Combustion chamber, gas turbine, and flashback control method for gas turbine

Abstract

The present application discloses a combustion chamber, a gas turbine, and a flashback control method for a gas turbine, relating to the technical field of gas turbines. The combustion chamber comprises: a premixing pipe section, a convergent pipe section, and a flame tube, which are sequentially connected; the inner diameter of the convergent pipe section decreases along the main flow direction; the convergent pipe section is also provided with an air cavity; and multiple groups of through holes are provided on the inner wall of the convergent pipe section; each group of through holes includes multiple jet holes, and the jet holes in the same group are arrayed around the axis of the convergent pipe section. The present application can form a jet using the jet air duct, the air cavity, and the jet holes, and the formed jet can form vortices with the main flow in the convergent pipe section. These vortices can increase the airflow velocity of the fluid in the boundary layer, thereby reducing the possibility of boundary layer flashback in the combustion chamber. Even if boundary layer flashback occurs, the flame can be prevented from propagating in the opposite direction along the boundary layer by controlling the jet flow rate, allowing the gas turbine to actively control boundary layer flashback.

Description

Technical Field

[0001] The present application relates to the technical field of gas turbines, and in particular to a combustion chamber, a gas turbine, and a flashback control method for a gas turbine. Background Art

[0002] Hydrogen is considered a promising green energy source due to its widespread availability, high calorific value, and low carbon emissions. Hydrogen-rich or pure hydrogen fuel is increasingly being used in gas turbines. Natural gas-fueled gas turbines are less susceptible to boundary layer flashback due to its lower flame propagation velocity. However, hydrogen's laminar flame propagation velocity is eight times that of natural gas, and hydrogen is less susceptible to quenching than natural gas. Therefore, gas turbines fueled by hydrogen-rich or pure hydrogen are more susceptible to boundary layer flashback.

[0003] To address the technical issue of boundary layer flashback in hydrogen-powered combustors, existing technologies typically directly modify the combustor structure to reduce the risk of flashback. For example, methods such as shrinking the inner diameter of the premixing channel to accelerate the main flow or introducing purge air by leveraging the internal and external pressure differentials between the walls of the combustor components can be used to mitigate flashback risk. However, these improvements are difficult to apply to flashback prevention under various gas turbine operating conditions. Furthermore, when flashback occurs, they are unable to proactively eliminate the flame that propagates into the combustor's premixing section (hereinafter referred to as the premixing channel). Summary of the Invention

[0004] The purpose of the present application is to provide a combustion chamber, a gas turbine and a flashback control method for a gas turbine, so as to solve the technical problem that the combustion chamber of the prior art cannot meet the flashback prevention requirements of a gas turbine using hydrogen fuel.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] In a first aspect, the present application proposes a technical solution for a combustion chamber, the combustion chamber comprising:

[0007] A premixing pipe section, a contracting pipe section and a flame tube are sequentially connected; the inner diameter of the contracting pipe section decreases along the main flow direction; an air cavity is also provided in the contracting pipe section;

[0008] a jet air duct, disposed in the contraction tube section, the jet air duct being used to guide compressed air to the air cavity;

[0009] Multiple groups of through holes are arranged on the inner wall of the contraction pipe section, and each group of through holes is distributed in sequence along the mainstream direction; each group of through holes includes multiple jet holes, and the jet holes in the same group are arrayed around the axial center line of the contraction pipe section, and each jet hole is used to eject the compressed air in the air cavity to form a jet, thereby causing the jet to form a vortex with the mainstream in the contraction pipe section.

[0010] As a specific solution in the technical solution of the present application, it also includes a fuel delivery pipe arranged inside the premixing pipe section; a premixing flow channel is formed between the fuel delivery pipe and the premixing pipe section, and the fuel delivery pipe is at least used to guide the fuel to the premixing flow channel.

[0011] As a specific solution in the technical solution of the present application, a swirler is further formed between the fuel delivery pipe and the premixing pipe section, and the swirler is at least used to form a swirling flow in the mainstream in the premixing flow channel.

[0012] As a specific solution in the technical solution of this application, the fuel delivery pipe includes:

[0013] a central bluff body; the axis of the central bluff body coincides with the axis of the premixing tube section; a first fuel flow channel is provided inside the central bluff body;

[0014] A plurality of fuel nozzles; each fuel nozzle is disposed on the central bluff body, and each fuel nozzle is connected to the first fuel flow channel; each fuel nozzle is distributed around the axis of the central bluff body.

[0015] As a specific solution in the technical solution of this application, the axis of the fuel nozzle is perpendicular to the axis of the central blunt body; a plurality of fuel holes are provided in the fuel nozzle, and the fuel holes are distributed in sequence along the axis direction of the fuel nozzle.

[0016] As a specific solution in the technical solution of the present application, the axis of the fuel hole is spatially perpendicular to the axis of the premixing pipe section.

[0017] As a specific solution in the technical solution of the present application, the inner diameters of the fuel holes are different, and the inner diameters of the fuel holes decrease along a first direction; the first direction is parallel to the axis of the fuel nozzle and points from the outer wall of the central blunt body to the inner wall of the premixing tube section.

[0018] As a specific solution in the technical solution of the present application, a second fuel flow channel and multiple air flow channels are further provided in the central bluff body. The second fuel flow channel and each air flow channel penetrate the central bluff body, and the axis of the second fuel flow channel coincides with the axis of the central bluff body; the axis of each air flow channel is parallel to the axis of the central bluff body, and each air flow channel is distributed around the axis of the central bluff body.

