U.S. patent application number 12/084601 was filed with the patent office on 2009-06-04 for combustion apparatus.
This patent application is currently assigned to SIEMENS AKTIENGESELLSCHAFT. Invention is credited to Iain Jubb, Peter Martin, Victoria Sanderson.
Application Number | 20090142716 12/084601 |
Document ID | / |
Family ID | 35601270 |
Filed Date | 2009-06-04 |
United States Patent
Application |
20090142716 |
Kind Code |
A1 |
Jubb; Iain ; et al. |
June 4, 2009 |
Combustion Apparatus
Abstract
A combustion apparatus comprising: a device for mixing a fuel
with an oxidant; a combustion chamber in which combustion of the
fuel/oxidant mix takes place; a pre-chamber located between the
device and the combustion chamber; and means for supplying a gas to
the pre-chamber so as to form a film of gas on the interior surface
of the pre-chamber so as to prevent a combustion flame from the
combustion chamber attaching itself to this interior surface
damaging the pre-chamber, the supply of gas to the pre-chamber
being such that where the gas first reaches the interior surface of
the pre-chamber it forms a substantially continuous film of gas
over this interior surface.
Inventors: |
Jubb; Iain; (Gainsborough,
GB) ; Martin; Peter; (Sturton, GB) ;
Sanderson; Victoria; (Newark, GB) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Assignee: |
SIEMENS AKTIENGESELLSCHAFT
Munchen
DE
|
Family ID: |
35601270 |
Appl. No.: |
12/084601 |
Filed: |
November 24, 2006 |
PCT Filed: |
November 24, 2006 |
PCT NO: |
PCT/EP2006/068870 |
371 Date: |
May 6, 2008 |
Current U.S.
Class: |
431/9 ; 60/737;
60/748 |
Current CPC
Class: |
F23R 3/14 20130101 |
Class at
Publication: |
431/9 ; 60/748;
60/737 |
International
Class: |
F23M 9/00 20060101
F23M009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 26, 2005 |
GB |
0524097.3 |
Claims
1.-10. (canceled)
11. A combustion apparatus comprising: a fuel mixing device that
mixes a fuel with an oxidant; a combustion chamber where combustion
of the fuel/oxidant mixture takes place; a pre-chamber arranged
between the fuel mixing device and the combustion chamber; and a
gas supply device that supplies a gas to the pre-chamber such that
a film of gas is formed on the interior surface of the pre-chamber
so as to prevent a combustion flame from the combustion chamber
attaching itself to the pre-chamber interior surface and damaging
the pre-chamber, wherein the supply of gas to the pre-chamber is
such that where the gas first reaches the interior surface of the
pre-chamber it forms a substantially continuous film of gas over
the pre-chamber interior surface.
12. The apparatus according to claim 11, wherein the gas supply
device comprises a swirler for creating a swirling flow of the gas
that travels over the interior surface of the pre-chamber to the
combustion chamber.
13. The apparatus according to claim 12, wherein the swirler
comprises a plurality of slots for guiding the gas, the slots being
arranged in a circle and extending generally radially inwardly.
14. The apparatus according to claim 13, wherein the swirler
comprises an annular base plate and a plurality of wedge pieces
arranged circumferentially spaced around the annular base plate so
as to form between adjacent wedge pieces the slots for guiding the
gas, the wedge pieces being set back from the radially inner edge
of the annular base plate thereby to define an annular ledge on the
annular base plate immediately radially outward of the radially
inner edge.
15. The apparatus according to claim 14, further comprising an
annular closing plate secured to the swirler such that one side of
the annular closing plate forms a wall of the slots, the wedge
pieces being set back from the radially inner edge of the annular
closing plate thereby to define an annular ledge on the annular
closing plate immediately radially outward of the radially inner
edge of the annular closing plate.
16. The apparatus according to claim 15, wherein the swirler is
arranged between the device and the pre-chamber, and the swirler
meets the pre-chamber by way of a smooth shoulder formed between
the annular ledge on the annular base plate of the swirler and the
interior surface of the pre-chamber.
17. The apparatus according to claim 13, wherein the gas supplying
device is arranged between the fuel mixing device and the
pre-chamber.
