Nozzle burner applied to combustion chamber of gas turbine

Abstract

The invention discloses the technical field of gas turbines, particularly relates to a nozzle combustor applied to a combustion chamber of a gas turbine, and aims to solve the problems that in the prior art, the gas turbine is difficult to stably combust at low emission under high-temperature and wide-load working conditions, and meanwhile, the cooling efficiency of a nozzle is relatively low; the nozzle structurally comprises an on-duty stage nozzle, a main combustion stage nozzle, a fuel rectifying plate and a nozzle upper cover plate, wherein the main combustion stage nozzle is positioned on the outer side of the on-duty stage nozzle; a mixture sprayed by the main combustion stage nozzle directly penetrates through a combustion area of the nozzle combustor; the fuel rectifying plate and the nozzle upper cover plate are wrapped to form an upper fuel cavity, the on-duty stage nozzle and the main combustion stage nozzle are communicated with a combustion area of the nozzle combustor through the nozzle upper cover plate, and fuel in the upper fuel cavity is in direct contact with the nozzle upper cover plate for heat exchange.

Description

Technical Field

[0001] The invention relates to a nozzle burner applied to a combustion chamber of a gas turbine, belonging to the technical field of combustion chambers of gas turbines. Background Art

[0002] Gas turbines have become an indispensable source of power in industrial production due to their high efficiency and cleanliness. With the iteration and update of technology, gas turbines are constantly developing towards higher efficiency and wider load regulation range. How to achieve stable, low-emission combustion within a wide load range is an important performance target of the gas turbine combustor.

[0003] Most of the existing gas turbines use burners with Dry Low NOx (DLN) combustion technology. Such burners mainly mix excess air and fuel into lean premixed gas to suppress the generation of nitrogen oxides. However, when the gas turbine develops to J level, its temperature level is close to the critical value of the DLN effective working range (1670-1900K). If the temperature rises further, on the one hand, even if the air and fuel are fully premixed, nitrogen oxide emissions will increase significantly. On the other hand, if conventional swirl premixed combustion is used, there are risks such as flashback, auto-ignition, and thermoacoustic oscillation. Therefore, Dry Low NOx (DLN) combustion technology can no longer meet the development of gas turbines.

[0004] Compared with traditional swirl burners, micro-premixed combustion technology mixes air and fuel in a tiny pipe, which improves the uniformity of gas mixing. In addition, the flame structure is small, the gas flow rate is high, and the quenching effect of the pipe diameter makes micro-premixed combustion technology not only reduce NOX emissions but also have good anti-flashback ability. However, due to the lack of swirl structure and the higher gas flow rate than traditional burners, the stability of micro-premixed combustion technology is poor, and it is difficult to achieve stable combustion in a wide range of operating conditions. Therefore, swirl combustion and micro-mixed combustion technology have their own advantages and disadvantages. If swirl combustion and micro-mixed combustion can be combined to take into account the advantages of both, it will be a feasible technical solution for the further development of gas turbine combustors. In addition, the upper end face of the nozzle is in direct contact with the combustion area, and the temperature of the nozzle end face is very high, so its cooling has always been a technical problem. Currently, air is basically used as the cooling medium. However, with the development of gas turbines, the contradiction between the increasing flame temperature and nozzle end face temperature and the increasing air intake temperature and the decreased cooling efficiency is becoming increasingly greater. Therefore, it is urgent to find a new cooling solution. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art. The existing gas turbines are difficult to stably perform low-emission combustion under high temperature and wide load conditions, and the cooling efficiency of the nozzles is low.

