U.S. patent application number 13/361445 was filed with the patent office on 2013-08-01 for jet micro-induced flow reversals combustor.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is Bassam Sabry Mohammad Abd El-Nabi, Ahmed Mostafa ElKady, Gary Lee Leonard. Invention is credited to Bassam Sabry Mohammad Abd El-Nabi, Ahmed Mostafa ElKady, Gary Lee Leonard.
Application Number | 20130196270 13/361445 |
Document ID | / |
Family ID | 47631310 |
Filed Date | 2013-08-01 |
United States Patent
Application |
20130196270 |
Kind Code |
A1 |
Abd El-Nabi; Bassam Sabry Mohammad
; et al. |
August 1, 2013 |
JET MICRO-INDUCED FLOW REVERSALS COMBUSTOR
Abstract
A jet micro-induced flow reversals combustor is used to reduce
NO.sub.x emissions. The combustor has a nozzle disposed at the head
end of the combustion chamber. The nozzle includes a plurality of
jets for injecting a fuel and oxidant mixture stream into the
combustion chamber. A combustion liner is disposed within the
casing on one side of the nozzle and a plenum chamber is disposed
on another side of the nozzle and configured to provide an input of
a fuel and oxidant. The nozzle and the combustion liner are sized
and shaped to input the fuel and oxidant mixture stream into the
combustion liner at a high velocity ratio wherein a jet velocity is
greater than a combustion mean velocity within the combustion
liner, to increase turbulence within the combustion liner and
reduce combustion emissions.
Inventors: |
Abd El-Nabi; Bassam Sabry
Mohammad; (Niskayuna, NY) ; ElKady; Ahmed
Mostafa; (West Chester, OH) ; Leonard; Gary Lee;
(Saratoga Springs, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Abd El-Nabi; Bassam Sabry Mohammad
ElKady; Ahmed Mostafa
Leonard; Gary Lee |
Niskayuna
West Chester
Saratoga Springs |
NY
OH
NY |
US
US
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
47631310 |
Appl. No.: |
13/361445 |
Filed: |
January 30, 2012 |
Current U.S.
Class: |
431/2 ;
431/350 |
Current CPC
Class: |
F23C 9/006 20130101;
F23C 2900/03005 20130101; F23R 3/286 20130101 |
Class at
Publication: |
431/2 ;
431/350 |
International
Class: |
F23D 14/46 20060101
F23D014/46 |
Claims
1. A combustor comprising: a casing having a longitudinal axis; a
nozzle coupled to the casing along the longitudinal axis, the
nozzle having a plurality of fuel and oxidant jets formed therein;
a combustion liner formed in the casing on one side of the nozzle;
and a plenum chamber formed in the casing on another side of the
nozzle and configured to provide an input of a fuel and oxidant,
wherein the nozzle and the combustion liner are sized and shaped to
input a fuel and oxidant mixture stream into the combustion chamber
at a high velocity ratio wherein a jet velocity is greater than a
combustion mean velocity within the combustion liner, to increase
turbulence within the combustion liner and reduce combustion
emissions.
2. A combustor as claimed in claim 1, wherein the nozzle is a
perforated plate.
3. A combustor as claimed in claim 1, wherein the combustion liner
is comprised of a ceramic material.
4. A combustor as claimed in claim 1, wherein the increase in
turbulence in the combustion liner reduces a length of a combustion
flame.
5. A combustor as claimed in claim 1, wherein the increase in
turbulence in the combustion liner reduces combustion
emissions.
6. A combustor as claimed in claim 1, wherein, the increase in
turbulence in the combustion liner mixes a portion of combustion
products in a flame front.
7. A combustor as claimed in claim 1, further comprising a cooling
sleeve disposed between the casing and the combustion liner.
8. A combustor as claimed in claim 1, wherein the increase in
turbulence within the combustion liner reduces NO.sub.x
emissions.
9. A combustor comprising: a casing having a longitudinal axis; a
cooling sleeve disposed within the casing; a perforated plate
coupled to the casing at an intermediate location along the
longitudinal axis, the plate having a plurality of fuel and oxidant
jets formed therein; a combustion liner disposed within the cooling
sleeve and on one side of the perforated plate; and a plenum
chamber formed on another side of the perforated plate and
configured to provide an input of a fuel and oxidant, wherein the
perforated plate and the combustion liner are sized and shaped to
input a fuel and oxidant mixture stream into the combustion chamber
at a high velocity ratio wherein a jet velocity is greater than a
combustion mean velocity within the combustion liner, to increase
turbulence within the combustion liner and reduce combustion
emissions.
