JP4015610B2 - Multi-stage method for low emission and stable combustion - Google Patents

Description

  The present invention relates to a multi-point fuel injector for use in a combustion chamber of a gas turbine engine or other types of combustion chambers.

  One of the biggest challenges for gas turbines, especially in industrial applications, is having good emission characteristics and combustion stability over a wide range of power settings and ambient conditions.

  There are industrial gas turbines with 100% output and low NOx, CO, and UHC emissions, and when their output is reduced, as typically done by reducing the amount of fuel to the engine, the fuel / air in the combustion chamber The mixture is generally more diluted. The leaner fuel / air mixture produces a flame that lowers the flame temperature and can be lost more easily by the cooler combustion chamber wall or the cooling film on the combustion chamber wall. The vanishing effect results in excess CO and UHC, as well as high dynamic pressure. If they are not further oxidized, CO and UHC become pollutants. Another problem with fuel / air mixtures that are too lean is that it causes unstable combustion. Conversely, there are gas turbines with low NOx, CO, UHC, and sound at partial power conditions, and increasing their power, as is generally done by increasing the amount of fuel to the engine, The fuel / air mixture is generally richer. A richer fuel / air mixture produces a flame that can increase the flame temperature and produce more NOx. Similar conditions can occur at different ambient temperatures. There are gas turbines with high NOx, CO, UHC and less sound at high ambient temperatures, and lower ambient temperatures can lead to lower flame temperatures and more CO, UHC, and unstable flames. Alternatively, there are NOx, CO, UHC, and less acoustic gas turbines at low ambient temperatures, and higher ambient temperatures can increase the flame temperature and produce excess NOx.

  Accordingly, it is an object of the present invention to provide a multi-point fuel injector that addresses emission and stability issues.

  It is a further object of the present invention to provide an improved method of injecting a fuel / air mixture into a combustion engine of a turbine engine or other application while avoiding excessive CO and UHC production at wide power levels and ambient conditions. is there.

  The above objective is accomplished by the present invention.

  In accordance with the present invention, a novel multipoint injector is provided. A multi-point injector generally comprises a plurality of nozzles arranged in at least two rows and means for independently controlling the flow of fuel to each row of nozzles. Each of the nozzles in each row includes an outer body defining a fluid passage and vane means for generating a swirl flow within the fluid passage.

  Further in accordance with the present invention, a method is provided for injecting a fuel / air mixture into a combustion chamber of a gas turbine engine. The method generally includes an injector having nozzles arranged in at least two rows; supplying a first amount of fuel to each nozzle in the outermost row of rows and a second amount of fuel. To each nozzle in the second row of rows to inject the fuel / air mixture into the combustion chamber stage; the outermost row of rows to provide a stable and less polluting flame. Maintaining a flame temperature high enough to maintain.

  Other details about the multi-point strategy for low emission and stable combustion of the present invention, as well as other objects and advantages associated with the present invention, can be found in the following detailed description and similar reference numbers. The accompanying drawings showing similar elements are disclosed.

  Referring now to the drawings, FIG. 1 illustrates a first embodiment of a multi-point injector 10 according to the present invention. The multipoint injector 10 has a nozzle 12 that injects a fuel-air mixture into a combustion chamber stage of a gas turbine engine. The nozzles 12 are arranged in a plurality of rows. In the embodiment of FIG. 1, the nozzles 12 are arranged in four concentric ring rows 14, 16, 18 and 20, with any nozzle arranged in the center. Although the nozzle rows are shown as concentric ring rows, as will be appreciated, the nozzles 12 may be in various forms such as, but not limited to, square, rectangular, hexagonal, or parallel lines. Can be arranged in

  In accordance with the present invention, means are provided for independently controlling the fuel flow rate for each of the trains 14, 16, 18 and 20 as well as any central nozzle. The fuel flow control means comprises a different fuel circuit 22 for each ring train 14, 16, 18 and 20 as well as for any central nozzle. Each fuel circuit 22 is each suitable for any control known in the art that allows control of the fuel flow rate provided to each one of the trains 14, 16, 18 and 20 as well as any one of the central nozzles. Valve and conduit configurations may also be included.