[0019] As a specific solution in the technical solution of the present application, the angle between the axis of the jet hole and the first plane is greater than or equal to 30° and less than or equal to 45°; the first plane is tangent to the inner wall surface of the contraction tube section, and the first point is located in the first plane; the first point is the intersection of the axis of the jet hole and the inner wall surface of the contraction tube section; the angle formed by the projection of the axis of the jet hole and the axis of the contraction tube section on the first plane is greater than or equal to 30° and less than or equal to 90°.

[0020] As a specific solution in the technical solution of this application, it also includes:

[0021] A plurality of temperature sensors; each temperature sensor is disposed on the inner wall surface of the premixing pipe section, and each temperature sensor is close to the contraction pipe section;

[0022] A control valve is provided in the jet air duct and is used to control the opening of the jet air duct.

[0023] As a specific solution in the technical solution of this application, it also includes:

[0024] A dynamic pressure sensor; the dynamic pressure sensor is arranged on the inner wall surface of the premixing pipe section, and the dynamic pressure sensor is close to the contraction pipe section;

[0025] A control valve is provided in the jet air duct and is used to control the opening of the jet air duct.

[0026] In a second aspect, the present application proposes a technical solution for a gas turbine, the gas turbine comprising:

[0027] The combustion chamber of the first aspect having a temperature sensor and a dynamic pressure sensor;

[0028] An air supply device is used to supply compressed air into the air cavity through a jet air duct.

[0029] In a third aspect, the present application provides a technical solution for a flashback control method for a gas turbine. The flashback control method is applied to the gas turbine according to the second aspect, and the flashback control method includes:

[0030] Acquiring flashback monitoring data; the flashback monitoring data includes at least one or a combination of a temperature value and a pulsating pressure amplitude at the connection between the premixing pipe section and the contraction pipe section;

[0031] Based on the tempering monitoring data, obtaining an opening value;

[0032] Based on the opening value, the opening of the jet air duct is adjusted.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] The present invention utilizes jet air ducts, air cavities, and jet orifices to form a jet, which can then form vortices with the main flow in the converging tube section. These vortices can increase the airflow velocity within the boundary layer, thereby reducing the likelihood of boundary layer flashback in the combustion chamber. Even if boundary layer flashback occurs, the flame's reverse propagation along the boundary layer can be prevented by controlling the jet flow rate, enabling the gas turbine to actively control boundary layer flashback. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic structural diagram of a combustion chamber proposed in an embodiment of the present application;

[0036] Figure 2 This is a schematic structural diagram of another combustion chamber proposed in an embodiment of the present application;

[0037] Figure 3 This is a schematic structural diagram of another combustion chamber proposed in an embodiment of the present application;

[0038] Figure 4 This is a schematic structural diagram of a fuel delivery pipe proposed in an embodiment of the present application;

[0039] Figure 5 This is a schematic structural diagram of another fuel delivery pipe proposed in an embodiment of the present application;

[0040] Figure 6 A three-dimensional schematic diagram of a contraction tube section proposed in an embodiment of the present application (without the air cavity and the jet air duct);

[0041] Figure 7 for Figure 6 Enlarged view of part B;

[0042] Figure 8 This is a flow chart of a flashback control method for a gas turbine proposed in an embodiment of the present application.

[0043] In the figure: 1. Premixing pipe section; 11. Premixing flow channel; 2. Converging pipe section; 21. Air cavity; 22. Jet hole; 3. Flame tube; 4. Jet air duct; 5. Fuel delivery pipe; 51. Central blunt body; 52. First fuel flow channel; 53. Fuel nozzle; 54. Fuel hole; 55. Second fuel flow channel; 56. Air flow channel; 6. Swirl; 7. Temperature sensor; 8. Dynamic pressure sensor. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] It should be noted that, in the description of this application, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on this application.

[0046] Furthermore, it should be understood that for the sake of ease of description, the sizes of the various components shown in the drawings are not drawn according to actual proportions. For example, the thickness or width of certain layers may be exaggerated relative to other layers.

[0047] It should be noted that like numbers and letters represent similar items in the following figures, so once an item is defined or described in one figure, it will not need to be further discussed and described in detail in the description of the subsequent figures.

[0048] Before understanding the embodiments of this application, it is important to understand that when a fluid flows over an object, the fluid's inherent viscosity causes its velocity near the surface to approach zero, while the velocity of the fluid a certain distance from the surface is unaffected by the fluid's inherent viscosity. The portion of fluid between the surface and the fluid whose velocity is unaffected by its inherent viscosity is the boundary layer. As is known from the background art, if the flame propagation velocity is greater than the fuel flow velocity, flashback is likely to occur. In other words, boundary layer flashback refers to the phenomenon in which the flame propagates in the opposite direction (with the fluid flow direction as the forward direction) along the boundary layer due to the fluid flow velocity in the boundary layer being lower than the flame propagation velocity.