10. A combustor as claimed in claim 9, wherein the increase in
turbulence in the combustion liner reduces a length of a combustion
flame.
11. A combustor as claimed in claim 9, wherein the increase in
turbulence in the combustion liner reduces combustion
emissions.
12. A combustor as claimed in claim 9, wherein, the increase in
turbulence in the combustion liner mixes a portion of combustion
products in a flame front.
13. A combustor as claimed in claim 9, wherein the increase in
turbulence within the combustion liner reduces NOx emissions.
14. A combustor as claimed in claim 9, wherein the fuel and oxidant
are premixed in the plenum chamber.
15. A method of reducing combustion emissions in a combustor
comprising: providing a casing having a longitudinal axis; coupling
a nozzle to the casing along the longitudinal axis, the nozzle
having a plurality of fuel and oxidant jets formed therein;
disposing a combustion liner within the casing and on one side of
the nozzle; and disposing a plenum chamber on another side of the
nozzle and configured to provide an input of a fuel and oxidant,
wherein the nozzle and the combustion liner are sized and shaped to
input a fuel and oxidant mixture stream into the combustion chamber
at a high velocity ratio wherein a jet velocity is greater than a
combustion mean velocity within the combustion liner, to increase
turbulence within the combustion liner and reduce combustion
emissions.
16. A method of reducing combustion emissions in a combustor as
claimed in claim 15, wherein the increase in turbulence in the
combustion liner reduces a length of a combustion flame and
combustion emissions.
17. A method of reducing combustion emissions in a combustor as
claimed in claim 15, wherein the increase in turbulence in the
combustion liner mixes a portion of combustion products in a flame
front.
18. A method of reducing combustion emissions in a combustor as
claimed in claim 15, wherein the increase in turbulence within the
combustion liner reduces NOx emissions.
19. A method of reducing combustion emissions in a combustor as
claimed in claim 15, further comprising disposing a cooling sleeve
between the casing and the combustion liner.
20. A method of reducing combustion emissions in a combustor as
claimed in claim 15, wherein the combustor comprises a jet
micro-induced flow reversals can combustor.
Description
BACKGROUND
[0001] Embodiments presented herein relate generally to combustors
for gas turbines and more particularly concerns a combustor sized
and shaped for reduced NO.sub.x emissions.
[0002] Generally described, gas turbine engines include a
compressor for compressing air, a combustor for mixing the
compressed air with fuel and igniting the mixture, and a turbine
blade assembly for producing power. Known turbine engines have
developed into highly complex and sophisticated devices.
[0003] It is well known that higher temperatures in gas turbines
result in a machine operation at high thermal efficiency. At issue
with known gas turbine engines is promoting operation at high
thermal efficiency without producing undesirable air emissions. The
primary air emissions usually produced by gas turbine engines
include nitrogen oxides (NO.sub.x) and carbon monoxide (CO).
NO.sub.x is temperature dependent, and thus at greatest challenge
when high firing temperatures are required. Many combustion
technologies have proposed to reduce NO.sub.x and CO to single
digits, but have not achieved doing so at high firing temperatures
near 3150.degree. F. High firing temperatures mean high thermal
efficiency which is translated in terms of reduced amount of
overall emissions (less fuel to burn per unit power generated).
[0004] Previous combustion technologies that have attempted to
reduce NO.sub.x and CO include stagnation point reverse flow
combustors (SPRFC), flameless oxidation combustors (FLOXCOM) and
advanced vortex combustors (AVC).
[0005] There is a desire, therefore, for a combustor for a gas
turbine engine that enables high firing temperatures with increased
thermal efficiency and reduced NO.sub.x and CO emissions.
Preferably, the emissions output is reduced while maintaining or
improving reliability, efficiency, and performance of the gas
turbine engine.
BRIEF DESCRIPTION
[0006] In accordance with one exemplary embodiment, disclosed is a
combustor including a casing having a longitudinal axis; a nozzle
coupled to the casing along the longitudinal axis, a combustion
liner formed in the casing on one side of the nozzle; and a plenum
chamber formed in the casing on another side of the nozzle and
configured to provide an input of a fuel and oxidant. The nozzle
includes a plurality of fuel and oxidant jets formed therein. The
nozzle and the combustion liner are sized and shaped to input a
fuel and oxidant mixture stream into the combustion chamber at a
high velocity ratio wherein a jet velocity is greater than a
combustion mean velocity within the combustion liner, to increase
turbulence within the combustion liner and reduce combustion
emissions.
