U.S. patent application number 13/806895 was filed with the patent office on 2013-05-02 for burner assembly.
The applicant listed for this patent is Siegfried Bode, Timothy A. Fox, Thomas Grieb, Matthias Hase, Jurgen Meisl, Sebastian Pfadler. Invention is credited to Siegfried Bode, Timothy A. Fox, Thomas Grieb, Matthias Hase, Jurgen Meisl, Sebastian Pfadler.
Application Number | 20130104554 13/806895 |
Document ID | / |
Family ID | 43531833 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130104554 |
Kind Code |
A1 |
Bode; Siegfried ; et
al. |
May 2, 2013 |
BURNER ASSEMBLY
Abstract
A burner assembly for a gas turbine is provided. The burner
assembly has a combustor, a centrally arranged pilot burner and
plurality of main burners surrounding the pilot burner. Each main
burner has a cylindrical housing having a lance which is centrally
arranged therein and has a fuel channel for liquid fuel. The lance
is supported on the housing by swirl blades and an attachment is
arranged on the lance in the direction of the combustor. The liquid
fuel nozzle is arranged in the attachment downstream of the swirl
blades and connected to the fuel channel. For the improved mixing
of the fuel with the air, the liquid fuel nozzle is designed as a
full jet nozzle and the full jet nozzle has a length and a
diameter, the ratio of the length to the diameter is at least
1.5.
Inventors: |
Bode; Siegfried; (Mulheim an
der Ruhr, DE) ; Fox; Timothy A.; (Hamilton, CA)
; Grieb; Thomas; (Krefeld, DE) ; Hase;
Matthias; (Mulheim, DE) ; Meisl; Jurgen;
(Mulheim an der Ruhr, DE) ; Pfadler; Sebastian;
(Mulheim an der Ruhr, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bode; Siegfried
Fox; Timothy A.
Grieb; Thomas
Hase; Matthias
Meisl; Jurgen
Pfadler; Sebastian |
Mulheim an der Ruhr
Hamilton
Krefeld
Mulheim
Mulheim an der Ruhr
Mulheim an der Ruhr |
|
DE
CA
DE
DE
DE
DE |
|
|
Family ID: |
43531833 |
Appl. No.: |
13/806895 |
Filed: |
July 1, 2011 |
PCT Filed: |
July 1, 2011 |
PCT NO: |
PCT/EP2011/061101 |
371 Date: |
December 26, 2012 |
Current U.S.
Class: |
60/740 |
Current CPC
Class: |
F23D 11/38 20130101;
F23R 3/286 20130101; F23R 3/343 20130101; F23C 2900/07021
20130101 |
Class at
Publication: |
60/740 |
International
Class: |
F23R 3/34 20060101
F23R003/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 2010 |
EP |
10168107.0 |
Claims
1.-36. (canceled)
37. A burner assembly for a gas turbine, comprising: a combustor; a
centrally arranged pilot burner; and a plurality of main burners
surrounding the pilot burner, wherein each of the main burners
comprises a cylindrical housing having a lance that is centrally
arranged therein and has a fuel channel for liquid fuel, wherein
the lance is supported on the housing by swirl blades, wherein an
attachment is arranged on the lance in a direction of the
combustor, wherein a liquid fuel nozzle is arranged in the
attachment downstream of the swirl blades and connected to the fuel
channel, wherein the liquid fuel nozzle is a full jet nozzle,
wherein a ratio of a length to a diameter of the full jet nozzle is
at least 1.5, and wherein a fuel and drop size distribution is
optimized as a function of an alignment of an injection position of
the full jet nozzle relative to a pilot cone.
38. The burner assembly as claimed in claim 37, wherein the
attachment has a cylindrical part and a part tapering conically in
the direction of the combustor, and wherein the conical part has a
cone angle of 10 to 20 degrees.
39. The burner assembly as claimed in claim 37, wherein the
attachment comprises a central attachment axis, and wherein the
full jet nozzle comprises a central axis and is arranged in the
attachment so that the central axis of the full jet nozzle is at an
angle of 90 degrees or between 90+/-30 degrees to the central
attachment axis of the attachment.
40. The burner assembly as claimed in claim 37, wherein the
attachment has an attachment surface, and wherein the full jet
nozzle comprises a central axis and is arranged in the attachment
so that the central axis of the full jet nozzle is perpendicular to
the attachment surface or at an angle of -10 degrees to +10 degrees
with a surface normal of the attachment surface.
41. The burner assembly as claimed in claim 37, wherein the full
jet nozzle is arranged along a peripheral line running around the
attachment.
42. The burner assembly as claimed in claim 41, wherein eight to
twelve full jet nozzles are provided for the each of the main
burners, and wherein diameters of the full jet nozzles are between
0.55 mm and 0.8 mm, or between 0.6 mm and 0.7 mm, or between 0.55
mm and 0.65 mm, or between 0.7 mm and 0.8 mm.
43. The burner assembly as claimed in claim 42, wherein more full
jet nozzles are arranged on a side of the attachment facing the
pilot burner than on a side of the attachment facing away from the
pilot burner, wherein a density of the full jet nozzles varies in a
peripheral direction along the peripheral line, wherein the full
jet nozzles are arranged along the peripheral line so that an
inclination of central axes of the full jet nozzles in a direction
of a central attachment axis of the attachment varies in the
peripheral direction, wherein the central axes of the full jet
nozzles are alternately aligned running perpendicular to the
central attachment axis and is angled maximum 20 degrees in a
direction of the central attachment axis, wherein the central axis
of at least one full jet nozzle has an inclination in the
peripheral direction from a position perpendicular to the central
attachment axis.
44. The burner assembly as claimed in claim 42, wherein the full
jet nozzles have different diameters or same diameter along the
peripheral line.