[0049] In order to solve the technical problem that the combustion chamber using pure hydrogen or hydrogen-rich fuel in the prior art is prone to boundary layer flashback, the present application proposes an embodiment of a combustion chamber. The combustion chamber includes a premixing pipe section 1, a convergent pipe section 2, a flame tube 3 and a jet air duct 4. Figures 1 to 3As shown, the premixing pipe section 1, the contracting pipe section 2 and the flame tube 3 are connected in sequence. The inner diameter of the contracting pipe section 2 decreases along the mainstream direction, and an air cavity 21 is also provided in the contracting pipe section 2. The jet air duct 4 is provided in the contracting pipe section 2, and the jet air duct 4 is used to guide the compressed air to the air cavity 21, that is, the jet air duct 4 is connected to the air cavity 21. The inner wall of the contracting pipe section 2 is also provided with a plurality of groups of through holes, and each group of through holes is distributed in sequence along the mainstream direction. Each group of through holes includes a plurality of jet holes 22, and the jet holes 22 of the same group are arrayed around the axis of the contracting pipe section 2. Each jet hole 22 is used to eject the compressed air in the air cavity 21 to form a jet, so that the jet and the mainstream in the contracting pipe section 2 form a vortex.

[0050] In this embodiment, if boundary flashback occurs in the combustion chamber, the flame inside the flame tube 3 will definitely propagate into the premixing pipe section 1 along the boundary layer of the convergent pipe section 2 (that is, the part of the fluid in the convergent pipe section 2 close to the inner wall of the convergent pipe section 2).

[0051] During operation, if boundary flashback occurs in the combustion chamber, compressed air can be injected into the air cavity 21 through the jet air duct 4. Furthermore, the compressed air in the air cavity 21 can be ejected through the various jet holes 22 to form jets. Each jet can form vortices with the main flow in the convergent tube section 2. These vortices can increase the airflow velocity of the fluid within the boundary layer, thereby reducing the possibility of boundary layer flashback in the combustion chamber. Even if boundary layer flashback does occur, the flame can be prevented from propagating back along the boundary layer by controlling the jet flow rate, allowing the combustion chamber to actively control boundary layer flashback.

[0052] It should be clear that the flow directions of the fluids (for example: air, fuel, a mixture of air and fuel, etc.) in various components or structures of the combustion chamber (for example: the premixing pipe section 1, the convergent pipe section 2, the flame tube 3 and the premixing flow channel 11, etc.) are different. However, the flow direction of most of the fluids (that is, the mainstream) in a certain component is along the axis of the component from the input end of the component (that is, the end where the fluid flows into the component) to the output end of the component (that is, the end where the fluid flows out of the component). In other words, in this embodiment, the mainstream direction of a component in the combustion chamber refers to a direction parallel to the axis of the component, and from the input end to the output end of the component. For example, the mainstream direction of the convergent pipe section 2 is as follows: Figure 1 and Figure 7 As shown in direction A in .

[0053] It should be noted that the components or structures (e.g., premixing pipe section 1, convergent pipe section 2, flame tube 3, and premixing flow channel 11) that can guide fluid (e.g., air, fuel, or a mixture of air and fuel) in the combustion chamber all have an input end and an output end, where the input end refers to the end where the fluid flows into the component or structure, and the output end refers to the end where the fluid flows out of the component or structure. In other words, in the combustion chamber proposed in the embodiments of the present application, the direction of fluid flow during use is always from the input end to the output end of a component or structure.

[0054] In the embodiment of the present application, the number of through hole groups can be set according to the needs, as long as the jet ejected from the jet hole 22 can form a vortex with the mainstream in the contraction tube section 2, thereby increasing the air flow velocity of the fluid in the boundary layer. Figure 6 As shown, two groups of through holes are provided.

[0055] In the embodiments of the present application, the diameter of the jet hole 22 can be set as required. For example, the diameter of the jet hole 22 can be greater than or equal to 0.5 mm and less than or equal to 1.0 mm. Specifically, the diameter of the jet hole 22 can be any one of 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1.0 mm, or any diameter between two adjacent diameters mentioned above. After multiple tests and verifications by the inventors, it was found that although jet holes 22 with diameters exceeding this range can also suppress boundary layer flashback, the suppression effect is limited.

[0056] In the examples of the present application, the ratio of the circumferential spacing between the jet holes 22 in each group of through holes (approximately equal to the distance between the axial centerlines of adjacent jet holes 22) to the diameter of the jet holes 22 can be greater than or equal to 8 and less than or equal to 12. Specifically, the above ratio can be any one of 8, 9, 10, 11, and 12, or any ratio between two adjacent ratios. The inventors have conducted multiple tests and found that if the above ratio is greater than 12, the tempering suppression effect is weakened; if the above ratio is less than 8, the flow fields of adjacent jet holes will interfere, and the structural strength of the contraction tube section 2 will be affected.

[0057] As can be seen from the foregoing, in an embodiment of the present application, the jet ejected through the jet hole 22 and the mainstream in the contraction tube section 2 form a vortex to increase the velocity of the boundary layer fluid, thereby achieving the purpose of suppressing the occurrence of boundary layer flashback. After repeated verification by the inventors, it was found that the effect of suppressing boundary layer flashback is closely related to the structure of the jet hole 22. For example, the angle of the jet hole 22 can determine the angle of the jet, and jets of different angles have different effects on suppressing boundary layer flashback. In order to enable the jet ejected from the jet hole 22 to significantly suppress the boundary layer flashback phenomenon, in one embodiment of the present application, the angle between the axis of the jet hole 22 and the first plane (hereinafter referred to as the first angle, that is, Figure 7 The angle α shown in the figure can be greater than or equal to 30° and less than or equal to 45°. After many experiments and verifications by the inventors, it was found that although the first angles of other angles exceeding this range can also suppress the boundary layer tempering phenomenon, their suppressive effects are limited. In this embodiment, the first plane is tangent to the inner wall surface of the contraction tube section 2, and the first point is located in the first plane. The first point is the intersection of the axis of the jet hole 22 and the inner wall surface of the contraction tube section 2. The angle formed by the projection of the axis of the jet hole 22 and the axis of the contraction tube section 2 on the first plane (hereinafter referred to as the second angle, that is, Figure 7 The angle β shown is greater than or equal to 30° and less than or equal to 90°. After multiple tests and verifications by the inventors, it was found that although second angles outside this range can also suppress boundary layer flashback, their suppression effect is limited.