[0007] In accordance with another exemplary embodiment, disclosed
is a combustor including a casing having a longitudinal axis; a
cooling sleeve disposed within the casing; a perforated plate
coupled to the casing at an intermediate location along the
longitudinal axis, a combustion liner disposed within the cooling
sleeve and on one side of the plate; and a plenum chamber formed on
another side of the plate and configured to provide an input of a
fuel and oxidant. The perforated late including a plurality of fuel
and oxidant jets formed therein. The plate and the combustion liner
are sized and shaped to input a fuel and oxidant mixture stream
into the combustion chamber at a high velocity ratio wherein a jet
velocity is greater than a combustion mean velocity within the
combustion liner, to increase turbulence within the combustion
liner and reduce combustion emissions.
[0008] In accordance with another exemplary embodiment, disclosed
is a method of reducing combustion emissions in a combustor. The
method including providing a casing having a longitudinal axis;
coupling a nozzle to the casing along the longitudinal axis,
disposing a combustion liner within the casing and on one side of
the nozzle; and disposing a plenum chamber on another side of the
nozzle and configured to provide an input of a fuel and oxidant.
The nozzle including a plurality of fuel and oxidant jets formed
therein. The nozzle and the combustion liner are sized and shaped
to input a fuel and oxidant mixture stream into the combustion
chamber at a high velocity ratio wherein a jet velocity is greater
than a combustion mean velocity within the combustion liner, to
increase turbulence within the combustion liner and reduce
combustion emissions.
[0009] Other objects and advantages of the present disclosure will
become apparent upon reading the following detailed description and
the appended claims with reference to the accompanying drawings.
These and other features and improvements of the present
application will become apparent to one of ordinary skill in the
art upon review of the following detailed description when taken in
conjunction with the several drawings and the appended claims.
DRAWINGS
[0010] The above and other features, aspects, and advantages of the
present disclosure will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0011] FIG. 1 is a cross-sectional side view of a jet micro-induced
flow reversals combustor according to an embodiment;
[0012] FIG. 2 shows a partially cut-away view of the a jet
micro-induced flow reversals combustor of FIG. 1 according to an
embodiment;
[0013] FIG. 3 is a cross-sectional side view of a portion of a jet
micro-induced flow reversals combustor according to an
embodiment;
[0014] FIG. 4 is an image taken through the combustion chamber of a
jet micro-induced flow reversals combustor according to an
embodiment;
[0015] FIG. 5 is a graph comparing the level of NO.sub.x emissions
as a function of flame temperature between experimental jet
micro-induced flow reversals combustors according to an embodiments
under varying pressure conditions; and
[0016] FIG. 6 is a graph comparing the level of NO.sub.x emissions
as a function of flame temperature between an experimental jet
micro-induced flow reversals combustor according to an embodiment
and the NO.sub.x emissions from a known combustor.
DETAILED DESCRIPTION
[0017] Referring to the drawings wherein identical reference
numerals denote the same elements throughout the various views,
FIGS. 1 and 2 show a jet micro-induced flow reversals combustion
system 10. The combustion system 10 comprises a casing, or housing,
12 which has a substantially open interior. The casing 12 is shown
in the form of a cylindrical tube but is not necessarily limited to
this shape. A nozzle 13, configured to include a plurality of fuel
and oxidant jets, is disposed at one end of the casing 12, along
the longitudinal axis of the casing 12. In an embodiment, nozzle 13
is configured as a perforated plate 14 and is disposed at an end of
the casing 12. In an alternate embodiment, the perforated plate 14
may be disposed inside the casing 12 at an intermediate location
with the diameter of the perforated plate 14 substantially equal to
the inner diameter of the casing 12 so that the plate 14 fits
snugly therein. In yet another alternate embodiment, the nozzle 13
may be configured as a plurality of tube-like structures for the
input of a fuel and oxidant to the combustion system 10.
[0018] In the illustrated embodiment, the nozzle 13, and more
particularly the perforated plate 14, divides the combustion system
10 into two distinct sections: a combustion chamber 16 defined
within the casing 12 and adjacent to the downstream side of the
plate 14 and a plenum chamber 18 adjacent to the upstream side of
the plate 14. The combustion chamber 16, which is where fuel is
burned, may further include a cooling sleeve 20, formed of a
material that is at least moderately resistant to high
temperatures, such as Inconel.RTM., an Inconel.RTM. alloy, or other
material typically used in temperature sensitive applications. The
cooling sleeve 20 may provide cooling to the combustion chamber 16
via an inlet air flow from a compressor (described presently) over
the outer surface of the cooling sleeve 20 prior to mixing with a
fuel in the plenum chamber 18. Thus, the relatively cool compressor
air will provide backside cooling to the cooling sleeve 20.