  Instead of reducing the fuel to all nozzles 12 to the same extent when power reduction is required or the ambient temperature is lowered, the fuel flow is reduced to each ring 14, 16, 18 and 20 or even For any central nozzle, it is reduced differently. The outermost ring 14 maintains a stable flame, thereby increasing the CO and UHC generated from the combustion chamber, and the flame temperature sufficiently high to reduce the dynamic pressure, but the ring 14 is excessive. Can be maintained at a flame temperature that is not so high as to produce NOx. The remaining ring trains 16, 18 and 20 as well as any central nozzle are preferably fueled at a lower fuel / air ratio. As a result, lower flame temperatures occur in these trains to achieve greater power reduction or to meet lower ambient temperatures. If desired, better flame stability is required, and if the NOx limit and power setting / ambient temperature allow, some or all of the remaining trains will have fuel at higher fuel / air ratios. Can supply. Since the nozzle ring rows 16, 18 and 20 do not interact with the cooler walls of the combustion chamber wall 24 or the cooling film, the flames from the nozzles 12 in these ring rows are less extinguished and thus Excess CO and UHC are avoided. In this way, CO and UHC emissions are reduced at lower engine power settings or at lower ambient temperatures. The nozzles 12 in the ring train 14 are kept at a sufficiently high flame temperature when the power is reduced or the ambient temperature decreases, so that these nozzles 12 are responsible for the overall combustion process for all nozzles 12. It functions as a flame stabilizer that stabilizes and extends the lean blowout limit.

  If desired, each ring train 14, 16, 18 and 20 can define a region, and the injector provides a means for controlling the flow of fuel to one region as a function of the flow of fuel to the second region. Can be provided.

  The injector 10 and the method outlined above can be used for various types of combustion chambers (can type or annular type). In the annular combustor shown in FIG. 5, the flame temperature in the region near the at least one combustion chamber wall 24 dilutes some others to reduce the output or adapt to a lower ambient temperature, while Kept high enough to stabilize. In general, the annular combustor has a plurality of nozzle ring rows such as nozzle ring rows 16, 18 and 20. The area that is kept at a high temperature to stabilize the flame is preferably the area immediately adjacent to the wall. In some cases this can be the outermost ring of nozzles. In other cases, this can be the innermost ring of nozzles. In certain situations, it may be preferable to keep the outer region hot, the middle region cold, and the inner region hot.

  Although FIG. 1 illustrates the use of four ring rows 14, 16, 18 and 20, the number of nozzle ring rows can be arbitrary. Different rings of nozzles are fueled differently to achieve the best emission and stability. For example, FIGS. 2 and 3 illustrate an embodiment of an injector 10 ′ having three concentric ring rows 30, 32 and 34 of nozzle 12. Nozzle rings 30, 32 and 34 can be fueled such that outermost ring 30 and innermost ring 34 are maintained at a higher temperature than center ring 32. As previously mentioned, each of the ring trains 30, 32 and 34 of the nozzle 12 can be supplied with fuel via independent fuel circuits 22A, 22B and 22C, respectively.

  In the injector embodiment of the present invention, the central body portion 36 can be closed if desired or can be used to inject fuel or fuel / air mixture, and the igniter 38 is located off-center. obtain.

  Each nozzle 12 used in the embodiment of FIGS. 1 and 2 can have a configuration such as that shown in FIG. In particular, each nozzle 12 may have an outer body 40, such as a cylindrical or other shaped casing, and a cylindrical, conical, rectangular, etc. centered or eccentric or even absent. There may be an inner body 42 and one or more swirler vanes 44 extending between the inner body 42 and the inner wall 46 of the casing 40. The swirler vanes 44 are used to generate a swirl flow in a fluid passage 47 formed by the inner wall of the outer body 40 and the inner body 42. It has been found that the generation of swirl in passage 47 facilitates fuel and air mixing that reduces NOx and flame stabilization. The swirler vanes 44 for each nozzle 12 can be in the same direction or in different directions.

