Combustion chamber and nozzle thereof

Abstract

The invention discloses a combustion chamber and a nozzle thereof, and relates to the technical field of combustion chambers. The nozzle comprises: a tubular body; the concave cavity front baffle and the concave cavity rear baffle are sequentially arranged on the outer wall of the body in the first direction; the first direction is parallel to the axis of the body and points to the rear end from the front end of the body; a plurality of fuel spray holes are formed in the concave cavity front baffle; and a plurality of air spray holes are formed in the concave cavity rear baffle. According to the nozzle, the air spraying hole and the fuel spraying hole are both located outside the nozzle body, and compared with a nozzle with the air spraying hole and the fuel spraying hole located inside, the nozzle is convenient to machine, the machining difficulty is small, and the machining precision is easy to control. In addition, fuel and air are mixed in the premixing cavity in a hedging backflow mode, and the mixing effect of the nozzle is slightly affected by the positions and the sizes of the air spraying holes and the fuel spraying holes.

Description

Technical Field

[0001] The present application relates to the technical field of combustion chambers, and specifically to a combustion chamber and its nozzle. Background Art

[0002] With the increasing enhancement of people's environmental protection awareness, flexible combustion mainly based on hydrogen has become an important development trend of current and future gas turbines. Since the flame speed of hydrogen fuel is one order of magnitude higher than that of natural gas fuel, when the flame is stretched, the instability will be significantly aggravated, thus easily causing thermoacoustic oscillations inside the combustion chamber. At the same time, the diffusion effect of hydrogen in the air is strong, the combustion intensity increases, and the extinction limit of the flame is also significantly different from that of conventional fuels. In addition, the high transmission characteristics of hydrogen make its mass diffusion coefficient smaller than the thermal diffusion coefficient, and coupled with the higher flame speed, backfire is extremely likely to occur. Traditional combustion chambers and nozzles cannot achieve safe and efficient combustion of flexible fuels mainly based on hydrogen (hereinafter referred to as hydrogen flexible fuels).

[0003] Existing technologies are based on nozzles of micro-mixing combustion technology to solve the technical problem that hydrogen flexible fuels cannot be safely and efficiently combusted. Micro-mixing combustion technology refers to reducing the mixing scale of fuel and air, strengthening the uniformity of the outlet micro-premixed gas, and under the condition of achieving ultra-low emissions, increasing the outlet flow rate of the micro-premixed gas, thereby enhancing the anti-backfire ability and flexible fuel adaptability of the nozzle. For example, patent application documents with publication numbers: CN118912532A, titled: A Radial Composite Nozzle Structure; and CN119123423A, titled: A Discrete Hydrogen Fuel Nozzle Structure with Anti-Oscillation Measures, both disclose similar nozzles. Although these nozzles can achieve safe and efficient combustion of hydrogen flexible fuels, they still have the following technical problems: First, both the fuel injection holes and the air injection holes are located inside the nozzle, making it difficult for mechanical processing (generally processed by 3D printing technology); Second, hydrogen fuel and air are mixed by forming a swirl through the fuel injection holes and the air injection holes. If the processing accuracy of the fuel injection holes or the air injection holes is low, it is difficult for hydrogen fuel and air to be mixed evenly, which also increases the content of pollutants (i.e., nitrogen oxides) generated by subsequent combustion. If the processing accuracy of the fuel injection holes and the air injection holes is improved, the processing cost will skyrocket. Summary of the Invention

[0004] The purpose of the present application is to provide a combustion chamber and its nozzle to solve the technical problems of high processing difficulty and high processing cost of nozzles based on micro-mixing combustion technology in the prior art.

[0005] To achieve the above purpose, the present application provides the following technical solutions:

[0006] In the first aspect, the present application proposes a technical solution for a nozzle, and the nozzle includes:

[0007] A tubular body;

[0008] A front baffle and a rear baffle of the concave cavity are sequentially arranged on the outer wall of the body along a first direction; the first direction is parallel to the axis of the body and points from the front end to the rear end of the body; a premixing concave cavity is arranged between the front baffle and the rear baffle of the concave cavity, and the premixing concave cavity is communicated with the inside of the body; the front baffle of the concave cavity is provided with a plurality of fuel injection holes, and each fuel injection hole is distributed around the axis of the body; the rear baffle of the concave cavity is provided with a plurality of air injection holes, and each air injection hole is distributed around the axis of the body.

[0009] As a specific solution in the technical solution of the present application, a fuel chamber cover plate is further arranged on the outer wall of the body; the front baffle of the concave cavity is located between the fuel chamber cover plate and the rear baffle of the concave cavity; a fuel chamber is arranged between the fuel chamber cover plate and the front baffle of the concave cavity.

[0010] As a specific solution in the technical solution of the present application, the body includes an air inlet pipe, a premixing pipe section and an outlet pipe section that are sequentially connected along the first direction; the premixing concave cavity is located between the air inlet pipe and the premixing pipe section.

