extension connects to a radially outwardly
located lateral surface of the air guide element. This in
particular includes that the air guide element and the extension
have substantially or exactly the same outer diameter. Thus,
through this extension, a maximal outer diameter of the nozzle is
enlarged at its end that projects into the combustion space in the
mounted state according to the intended use.
[0021] Alternatively or additionally, an inner lateral surface of
the extension connects to an inner lateral surface of the air guide
element of the at least one further air channel in the axial
direction. An inner lateral surface of the air guide element thus
transitions into the inner lateral surface of the extension without
any steps or without any projection or recess, for example. In this
way, the lateral surfaces of the extension and of the air guide
element continuously transition into each other in such an
embodiment variant.
[0022] In one embodiment variant, the extension has at least two
sections succeeding each other in the axial direction and having
different inner diameters. This for example includes that a first
section of the extension with an inner diameter which remains
constant in the axial direction (along the nozzle longitudinal
axis) is provided upstream of a second section, with the latter
having a different inner diameter that be increasing up to the end
of the extension, if necessary. Here, a continuous widening of the
opening that is passed by the flow can be provided in the second
section.
[0023] In a further development, a length of a second (end-side)
section measured in the axial direction and having a larger and/or
increasing inner diameter in the axial direction is considerably
smaller than a corresponding (axial) length of the first section.
For example, the length of the second downstream, shorter section
represents only a fraction of the length of the first section.
[0024] Alternatively or additionally, an inner diameter (of the
nozzle exit opening) can increase continuously or at least with one
step in the axial direction at least at one section of the
extension. Thus, this variant in particular includes the previously
described variant in which two sections with different inner
diameters are provided. But this also includes variants in which
not only a section of the extension, but the extension itself has
an inner diameter that increases continuously in a diffuser-like
manner. In particular, it can be provided that the at least one
section of the extension or the extension itself has an inner
lateral surface that extends in a manner pointing radially outwards
with respect to the nozzle longitudinal axis and/or that is
concavely curved. For example, in one exemplary embodiment, the
inner lateral surface of the extension defines a (nozzle exit)
opening for the fuel-air mixture widening in the shape of a
truncated cone. With regard to the flow guidance, where
appropriate, an additionally provided widening of the (nozzle exit)
opening defined by the extension can be provided, in particular at
an end of the extension that is located in the axial direction.
[0025] In contrast to the previously explained embodiment variants,
in one embodiment variant it can also be provided that the
extension has a constant inner diameter in the axial direction.
[0026] A further aspect of the suggested solution relates to the
provision of a combustion chamber assembly group, with a burner
seal that comprises a bearing section having a passage opening and
extending along the nozzle longitudinal axis, and with a nozzle
that is positioned inside the passage opening of the bearing
section. In that case, the nozzle also here has an extension for
guiding the fuel-air mixture extending in the axial direction.
[0027] Here, it is provided in one embodiment variant that the
extension of the nozzle projects in the axial direction (which is
oriented to a combustion space of the combustion chamber if the
combustion chamber assembly group is arranged at a combustion
chamber according to the intended use) beyond the bearing section.
Thus, the guidance of the fuel-air mixture that is provided at the
nozzle exit opening in the direction of the combustion space is
realized exclusively by means of the nozzle and its axial
extension.
[0028] In particular against this background, it can be provided in
one embodiment variant that the burner seal is formed without flow
guiding elements (at the combustion-space side). The burner seal is
thus limited to its sealing function and is not designed for an
aerodynamic function. In that case, the function of the flow
guidance of the fuel-air mixture is taken over exclusively or at
least predominantly by the nozzle with its axial extension.
[0029] Moreover, an engine with at least one nozzle according to
the invention or a combustion chamber assembly group according to
the invention is also provided within the scope of the solution
according to the invention.
[0030] The attached Figures illustrate possible embodiment variants
of the suggested solution by way of example.
[0031] Herein:
[0032] FIGS. 1 to 7 show, respectively in sections and in
cross-sectional view, different embodiment variants of a nozzle
according to the invention with an axial extension in the area of a
nozzle exit opening;
[0033] FIG. 8A shows an engine in which a combustion chamber with a
nozzle according to one of the embodiment variants of FIGS. 1 to 7
is used;
[0034] FIG. 8B shows, in sections and an enlarged scale, the
combustion chamber of the engine of FIG. 8A;
[0035] FIG. 8C shows, in a cross-sectional view, the basic
structure of a nozzle according to the state of the art and the
surrounding components of the engine in the installed state of the
nozzle;
[0036] FIG. 8D shows a back view of a nozzle exit opening, also
illustrating swirling elements that are provided in radially
outwardly located air guiding channels of the nozzle.