[0019] The combustion chamber 16 may further have disposed therein
a protective combustion liner 22. In an embodiment, the protective
combustion liner 22 may be formed of a ceramic material, or other
material typically used in high temperature applications. The flow
of combustion products exiting the downstream end of the combustion
chamber 16 may be utilized to drive a turbine, or the like.
[0020] In the illustrated embodiment, the nozzle 13, and more
specifically the perforated plate 14, is generally configured
having a plurality of perforations or orifices 24 formed therein.
In an embodiment, the perforations 24 are configured as a plurality
of fuel and oxidant jets 26. As used herein, the term "jet" refers
to an opening from which a stream of fluid is discharged. Thus, by
definition, the fuel and oxidant jets 26 discharge a fuel and
oxidant mixture stream 28 into the combustion chamber 16, and more
particularly into an area defined within the combustion liner 22.
In an embodiment, an input fuel and air 27 are premixed prior to
injection into the combustion chamber 16, and more specifically
premixed outside of the combustion chamber 16 to form the fuel and
oxidant mixture stream 28. More specifically, the input fuel and
air 27 may be mixed by the nozzle 13, or premixed prior to reaching
the nozzle 13. As shown in the Figures, the fuel and oxidant jets
26 are oriented normal to the planar surfaces of the plate 14.
Thus, the jets inject the fuel and oxidant mixture stream 28
axially into the combustion chamber 16, and more particularly into
the combustion liner 22. The fuel and oxidant jets 26 may
alternatively be oriented at an angle to the plate 14 to produce an
angular injection of the fuel and oxidant mixture stream 28. The
angular injection may create some net swirl in the fuel and oxidant
mixture stream 28 which will improve flame stability. Angled
injection can also be used to direct the flame front away from the
wall of the combustion chamber 16, and more particularly the
combustion liner 22, thereby increasing the life of the combustion
system 10.
[0021] The input fuel and air 27 is delivered to the jets 26 via
the plenum chamber 18 with which they are in fluidic communication.
The plenum chamber 18 is connected to an external source of fuel
(not shown) and a source of air (not shown) which is typically a
compressor, which deliver the fuel and oxidant to each one of the
plurality of jets 26 via the plenum chamber 18 in one of a mixed,
or unmixed state. As previously eluded to, in an embodiment, an air
inlet may be configured so that the inlet air flows over the outer
surface of the cooling sleeve 20 prior to mixing with the fuel in
the plenum chamber 18 or via the nozzle 13. Thus, the relatively
cool compressor air may provide backside cooling to the cooling
sleeve 20 and the combustion liner 22.
[0022] The number of fuel and oxidant jets 26 formed in the
perforated plate 14, or the number of tubes carrying the input fuel
and oxidant 27 in the nozzle 13, is not restricted to what is shown
in FIGS. 1 and 2 but should be sufficient to provide a uniform flow
distribution across the combustion chamber 16. Furthermore, in an
embodiment incorporating the perforated plate 14, the fuel and
oxidant jets 26 should be evenly distributed about the plate 14 to
produce a uniform flow distribution.
[0023] To achieve reduced combustion emissions, the nozzle 13, and
in the illustrated embodiment more particularly the perforated
plate 14, and the combustion liner 22 are sized and shaped to input
the fuel and oxidant mixture stream 28 into the combustion chamber
16 at a high velocity ratio. More specifically, the fuel and
oxidant mixture stream 28 is input into the combustion chamber 16
at a high jet velocity, via jets 26, that is greater than a
combustion mean velocity within the combustion chamber 16, to
increase turbulence within the combustion chamber 16 and reduce
combustion emissions. Simply stated, the jet speed is greater than
the mean flow speed within the combustion chamber 16. The increase
in turbulence in the combustion chamber 16, and more particularly
the combustion liner 22, provides reduction in a length of a
combustion flame, reduced combustion emissions, and provides mixing
of a portion of combustion products in a flame front.
[0024] The high velocity ratio between the jet velocity and the
combustion mean velocity provides the development of flow reversals
and a stirring action within the combustion chamber 16 that will
result in the reduction of combustion emissions. Referring more
specifically, to FIG. 3, illustrated in a simplified cross-section
is the combustion chamber 16 and a plurality of vortical structures
25 formed during combustion and showing a flame length of "x".