[0058] In an embodiment of the present application, the first angle can be any one of 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44° and 45°, or any degree between two adjacent degrees mentioned above.

[0059] In an embodiment of the present application, the second angle can be any one of 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85° and 90°, or any degree between two adjacent degrees mentioned above.

[0060] In the embodiments of the present application, a premixed gas mixture (i.e., a mixture of air and fuel) can be directly injected into the premixing pipe section 1, thereby enabling lean premixed combustion in the combustion chamber. Lean premixed combustion refers to premixing the fuel and excess air before entering the combustion zone (i.e., the flame tube 3). The combustion temperature is controlled by adjusting the fuel-to-air ratio, thereby keeping the combustion zone temperature within a range with a low nitrogen oxide generation rate, thereby reducing nitrogen oxide generation and achieving low-pollution combustion.

[0061] In order to enable the fuel (for example, hydrogen or methane) and air to be premixed in the premixing pipe section 1 to form a mixed gas, in one embodiment of the present application, as shown in FIG. Figure 2 As shown, the combustion chamber may further include a fuel delivery pipe 5 disposed within the premixing pipe section 1. A premixing channel 11 is formed between the fuel delivery pipe 5 and the premixing pipe section 1. The fuel delivery pipe 5 is at least used to guide fuel to the premixing channel 11. During use, fuel is injected into the premixing channel 11 through the fuel delivery pipe 5. The fuel in the premixing channel 11 can then be premixed with the air in the premixing channel 11 to form a mixed gas.

[0062] It should be understood that the more uniform the air and fuel are mixed in the premixing channel 11, the more uniform the mixed gas will be. The more uniform the mixed gas is, the more complete the combustion will be, that is, the lower the pollutant content produced after combustion will be. In order to ensure that the air and fuel in the premixing channel 11 are mixed uniformly, in one embodiment of the present application, Figure 2 and Figure 3 As shown, a swirler 6 is formed between the fuel delivery pipe 5 and the premixing pipe section 1. The swirler 6 is used to generate a swirl in at least the main flow in the premixing channel 11. During use, the air and fuel in the premixing channel 11 form a swirl after passing through the swirler 6, which facilitates uniform mixing of the air and fuel.

[0063] In the embodiments of the present application, there is no limitation on the shape and structure of the fuel delivery pipe 5, as long as the fuel delivery pipe 5 can guide the fuel to the premixing channel 11. For example, the fuel delivery pipe 5 can be as shown in at least the following two embodiments.

[0064] Example 1 of fuel delivery pipe

[0065] In this embodiment, if Figure 2 As shown, the axis of the fuel delivery pipe 5 coincides with the axis of the premixing pipe section 1. Figure 4 As shown, the side wall of the fuel delivery pipe 5 is provided with a plurality of fuel holes 54 communicating with the interior of the fuel delivery pipe 5 .

[0066] During use, fuel is supplied to the interior of the fuel delivery pipe 5 through a fuel supply device (mature technology, no further description is needed); further, the fuel inside the fuel delivery pipe 5 can enter the premixing channel 11 through each fuel hole 54 .

[0067] In a specific embodiment of the present application, in order to make the fuel injected from the fuel delivery pipe 5 pass through the swirler 6 to form a swirling flow, as shown in FIG. Figure 2 As shown, each fuel hole 54 in the fuel delivery pipe 5 is located before the swirler 6 along the main flow direction in the premixing flow channel 11 .

[0068] Example 2 of fuel delivery pipe

[0069] In this embodiment, if Figure 5 As shown, the fuel delivery pipe 5 includes a central bluff body 51 and multiple fuel nozzles 53. The axis of the central bluff body 51 coincides with the axis of the premixing pipe section 1, and a first fuel flow channel 52 is disposed within the central bluff body 51. Each fuel nozzle 53 is disposed on the central bluff body 51 and is connected to the first fuel flow channel 52. The fuel nozzles 53 are distributed around the axis of the central bluff body 51, and can be evenly distributed.

[0070] During use, fuel is supplied to the first fuel flow channel 52 via the fuel supply device. Furthermore, the fuel in the first fuel flow channel 52 can enter the premixing flow channel 11 through the various fuel nozzles 53. Because the various fuel nozzles 53 are evenly distributed around the axis of the central bluff body 51, the fuel entering the premixing flow channel 11 is evenly distributed, thereby facilitating the subsequent uniform mixing of the fuel and air.

[0071] In this embodiment, the number of fuel nozzles 53 can be appropriately set. For example, the number of fuel nozzles 53 can be 4, 6, 8, 10, 12, 14, or 16. It should be noted that if the number of fuel nozzles 53 is too small (e.g., less than 4), the fuel will be unevenly distributed circumferentially. If the number of fuel nozzles 53 is too large (e.g., greater than 16), the mainstream air flow resistance of the premixing channel 11 will increase.