[0006] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions: Provided is a nozzle burner applied to a combustion chamber of a gas turbine, comprising an air intake assembly, a fuel intake pipe, a nozzle body and a flame tube, wherein the air intake assembly and the nozzle body are coaxially connected, the fuel intake pipe is annularly arranged on the side wall of the nozzle body, the flame tube is installed at the outlet of the nozzle body, and the inner cylindrical area formed by the flame tube is the combustion area of ​​the nozzle burner; The nozzle body comprises a duty class nozzle, a main combustion class nozzle, a fuel rectifying plate and a nozzle upper cover plate, wherein the main combustion class nozzle is located outside the duty class nozzle; the mixture sprayed from the main combustion class nozzle directly passes through the nozzle burner combustion zone; the fuel rectifying plate and the nozzle upper cover plate are wrapped to form an upper fuel cavity, the duty class nozzle and the main combustion class nozzle are both connected to the nozzle burner combustion zone through the nozzle upper cover plate, and the fuel in the upper fuel cavity is heat exchanged by direct contact with the nozzle upper cover plate; Among them, the movement mode of the mixture sprayed out by the duty nozzle is spiral movement.

[0007] Further, the air intake assembly includes an air intake pipe, an air cavity, an air baffle and a baffle bracket; One bottom surface of the air cavity is connected to the nozzle body, and the air intake pipe is coaxially installed on the other bottom surface relative to the nozzle body; the air baffle is coaxially installed on the bottom surface of the air cavity where the air intake pipe is located through a baffle bracket.

[0008] Furthermore, the nozzle body also includes a nozzle lower cover plate; The nozzle lower cover plate and the fuel rectifying plate are wrapped to form a lower fuel cavity; the fuel inlet pipe is connected to the upper fuel cavity; A fuel rectifying hole is opened on the surface of the fuel rectifying plate, penetrating the upper fuel cavity and the lower fuel cavity.

[0009] Further, the main combustion stage nozzle is provided in plurality, and the main combustion stage nozzle penetrates the upper fuel cavity and the lower fuel cavity; One end of the main combustion stage nozzle is connected to the combustion zone of the nozzle burner through the nozzle upper cover plate, and the other end is connected to the interior of the air intake component through the nozzle lower cover plate.

[0010] Furthermore, the portion of the main combustion stage nozzle located in the lower fuel cavity is evenly axially provided with main combustion stage fuel inlet holes.

[0011] Furthermore, a spiral blade is provided inside the duty nozzle, and the spiral blade is fixedly mounted on the inner side wall of the duty nozzle; The spiral blade is structured to be hollow.

[0012] Furthermore, the portion of the duty class nozzle located in the lower fuel cavity is evenly axially provided with duty class fuel inlet holes.

[0013] Furthermore, the mixture is a mixture of air and fuel.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present application, the nozzle upper cover plate is cooled by the fuel gas flow through the upper fuel cavity, and at the same time, the nozzle upper cover plate is reversely heated, the chemical reaction is enhanced, the combustion of the combustion gas is promoted, and the flame propagation speed is increased, thereby improving the combustion efficiency of the nozzle burner and improving the combustion stability performance of the nozzle burner.

[0015] 2. The spiral fuel gas sprayed out by the duty-class nozzle in the present application can, on the one hand, promote the rapid mixing of fuel and air, and on the other hand, form a recirculation zone at the nozzle outlet, and generally form a mixed flow structure of an outer circle swirl central jet in the combustion zone. At the same time, the main combustion stage nozzle is in the outer circle, which can play a good role in stabilizing the flame and make up for the shortcoming of easy flashback of swirl premixed combustion. Therefore, the present invention takes into account the two technical advantages of swirl combustion and micro-mixed combustion, so that the nozzle burner can achieve stable and efficient combustion in a wide range of operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is an exploded view of an embodiment of the present invention; Figure 2 Shown is an overall cross-sectional view of an embodiment of the present invention; Figure 3 Shown is a structural diagram of a main combustion stage nozzle according to an embodiment of the present invention; Figure 4 Shown is a three-dimensional cross-sectional view of a nozzle body according to an embodiment of the present invention; Figure 5 The figure shows a schematic diagram of the air cavity structure of an embodiment of the present invention; Figure 6 Shown is a diagram of the internal structure of an air intake assembly according to an embodiment of the present invention.