18. The apparatus according to claim 17, wherein the fuel mixing
device comprises a swirler for creating a swirling mix of the fuel
and oxidant that travels along the pre-chamber to the combustion
chamber.
19. The apparatus according to claim 18, wherein the oxidant is air
and the gas is air.
20. A gas turbine engine, comprising: a compressor section that
receives a working fluid and produces a compressed working fluid; a
combustion section that receives the compressed working fluid and
provides a hot working fluid, wherein the combustion section
comprises: a fuel mixing device that mixes a fuel with a majority
portion of the compressed working fluid; a combustion chamber where
combustion of the fuel/working fluid mixture takes place; a
pre-chamber arranged between the fuel mixing device and the
combustion chamber; and a supply device that supplies a minority
portion of the compressed working fluid to the pre-chamber such
that a film of gas is formed on the interior surface of the
pre-chamber so as to prevent a combustion flame from the combustion
chamber attaching itself to the pre-chamber interior surface and
damaging the pre-chamber, wherein the supply of gas to the
pre-chamber is such that where the gas first reaches the interior
surface of the pre-chamber it forms a substantially continuous film
of gas over the pre-chamber interior surface. a turbine section
that expands the hot working fluid to extract mechanical
energy.
21. The gas turbine engine according to claim 20, wherein the gas
supply device comprises a swirler for creating a swirling flow of
the gas that travels over the interior surface of the pre-chamber
to the combustion chamber.
22. The gas turbine engine according to claim 21, wherein the
swirler comprises a plurality of slots for guiding the gas, the
slots being arranged in a circle and extending generally radially
inwardly.
23. The gas turbine engine according to claim 22, wherein the
swirler comprises an annular base plate and a plurality of wedge
pieces arranged circumferentially spaced around the annular base
plate so as to form between adjacent wedge pieces the slots for
guiding the gas, the wedge pieces being set back from the radially
inner edge of the annular base plate thereby to define an annular
ledge on the annular base plate immediately radially outward of the
radially inner edge.
24. The gas turbine engine according to claim 23, further
comprising an annular closing plate secured to the swirler such
that one side of the annular closing plate forms a wall of the
slots, the wedge pieces being set back from the radially inner edge
of the annular closing plate thereby to define an annular ledge on
the annular closing plate immediately radially outward of the
radially inner edge of the annular closing plate.
25. The gas turbine engine according to claim 24, wherein the
swirler is arranged between the device and the pre-chamber, and the
swirler meets the pre-chamber by way of a smooth shoulder formed
between the annular ledge on the annular base plate of the swirler
and the interior surface of the pre-chamber.
26. The gas turbine engine according to claim 22, wherein the gas
supplying device is arranged between the fuel mixing device and the
pre-chamber.
27. The gas turbine engine according to claim 26, wherein the fuel
mixing device comprises a swirler for creating a swirling mix of
the fuel and oxidant that travels along the pre-chamber to the
combustion chamber.
28. The gas turbine engine according to claim 27, wherein the
oxidant is air and the gas is air.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2006/068870, filed Nov. 24, 2006 and claims
the benefit thereof. The International Application claims the
benefits of British application No. 0524097.3 filed Nov. 26, 2005,
both of the applications are incorporated by reference herein in
their entirety.
FIELD OF INVENTION
[0002] The present invention relates to a combustion apparatus.
BACKGROUND OF THE INVENTION
[0003] More particularly the present invention relates to a
combustion apparatus comprising: a device for mixing a fuel with an
oxidant; a combustion chamber in which combustion of the
fuel/oxidant mix takes place; a pre-chamber located between the
device and the combustion chamber; and means for supplying a gas to
the pre-chamber so as to form a film of gas on the interior surface
of the pre-chamber so as to prevent a combustion flame from the
combustion chamber attaching itself to this interior surface
damaging the pre-chamber.
[0004] It is known to achieve the film of gas on the interior
surface of the pre-chamber by forming holes in the walls of the
pre-chamber, and supplying the gas to the pre-chamber via the
holes. This has the disadvantage that where the gas first reaches
the interior surface of the pre-chamber it is in the form of a
number of discrete gas flows, one gas flow from each hole.