[0011] As a specific solution in the technical solution of the present application, the inner diameter of the outlet pipe section decreases along the first direction.

[0012] As a specific solution in the technical solution of the present application, an end face plate is arranged on the outer wall of the outlet pipe section; an impact plate is arranged on the outer wall of the premixing pipe section; a cooling cavity is arranged between the end face plate and the impact plate; the impact plate is provided with impact cooling holes; the premixing pipe section is provided with a plurality of air blowing holes, and each air blowing hole is distributed around the axis of the body, and each air blowing hole is used to communicate the cooling cavity and the inside of the outlet pipe section.

[0013] As a specific solution in the technical solution of the present application, the included angle between the axis of the outlet pipe section and the axis of the air blowing hole is greater than or equal to 15° and less than or equal to 30°.

[0014] As a specific solution in the technical solution of the present application, the axis line of the body, the axis lines of each fuel injection hole, and the axis lines of each air injection hole are all parallel; the included angle between the first line segment and the second line segment is greater than or equal to 0° and less than or equal to 30°; the length of the first line segment is longer than that of the second line segment; the first line segment is the connecting line segment between the first point and the second point; the second line segment is the connecting line segment between the first point and the third point; the first point is the center point of the projection of the body on the first plane; the first plane is perpendicular to the axis line of the body; the second point is the center point of the projection of any one of the air injection holes on the first plane; the third point is the center point of the projection of the fuel injection hole closest to the air injection hole on the first plane; or, the second point is the center point of the projection of any one of the fuel injection holes on the first plane; the third point is the center point of the projection of the air injection hole closest to the fuel injection hole on the first plane.

[0015] As a specific solution in the technical solution of the present application, the diameters of the fuel injection holes and the air injection holes are equal; the lengths of the first line segment and the second line segment satisfy the following calculation formula:

[0016]

[0017] Wherein, D represents the diameter of the fuel injection hole; S1 represents the length value of the first line segment; S2 represents the length value of the second line segment; cos represents the cosine function; B represents the included angle between the first line segment and the second line segment.

[0018] As a specific solution in the technical solution of the present application, a radial swirler is further provided in the premixing cavity.

[0019] In a second aspect, the present application provides a technical solution for a combustion chamber, which includes:

[0020] A combustion chamber casing and a flame tube; the flame tube is arranged inside the combustion chamber casing, and an air flow passage is arranged between the outer wall of the flame tube and the inner wall of the combustion chamber casing;

[0021] Multiple nozzles as described in any one of the first aspect; each nozzle shares the same fuel cavity and the same premixing cavity;

[0022] A main combustion stage fuel pipe, which is arranged on the combustion chamber casing and is communicated with the fuel cavity.

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

[0024] A partition plate is disposed in the fuel chamber and the premixing cavity; the partition plate is used to divide the fuel chamber into a main combustion stage fuel chamber and a pilot fuel chamber, and to divide the premixing cavity into a main combustion stage cavity and a pilot cavity; the main combustion stage fuel pipe is communicated with the main combustion stage fuel chamber;

[0025] A pilot fuel pipe is disposed in the combustion chamber casing, and the pilot fuel pipe is communicated with the pilot fuel chamber.

[0026] Compared with the prior art, the beneficial effects of this application are as follows:

[0027] Both the air injection holes and the fuel injection holes of the nozzle in this application are located outside the nozzle body. Compared with a nozzle in which the air injection holes and the fuel injection holes are located inside, it is convenient for machining, that is, the machining difficulty is small, and the machining accuracy is easy to control. Moreover, the nozzle mixes fuel and air by forming a counter-flow recirculation in the premixing cavity, and its mixing effect is less affected by the positions and sizes of the air injection holes and the fuel injection holes. That is to say, compared with a nozzle based on swirl mixing, the nozzle proposed in the embodiments of this application has lower requirements for the machining accuracy of the air injection holes and the fuel injection holes (for example: hole diameter accuracy, direction accuracy, etc.), that is, the machining cost can be reduced. Description of the Drawings

[0028] Figure 1 It is a cross-sectional view of a nozzle proposed in an embodiment of this application;

[0029] Figure 2 It is a cross-sectional view of a nozzle proposed in an embodiment of this application according to Figure 1 the cross-section along line E-E in;

[0030] Figure 3 It is a cross-sectional view of another nozzle proposed in an embodiment of this application according to Figure 1 the cross-section along line E-E in;

[0031] Figure 4 It is a cross-sectional view of another nozzle proposed in an embodiment of this application;

[0032] Figure 5 It is a three-dimensional cross-sectional view of a combustion chamber proposed in an embodiment of this application;

[0033] Figure 6 It is a cross-sectional view of a combustion chamber proposed in an embodiment of this application.