Illustrated in FIG. 4 is an image of the vortical structures 25
taken during combustion. The difference in velocity will yield an
internal stirring action that mixes the combustion products with
the input fuel and oxidant mixture stream 28. The stirring action
is mainly due to the large numbers of vortical structures 25 that
develop around the jet 26 edges, and more particularly around a
perimeter of each of the perforations or orifices 24 formed in the
plate 14 or around each of the tube-like structures that form
nozzle 13. As can be seen in FIGS. 3 and 4, the density of the
vortical structures 25 increase with the increase in velocity
ratio. The internal recirculation damps the NO.sub.x generation and
burns CO. The end result is a single digit NO.sub.x and CO over a
wide range of flame temperatures.
[0025] In general, three factor influence NO.sub.x generation:
temperature, oxygen and residence time. The combustion system 10
permits reduction of the NO.sub.x concentrations based on reduction
of the free oxygen radicals due to internal mixing and increased
velocity. This is achieved through the increase of the reacting
mixture velocity while reducing the combustion products velocity.
The effective residence time of the combustion products is much
less than the effective flame residence time. As a result, NO.sub.x
production in a low oxygen environment will be suppressed. Given
enough residence time, CO concentration will be kept low as
influenced by the high firing temperature as well as the expected
high degree of homogeneity. The high degree of homogeneity and
internal mixing ensures CO burn out at low flame temperatures. This
is primarily due to forcing the fresh premixed fuel and oxidant
mixture stream 28 to react in the presence of hot gases.
[0026] The concept of the present disclosure was tested on various
laboratory-scale jet micro-induced flow reversals combustors. The
testing was performed under substantially high pressure conditions.
Illustrated in FIG. 5 is a comparison between the NO.sub.x
emissions resulting from a jet micro-induced flow reversals
combustor as disclosed herein operating under different high
pressure conditions. Illustrated comparatively are the NO.sub.x
emissions in parts per million against the flame temperature. The
plotted points show combustion emissions data from three variations
of the laboratory-scale device of the present disclosure
represented by the plotted points and Curves A, B and C. Curve A is
representative of a jet micro-induced flow reversals combustor
according to an embodiment disclosed herein operating at
approximately 300 psi. Curve B is representative of a jet
micro-induced flow reversals combustor according to an embodiment
disclosed herein operating at approximately 245 psi. Curve C is
representative of a jet micro-induced flow reversals combustor
according to an embodiment disclosed herein operating at
approximately 180 psi. The results show that by decreasing the
operating pressure and sizing and shaping the combustion chamber
16, and more particularly the nozzle 13 relative to the combustion
liner 22, to input the fuel and oxidant mixture stream 28 into the
combustion chamber 16 at a high velocity ratio (jet velocity
greater than a combustion mean velocity within the combustion
chamber 16), the NO.sub.x emissions are decreased at increasing
flame temperatures. It should be kept in mind that these results
are based on laboratory-scale experiments.
[0027] In addition, illustrated in FIG. 6 is a comparison between
the NO.sub.x emissions of a laboratory-scale jet micro-induced flow
reversals combustors disclosed herein and the NO.sub.x emissions
from a combustion device running under low velocity ratio. Data is
represented by the plotted points that form Curve D representative
of data collected from a known conventional combustor (running
under low velocity ratio). Data is represented by the plotted
points that form Curve E representative of data collected from a
laboratory-scale jet micro-induced flow reversals combustor as
disclosed herein. The curves illustrate the increase in NO.sub.x
emissions at increasing flame temperatures of the combustors. It
should be noted that as evidenced by Curve E, the NO.sub.x
reduction benefits from the jet micro-induced flow reversals
combustor as disclosed herein are shown. Results show that the jet
micro-induced flow reversals combustor sized and shaped as
disclosed herein may achieve an approximate 75% reduction in
combustion emissions over that of the low velocity ratio.
[0028] The foregoing has described a jet micro-induced flow
reversals combustor which provides low combustion emissions at
elevated temperatures. More particularly, disclosed is a jet
micro-induced flow reversals combustor that provides reduced
NO.sub.x emissions from those currently known in the art, thereby
increasing gas turbine thermal efficiency to higher levels than
current combustors, increasing turndown with minimal CO penalty and
enabling the use of liquid fuel while maintaining emission
compliancy. While the disclosure has been illustrated and described
in typical embodiments, it is not intended to be limited to the
details shown, since various modifications and substitutions can be
made without departing in any way from the spirit of the present
disclosure. As such, further modifications and equivalents of the
disclosure herein disclosed may occur to persons skilled in the art
using no more than routine experimentation, and all such
modifications and equivalents are believed to be within the spirit
and scope of the disclosure as defined by the subsequent
claims.
* * * * *