45. The burner assembly as claimed in claim 42, wherein the full
jet nozzles are arranged along an upstream peripheral line and a
downstream peripheral line running in a ring shape and
perpendicular to a central attachment axis of the attachment at
different axial positions, wherein the full jet nozzles arranged
along the upstream peripheral line have a larger diameter than the
full jet nozzles arranged along the downstream peripheral line, or
wherein the full jet nozzles arranged along the upstream peripheral
line have a smaller diameter than the full jet nozzles arranged
along the downstream peripheral line.
46. The burner assembly as claimed in claim 45, wherein the full
jet nozzles arranged along the downstream peripheral line are
arranged on common flow lines with the full jet nozzles arranged
along the upstream peripheral line so that air can be swirled along
the flow lines when the air flows through the swirl blades, or
wherein the full jet nozzles arranged along the downstream
peripheral line are arranged offset with the full jet nozzles
arranged along the upstream peripheral line so that air can be
swirled along flow lines on which only one of the full jet nozzles
is arranged when the air flows through the swirl blades.
47. The burner assembly as claimed in claim 45, wherein the full
jet nozzles arranged along the downstream peripheral line inject
fuel to a same radial position as the full jet nozzles arranged
along the upstream peripheral line.
48. The burner assembly as claimed in claim 42, wherein the full
jet nozzles are arranged along a helical peripheral line, wherein
diameters of the full jet nozzles arranged along the helical
peripheral line increase in a flow direction or increase counter to
the flow direction.
49. The burner assembly as claimed in claim 42, wherein the full
jet nozzles are arranged along two helical peripheral lines.
50. The burner assembly as claimed in claim 42, wherein the full
jet nozzles arranged along the peripheral line are at distances
from one another and diameters of the full jet nozzles are repeated
along the peripheral line.
51. The burner assembly as claimed in claim 50, wherein a full jet
nozzle with a smaller diameter is arranged along the peripheral
line between two full jet nozzles of same diameter, wherein the
full jet nozzle with the smaller diameter is arranged closer to one
of the two full jet nozzles with a larger diameter.
52. The burner assembly as claimed in claim 50, wherein the full
jet nozzles arranged along the peripheral line inject a fuel having
a radial distribution about a central attachment axis of the
attachment, and wherein the fuel distribution comprises a
ring-shaped zone of a first fuel distribution and a ring-shaped
zone of a second fuel distribution.
53. The burner assembly as claimed in claim 52, wherein the
ring-shaped zone of the first fuel distribution overlaps with the
ring-shaped zone of the second fuel distribution, or wherein the
ring-shaped zone of the first fuel distribution is at a distance
from the ring-shaped zone of the second fuel distribution.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International
Application No. PCT/EP2011/061101 filed Jul. 1, 2011 and claims the
benefit thereof. The International Application claims the benefits
of European application No. 10168107.0 filed Jul. 1, 2010, both of
the applications are incorporated by reference herein in their
entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a burner assembly for a gas
turbine having at least one combustor, wherein the burner assembly
comprises a centrally arranged pilot burner and a number of main
burners surrounding the pilot burner, wherein each of the main
burners comprises a cylindrical housing having a lance which is
centrally arranged therein and has a fuel channel for liquid fuel,
wherein the lance is supported on the housing by means of swirl
blades and an attachment is arranged on the lance in the direction
of the combustor, wherein at least one liquid fuel nozzle is
arranged in the attachment preferably downstream of the swirl
blades and connected to the fuel channel.
BACKGROUND OF THE INVENTION
[0003] During operation of the gas turbine compressed air from the
compressor is supplied to the combustor. The compressed air is
mixed with a fuel, for example oil or gas, and the mixture is
combusted in the combustor. The hot combustion gases are finally
supplied by way of a combustor output as a working medium to the
turbine, where they expand and cool to transmit pulses to the
blades, thereby performing work. The vanes here serve to optimize
pulse transmission.
[0004] In internal combustion engines, particularly those operated
using two different fuels, the oil fuel is injected in for example
by way of swirl generators, in which the oil is mixed with air. To
improve the mixing of oil and air the oil is made to swirl within
the nozzles used for injection. Such an oil nozzle is also referred
to as a pressure swirl nozzle.
[0005] In machines with two different fuels the oil nozzles cannot
be arranged in such a manner that the mixing of the fuel with air
produces an optimum result in respect of pressure pulsation.
SUMMARY OF THE INVENTION
[0006] The object of the present invention is therefore to specify
a burner assembly of the type mentioned in the introduction, which
resolves the above problem.
[0007] According to the invention the object is achieved with a
burner assembly of the type mentioned in the introduction in that
the at least one liquid fuel nozzle is embodied as a full jet
nozzle and the at least one full jet nozzle has a length and
diameter, the ratio of the length to the diameter being at least
1.5. The further subclaims contain advantageous embodiments of the
invention.
[0008] The use of full jet nozzles allows the setting of the fuel
profile, in particular of the radial fuel distribution, to be
changed very effectively. Full jet nozzles produce a full jet
without interfering turbulence. Compared with the pressure swirl
nozzle the full jet nozzle has the advantage that a higher
preliminary fuel pressure can be converted to a greater penetration
depth. With pressure swirl nozzles a higher preliminary pressure
causes smaller drops to form, which in turn penetrate less
effectively. This means that for greater penetration depth with
pressure swirl nozzles a much higher pressure is required than with
full jet nozzles. There is therefore no need for expensive pumps
for example which can supply a higher preliminary fuel pressure, or
pipe systems with high pressure stages, with the full jet nozzle.
The full jet nozzle can be embodied as a hole running in the
attachment.
[0009] The liquid fuel nozzles configured as full jet nozzles
inventively have a length to diameter ratio of at least 1.5.
According to the invention this provides a liquid fuel jet exiting
from the nozzle which mixes optimally with the air swirled by the
swirl blades. The length to diameter ratio of at least 1.5 ensures
that for example steam bubble formation in the liquid fuel jet is
reliably prevented and a sufficiently low turbulence level is
maintained in the jet. It also ensures an adequate penetration
depth of the fuel jet and good mixing behavior of the jet with the
air flowing past. The length to diameter ratio is advantageously
selected in a range from 6 to 14. A liquid fuel jet produced by a
full jet nozzle with such a length to diameter ratio behaves
particularly optimally in respect of penetration depth and mixing
properties.