[0037] FIG. 8A schematically illustrates, in a sectional view, a
(turbofan) engine T in which the individual engine components are
arranged in succession along a rotational axis or central axis M
and the engine T is embodied as a turbofan engine. By means of a
fan F, air is suctioned in along an entry direction at an inlet or
an intake E of the engine T. This fan F, which is arranged inside a
fan housing FC, is driven via a rotor shaft S that is set into
rotation by a turbine TT of the engine T. Here, the turbine TT
connects to a compressor V, which for example has a low-pressure
compressor 11 and a high-pressure compressor 12, and where
necessary also a medium-pressure compressor. The fan F supplies air
to the compressor V in a primary air flow F1, on the one hand, and,
on the other, to a secondary flow channel or bypass channel B in a
secondary air flow F2 for creating a thrust. Here, the bypass
channel B extends about a core engine that comprises the compressor
V and the turbine TT, and also comprises a primary flow channel for
the air that is supplied to the core engine by the fan F.
[0038] The air that is conveyed via the compressor V into the
primary flow channel is transported into the combustion chamber
section BKA of the core engine where the driving power for driving
the turbine TT is generated. For this purpose, the turbine TT has a
high-pressure turbine 13, a medium-pressure turbine 14, and a
low-pressure turbine 15. The turbine TT drives the rotor shaft S
and thus the fan F by means of the energy that is released during
combustion in order to generate the necessary thrust by means of
the air that is conveyed into the bypass channel B. The air from
the bypass channel B as well as the exhaust gases from the primary
flow channel of the core engine are discharged via an outlet A at
the end of the engine T. Here, the outlet A usually has a thrust
nozzle with a centrally arranged outlet cone C.
[0039] FIG. 8B shows a longitudinal section through the combustion
chamber section BKA of the engine T. Here, in particular an
(annular) combustion chamber 3 of the engine T can be seen. A
nozzle assembly group is provided for injecting fuel or an
air-fuel-mixture into a combustion space 30 of the combustion
chamber 3. It comprises a combustion chamber ring R along which
multiple (fuel/injection) nozzles 2 are arranged along a circular
line about the central axis M. Here, the nozzle exit openings of
the respective nozzles 2 that are positioned inside the combustion
chamber 3 are provided at the combustion chamber ring R. Here, each
nozzle 2 comprises a flange by means of which a nozzle 2 is screwed
to an outer housing G of the combustion chamber 3.
[0040] FIG. 8C now shows a cross-sectional view of the basic
structure of a nozzle 2 as well as the surrounding components of
the engine T in the installed state of the nozzle 2. Here, the
nozzle 2 is part of a combustion chamber system of the engine T.
The nozzle 2 is located downstream of a diffuser DF and during
mounting is inserted through an access hole L through a combustion
chamber head 31, through a heat shield 300 and a head plate 310 of
the combustion chamber 3 up to the combustion space 30 of the
combustion chamber 3, so that a nozzle exit opening formed at a
nozzle main body 20 reaches all the way to the combustion space 30.
The nozzle 2 further comprises a nozzle neck 21 which substantially
extends radially with respect to the central axis M and inside of
which a fuel supply 210 conveying fuel to the nozzle main body 20
is accommodated. Further formed at the nozzle main body 20 are a
fuel chamber 22, fuel passages 220, heat shields 23 as well as air
chambers for insulation 23a and 23b.
[0041] In addition, the nozzle main body 20 forms a (first) inner
air channel 26 extending centrally along a nozzle longitudinal axis
DM and, positioned radially further outside with respect to the
same, a (second and third) outer air guiding channel 27a and 27b.
These air guiding channels 26, 27a and 27b extend in the direction
of the nozzle exit opening of the nozzle 2.
[0042] Further, also at least one fuel guiding channel 26 is formed
at the nozzle main body 20. This fuel guiding channel 25 is located
between the first inner air channel 26 and the second outer air
channel 27a. The end of the fuel guiding channel 25, via which fuel
flows out in the direction of the air from the first inner air
channel 26 during operation of the nozzle 2, is located--with
respect to the nozzle longitudinal axis DM and in the direction of
the nozzle exit opening--in front of the end of the second air
channel 27a from which air from the second, outer air channel 27a
flows out in the direction of a mixture of air from the first,
inner air channel 26 and fuel from the fuel guiding channel 25.
[0043] Swirling elements 270a, 270b for swirling the air supplied
through the air guiding channels 27a and 27b are provided in the
outer air guiding channels 27a and 27b. Further, the nozzle main
body 20 also comprises an outer, radially inwardly oriented air
guide element 271b at the end of the third outer air channel 27b.