[0017] In the figure: 1. Air intake assembly; 11. Air intake pipe; 12. Air cavity; 13. Air baffle; 14. Baffle bracket; 2. Fuel intake pipe; 3. Nozzle body; 31. Duty class nozzle; 311. Spiral blade; 312. Duty class fuel inlet hole; 32. Main combustion stage nozzle; 321. Main combustion stage fuel inlet hole; 33. Fuel rectifying plate; 331. Fuel rectifying hole; 34. Nozzle upper cover plate; 35. Upper fuel cavity; 36. Nozzle lower cover plate; 37. Lower fuel cavity; 4. Flame tube. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0019] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances. Embodiment 1:

[0020] This embodiment discloses a nozzle burner suitable for a gas turbine combustion chamber, comprising: an air intake assembly 1, a fuel intake pipe 2, a nozzle body 3 and a flame tube 4, wherein the air intake assembly 1 and the nozzle body 3 are coaxially connected, the fuel intake pipe 2 is annularly arranged on the side wall of the nozzle body 3, the flame tube 4 is installed at the outlet of the nozzle body 3, and the inner cylindrical area formed by the flame tube 4 is the combustion area of ​​the nozzle burner; The nozzle body 3 includes a duty class nozzle 31, a main combustion class nozzle 32, a fuel rectifying plate 33 and a nozzle upper cover plate 34, wherein the main combustion class nozzle 32 is located outside the duty class nozzle 31; the mixture sprayed from the main combustion class nozzle 32 directly passes through the nozzle burner combustion zone; the fuel rectifying plate 33 and the nozzle upper cover plate 34 wrap to form an upper fuel cavity 35, the duty class nozzle 31 and the main combustion class nozzle 32 are both connected to the nozzle burner combustion zone through the nozzle upper cover plate 34, and the fuel in the upper fuel cavity 35 is directly in contact with the nozzle upper cover plate 34 for heat exchange; The movement of the mixture sprayed out by the duty nozzle 31 is spiral movement.

[0021] like Figure 1-2 As shown, the air intake assembly 1 includes an air intake pipe 11, an air cavity 12, an air baffle 13 and a baffle bracket 14; The air intake assembly 1 and the nozzle body 3 are connected by a flange, and part of the nozzle body 3 is embedded in the air intake assembly 1 to form an air cavity 12. The compressed air enters the air cavity 12 along the air flow direction. Under the obstruction of the air baffle 13, the air flow changes from axial to horizontal flow, and then enters the two-stage nozzle along the duty class air flow direction and the main combustion stage air flow direction respectively. The fuel intake pipe 2 is evenly arranged on the side wall of the nozzle body 3 in the circumferential direction and is connected to the upper fuel cavity 35. The total intake area of ​​the fuel intake pipe 2 is marked as A1. In order to reduce the fuel intake flow rate and improve the circumferential intake uniformity of the fuel, the fuel pipe is designed as a flat expansion section at the outlet. The fuel gas enters the upper fuel chamber 35 through the fuel flow direction, cools the nozzle upper cover plate 34, and then flows into the lower fuel chamber 37 through the fuel rectifying hole 331 on the fuel rectifying plate 33, and then flows into the two-stage nozzle through the main combustion stage fuel inlet hole 321 and the duty stage fuel inlet hole 312 respectively, and flows out of the nozzle after mixing with the compressed air, and burns in the combustion area formed by the flame tube 4.

[0022] One bottom surface of the air cavity 12 is connected to the nozzle body 3, and the air intake pipe 11 is coaxially installed on the other bottom surface relative to the nozzle body 3; the air baffle 13 is coaxially installed on the bottom surface of the air cavity 12 where the air intake pipe 11 is located through the baffle bracket 14. Embodiment 2:

[0023] Based on the first embodiment, Figure 3-4 As shown, the nozzle body 3 also includes a nozzle lower cover plate 36; The nozzle lower cover plate 36 and the fuel rectifying plate 33 are wrapped to form a lower fuel cavity 37; the fuel intake pipe 2 is connected to the upper fuel cavity 35; A fuel rectifying hole 331 is formed on the surface of the fuel rectifying plate 33 , penetrating the upper fuel cavity 35 and the lower fuel cavity 37 .