[0072] In order to further facilitate the uniform distribution of fuel in the premixing channel 11, in the embodiment of the present application, Figure 5 As shown, the axis of the fuel nozzle 53 may be perpendicular to the axis of the central bluff body 51. The fuel nozzle 53 is provided with a plurality of fuel holes 54, and the fuel holes 54 are sequentially distributed along the axis of the fuel nozzle 53.

[0073] During use, the fuel in the fuel nozzle 53 can be ejected through the fuel holes 54. Since the fuel holes 54 on the fuel nozzle 53 are sequentially distributed along the axis of the fuel nozzle 53, the greater the number of fuel holes 54, the more evenly the fuel is distributed in the premixing flow channel 11, which is more conducive to uniform mixing of the fuel and air.

[0074] In the embodiments of the present application, the number and aperture of the fuel holes 54 can be reasonably selected. For example, the number of fuel holes 54 can be 2, 4, 6, 8 or 10, etc. The diameter of the fuel hole 54 can be 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm or 3.0 mm, etc. It should be noted that, when the total runoff area formed by each fuel through hole 54 remains unchanged, if the diameter of the fuel hole 54 is larger, the number of fuel holes 54 required is smaller, that is, the more uneven the mixing of fuel and air is; if the diameter of the fuel hole 54 is smaller, the number of fuel holes 54 required is larger, although the mixing of fuel and air will be more uniform, but the fuel hole 54 is more difficult to process and is more prone to clogging.

[0075] It should be noted that, in order to improve the uniformity of fuel and air mixing in the premixing passage 11, in the embodiment of the present application, the axis of the fuel hole 54 can be spatially perpendicular to the axis of the premixing pipe section 1 (i.e., the two are perpendicular and non-planar lines). Of course, in other embodiments of the present application, the direction of the fuel jet ejected from the fuel hole 54 can be opposite to the direction of the mainstream air, or form an angle greater than 90° with the direction of the mainstream air.

[0076] As previously mentioned, due to the relatively low velocity of the fluid in the boundary layer (i.e., the mixed gas near the inner wall of the premixing tube segment 1), the flame is easily propagated in the reverse direction through the fluid in the boundary layer, resulting in boundary layer flashback. To further prevent boundary layer flashback, in the embodiment of the present application, the inner diameters of the fuel holes 54 vary, and the inner diameters of the fuel holes 54 decrease along a first direction. This first direction is parallel to the axis of the fuel nozzle 53 and extends from the outer wall of the central bluff body 51 toward the inner wall of the premixing tube segment 1.

[0077] It should be noted that the amount of fuel ejected from each location in the fuel nozzle 53 is positively correlated with the aperture size of each fuel hole 54. That is, the larger the aperture of the fuel hole 54, the larger the amount of fuel ejected from the fuel hole 54; and the smaller the aperture of the fuel hole 54, the smaller the amount of fuel ejected from the fuel hole 54. In this embodiment, since the inner diameter of each fuel hole 54 decreases along the first direction, the amount of fuel in the premixing channel 11 along the first direction also decreases. That is, the closer the mixed gas is to the inner wall of the premixing tube section 1 in the premixing channel 11, the less fuel it contains. In other words, the mixed gas close to the inner wall of the premixing tube section 1 is difficult to ignite even if its flow velocity is low, because the amount of fuel inside it is small, which means that the boundary layer flashback phenomenon can be avoided.

[0078] It should be noted that the stability of diffusion combustion is much greater than that of lean premixed combustion. In order to prevent the gas turbine from being difficult to start or flameout during startup or at low operating conditions due to the small amount of fuel in the mixture, in one embodiment of the present application, a second fuel flow channel 55 and multiple air flow channels 56 are further provided in the central bluff body 51. Figure 5 As shown, the second fuel flow channel 55 and each air flow channel 56 all penetrate the central bluff body 51, and the axis of the second fuel flow channel 55 coincides with the axis of the central bluff body 51. The axis of each air flow channel 56 is parallel to the axis of the central bluff body 51, and each air flow channel 56 is distributed around the axis of the central bluff body 51, and can be evenly distributed.

[0079] During gas turbine startup or when operating at a low level, most of the fuel is injected into the flame tube 3 through the second fuel flow passage 55, and air is injected into the flame tube 3 through the air flow passage 56. This fuel can then undergo diffusion combustion in the flame tube 3, facilitating gas turbine startup and preventing flameout at low operating levels. When the gas turbine is operating at a high level, most of the fuel is injected into the premixing flow passage 11 through the first fuel flow passage 52. This fuel can then be premixed with the air in the premixing flow passage 11 to form a mixed gas. Furthermore, the mixed gas enters the flame tube 3 to form lean premixed combustion, which helps reduce the generation of pollutants (i.e., nitrogen oxides).

[0080] It should be noted that, in this embodiment, the provision of air flow channel 56 allows the air ejected from air flow channel 56 to destroy the recirculation zone behind central bluff body 51, thereby preventing central flow flashback. Furthermore, the air in air flow channel 56 cools central bluff body 51, thereby extending the service life of central bluff body 51.

[0081] In this embodiment, a plurality of fuel injection holes may be provided in the central bluff body 51, and the fuel injection holes are connected to the second fuel flow channel 55. In other words, the fuel in the second fuel flow channel 55 may be injected through each fuel injection hole.