In the nozzle 2, which may e.g. be a pressure-assisted injection
nozzle, the ends of the second and third radially outwardly located
air guiding channels 27a and 27b follow--with respect to the nozzle
longitudinal axis DM and in the direction of the nozzle exit
opening--the end of the fuel guiding channel 25 from which fuel is
supplied to the air from the first inner centrally extending air
channel 26 during operation of the engine T, according to FIG. 8C.
Air that is swirled by means of the swirling elements 270a, 270b is
transported to the nozzle exit opening form these second and third
air guiding channels 27a and 27b. As is shown in the back view of
FIG. 8D with a view of the nozzle exit opening along the nozzle
longitudinal axis DM, these swirling elements 270a, 270b are
arranged inside the respective air channel 27a, 27b in a
circumferentially distributed manner.
[0044] A sealing element 28 is also provided at the nozzle main
body 20 at its circumference for sealing the nozzle 2 towards the
combustion space 30. This sealing element 28 forms a counter-piece
to a burner seal 4. This burner seal 4 is floatingly mounted
between the heat shield 300 and the head plate 310 to compensate
for radial and axial movements between the nozzle 2 and the
combustion chamber 3 and to ensure reliable sealing in different
operational states.
[0045] The burner seal 4 usually has a flow guiding element 40
towards the combustion space 30. In connection with the third outer
air channel 27b at the nozzle 2, this flow guiding element 40
ensures a desired flow guidance of the fuel-air mixture that
results from the nozzle 2, more precisely the swirled air from the
air guiding channels 26, 27a and 27b, as well as the fuel guiding
channel 25.
[0046] In an embodiment of a burner assembly group according to
FIG. 8C as it is known in the state of the art, it is
disadvantageous that the relative position of the burner seal 4,
and in particular its flow guiding element 40, to the nozzle 2 can
change during operation of the engine T in particular due to
thermal extensions. Thus, an aerodynamic effect of the burner seal
4, and in particular the guidance of the fuel-air mixture across
the flow guiding element 40, varies depending on the operational
conditions.
[0047] This problem is remedied by the suggested solution, for
which different embodiment variants are shown in the FIGS. 1 to
7.
[0048] Here, it is respectively provided that an extension 5 is
provided at the air guide element 271b of the outermost, third air
channel 27b, extending in the axial direction in order to guide the
resulting fuel-air mixture in the direction of the combustion space
30. This extension 5, which may for example be formed or molded
integrally at the nozzle main body 20, respectively projects beyond
a bearing section 41 of the burner seal 4 at the combustion chamber
side. The passage opening through which the nozzle 2 is positioned
at the burner seal 4 is provided in this bearing section 41. By
thus guiding the fuel-air mixture through the nozzle-side extension
5 in the direction of the combustion space 30 at the nozzle exit
opening, the burner seal 4 does no longer take over an aerodynamic
function. The burner seal 4 now only serves the purpose of sealing,
and is correspondingly formed without a flow guiding element
40.
[0049] In particular in the nozzle 2 of FIG. 1 it is provided that
the extension 5 of the shown embodiment variants that connects to
the air guide element 271b has an outer diameter D2 that
substantially corresponds to the outer diameter of the air guide
element 271b and thus the nozzle 2 in the area of the burner seal
4. The extension 5 of the respective nozzle 2 is further designed
in a tubular manner, and has an axial length l.sub.5 that is less
than 3.5. times a height H of the swirling element 270b provided in
the third air channel 27b.
[0050] Further, the axial expansion of extension 5 is respectively
dimensioned in such a manner that other geometric conditions having
proven to be advantageous are met. Thus, for guiding the air
flowing out of the air channel 27b radially inwards, the air guide
element 271b of the third air channel 27b defines an area with a
minimal inner diameter D1 and thus a minimal cross-sectional
surface of the nozzle exit opening through which the flow passes. A
distance I of a reference point E1 at the location of this minimal
inner diameter D1 to a further reference point E2 located in the
axial direction and marking the end of the extension 5 is now
dimensioned such that the following applies:
H.ltoreq.I.ltoreq.3.5.ltoreq.H.
[0051] In particular the extension 5 of the nozzle 2 shown in FIG.
1 has two successive sections 50 and 51 with different inner
diameters. Thus, initially a first section 50 with an inner
diameter which remains constant along the nozzle longitudinal axis
DM connects to the air guide element 271b. If is followed in the
direction of the combustion space 30 by a considerably shorter,
second section 51, where the inner diameter increases and
accordingly the extension 5 widens.
[0052] While in the embodiment variant of FIG. 1 the extension 5
forms a ledge, and thus a recess at which the inner diameter is
enlarged comparatively abruptly, in the transition from the air
guide element 271b of the radially outermost, third air channel
27b, the embodiment variant of FIG. 2 provides an extension 5 with
a smoother transition between an inner lateral surface of the air
guide element 271b and an inner lateral surface of the extension 5.