Consequently, protection of the interior surface against flame
attachment is not present in respect of areas of the interior
surface between the discrete gas flows.
SUMMARY OF INVENTION
[0005] According to the present invention there is provided a
combustion apparatus comprising: a device for mixing a fuel with an
oxidant; a combustion chamber in which combustion of the
fuel/oxidant mix takes place; a pre-chamber located between the
device and the combustion chamber; and means for supplying a gas to
the pre-chamber so as to form a film of gas on the interior surface
of the pre-chamber so as to prevent a combustion flame from the
combustion chamber attaching itself to this interior surface
damaging the pre-chamber, the supply of gas to the pre-chamber
being such that where the gas first reaches the interior surface of
the pre-chamber it forms a substantially continuous film of gas
over this interior surface.
[0006] In an apparatus according to the preceding paragraph, it is
preferable that the means for supplying comprises a swirler for
creating a swirling flow of the gas which travels over the interior
surface of the pre-chamber to the combustion chamber.
[0007] In an apparatus according to the preceding paragraph, it is
preferable that the swirler comprises a plurality of slots for
guiding the gas, the slots being arranged in a circle and extending
generally radially inwardly.
[0008] In an apparatus according to the preceding paragraph, it is
preferable that the swirler comprises an annular base plate and a
plurality of wedge pieces arranged circumferentially spaced around
the annular base plate so as to form between adjacent wedge pieces
the slots for guiding the gas, the wedge pieces being set back from
the radially inner edge of the annular base plate thereby to define
an annular ledge on the annular base plate immediately radially
outward of the radially inner edge.
[0009] It is preferable that an apparatus according to the
preceding paragraph further comprises an annular closing plate
secured to the swirler such that one side of the annular closing
plate forms a wall of the slots, the wedge pieces being set back
from the radially inner edge of the annular closing plate thereby
to define an annular ledge on the annular closing plate immediately
radially outward of the radially inner edge of the annular closing
plate.
[0010] In an apparatus according to either of the preceding two
paragraphs, it is preferable that the swirler is located between
the device and the pre-chamber, and the swirler meets the
pre-chamber by way of a smooth shoulder formed between the annular
ledge on the annular base plate of the swirler and the interior
surface of the pre-chamber.
[0011] In an apparatus according to any one of the preceding three
paragraphs but three, it is preferable that the means for supplying
is located between the device and the pre-chamber.
[0012] In an apparatus according to any one of the preceding seven
paragraphs, the device may comprise a swirler for creating a
swirling mix of the fuel and oxidant which travels along the
pre-chamber to the combustion chamber.
[0013] In an apparatus according to any one of the preceding eight
paragraphs, the oxidant may be air and the gas may be air.
[0014] The present invention also extends to a gas turbine engine
including an apparatus according to any one of the preceding nine
paragraphs, wherein compressed gas from the compressor of the
engine is shared between the device and the means for supplying,
the majority of the gas being supplied to device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention will now be described, by way of example, with
reference to the accompanying drawings, in which:
[0016] FIG. 1 is an exploded perspective view of a combustion
apparatus according to the present invention;
[0017] FIG. 2 is an exploded perspective view of the combustion
apparatus of FIG. 1 taken from a different perspective to that of
FIG. 1, and with most of a combustion chamber of the apparatus
omitted;
[0018] FIG. 3 is an exploded side view of the apparatus of FIG. 1
with the combustion chamber omitted;
[0019] FIG. 4 is a view on the line IV-IV in FIG. 3;
[0020] FIG. 5 is a view on the line V-V in FIG. 3;
[0021] FIG. 6 is a cross section on the line VI-VI in FIG. 3;
[0022] FIG. 7 is a side view of the apparatus of FIG. 1 when
assembled with the combustion chamber omitted;
[0023] FIG. 8 is a cross section on the line VIII-VIII in FIG.
7;
[0024] FIG. 9 is a cross section on the line IX-IX in FIG. 7;
and
[0025] FIG. 10 is a schematic cross section along the length of the
apparatus of FIG. 1.