  Each nozzle 12 used in the embodiment of FIGS. 1 and 2 can have other configurations, such as the configuration shown in FIG. In the embodiment of FIG. 6, fuel and air are injected tangentially from the outer wall of the swirl cup 58 via tangential inlets 60 and 62, respectively, to produce a swirl motion. The injection direction need not be perpendicular to the axis of the swirl cup 58. One or more fuel inlets can inject fuel upstream or downstream of one or more air injections, or between air injections. Further, axial air and / or fuel can be added.

  Although swirl can be used within each nozzle, the present invention will work without swirl, and therefore the vane 44 can be omitted if desired.

  In addition, each nozzle 12 is supplied with a fuel / air mixture. If desired, a fuel injection unit 49 can be positioned adjacent to the inlet 51 of the nozzle 12 for the premixed flame or adjacent to the outlet 52 for the diffusion flame. The fuel injection unit 49 may have one or more fuel inlets 50 that supply fuel into the fuel injection unit 49. The fuel injection unit can also be suspended in the air stream. The fuel inlet 50 can be upstream or downstream of the vane 44, in the region of the vane 44, in the vane 44, from the wall of the outer body 40, or from the inner body 42. Fuel may be supplied to the fuel inlet 50 from one of the fuel circuits 22A, 22B and 22C. The fuel injection unit 49 and the nozzle 12 can be separate elements, but can also be a single integrated unit. In addition, diffusion or premix pilots can be added to the inner body 42.

  As noted, in an axial swirler structure, the swirl vane angle need not be the same within the swirler, within one region, or between different regions. Furthermore, the outlets of all nozzles need not be in one plane.

  Also, in the high temperature region near the wall 24, some swirlers can be kept cool, and some others are kept hot as long as the overall flame is stable.

  The liquid fuel can be vaporized beforehand or injected directly into the nozzle 12. In the direct injection of liquid fuel in the axial swirler structure of FIG. 4, the liquid fuel can be injected from the inner body 42, the outer body 40, the vane, or from a separate injection unit or multiple injection units. In the tangential inflow structure shown in FIG. 6, liquid fuel can be injected from the bottom, outer wall, inlets 60, 62 of the swirl cup 58, or from a separate injection unit or multiple injection units.

  Also, the nozzles 12 in each row of the embodiment of FIGS. 1 and 2 preferably have an outlet 52 that ends in a common plane 54, but this is not essential. By providing such a non-alternating nozzle arrangement, the nozzles 12 in one row can be fueled in that row or in the nozzles 12 of the adjacent row by this arrangement and the turbulent flow out of the nozzle 12. / It has been found that it can help burn the air mixture. This is highly desirable from the standpoint of promoting flame stability. Such help is less effective, although it is still possible with an alternating nozzle outlet configuration.

  With the injector 10 of the present invention, low NOx, CO and UHC production can be achieved over a wider power range and ambient conditions. For example, with the injector 10 'of FIG. 2, at a wider output or ambient range, the NOx level should be less than 7.0 ppm, and both the CO level and UHC level should be less than 10 ppm. Is possible.

  The injector of the present invention does not stop fuel to a particular row or ring. Fuel is always supplied to each nozzle in each row or ring. Therefore, in the injector of the present invention, there is no need to worry about the invalid area that causes the usable area to disappear. As a result, it is not necessary to have at least one of an annular baffle and axial isolation. In the injector of the present invention, various rows or ring rows of nozzles 12 are designed to interact with each other.

  FIG. 7 illustrates a parallel combustor having five fuel regions 70, 72, 74, 76, 78, each fuel region being independently independent to step the flame temperature within at least one region. A controlled and preferably area near the combustor wall 24 is kept high enough to stabilize the entire flame.