[0010] At least one such full jet nozzle can be arranged in the
attachment both in the main burners (which can also be referred to
as main swirl generators) and also in the pilot burner
respectively. The attachment arranged on the lance can be a
different component from the lance. However the attachment could
also be configured from a number of pieces or as a single piece
with the lance.
[0011] It is important for the invention to consider the overall
concept of the combustion system consisting of a central pilot
burner with pilot cone and the main burners arranged around the
pilot burner. In principle the penetration depth of the fuel can be
varied specifically by adjusting the nozzle diameter, to achieve an
advantageous radial fuel profile. Interaction with the central
pilot burner also requires optimization of the fuel and drop size
distribution, primarily as a function of the relative alignment of
the injection position to the pilot cone, in order thus to set the
ignition of the fuel/air mixture with an advantageous time delay.
This time delay between injection position and fuel combustion is
largely responsible for the formation of thermoacoustic feedback,
from which combustor pulsations can result.
[0012] In addition to the radial fuel profile, the local drop size
distributions and air/fuel ratios and also the axial injection
position are the main influencing parameters here, which have to be
adjusted as a function of local flow conditions of the combustion
air. According to the invention therefore the fuel and drop size
distribution in the peripheral direction are optimized by means of
the appropriately embodied full jet nozzles, to achieve ignition of
the fuel/air mixture with an advantageous time delay.
[0013] In one advantageous embodiment of the invention provision
can be made for the attachment to comprise a central attachment
axis and the at least one full jet nozzle to comprise a central
axis and the at least one full jet nozzle to be arranged in the
attachment in such a manner that the central axis of the at least
one full jet nozzle is at an angle of 90 degrees to the central
attachment axis of the attachment.
[0014] The central axis of the full jet nozzle runs in the
longitudinal direction of the full jet nozzle. According to this
advantageous embodiment of the invention the fuel is injected
essentially perpendicular to the flow direction of the air, thereby
achieving a particularly large penetration depth. This allows
favorable mixing with the air flowing past.
[0015] Provision can advantageously also be made for the attachment
to comprise a central attachment axis, the at least one full jet
nozzle to comprise a central axis and the at least one full jet
nozzle to be arranged in the attachment in such a manner that the
central axis of the at least one full jet nozzle is at an angle of
between 90+/-30 degrees to the central attachment axis of the
attachment.
[0016] The angle details relate to the inclination of the central
axis in the direction of the central attachment axis. The angle
range is selected so that by inclining the central axis of the at
least one full jet nozzle it is possible to set a variation of the
penetration depth with essentially the same droplet size
distribution and fuel injection quantity. This allows the radial
fuel profile to be matched in respect of the overall burner
assembly, in particular the radial fuel profile of a main burner in
respect of the pilot burner.
[0017] It can also be considered advantageous for the attachment to
have an attachment surface and the at least one full jet nozzle to
comprise a central axis, and the at least one full jet nozzle to be
arranged in the attachment in such a manner that the central axis
of the at least one full jet nozzle is perpendicular to said
attachment surface.
[0018] The advantageous embodiment of the invention allows
injection of the liquid fuel jet perpendicular to the flow
direction for a region of the attachment tapering conically to an
attachment tip, thereby allowing the greatest possible penetration
depth for the fuel for full jet nozzles arranged in this region of
the attachment.
[0019] It can also be considered advantageous for the attachment to
have an attachment surface and the at least one full jet nozzle to
comprise a central axis and the at least one full jet nozzle to be
arranged in the attachment in such a manner that the central axis
of the at least one full jet nozzle forms an angle of -10 degrees
to +10 degrees with the surface normal of the attachment
surface.
[0020] The surface normal runs perpendicular to the attachment
surface and is to be considered in each instance in the region of
the intersection of central axis and attachment surface. Starting
from the surface normal the central axis can run in an inclined
manner for this purpose both in the direction of the central
attachment axis and in the peripheral direction (azimuthal angle).
The specified angle range of -10 degrees to +10 degrees for the
inclination of the central axis ensures a large penetration depth
for the fuel jet without changing the droplet size distribution or
the injected fuel quantity. This allows the fuel profile to be
produced around the lance to be set both in the radial and
peripheral direction of the lance. This allows the fuel profiles of
the individual main burners to be matched to one another in respect
of the overall burner assembly.
[0021] Provision can advantageously also be made for eight to
twelve full jet nozzles to be provided with a diameter for each of
the main burners, the diameter being between 0.55 mm and 0.8
mm.
[0022] The number from eight to twelve full jet nozzles is
preferred. A number from 6 to 16 full jet nozzles per main burner
can also be seen as advantageous. A number from 8 to 20 full jet
nozzles can also be considered advantageous.
[0023] It can also be considered advantageous for full jet nozzles
with a diameter between 0.6 mm and 0.7 mm to be provided.
[0024] Provision can further be made for full jet nozzles with a
diameter between 0.55 mm and 0.65 mm to be provided.
[0025] In a further advantageous embodiment of the invention
provision can be made for full jet nozzles with a diameter between
0.7 mm and 0.8 mm to be provided.
[0026] According to a further advantageous embodiment of the
invention provision can be made in at least one of the main burners
for full jet nozzles to be arranged along at least one peripheral
line running around the attachment.
[0027] The peripheral line here does not require a material
manifestation but simply serves to describe the arrangement of the
full jet nozzles. The at least one peripheral line can run for
example in a flat and closed manner around the lance. The
peripheral line can for example run in a ring shape and
perpendicular to the central attachment axis. By varying the nozzle
arrangement and nozzle diameter in the peripheral direction, it is
possible to produce fuel profiles that are suitable for suppressing
pressure pulsations.