[0082] In this embodiment, the diameter of the fuel injection holes can be appropriately selected. For example, the diameter of the fuel injection holes can be 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, or 3.0 mm. It should be noted that, in this embodiment, if the diameter of the fuel injection holes is too large (for example, greater than 3.0 mm), the fuel injection velocity will be insufficient, which can easily lead to fuel enrichment, increase the amount of pollutants generated, and increase the risk of ablation of the central bluff body 51. If the diameter of the fuel injection holes is too small (for example, less than 0.5 mm), processing will be difficult and clogging will occur easily. In this embodiment, the number and diameter of the air flow channels 56 can be appropriately selected. For example, the number of air flow channels 56 can be 1, 2, 4, 6, 8, or 10. The diameter of the air flow channels 56 can be 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, or 4.0 mm. It should be noted that if the diameter of the air flow channel 56 is too small (for example, less than 1.0 mm), the air flow channel 56 is easily clogged, and the air flow rate is too small to destroy the recirculation zone downstream of the central bluff body 51. If the diameter of the air flow channel 56 is too large (for example, greater than 4.0 mm), the air flow rate is large, which can easily cause a local low equivalence ratio zone downstream of the central bluff body 51, affecting combustion stability and combustion efficiency.

[0083] This concludes the introduction to the second embodiment of the fuel delivery pipe.

[0084] As mentioned above, boundary layer flashback refers to the flame propagating back along the mixture in the boundary layer to the premixing channel 11. In other words, if boundary layer flashback occurs, the temperature and pulsating pressure amplitude in the premixing channel 11 will increase abnormally.

[0085] In order to accurately know whether the gas turbine has flashback, in one embodiment of the present application, the combustion chamber may further include a plurality of temperature sensors 7. Figure 3As shown, each temperature sensor 7 is disposed on the inner wall of the premixing pipe section 1, and each temperature sensor 7 is located near the converging pipe section 2. During operation, if each temperature sensor 7 detects an abnormal temperature rise in the premixing pipe section 1, it can be determined that the gas turbine has experienced flashback. It should be noted that if boundary layer flashback occurs, the flame generally passes axially through the converging pipe section 2 before entering the premixing pipe section 1. If the temperature sensor 7 is axially close to the converging pipe section 2, the temperature sensor 7 is susceptible to interference from the air jet orifice 22 (thus affecting the monitoring results). If the temperature sensor 7 is axially far from the converging pipe section 2, the temperature sensor 7 may have difficulty quickly detecting less severe flashbacks. Therefore, in the embodiments of the present application, the proximity of the temperature sensor 7 to the converging pipe section 2 means that the temperature sensor 7 can quickly detect most abnormal temperature rises (i.e., flashbacks) while also avoiding interference from the jet air. For example, the shortest axial distance between the temperature sensor 7 and the converging pipe section 2 along the premixing pipe section 1 can be greater than or equal to 1 cm and less than or equal to 5 cm. The distance control between the dynamic pressure sensor 8 and the contraction tube section 2 described below is also the same, and will not be described in detail later.

[0086] It should be understood that measuring the temperature of the premixing pipe section 1 in the combustion chamber by the temperature sensor 7 and measuring the pulsating pressure amplitude of the premixing pipe section 1 in the combustion chamber by the dynamic pressure sensor 8 are mature technologies and will not be described in detail here.

[0087] In order to accurately know whether the gas turbine has flashback, in another embodiment of the present application, the combustion chamber may further include a dynamic pressure sensor 8. Figure 3 As shown, the dynamic pressure sensor 8 is disposed on the inner wall of the premixing pipe section 1, near the contracting pipe section 2. During operation, if the dynamic pressure sensor 8 detects an abnormal increase in the amplitude of the pulsating pressure in the premixing pipe section 1, it can be determined that the gas turbine has flashed back. In this embodiment, there is no limit to the number of dynamic pressure sensors 8; for example, one or more dynamic pressure sensors 8 may be provided.

[0088] In different embodiments of the present application, only the temperature sensor 7 may be provided in the premixing pipe section 1 ; of course, the temperature sensor 7 and the dynamic pressure sensor 8 may also be provided at the same time.

[0089] As mentioned above, if flashback is determined to have occurred in the gas turbine, the flame's reverse propagation along the boundary layer can be blocked by controlling the jet flow rate. To control the jet flow rate, in one embodiment of the present application, the combustion chamber may further include a control valve (not shown). The control valve is disposed in the jet air duct 4 and is used to control the opening of the jet air duct 4. It should be noted that controlling the opening of a duct (i.e., the jet air duct 4) using a valve (i.e., a control valve) is a mature technology and will not be described in detail here.

[0090] In the embodiment of the present application, the control valve may be any valve that can control the opening of the jet air duct 4 , for example, the control valve may be a butterfly valve, a ball valve or a stop valve.

[0091] The combustion chamber embodiment proposed in this application utilizes the jet air duct 4, air cavity 21, and jet orifice 22 to form a jet. This jet can then form vortices with the main flow in the converging tube section 2. These vortices increase the airflow velocity within the boundary layer, thereby reducing the likelihood of boundary layer flashback in the combustion chamber. Even if boundary layer flashback does occur, the flame's reverse propagation along the boundary layer can be prevented by controlling the jet flow rate, enabling the combustion chamber to actively control boundary layer flashback.