[0024] The total area of ​​the fuel rectifying hole 331 is marked as A2. The inlet and outlet of the nozzle bundle are respectively connected to the lower end cover of the nozzle and the upper end cover of the nozzle, and penetrate the lower fuel cavity 37 and the upper fuel cavity 35. The nozzle bundle can be modularly arrayed according to the actual load requirements, and the number of layers is preferably 3 to 8 layers, and 4 layers in this embodiment, which are staggered to reduce the influence of the air intake of the outer layer bundle on the air intake of the inner layer bundle. The nozzle bundle is provided with a main combustion stage fuel inlet hole 321 on the side wall of the lower fuel cavity 37. The main combustion stage fuel inlet holes 321 are evenly arranged along the circumference of the single nozzle tube, the number N is preferably 2-4, and the aperture D is preferably 0.5-1.5mm. From outside to inside, the distance between the main combustion stage fuel inlet hole 321 and the nozzle upper cover plate 34 can be staggered according to actual needs, or can be changed linearly. In this embodiment, from outside to inside, the distance between the main combustion stage fuel inlet hole 321 and the nozzle upper cover plate 34 gradually decreases, which can reduce the mutual influence of each circle of intake, and can also make the fuel-air mixing uniformity (mixing length) of each circle of nozzles different, which can also improve the combustion stability. The total area of ​​the main combustion stage fuel inlet hole 321 is marked as A3.

[0025] The main combustion stage nozzle 32 is provided in plurality, and the main combustion stage nozzle 32 penetrates the upper fuel cavity 35 and the lower fuel cavity 37; One end of the main combustion stage nozzle 32 is connected to the nozzle burner combustion zone through the nozzle upper cover plate 34 , and the other end is connected to the interior of the air intake assembly 1 through the nozzle lower cover plate 36 .

[0026] The portion of the main combustion stage nozzle 32 located in the lower fuel cavity 37 is axially and evenly provided with main combustion stage fuel inlet holes 321 .

[0027] The duty nozzle 31 is provided with a spiral blade 311 inside, and the spiral blade 311 is fixedly mounted on the inner side wall of the duty nozzle; The spiral blade 311 is configured to be hollow.

[0028] The duty class nozzle 31 is the central cavity area of ​​the nozzle body 3. The spiral blade 311 is fixed on the side wall of the duty class nozzle 31 in the form of a screw thread. The side wall of the duty class nozzle 31 is also provided with a circle of duty class fuel inlet holes 312. The distance between the duty class fuel inlet holes 312 and the nozzle upper cover plate 34 and the number of circles (total number) can be set according to the load of the duty class nozzle 31 and the uniformity of fuel mixing. The total area of ​​the duty class fuel inlet holes 312 is marked as A4. The above-mentioned intake areas are preferably A1>A2>A3+A4, so as to ensure that the position of the fuel inlet hole is the fuel intake cutoff position to improve the uniformity of fuel distribution.

[0029] The portion of the duty class nozzle 31 located in the lower fuel cavity 37 is evenly axially provided with duty class fuel inlet holes 312 .

[0030] The mixture is a mixture of air and fuel.

[0031] Working principle of the duty class nozzle 31: compressed air enters the duty class nozzle 31 along the air flow direction, and the compressed air near the wall rotates under the induction of the spiral blade 311, while the compressed air at the center still mainly maintains the high-speed jet flow shape unchanged, and the duty class fuel is sprayed into the duty class nozzle 31 through the duty class fuel inlet hole 312, and is quickly mixed with the air under the action of the rotating airflow. At the outlet of the duty class nozzle 31, the rotating airflow near the wall develops radially under the action of centrifugal force, thereby forming a reflow area (low-speed area) in the combustion area, but the mixed gas in the center area still flows downstream in the form of a high-speed jet, and generally forms a mixed flow structure of an outer circle swirl and a central jet in the combustion area. The outer circle swirl airflow can play a good role in stabilizing the flame, and the central high-speed airflow makes up for the shortcoming that the swirl premixed flame is easy to flash back. Therefore, this embodiment takes into account two technical advantages, so that the nozzle burner 1 can achieve stable and efficient combustion in a wide range of working conditions.