[0028] It is important for the invention to consider the overall
concept of the combustion system consisting of a central pilot
burner with pilot cone and the main burners arranged around the
pilot burner. The interaction with the central pilot burner
requires optimization of the fuel and drop size distribution
primarily as a function of the relative alignment of the injection
position to the pilot cone, in order thus to set the ignition of
the fuel/air mixture with an advantageous time delay.
[0029] It can also be considered advantageous in at least one of
the main burners for more full jet nozzles to be arranged on the
side of the attachment facing the pilot burner than on the side of
the attachment facing away from the pilot burner.
[0030] Optimum conditions should be set in particular for the two
special instances--injection position in the direction of the pilot
flow (which can also be referred to as pilot cone flow) and in the
counter direction toward the combustor outer wall. As in the first
instance the mixture formation and atomization mechanism produced
by powerful shear flows are different from in the second instance,
this should be taken into account when setting the fuel
profile.
[0031] By increasing the number of full jet nozzles in the
direction of the pilot burner it is possible to produce a higher
fuel concentration in the direction of the pilot burner with the
same radial fuel profile and therefore identical penetration depth.
This allows the flame position to be set. The inventive embodiment
can be realized with one or a number of the main burners, for
example with every second of the main burners arranged around the
pilot burner.
[0032] In a further advantageous development of the invention
provision can be made for the number density of the full jet
nozzles to vary in the peripheral direction along at least one
peripheral line.
[0033] According to one exemplary embodiment of the advantageous
development of the invention the peripheral line can run in a ring
shape and perpendicular to the central attachment axis, with the
full jet nozzles arranged along the peripheral line all having the
same diameter. According to this exemplary embodiment of the
development the number density of the full jet nozzles increases
along the peripheral line in the direction of the pilot burner.
This allows a higher fuel concentration to be produced in the
direction of the pilot burner with the same radial fuel
profile.
[0034] It can also be considered advantageous for full jet nozzles
to be arranged along at least one peripheral line in such a manner
that an inclination of the central axes of the full jet nozzles in
the direction of the central attachment axis varies in the
peripheral direction.
[0035] This allows a periphery-based variation of the penetration
depth. The angle of inclination in the direction of the central
attachment axis can be selected for example between 90+/-20
degrees, with the angle details relating to the angle between the
central axis inclined in the direction of the central attachment
axis and the central attachment axis. Obtuse setting angles are
therefore possible. A periphery-based variation of the penetration
depth can be achieved in the cited angle range, regardless of the
drop size distribution and the injection quantity.
[0036] Provision can advantageously be made for the central axes of
the full jet nozzles arranged along the peripheral line to be
aligned in an alternating manner, with the central axes alternately
running perpendicular to the central attachment axis and being
inclined as a maximum 20 degrees from this in the direction of the
central attachment axis.
[0037] In other words the central axis of every second full jet
nozzle runs on the peripheral line perpendicular to the central
attachment axis and the central axis of the full jet nozzle
arranged in between is inclined in each instance in the direction
of the central attachment axis. For example by 10 degrees from the
surface normal in the direction of the central attachment axis in
the flow direction.
[0038] The peripheral line can run for example perpendicular to the
central attachment axis in a ring shape around the lance.
[0039] Provision can also advantageously be made for full jet
nozzles to be arranged along at least one peripheral line in such a
manner that the central axis of at least one full jet nozzle has an
inclination in the peripheral direction from a position
perpendicular to the central attachment axis.
[0040] This embodiment of the invention allows an inclination in
the peripheral direction (azimuthal angle) as an alternative or in
addition to the inclination of the central axis in the direction of
the central attachment axis. This allows the interaction of the
full fuel jet with the swirl flow to be set in respect of
atomization. Isolated adjustment of the drop size distribution can
largely be achieved over a limited range here, without producing a
substantial change in the radial penetration depth. This azimuthal
setting of the central axis of the at least one full jet nozzle can
be selected to be the same for example for all the full jet nozzles
arranged along the peripheral line. The azimuthal angle of
inclination of the central axes could however also be selected for
example as a function of the periphery. According to one exemplary
embodiment of the advantageous development of the invention the
peripheral line runs perpendicular to the central attachment axis
in a ring shape around the lance, with the fill jet nozzles having
the same diameter along the peripheral line. The central axes of
the full jet nozzles run in an alternating manner, with the central
axis of every second full jet nozzle running perpendicular to the
attachment surface and the central axis of the full jet nozzle
arranged in between having an azimuthal angle of 20 degrees to the
surface normal.
[0041] It can also be considered advantageous for the full jet
nozzles to have different diameters along at least one peripheral
line.
[0042] The different diameters result in different penetration
depths for the fuel in the peripheral direction. This allows
adjustment of the radial fuel profile of a main burner in respect
of the overall burner assembly.
[0043] Provision can also advantageously be made for the full jet
nozzles to have the same diameter along at least one peripheral
line.
[0044] In a further advantageous embodiment of the invention
provision can be made for the full jet nozzles to be arranged at
least along two peripheral lines.
[0045] An at least two-row arrangement of the full jet nozzles
allows a much larger variation of the fuel profiles than with a
single-row arrangement. According to one advantageous development
of the invention the at least two peripheral lines run in a ring
shape and perpendicular to the central attachment axis around the
lance at different axial positions.
[0046] An equal or different number of full jet nozzles can be
arranged along the two peripheral lines. For example 4 to 10
nozzles can be arranged on each peripheral line. The at least
double arrangement of the peripheral lines allows better
atomization of the fuel. The arrangement of the full jet nozzles in
two axial planes also allows fuel to be distributed in a more
regular manner radially at the same peripheral position, by
injecting it to different depths into the same flow line of the air
flowing past at two axial positions.
[0047] It can also be considered advantageous for the full jet
nozzles arranged along an upstream peripheral line to have a larger
diameter than the full jet nozzles arranged along a downstream
peripheral line.
[0048] This embodiment of the invention is advantageous when a
regular radial distribution is to be achieved.