[0092] Having introduced the combustion chamber proposed in the embodiments of this application, we now introduce an embodiment of a gas turbine proposed in this application. Specifically, the gas turbine includes an air supply device (not shown) and the combustion chamber described in any of the aforementioned embodiments. In this embodiment, the air supply device is used to supply compressed air into the air cavity 21 via the jet air duct 4. In other words, the air supply device can be any compressed air supply device, for example, an air compressor or an air tank storing compressed air.

[0093] To generate a jet without adding other equipment (e.g., an air compressor or compressed air storage tank), in one embodiment of the present application, the air supply device can be the compressor of a gas turbine. The jet air duct 4 directs compressed air from the midsection of the compressor into the air cavity 21, thereby forming a jet. It should be noted that during normal gas turbine operation, the compressed air flow required to form the jet is relatively small, accounting for approximately 0.5% to 1% of the mainstream compressed air flow in the compressor. Therefore, midsection bleed air has a minimal impact on the overall efficiency of the gas turbine. Furthermore, the relative momentum of the resulting jet and the mainstream air in the premixing channel 11 is relatively small, meaning that the jet penetration depth is relatively low. This does not significantly affect the mixing of fuel and air in the premixing channel 11, and therefore does not affect the generation of pollutants (i.e., nitrogen oxides) in the combustion chamber.

[0094] The gas turbine embodiment proposed in this application utilizes the jet air duct 4, air cavity 21, and jet orifice 22 to form a jet. This jet can then form vortices with the main flow in the converging tube section 2. These vortices increase the velocity of the fluid within the boundary layer, thereby reducing the likelihood of boundary layer flashback in the combustion chamber. Even if boundary layer flashback does occur, the flame's reverse propagation along the boundary layer can be prevented by controlling the jet flow rate, enabling the gas turbine to actively control boundary layer flashback.

[0095] After introducing the gas turbine proposed in the embodiment of the present application, the following describes a flashback control method for a gas turbine proposed in the present application. Specifically, the flashback control method is applied to the gas turbine described above. Figure 8 As shown, the tempering control method includes steps S100 to S300.

[0096] Step S100: Acquire tempering monitoring data.

[0097] In this embodiment, the flashback monitoring data may be any data that can indicate whether flashback has occurred. For example, the flashback monitoring data may include at least one of the temperature value and the pulsating pressure amplitude at the connection between the premixing pipe section 1 and the contraction pipe section 2, or a combination thereof.

[0098] Step S200: obtaining an opening value based on the tempering monitoring data.

[0099] As previously mentioned, if flashback occurs, the opening of the jet air duct 4 can be increased, thereby increasing the jet flow rate to prevent the flame from propagating backward along the boundary layer, allowing the gas turbine to actively control boundary layer flashback. In other words, in this embodiment, the opening of the jet air duct 4 can be adjusted before or after flashback occurs, thereby suppressing or eliminating boundary layer flashback.

[0100] In this embodiment, any reasonable method can be used to determine whether flashback has occurred in the combustion chamber. For example, if the temperature value monitored by a temperature sensor 7 or the average of the temperature values ​​monitored by all temperature sensors 7 is greater than a first threshold (hereinafter referred to as "detected temperature value greater than first threshold"), flashback can be considered to have occurred in the combustion chamber. Alternatively, if the pulsating pressure amplitude monitored by a dynamic pressure sensor 8 or the average of the pulsating pressure amplitudes monitored by all dynamic pressure sensors 8 is greater than a second threshold (hereinafter referred to as "detected pulsating pressure amplitude greater than second threshold"), flashback can be considered to have occurred in the combustion chamber.

[0101] Of course, in other embodiments of the present application, if either the detected temperature value is greater than the first threshold or the detected pulsating pressure amplitude is greater than the second threshold, then flashback may be considered to have occurred in the combustion chamber. Alternatively, if both the detected temperature value is greater than the first threshold and the detected pulsating pressure amplitude is greater than the second threshold are met, then flashback may be considered to have occurred in the combustion chamber.

[0102] In this embodiment, any reasonable method can be used to obtain the opening value based on the flashback monitoring data. For example, in step S200, the calculation formula for obtaining the opening value based on the flashback monitoring data can be as follows:

[0103]

[0104] in, Indicates the current opening value. Indicates the current temperature value (which may be the current maximum temperature value of each temperature sensor 7 or the current average temperature value of each temperature sensor 7); represents the first threshold; Indicates the minimum opening value; Indicates the temperature value (preset) at which the valve is at maximum opening. In other words, in this embodiment, the opening of the jet air duct 4 can be dynamically adjusted based on the temperature in the premixing pipe section 1. In other words, if the temperature in the premixing pipe section 1 rises, the opening of the jet air duct 4 is increased (to a maximum of 100%); if the temperature in the premixing pipe section 1 drops, the opening of the jet air duct 4 is decreased (for example, the minimum opening value can be set to 10%).

[0105] In a specific embodiment of the present application, the first threshold It can be 1000K; the temperature value when the valve is at maximum opening Can be 1300K; minimum opening value It can be 10%. If the current temperature value is 1150K, then the current opening value of the valve Of course, in other embodiments of the present application, the first threshold , Temperature value when the valve is at maximum opening and minimum opening value Both can be set according to needs.

[0106] Step S300: adjusting the opening of the jet air duct 4 based on the opening value.