DETAILED DESCRIPTION OF INVENTION
[0026] Referring to the drawings, the apparatus comprises a first
swirler 1 for creating a swirling mix of a fuel and air, a
combustion chamber 3 in which combustion of the fuel/air mix takes
place, a second swirler 5 for creating a swirling flow of air, an
annular closing plate 7 that separates swirlers 1 and 5, and a
pre-chamber 9 located between second swirler 5 and combustion
chamber 3.
[0027] First swirler 1 comprises an annular base plate 11, and a
plurality of wedge pieces 13 arranged circumferentially spaced
around annular base plate 11 so as to form, between adjacent wedge
pieces 13, slots 15. Plate 11 includes at the radially outer end of
each slot 15 a port 17 by means of which fuel is supplied to first
swirler 1. Each wedge piece 13 includes at the radially outer end
of one side 19 thereof a hole 21 by means of which fuel is also
supplied to first swirler 1. A plurality of fixing holes 23 extend
through wedge pieces 13 and base plate 11. The radially inner thin
ends 25 of wedge pieces 13 are set back from the radially inner
edge 27 of annular base plate 11 thereby to define an annular ledge
29 immediately radially outward of edge 27.
[0028] Second swirler 5 is similar in form to first swirler 1 and
comprises an annular base plate 31, and a plurality of wedge pieces
33 arranged circumferentially spaced around annular base plate 31
so as to form, between adjacent wedge pieces 33, slots 35. The
height of wedge pieces 33 above base plate 31 is much reduced as
compared to the height of wedge pieces 13 above base plate 11 in
first swirler 1. A plurality of fixing holes 37 extend through
wedge pieces 33 and base plate 31. The radially inner thin ends 39
of wedge pieces 33 are set back from the radially inner edge 41 of
annular base plate 31 thereby to define an annular ledge 43
immediately radially outward of edge 41.
[0029] Pre-chamber 9 is cylindrical in form and has an interior
surface 47. Pre-chamber 9 is formed integrally with second swirler
5. In this regard, at the point where pre-chamber 9 meets second
swirler 5, a smooth 90.degree. shoulder 49 is formed between
interior surface 47 of pre-chamber 9 and annular ledge 43 of second
swirler 5.
[0030] Annular closing plate 7 includes a plurality of fixing holes
45.
[0031] First swirler 1, annular closing plate 7, and second swirler
5 (together with integrally formed pre-chamber 9) are secured
together by means of nut and bolt fixings utilising fixing holes 23
in swirler 1, 45 in plate 7, and 37 in swirler 5. Thus, one side of
plate 7 forms a wall of each of slots 15 of first swirler 1, and
the other side of plate 7 forms a wall of each of slots 35 of
second swirler 5. The relationship of wedge pieces 13 of first
swirler 1 to annular closing plate 7 can be seen in FIG. 8. The
radially inner thin ends 25 of wedge pieces 13 extend precisely as
far as the radially inner edge 51 of annular closing plate 7. The
relationship of wedge pieces 33 of second swirler 5 to annular
closing plate 7 can be seen in FIG. 9. The radially inner thin ends
39 of wedge pieces 33 are set back from the radially inner edge 51
of annular closing plate 7 thereby to define an annular ledge 53
immediately radially outward of edge 51.
[0032] Operation of the combustion apparatus will now be
described.
[0033] Air is supplied to the radially outer ends of slots 15 of
first swirler 1 and travels generally radially inwardly along slots
15. Fuel is supplied to ports 17 and holes 21 of first swirler 1 so
as to enter slots 15 and mix with the air travelling along slots
15. Thus, first swirler 1 creates a swirling mix of fuel and air in
an annular region immediately radially inward of the radially inner
ends of slots 15, see arrows 55 in FIG. 8. This swirling mix
travels axially along the apparatus to combustion chamber 3,
passing through annular closing plate 7, second swirler 5, and
pre-chamber 9, see arrows 57 in FIG. 10.
[0034] Ignition of the fuel/air mix is achieved by means of an
ignition device (not shown) located in the circular opening of
annular base plate 11 of first swirler 1. In this regard, the
combustion apparatus includes a further part (not shown) disposed
to the left of the apparatus as shown in FIG. 1, which part
includes a face that occupies the circular opening of annular base
plate 11. The ignition device is disposed within this face.
Following ignition by the ignition device, the combustion is
self-sustaining.