[0049] It can also be considered advantageous for the full jet
nozzles arranged along an upstream peripheral line to have a
smaller diameter than the full jet nozzles arranged along a
downstream peripheral line.
[0050] This embodiment of the invention is advantageous when a
narrow radial distribution is to be achieved.
[0051] Provision can also advantageously be made for full jet
nozzles arranged along the downstream peripheral line and full jet
nozzles arranged along the upstream peripheral line to be arranged
on common flow lines, so that when air flows through the swirl
blades, said air can be swirled along the flow lines.
[0052] This embodiment of the invention is advantageous in order to
achieve a regular radial fuel distribution, when the fuel injected
by the downstream full jet nozzles in particular has a smaller or
much greater penetration depth than the fuel injected by the
upstream full jet nozzles. A smaller penetration depth in
particular is considered advantageous. However this embodiment also
allows a narrow radial fuel distribution to be achieved, with the
fuel injected by the downstream full jet nozzles being injected to
the same radial position as the fuel injected by the upstream full
jet nozzles. The radial position here is selected in such a manner
that the flame stabilizes at a point, the associated time delay of
which cannot be initiated in the combustion system.
[0053] Provision can advantageously also be made for full jet
nozzles arranged along the downstream peripheral line and full jet
nozzles arranged along the upstream peripheral line to be arranged
so that they are offset from one another in such a manner that when
air flows through the swirl blades, said air can be swirled along
flow lines on which only one of the full jet nozzles is arranged in
each instance.
[0054] This embodiment of the invention is particularly
advantageous for achieving a regular peripheral distribution of the
fuel profile. It can be combined for example with a narrow or
regular radial and axial distribution. A regular radial and regular
axial distribution in particular is considered advantageous.
[0055] Provision can advantageously also be made for full jet
nozzles arranged along the downstream peripheral line to inject
fuel to the same radial position as full jet nozzles arranged along
the upstream peripheral line.
[0056] The radial position here is selected in such a manner that
the flame stabilizes at a point, the associated time delay of which
cannot be initiated in the combustion system.
[0057] Provision can advantageously be made for the full jet
nozzles to be arranged along at least one helical peripheral
line.
[0058] In addition to the illustrated periphery-based and axial
variations of injection guidance through the full jet nozzles,
which allow optimization of the fuel and drop size distribution in
the peripheral, axial and radial directions, the time delay
spectrum can also be further broadened by the additional helical
arrangement of the full jet nozzles.
[0059] If injection of the fuel takes place for example along a
single helical peripheral line and this peripheral line runs along
a flow line of the swirled air flow, a regular radial fuel profile
can be achieved with the same full jet nozzle diameters. This
embodiment can be advantageous when an alternating periphery-based
fuel distribution is required with the greatest possible shift of
the time delay spectrum. The arrangement of different full jet
nozzle diameters here allows different radial fuel profiles to be
set, with regular radial profiles being considered
advantageous.
[0060] Provision can advantageously be made for the diameters of
the full jet nozzles arranged along the at least one helical
peripheral line to be configured in such a manner that the
diameters increase in the flow direction. This embodiment of the
invention is advantageous, when the radial profile is to be
homogenized by enrichment of the region close to the axis.
[0061] It can also be considered advantageous for the diameters of
the full jet nozzles arranged along the at least one helical
peripheral line to be configured in such a manner that the
diameters increase counter to the flow direction. This embodiment
of the invention is advantageous when a narrow radial fuel profile
is preferred.
[0062] According to a further embodiment of the invention the
helical peripheral line may not run along a flow line. This
embodiment allows regular periphery-based fuel distribution, it
being possible for the diameters of the full jet nozzles arranged
along the peripheral line to increase or decrease in the flow
direction, depending on the desired radial fuel profile. The angle
of inclination of the central axis of the full jet nozzles can also
be varied in the flow direction toward the central attachment axis
and/or in the peripheral direction along the helical peripheral
line, to set the interaction of the swirled flow of air with the
full fuel jet in respect of atomization as a function of the nozzle
position.
[0063] It can also be considered advantageous for the full jet
nozzles to be arranged along two helical peripheral lines.
[0064] This is advantageous particularly for short attachments,
when the greatest possible axial distribution of the nozzle
assembly is to be achieved. In addition to a parallel arrangement
the double helix can also run anti-parallel, thereby allowing more
regular peripheral distributions to be achieved.
[0065] According to a further advantageous embodiment of the
invention provision is made, for the periphery-based enrichment of
the fuel concentration, for the full jet nozzles to be arranged
along a helical peripheral line, with the helical peripheral line
overlapping to some degree. The diameters of the full jet nozzles
here can all be selected to be the same size. The enrichment of the
fuel concentration can serve to enrich the shear flow between pilot
burner and a main burner.
[0066] In one advantageous development of the invention provision
can be made for the full jet nozzles arranged along a peripheral
line to be at distances from one another and have diameters, such
that their sequence is repeated along the peripheral line.
[0067] The full jet nozzles arranged along the peripheral line can
have regular distances from one another and can all have the same
diameter. The distances and/or diameters can however all vary in a
regular sequence. This allows additional setting of the radial fuel
profile. The radial fuel profile is essential for thermoacoustic
stability, as it determines the delay time between injection and
combustion. The delay time in turn determines which combustor
frequencies can be initiated. According to one exemplary embodiment
of the advantageous embodiment of the invention an independent
variation of the penetration depth and fuel distribution can be
achieved by a sequence of combined full jet nozzle diameters along
the peripheral line. For example two different diameters or more
can be combined in a regular sequence. By selecting the size ratios
of the full jet nozzle diameters it is possible to set the radial
region, in which the fuel distribution of the different nozzle
diameters is superimposed. The degree of overlap can also be set by
selecting the peripheral positions of the full jet nozzles, in
particular the mutual distances.
[0068] According to one advantageous development of the invention a
full jet nozzle with a smaller diameter is arranged along the
peripheral line between two full jet nozzles of the same diameter,
to produce a fuel profile with a ring-shaped zone of a first fuel
distribution and a ring-shaped zone of a second fuel
distribution.