[0107] It should be understood that manually or automatically adjusting the opening of the jet air duct 4 to a certain opening value through a control valve is a mature technology and will not be described in detail here.

[0108] The embodiment of the gas turbine flashback control method proposed in this application utilizes the jet air duct 4, air cavity 21, and jet orifice 22 to form a jet. This jet can then form vortices with the main flow in the converging tube section 2. These vortices increase the airflow velocity within the boundary layer, thereby reducing the likelihood of boundary layer flashback in the combustion chamber. Even if boundary layer flashback does occur, the flame's reverse propagation along the boundary layer can be blocked by controlling the jet flow rate, enabling the gas turbine to actively control boundary layer flashback.

[0109] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A flashback control method for a gas turbine, the gas turbine comprising a combustion chamber, characterized in that: The combustion chamber comprises: A premixing pipe section (1), a contraction pipe section (2), and a flame tube (3) are sequentially connected; the inner diameter of the contraction pipe section (2) decreases along the main flow direction; an air cavity (21) is also provided in the contraction pipe section (2); A jet air duct (4) is provided on the contraction tube section (2), and the jet air duct (4) is used to guide compressed air to the air cavity (21); A plurality of groups of through holes are provided on the inner wall of the contraction tube section (2), and each group of through holes is sequentially distributed along the main flow direction; each group of through holes includes a plurality of jet holes (22), and each jet hole (22) of the same group is arrayed around the axis of the contraction tube section (2), and each jet hole (22) is used to eject the compressed air in the air cavity (21) to form a jet, thereby causing the jet to form a vortex with the main flow in the contraction tube section (2); The angle between the axis of the jet hole (22) and the first plane is greater than or equal to 30° and less than or equal to 45°; the first plane is tangent to the inner wall surface of the contraction tube section (2), and the first point is located in the first plane; the first point is the intersection of the axis of the jet hole (22) and the inner wall surface of the contraction tube section (2); the angle formed by the projection of the axis of the jet hole (22) and the axis of the contraction tube section (2) on the first plane is greater than or equal to 30° and less than or equal to 90°; A plurality of temperature sensors (7) and / or dynamic pressure sensors (8); each temperature sensor (7) is arranged on the inner wall surface of the premixing pipe section (1), and each temperature sensor (7) is close to the contraction pipe section (2); the dynamic pressure sensor (8) is arranged on the inner wall surface of the premixing pipe section (1), and the dynamic pressure sensor (8) is close to the contraction pipe section (2); a control valve, provided on the jet air duct (4), for controlling the opening of the jet air duct (4); Air supply equipment for supplying compressed air into the air chamber (21) through the jet air duct (4) The tempering control method comprises: Acquiring flashback monitoring data; the flashback monitoring data at least includes any one or a combination of two of a temperature value and a pulsating pressure amplitude at the connection between the premixing pipe section (1) and the contraction pipe section (2); Based on the tempering monitoring data, obtaining an opening value; Based on the opening value, the opening of the jet air duct (4) is adjusted.

2. The flashback control method for a gas turbine according to claim 1, wherein: It also includes a fuel delivery pipe (5) arranged inside the premixing pipe section (1); a premixing flow channel (11) is formed between the fuel delivery pipe (5) and the premixing pipe section (1), and the fuel delivery pipe (5) is at least used to guide fuel to the premixing flow channel (11).

3. The flashback control method for a gas turbine according to claim 2, wherein: A swirler (6) is also formed between the fuel delivery pipe (5) and the premixing pipe section (1), and the swirler (6) is used at least to form a swirling flow in the main flow in the premixing flow channel (11).

4. The flashback control method for a gas turbine according to claim 3, wherein: The fuel delivery pipe (5) comprises: A central bluff body (51); the axis of the central bluff body (51) coincides with the axis of the premixing tube section (1); a first fuel flow channel (52) is provided inside the central bluff body (51); A plurality of fuel nozzles (53); each fuel nozzle (53) is disposed on the central bluff body (51), and each fuel nozzle (53) is connected to the first fuel flow channel (52); and each fuel nozzle (53) is distributed around the axis of the central bluff body (51).

5. The flashback control method for a gas turbine according to claim 4, wherein: The axis of the fuel nozzle (53) is perpendicular to the axis of the central bluff body (51); a plurality of fuel holes (54) are provided in the fuel nozzle (53), and the fuel holes (54) are distributed in sequence along the axis of the fuel nozzle (53).

6. The flashback control method for a gas turbine according to claim 5, wherein: The axis of the fuel hole (54) is spatially perpendicular to the axis of the premixing pipe section (1).

7. The flashback control method for a gas turbine according to claim 5, wherein: The inner diameters of the fuel holes (54) are different, and the inner diameters of the fuel holes (54) decrease along a first direction; the first direction is parallel to the axis of the fuel nozzle (53) and points from the outer wall of the central bluff body (51) to the inner wall of the premixing pipe section (1).

8. The flashback control method for a gas turbine according to claim 4, wherein: The central bluff body (51) is further provided with a second fuel flow channel (55) and a plurality of air flow channels (56). The second fuel flow channel (55) and the air flow channels (56) all penetrate the central bluff body (51), and the axis of the second fuel flow channel (55) coincides with the axis of the central bluff body (51); the axis of the air flow channels (56) is parallel to the axis of the central bluff body (51), and the air flow channels (56) are distributed around the axis of the central bluff body (51).

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