[0035] Air is also supplied to the radially outer ends of slots 35
of second swirler 5 and travels generally radially inwardly along
slots 35. Thus, second swirler 5 creates a swirling flow of air in
an annular region immediately radially inward of the radially inner
ends of slots 35, see arrows 59 in FIG. 4. This swirling flow
swirls between annular ledge 53 of annular closing plate 7 and
annular ledge 43 of second swirler 5, passes over 90.degree.
shoulder 49 between annular ledge 43 and interior surface 47 of
pre-chamber 9, and travels axially along pre-chamber 9 to
combustion chamber 3, see arrows 61 in FIG. 10.
[0036] The purpose of the air flow provided by second swirler 5 is
to provide a film of air on interior surface 47 of pre-chamber 9
thereby to prevent a combustion flame from combustion chamber 3
attaching itself to interior surface 47 damaging pre-chamber 9. The
supply of air by second swirler 5 is such that where the air first
reaches interior surface 47, i.e. following 90.degree. shoulder 49,
it forms a continuous film of air over interior surface 47. This
continuous nature is due to (i) the presence of annular ledge 43,
created by setting back wedge pieces 33 from edge 41 of second
swirler 5, (ii) the presence of annular ledge 53, created by
setting back wedge pieces 33 from edge 51 of annular closing plate
7, and (iii) the presence of 90.degree. shoulder 49 between second
swirler 5 and pre-chamber 9.
[0037] The design intent is that the velocity of the air flow from
second swirler 5, see arrows 61 in FIG. 10, is as close as possible
to the velocity of the fuel/air mix from first swirler 1, see
arrows 57 in FIG. 10. In this way there is minimum disturbance of
air flow 61 by mix flow 57, minimising corruption of protective air
film 61.
[0038] In the above described apparatus, a protective film of air
is provided on the interior surface of pre-chamber 9. It is to be
realised that this protective film need not be of air but could be
of another gas, e.g. carbon dioxide. Similarly, the protective film
could be a mix of a gaseous fuel and air, provided the particular
mix used (concentration of the fuel in the air) does not ignite in
the conditions present in pre-chamber 9 in the region of the
interior surface of pre-chamber 9. Thus, a lean mix could be used
wherein the concentration of the fuel is below that at which
ignition can occur, or a rich mix could be used wherein the
concentration of fuel is above that at which ignition can occur.
Indeed, in the case of the rich mix, the concentration of the fuel
could be 100 percent, i.e. no air present.
[0039] In the above described apparatus, a swirler is used to
provide a mix of fuel and air for combustion. It is to be realised
that the fuel/air mix could be provided by an alternative device
able to provide a sufficiently homogeneous mix of fuel and air.
[0040] In the above described apparatus, a swirler is used to
supply air for the protective film on the interior surface of
pre-chamber 9. It is to be realised that an alternative means could
be used for this purpose, provided the supply of air is such that
where the air first reaches the interior surface it forms a
substantially continuous film of air over this surface.
[0041] In the apparatus described above, second swirler 5 is
located immediately prior to pre-chamber 9. It is to be realised
that swirler 5 could be located partway along the length of
pre-chamber 9, such that the protective film of air is provided
only in respect of the remaining portion of pre-chamber 9 between
swirler 5 and combustion chamber 3. Further, the apparatus could
include two second swirlers 5, one located immediately prior to
pre-chamber 9, the other located partway along the length of
pre-chamber 9. The swirler 5 located partway along the length of
pre-chamber 9 would then provide protective air to supplement that
provided by the swirler 5 located immediately prior to pre-chamber
9. This supplementary air would assist in the protection of
pre-chamber 9 downstream of the swirler 5 located partway along the
length of the pre-chamber.
[0042] The present invention finds particular application in gas
turbine engines. In the case of the apparatus described above,
compressed air from the compressor of the engine would be shared
between first swirler 1 and second swirler 5, the majority of the
air being supplied to first swirler 1.
[0043] The present invention is particularly useful in the
combustion of fuels of high flame speed. When using such fuels
there is a greater tendency for a combustion flame from the
combustion chamber to flashback to the pre-chamber and attach
itself to the interior surface of the pre-chamber.
* * * * *