[0069] According to one exemplary embodiment of the advantageous
embodiment 8 to 16 full jet nozzles for example can be provided on
the lance. A diameter between 0.5 mm and 0.7 mm can be selected for
the smaller full jet nozzles and a diameter between 0.6 mm and 0.8
mm can be selected for the larger full jet nozzles.
[0070] According to one advantageous development of the invention
the two zones can overlap, for example by arranging the full jet
nozzle with the smaller diameter closer to one of the two full jet
nozzles with a larger diameter.
[0071] It can also be considered advantageous for the full jet
nozzles arranged along at least one peripheral line to be
configured in such a manner that a fuel injected by means of the
nozzles has a radial fuel distribution about the central attachment
axis, the fuel distribution comprising a ring-shaped zone of a
first fuel distribution and a ring-shaped zone of a second fuel
distribution.
[0072] The advantageous fuel distribution can be produced by
varying the distances, diameters, angles of inclination and/or
course of the peripheral line. As already set out above, such a
fuel profile can be produced by means of a peripheral line running
in a ring shape perpendicular to the central attachment axis, along
which full jet nozzles are arranged at equal distances from one
another, their diameters alternating between two different
sizes.
[0073] It can also be considered advantageous for the ring-shaped
zone of a first fuel distribution and the ring-shaped zone of a
second fuel distribution to overlap.
[0074] It can also be considered advantageous for the ring-shaped
zone of a first fuel distribution and the ring-shaped zone of a
second fuel distribution to be at a distance from one another.
BRIEF DESCRIPTION OF THE DRAWINGS
[0075] Further advantages, features and properties of the present
invention are described in more detail below based on exemplary
embodiments with reference to the accompanying figures. The
features of the exemplary embodiments can be advantageous
individually or in combination here.
[0076] FIG. 1 shows a schematic diagram of a section through a main
burner of the inventive burner assembly according to a first
exemplary embodiment,
[0077] FIG. 2 shows a schematic diagram of a perspective view of a
section through the attachment 13 of the exemplary embodiment
illustrated in FIG. 1,
[0078] FIG. 3 shows a schematic diagram of a section through a main
burner of the inventive burner assembly according to a second
exemplary embodiment,
[0079] FIG. 4 shows a schematic diagram of a section through a main
burner of the inventive burner assembly according to a third
exemplary embodiment,
[0080] FIG. 5 shows a diagram to clarify the exemplary embodiment
illustrated in FIG. 4,
[0081] FIG. 6 shows a schematic diagram of a section through a main
burner of the inventive burner assembly according to a fourth
exemplary embodiment,
[0082] FIG. 7 shows a cross section through the attachment
illustrated in FIG. 6,
[0083] FIG. 8 shows a diagram to clarify the exemplary embodiment
illustrated in FIG. 6,
[0084] FIG. 9 shows a schematic diagram of a section through a main
burner of the inventive burner assembly according to a fifth
exemplary embodiment,
[0085] FIG. 10 shows a schematic diagram of a section through a
main burner of the inventive burner assembly according to a sixth
exemplary embodiment,
[0086] FIG. 11 shows a schematic diagram of a cross section through
a radial fuel profile, which can be produced by means of the main
burner illustrated in FIG. 10, and
[0087] FIG. 12 shows a schematic diagram of a perspective view of
an inventive burner assembly.
DETAILED DESCRIPTION OF THE INVENTION
[0088] FIG. 1 shows a detail of an inventive burner assembly in the
region of a main burner 107. Swirl blades 17 are arranged around
the lance in the housing 12 of the main burner 107. The swirl
blades 17 are arranged along the periphery of the lance in the
housing 12. The swirl blades 17 direct a compressor air flow 15
into the part of the burner 107 leading to a combustor. The air is
made to swirl by the swirl blades 17. The lance also comprises a
fuel channel 16. The burner 107 further comprises an attachment 13
on the side leading to a combustor. The attachment 13 can be welded
or screwed to the lance for example. The fuel nozzles are
preferably arranged downstream of the swirl blades 17 in the
attachment 13 and are thus connected for flow purposes to the fuel
channel 16, shown here as an oil channel. The inventive burner
assembly preferably comprises eight such main burners 107 arranged
in a circle (see FIG. 12). The main burners 107 here are arranged
around a pilot burner (see FIG. 12) with pilot cone.
[0089] Pressure swirl nozzles used hitherto in the prior art
exhibit significant pressure pulsations. However major problems
then occur in basic load operation. This is now avoided with the
aid of the invention.
[0090] The plurality of fuel nozzles are therefore embodied as full
jet nozzles 1 according to the invention. The embodiment of the
nozzle as a full jet nozzle 1, the full jet nozzle size and
arrangement allow the penetration depth of the fuel to be set so
that an advantageous fuel profile results. The parameters available
here are the diameters of the full jet nozzles 1 and the number of
full jet nozzles 1. In interaction with the central pilot burner
the fuel distribution is set so that ignition of the fuel/air
mixture takes place with an advantageous time delay. The time delay
between injection and combustion of the fuel is significant for the
formation of thermoacoustic feedback loops, from which combustor
pulsations can result. The full jet nozzles 1 have a length, the
length to diameter ratio being at least 1.5, to achieve thorough
mixing. It means that the divergence of the full jet is small
enough to prevent drops spinning off in an unwanted manner.
[0091] The use of full jet nozzles 1 therefore allows the setting
of the fuel profile, in particular of the radial fuel distribution,
to be changed very effectively. Compared with a pressure swirl
nozzle, the full jet nozzle 1 has the advantage that a higher
preliminary fuel pressure can be converted primarily to a greater
penetration depth. With the pressure swirl nozzles of the prior art
smaller drops are formed due to a higher preliminary pressure and
these penetrate less effectively. Therefore a much higher pressure
is required for a greater penetration depth with pressure swirl
nozzles than with full jet nozzles. There is therefore no need for
expensive pumps, which can supply a greater preliminary fuel
pressure, or pipe systems with high pressure stages for example
with the full jet nozzle 1.