[0032] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A nozzle burner used in a gas turbine combustion chamber, characterized in that: The invention comprises an air intake assembly (1), a fuel intake pipe (2), a nozzle body (3) and a flame tube (4), wherein the air intake assembly (1) and the nozzle body (3) are coaxially connected, the fuel intake pipe (2) is arranged in an annular manner on the side wall of the nozzle body (3), the flame tube (4) is installed at the outlet of the nozzle body (3), and the internal cylindrical area formed by the flame tube (4) is the combustion area of ​​the nozzle burner; The nozzle body (3) comprises a duty class nozzle (31), a main combustion stage nozzle (32), a fuel rectifying plate (33) and a nozzle upper cover plate (34); the main combustion stage nozzle (32) is located outside the duty class nozzle (31); the mixture sprayed by the main combustion stage nozzle (32) directly passes through the nozzle burner combustion zone; the fuel rectifying plate (33) and the nozzle upper cover plate (34) are wrapped to form an upper fuel cavity (35); the duty class nozzle (31) and the main combustion stage nozzle (32) are both connected to the nozzle burner combustion zone through the nozzle upper cover plate (34); the fuel in the upper fuel cavity (35) is heat exchanged by direct contact with the nozzle upper cover plate (34); The mixture sprayed out from the duty nozzle (31) moves in a spiral motion.

2. The nozzle burner used in a gas turbine combustion chamber according to claim 1, characterized in that: The air intake assembly (1) comprises an air intake pipe (11), an air cavity (12), an air baffle (13) and a baffle bracket (14); One bottom surface of the air cavity (12) is connected to the nozzle body (3), and the air intake pipe (11) is coaxially mounted on the other bottom surface relative to the nozzle body (3); the air baffle (13) is coaxially mounted on the bottom surface of the air cavity (12) where the air intake pipe (11) is located via a baffle bracket (14).

3. The nozzle burner used in a gas turbine combustion chamber according to claim 1, characterized in that: The nozzle body (3) further comprises a nozzle lower cover plate (36); The nozzle lower cover plate (36) and the fuel rectifying plate (33) are wrapped to form a lower fuel cavity (37); the fuel intake pipe (2) is in communication with the upper fuel cavity (35); A fuel rectifying hole (331) is provided on the surface of the fuel rectifying plate (33) and passes through the upper fuel cavity (35) and the lower fuel cavity (37).

4. The nozzle burner used in a gas turbine combustion chamber according to claim 3, characterized in that: The main combustion stage nozzle (32) is provided in plurality, and the main combustion stage nozzle (32) penetrates the upper fuel cavity (35) and the lower fuel cavity (37); One end of the main combustion stage nozzle (32) is connected to the combustion zone of the nozzle burner through the nozzle upper cover plate (34), and the other end is connected to the interior of the air intake assembly (1) through the nozzle lower cover plate (36).

5. The nozzle burner used in a gas turbine combustion chamber according to claim 4, characterized in that: The portion of the main combustion stage nozzle (32) located in the lower fuel cavity (37) is evenly and axially provided with main combustion stage fuel inlet holes (321).

6. The nozzle burner used in a gas turbine combustion chamber according to claim 1, characterized in that: A spiral blade (311) is provided inside the duty nozzle (31), and the spiral blade (311) is fixedly mounted on the inner side wall of the duty nozzle; The spiral blade (311) is structured to be hollow.

7. The nozzle burner used in a gas turbine combustion chamber according to claim 6, characterized in that: The portion of the duty class nozzle (31) located in the lower fuel cavity (37) is evenly and axially provided with duty class fuel inlet holes (312).

8. The nozzle burner used in a gas turbine combustion chamber according to claim 1, characterized in that: The mixture is a mixture of air and fuel.

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