Here, the extension 5 is further continuously enlarged in a
diffuser-like manner, so that an inner diameter of the extension 5
is continuously enlarged in the axial direction, and the inner
lateral surface of the extension 5 extends radially outwards with
respect to the nozzle longitudinal axis DM.
[0053] In contrast, in the variants of FIGS. 3 and 4, the
transition between the air guide element 271b and the extension 5
is realized through a ledge. However, in contrast to the variants
of FIGS. 1 and 2, here the downstream (end-side) section 51 is
embodied so as to taper off towards the trailing edge.
[0054] In the variant shown in FIG. 5, the extension 5 has a
slightly concave inner curvature for a smoother transition between
the air guide element 271b and the extension 5. Here, the lateral
surfaces of the air guide element 271b and the extension 5
transition into each other without steps. Thus, a flow is guided
along the air guide element 271b and the extension 5 along their
inner lateral surface, which transitions without any edges.
Further, a slightly convex inner curvature is provided at the
downstream distal end of the extension 5.
[0055] In the embodiment variant of FIG. 6, the extension 5 is also
designed in such a manner that the lateral surfaces of the air
guide element 271b and the extension 5 transition into each other
without any steps at a transition 52, and the extension 5 thus
directly connects to the air guide element 271b of the radially
outermost, third air channel 27b. Also in this case, the extension
5 is embodied in such a manner that the extension 5 widens
continuously in the axial direction along the nozzle longitudinal
axis DM all the way to a tapering trailing edge. Here, the inner
lateral surface of the extension 5 is slightly concavely
curved.
[0056] In contrast to the embodiment variant of FIG. 6, the
embodiment variant of FIG. 7 provides a continuous, diffuser-like
widening of the extension 5 directly connecting to the air guide
element 271b through an inner lateral surface that extends in a
linear manner and is oriented radially outwards at a constant angle
to the nozzle longitudinal axis DM.
[0057] In the shown embodiment variants of FIGS. 1 to 7, the nozzle
2 is respectively axially extended at a radially outermost third
air channel 27b downstream of an air guide element 271b. The axial
extension 5 provided for this purpose is respectively formed in a
tubular manner and has the same outer diameter D2 as the nozzle 2
in the area of the burner seal 4. Here, the inner contour of the
extension 5 is respectively chosen in such a manner that a widening
of the extension 5 occurs along the nozzle longitudinal axis DM in
the direction of the combustion space 30 at least in one section.
Through the embodiment of the extension 5 at the nozzle 2 at which
the resulting fuel-air mixture is guided in the direction of the
combustion space 30, an admissible axial displaceability of the
burner seal 4 and the nozzle 2 relative to each other does not
influence the guidance of the fuel-air mixture. This is in
particular advantageous when it comes to avoiding interfering soot
emissions. Further, here the burner seal 4 seal only has to be
configured and embodied for ensuring the sealing effect. The
integration of a flow guiding element 40 at the burner device 4 may
be omitted.
PARTS LIST
[0058] 11 low-pressure compressor [0059] 12 high-pressure
compressor [0060] 13 high-pressure turbine [0061] 14
medium-pressure turbine [0062] 15 low-pressure turbine [0063] 2
nozzle [0064] 20 nozzle main body [0065] 21 neck [0066] 210 fuel
supply [0067] 22 fuel chamber [0068] 220 fuel passage [0069] 23
heat shield [0070] 24a, 24b air chamber [0071] 25 fuel guiding
channel [0072] 26 first air channel [0073] 270a, 270b swirling
element [0074] 271b air guide element [0075] 27a second air channel
[0076] 27b third air channel [0077] 28 sealing element [0078] 3
combustion chamber [0079] 30 combustion space [0080] 300 heat
shield [0081] 31 combustion chamber head [0082] 310 head plate
[0083] 4 burner seal [0084] 40 flow guiding element [0085] 41
bearing section [0086] 5 extension [0087] 50, 51 section [0088] 52
transition [0089] A outlet [0090] B bypass channel [0091] BKA
combustion chamber section [0092] C outlet cone [0093] D1, D2
diameter [0094] DF diffuser [0095] DM nozzle longitudinal axis
[0096] E inlet/intake [0097] E1, E2 reference point/end area [0098]
F fan [0099] F1, F2 fluid flow [0100] FC fan housing [0101] G outer
housing [0102] H height [0103] L access hole [0104] I distance
[0105] l.sub.5 length [0106] M central axis/rotational axis [0107]
R combustion chamber ring [0108] S rotor shaft [0109] T (turbofan)
engine [0110] TT turbine [0111] V compressor
* * * * *