[0092] FIG. 2 shows a schematic diagram of a perspective view of a
section through the attachment 13. The central attachment axis of
the attachment 13 is shown with the reference character 18. The
attachment 13 is embodied to taper conically in the direction of
the combustor. It comprises a number of full jet nozzles 1, in the
present exemplary embodiment four. The full jet nozzles 1 are
arranged on the outer periphery of the attachment 13. The central
axes of the full jet nozzles 1 are shown with the reference
character 19. The central axes 19 of the full jet nozzles 1 are at
an angle 20 to the central attachment axis 18 of the attachment 13.
The fuel enters the attachment 13 through the fuel channel 16 along
the flow direction shown with the reference character 26. The fuel
is then injected by the full jet nozzles 1 in direction 25 into the
air flow coming from the swirl blades 17. The central axis 19 of
the full jet nozzles 1 is arranged essentially perpendicular (90
degrees) to the central attachment axis 18 of the full jet nozzles
1. The central axis 19 of the nozzle 1 can also be perpendicular to
the attachment surface. The jet is thus introduced into the air
flow in a perpendicular manner, resulting in thorough mixing. An
arrangement of 90+/-30 degrees, in particular 90+/-10 degrees, from
the central axis 19 of the full jet nozzles 1 to the axis 18 or the
attachment surface however also produces a very advantageous
assembly.
[0093] The attachment 13 comprises a cylindrical part 130 and a
part 140 tapering conically in the direction of a combustor. The
conical part 140 can have a cone angle of 10 to 20 degrees. This
embodiment prevents the flow being fractured at the attachment tip.
The full jet nozzles 1 here can be arranged on the conically
tapering part 140 of the attachment 13. The position of the full
jet nozzles 1 can change as a function of the automatic ignition of
the mixture. To achieve a good fuel distribution, eight to twelve
full jet nozzles are preferably used (not shown) per attachment 13.
Six to sixteen full jet nozzles 1 (not shown) are also
advantageous. These are distributed in a regular manner on the
periphery of the attachment 13. A good fuel distribution is
necessary to comply with emission limits and prevent soot forming.
The full jet nozzles 1 can be configured as holes in the attachment
13. A length to diameter ratio of six to fourteen in particular is
advantageous in respect of mixing. The length of the full jet
nozzle is shown with the reference character 32. The diameter of
the full jet nozzle is shown with the reference character 33. The
preferred diameter of the full jet nozzles 1 here is 0.55 mm to 0.8
mm but 0.5 mm to 1 mm (not shown) is also advantageous.
[0094] Combinations of eight nozzles with a diameter of 0.7 to 0.8
mm or of ten nozzles with 0.6 to 0.7 mm diameter and twelve nozzles
with 0.55 mm to 0.65 mm diameter (also not shown) in particular are
advantageous.
[0095] The full jet nozzles 1 also allow easy adjustment for
different thermodynamic conditions, which result for example in a
changed air crossflow speed, air density or fuel mass flow, by
adjusting the diameters 33 of the full jet nozzles 1
correspondingly.
[0096] It is also possible to optimize the design of water
components by adjusting the diameter 33 of the full jet nozzles 1.
This may be of interest for example, when the emission limits are
increased, in particular for NOx. This happens for example in
water-poor regions, where gas turbines 1 are also used to produce
fresh water.
[0097] FIG. 3 shows a detail of the inventive burner assembly in
the region of a main burner 107. The main burner 107 comprises a
cylindrical housing 12, in which a lance 14 is arranged centrally,
being enclosed by a main swirler 10. The schematically illustrated
main swirler 10 has swirl blades 17 (not shown), which support the
lance 14 on the housing 12. A compressor air flow 15 flows through
the main swirler 10 in the direction of the combustor (not shown).
The lance 14 extends along a central attachment axis 18, on which
an attachment 13 is arranged in the direction of the combustor (not
shown). The attachment 13 has a cylindrical part 130 and
transitions into a conically tapering part 140 in the direction of
the combustor. Present in the conically tapering part 140 of the
attachment 13 are full jet nozzles 1 (shown by circles), which are
arranged along a peripheral line 11 that runs perpendicular to the
central attachment axis 18 and in a ring shape around the central
attachment axis 18. In other words the outlets of the full jet
nozzles 1 opening toward the attachment surface are arranged along
a peripheral line 11 running on the attachment surface, the
peripheral line 11 running in the peripheral direction 22 around
the attachment 13. Half of the peripheral line 11 is shown in the
sectional view. The peripheral direction 22 does not necessarily
run perpendicular to the central attachment axis 18. It is only
important here that the peripheral line 11 running in a peripheral
direction 22 on the attachment surface encircles the central
attachment axis 18. The peripheral line 11 illustrated in FIG. 3
does not have to have an actual correspondence but simply serves to
describe the full jet nozzle arrangement. According to the
illustrated second exemplary embodiment of the inventive burner
assembly the number density of the full jet nozzles 1 varies in the
peripheral direction 22, as the number density of the full jet
nozzles 1 above the central attachment axis 18 is greater than
below the central attachment axis 18. To increase the fuel
concentration between pilot burner (not shown) and main burner 107,
the side of the attachment 13 shown above the central attachment
axis 18 faces the pilot burner (not shown). According to the
illustrated exemplary embodiment the central axes 19 of the full
jet nozzles 1 run perpendicular to the attachment surface. In other
words each of the central axes 19 runs in the direction of a
surface normal 23. To clarify the concept of surface normals,
randomly selected surface normals 23a, 23b, 23c are shown in FIG.
3, the surface normal 23b being shown in the outlet region of a
full jet nozzle 1.