  Obviously, in accordance with the present invention, a multi-point injector and injection method for low emission and stable combustion have been provided that fully satisfy the objects, means, and advantages described above. Although the present invention has been described in the context of its specific embodiments, other alternatives, modifications, and variations will become apparent to those skilled in the art after reading the foregoing description. Accordingly, it is intended to include these alternatives, modifications, and variations as included within the broad scope of the appended claims.

1 is a schematic diagram illustrating a first embodiment of a multi-point injector according to the present invention. FIG. 3 is a schematic diagram illustrating a second embodiment of a multi-point injector according to the present invention. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. It is an enlarged view of the nozzle used for the multipoint injector of this invention. 1 is a schematic diagram illustrating an annular combustor having an injector according to the present invention. 1 is a schematic diagram illustrating a tangential inflow swirl device that can be used in the injector of the present invention. 1 is a schematic diagram illustrating a parallel combustor having five fuel regions. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10 '... Multi-point injector 12 ... Nozzle 14, 16, 18, 20, 30, 32, 34 ... Ring train 22, 22A, 22B, 22C ... Fuel circuit 24 ... Combustion chamber wall 44 ... Swirler vane 47 ... Fluid passage 54 ... Common plane 58 ... Swirl cup 60, 62 ... Tangential inlet 70, 72, 74, 76, 78 ... Fuel region

Claims (14)