[0098] FIG. 4 shows a schematic sectional view of a detail of an
inventive burner assembly in the region of a main burner 107
according to a third exemplary embodiment. The structure of the
main burner here corresponds to the exemplary embodiment
illustrated in FIG. 3 apart from the arrangement of the full jet
nozzles 1. According to the third exemplary embodiment these are
arranged along a peripheral line 11 running in a ring shape and
perpendicular to the main attachment line 18. The inclination of
the central axes 19 of the full jet nozzles here runs in an
alternating manner along the peripheral line 11. The central axis
19 and therefore also the direction 25 of the fuel jet, in which it
leaves the full jet nozzle, run perpendicular to the attachment
surface and therefore in the direction of a surface normal 23 in a
first full jet nozzle. The central axis 19 of the full jet nozzle 1
following on the peripheral line 11 is inclined 10 degrees from
this in the direction of the central attachment axis 18 in the flow
direction of the compressor air flow 15. In this sense the
inclination of the central axes 19 of the full jet nozzles 1 varies
in the peripheral direction 22 along the peripheral line 11. The
marked angle .phi. shows the angle between central axis 19 and
attachment surface.
[0099] FIG. 5 shows a diagram to clarify the exemplary embodiment
illustrated in FIG. 4. By way of example it shows the angle .phi.
between central axis 19 and attachment surface of several full jet
nozzles 1 as a function of the peripheral position along the
peripheral line 11. The angle .phi. is referred to as the setting
angle.
[0100] FIG. 6 shows a schematic sectional view of a main burner 107
according to a fourth exemplary embodiment. The structure of the
main burner 07 here corresponds to the exemplary embodiment
illustrated in FIG. 3 apart from the arrangement of the full jet
nozzles 1. According to the fourth exemplary embodiment the full
jet nozzles 1 are arranged along a peripheral line 11 running in a
ring shape and perpendicular to the main attachment line 18. The
inclination of the central axes 19 of the full jet nozzles here
runs in an alternating manner along the peripheral line 11. The
central axis 19 and therefore also the direction 25 of the fuel
jet, in which it leaves the full jet nozzle 1, run perpendicular to
the attachment surface and therefore in the direction of a surface
normal 23 in a first full jet nozzle 1. The central axis 19 of the
full jet nozzle 1 following on the peripheral line 11 is inclined
20 degrees from this in the peripheral direction 22. The angle of
inclination in the peripheral direction 22 can also be referred to
as the azimuthal angle.
[0101] FIG. 7 shows a cross section through the attachment 13 at
the axial height of the peripheral line 11 to clarify the fourth
exemplary embodiment illustrated in FIG. 6. The full jet nozzles 1
arranged along the peripheral line 11 are shown by circles. In
other words the openings of the full jet nozzles are arranged along
the peripheral line 11. The central axes 19 of the full jet nozzles
1 and therefore also the direction 25 of the fuel jet leaving the
full jet nozzle run in an alternating manner perpendicular to the
attachment surface and are therefore inclined in the direction of a
surface normal 23 or 20 degrees from this in the peripheral
direction 22. The angle between surface normal 23 and central axis
19 is shown as iv.
[0102] FIG. 8 shows a diagram to clarify the fourth exemplary
embodiment illustrated in FIG. 6. By way of example it shows the
angle between central axis 19 and surface normal 23 in the
peripheral direction (azimuthal angle .psi.) of several full jet
nozzles 1 as a function of the peripheral position along the
peripheral line 11.
[0103] FIG. 9 shows a schematic sectional view of a main burner 107
according to a fifth exemplary embodiment. The structure of the
main burner 107 here corresponds to the exemplary embodiment
illustrated in FIG. 3 apart from the arrangement of the full jet
nozzles 1. These are arranged along a helical peripheral line 11,
the diameter of the full jet nozzles 1 increasing counter to the
flow direction of the compressor air flow 15. The air, which is
swirled as it flows through the main swirler 10, flows along flow
lines 27 along the attachment 13 in the direction of the combustor
(not shown). The helical peripheral line 11 here runs in such a
manner that the full jet nozzles 1 are arranged on a common flow
line 27.
[0104] FIG. 10 shows a schematic sectional view of a main burner
107 according to a sixth exemplary embodiment. The structure of the
main burner 107 here corresponds to the exemplary embodiment
illustrated in FIG. 3 apart from the arrangement of the full jet
nozzles 1. These are arranged along a peripheral line 11 running in
a ring shape and perpendicular to the central attachment axis, the
full jet nozzles 1 having distances from one another and diameters
along the peripheral line 11, the sequence of which is repeated
along the peripheral line 11. According to the illustrated
exemplary embodiment the full jet nozzles 1 are an equal distance
from one another, with a full jet nozzle 1 with a smaller diameter
arranged between two full jet nozzles 1 of the same diameter. The
central axes (not shown) of the full jet nozzles 1 point
perpendicular to the central attachment axis 18 in a radial
direction.
[0105] FIG. 11 shows a fuel profile that can be produced by means
of the full jet nozzles 1 illustrated in FIG. 10. The injected fuel
here produces a radial fuel distribution around the central
attachment axis 18, the fuel channel 16 and the attachment 13, the
fuel distribution comprising a ring-shaped zone of a first fuel
distribution 28 from the full jet nozzles with large diameter and a
ring-shaped zone of a second fuel distribution 29 from the full jet
nozzles with small diameter. The fuel distribution from an
individual full jet nozzle with large diameter is shown with the
reference character 30. The fuel distribution from an individual
full jet nozzle with small diameter is shown with the reference
character 31. The selected distances between the full jet nozzles 1
and the size ratios of the diameters mean that the ring-shaped zone
of a first fuel distribution 28 and the ring-shaped zone of a
second fuel distribution 29 overlap.
[0106] FIG. 12 shows an inventive burner assembly 108 with a pilot
burner 106 with pilot cone 109 and a plurality of main burners 107
arranged around the pilot burner 106. Each of the main burners 107
comprises an essentially cylindrical housing 12, in which a lance
is arranged centrally, with an attachment 13 arranged on the lance
in the direction of a combustor (not shown).
* * * * *