A multi-point fuel injector for use in a combustion chamber stage of a gas turbine engine,
A plurality of nozzles arranged in at least two rows;
Means for independently controlling the flow of fuel to the nozzles in each of the rows;
With
Each of the nozzles includes a fluid passage and means for generating a swirl flow in the fluid passage;
The swirl flow generating means includes vane means or angled injectors,
The vane means includes a plurality of swirler vanes in the fluid passageway,
The row includes an outer ring row of nozzles and at least one inner ring row of nozzles, and each swirler vane in each nozzle in the outer ring row is a swirl for each swirler vane in each nozzle in each inner ring row. Have a swirler vane different from the angle,
The nozzles in the at least one inner ring train are fueled at a fuel / air ratio that is less than the fuel / air ratio to which the outer ring fuels to achieve power reduction or lower ambient Multi- point fuel injector characterized by adapting to temperature.   The multi-point fuel injector of claim 1, wherein the independent fuel flow control means includes different fuel circuits for the nozzles in each row of the rows.   The multi-point fuel injector of claim 1, wherein the row includes at least two concentric ring rows. Wherein the said swirl angle for each swirler vane in the outer ring column, multi-point fuel injector of claim 1 wherein the less than the swirl vane angle for each swirler vane in each inner ring column. The outer ring train is kept at a flame temperature that is high enough to reduce the CO and UHC produced by the outer ring train, but not high enough to produce excess NOx. The multipoint fuel injector according to claim 1 .   Each nozzle in each said row has an outlet, which ends in a common plane and promotes the interaction and flame stability between nozzles in adjacent rows of said row. The multi-point fuel injector according to claim 1. 2. The multi-point fuel injector according to claim 1, further comprising means associated with each nozzle and supplying a fuel and air mixture to each nozzle. A multi-point fuel injector for use in a combustion chamber stage of a gas turbine engine,
A plurality of nozzles arranged in at least two rows;
Means for independently controlling the flow of fuel and air to the nozzles in each said row;
With
Each of the nozzles in each row of the row has an inlet and an outlet,
The nozzle outlets in each row of the rows are arranged in a common plane to promote interaction and flame stability between nozzles in adjacent rows;
A multi-point fuel injector,
The multi-point fuel injector further comprises means for generating turbulent flow in each nozzle to mix fuel and air, the turbulent flow generating means comprising a plurality of swirler vanes,
The independent fuel air control means provides a first fuel / air ratio to nozzles in the outermost row of the rows and a second fuel to nozzles in the inner row of the rows. A multi- point fuel injector comprising means for providing an air / air ratio, wherein the first fuel / air ratio is sufficiently large to stabilize the entire flame. A multi-point fuel injector for use in a combustion chamber stage of a gas turbine engine,
A plurality of nozzles arranged in at least two rows;
Means for independently controlling the flow of fuel and air to the nozzles in each said row;
With
Each of the nozzles in each row of the row has an inlet and an outlet,
The nozzle outlets in each row of the rows are arranged in a common plane to promote interaction and flame stability between nozzles in adjacent rows;
A multi-point fuel injector,
The multi-point fuel injector further comprises means for generating turbulent flow in each nozzle to mix fuel and air, the turbulent flow generating means comprising a plurality of swirler vanes,
The nozzles in the outermost row of the rows are kept at a first flame temperature and the nozzles in the inner row of the rows are kept at a second flame temperature, the first flame. A multi- point fuel injector characterized in that the temperature is kept high enough to stabilize the entire flame. A multi-point fuel injector for use in a combustion chamber stage of a gas turbine engine,
A plurality of nozzles arranged in at least two rows;
Means for independently controlling the flow of fuel and air to the nozzles in each said row;
With
Each of the nozzles in each row of the row has an inlet and an outlet,
The nozzle outlets in each row of the rows are arranged in a common plane to promote interaction and flame stability between nozzles in adjacent rows;
A multi-point fuel injector,
The multi-point fuel injector further comprises means for generating turbulent flow in each nozzle to mix fuel and air, the turbulent flow generating means comprising a plurality of swirler vanes,
Each of the columns, defining a region, said injector, multi-point fuel injection, characterized in that it further comprises means for controlling the flow to the first region as a function of the flow to the second region vessel. A method for injecting a fuel / air mixture into a combustion chamber stage of a gas turbine engine comprising:
Providing an injector having nozzles arranged in a plurality of rows;
Fuel is supplied to each nozzle in each row of the row via an independent flow circuit, whereby a nozzle in the first row of the row receives fuel from the first flow circuit, and the row Injecting a fuel / air mixture into the combustion chamber stage such that the nozzles in the second row of receive fuel from the second flow circuit;
Maintaining the nozzles in the outermost row of the rows at a flame temperature high enough to maintain a stable and less contaminated flame;
Including
The method further includes mixing the fuel and air supplied to each nozzle and generating turbulent flow in each of the nozzles to improve the mixing of the air and fuel, the turbulent flow generating a is provided with a plurality of swirler vanes in each of the nozzles, how to comprising a, flowing the fuel / air mixture through the passage between the swirler vanes adjacent the swirler vanes. The injecting method of claim 1 1, wherein the comprises constantly supplied the flow of fuel to each of the nozzles. The method includes the nozzles in each row of the rows such that the outlets of the nozzles are located in a common plane to improve interaction and flame stability between the nozzles in adjacent rows of the rows. the method of claim 1 1, wherein the method further comprises placing the. A method for injecting a fuel / air mixture into a combustion chamber stage of a gas turbine engine comprising:
Providing an injector having nozzles arranged in a plurality of rows;
Fuel is supplied to each nozzle in each row of the row via an independent flow circuit, whereby a nozzle in the first row of the row receives fuel from the first flow circuit, and the row Injecting a fuel / air mixture into the combustion chamber stage such that the nozzles in the second row of receive fuel from the second flow circuit;
Maintaining the nozzles in the outermost row of the rows at a flame temperature high enough to maintain a stable and less contaminated flame;
Including
The providing includes providing a multi-point injector having nozzles arranged in three ring rows, and maintaining maintains the outermost ring row of the ring rows at a first flame temperature. Maintaining a central ring of the ring train at a second flame temperature lower than the first flame temperature, and maintaining an inner ring train of the ring train of the first flame temperature and the way, characterized in that it comprises maintaining the at least than one high third flame temperature of the second flame temperature.

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