[0034] In the figure: 1. combustion chamber casing; 2. nozzle; 3. flame tube; 4. main combustion stage fuel pipe; 5. duty class fuel pipe; 6. partition plate; 7. air; 8. fuel; 81. main combustion stage fuel; 82. duty class fuel; 10. micro-premixed gas; 21. fuel cavity; 211. fuel cavity cover plate; 214. main combustion stage fuel cavity; 215. duty class fuel cavity; 22. fuel spray hole; 225. radial swirler; 23. air inlet pipe; 24. premixing cavity; 241. cavity front baffle plate; 242. cavity rear baffle plate; 244. main combustion stage cavity; 245. duty class cavity; 25. air spray hole; 26. premixing pipe section; 27. impact cooling hole; 28. blowing hole; 29. outlet pipe section; 31. end panel; 32. cooling cavity; 33. impact plate. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] It should be noted that, in the description of the present application, the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0037] 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.

[0038] It should be noted that like reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined or described in one drawing, it will not require further detailed discussion and description in the description of the subsequent drawings.

[0039] Before understanding the embodiments of the present application, it should be clear that in the present application, the front end and the rear end are defined for the nozzle or the components or structures in the combustion chamber for guiding fluids (for example: nozzle 2, body or premixing pipe section 26, etc.). Among them, the front end refers to the end where the fluid (for example, air 7, fuel 8 or micro-premixed gas 10, etc.) flows into the component or structure, and the rear end refers to the end where the fluid flows out of the component or structure. That is to say, in the nozzle or combustion chamber proposed in the embodiments of the present application, when in use, the flow direction of the fluid is always from the front end of a certain component or structure to the rear end.

[0040] In order to solve the technical problems of high processing difficulty and high processing cost of the nozzle based on the micro-mixing combustion technology in the prior art proposed in the background art, the present application proposes a nozzle. Specifically, the nozzle 2 includes a tubular body, a cavity front baffle 241 and a cavity rear baffle 242 sequentially arranged on the outer wall of the body along a first direction.

[0041] In this embodiment, the first direction is parallel to the axis of the body (that is, the axis of the nozzle 2), and points from the front end of the body to the rear end (that is, from the front end of the nozzle 2 to the rear end). As Figure 1 shown, a premixing cavity 24 is arranged between the cavity front baffle 241 and the cavity rear baffle 242, and the premixing cavity 24 is communicated with the inside of the body. The cavity front baffle 241 is provided with a plurality of fuel injection holes 22, and each fuel injection hole 22 is distributed around the axis of the body. The cavity rear baffle 242 is provided with a plurality of air injection holes 25, and each air injection hole 25 is distributed around the axis of the body.

[0042] When in use, as Figure 1 shown, the fuel 8 located outside the nozzle 2 enters the premixing cavity 24 through the fuel injection holes 22; as Figure 6 shown, the air 7 located outside the nozzle 2 enters the premixing cavity 24 through the air injection holes 25; further, the air 7 and the fuel 8 entering the premixing cavity 24 can form a counter-jet, and multiple counter-jets can counter-mix with each other, and the jet in the premixing cavity 24 can drive the surrounding gas to form a recirculation zone to further improve the mixing effect. That is to say, the nozzle 2 proposed in the present application can make the air 7 and the fuel 8 fully diffuse and mix in the premixing cavity 24, and improve the premixing uniformity of the air 7 and the fuel 8 in the nozzle 2.

[0043] It should be noted that, in the embodiments of the present application, both the air injection holes and the fuel injection holes are located outside the nozzle body. Compared with the nozzles in which the air injection holes and the fuel injection holes are located inside, it is convenient for mechanical processing, that is, the processing difficulty is small, and the processing accuracy is easy to control. Moreover, the nozzle mixes fuel and air by forming a counter-flow in the premixing cavity, and its mixing effect is less affected by the positions and sizes of the air injection holes and the fuel injection holes. That is to say, compared with the nozzles based on swirl mixing, the nozzles proposed in the embodiments of the present application have lower requirements for the processing accuracy of the air injection holes and the fuel injection holes (for example: aperture accuracy, direction accuracy, etc.), that is, the processing cost can be reduced.

[0044] It should also be noted that since both the air injection holes and the fuel injection holes are located on the flat plate (that is, the front baffle 241 or the rear baffle 242 of the cavity), when processing, multiple flat plates can be stacked together, and multiple front baffles 241 or rear baffles 242 of the cavity can be produced at one time by stamping or drilling, further reducing the production cost and shortening the production cycle.

[0045] In order to facilitate the injection of fuel 8 into the premixing cavity 24 through each fuel injection hole 22, in an embodiment of the present application, a fuel cavity cover plate 211 may further be provided on the outer wall of the body. As Figure 1 shown, the front baffle 241 of the cavity is located between the fuel cavity cover plate 211 and the rear baffle 242 of the cavity. A fuel cavity 21 is provided between the fuel cavity cover plate 211 and the front baffle 241 of the cavity. During use, only by injecting fuel 8 into the fuel cavity 21, the fuel 8 located in the fuel cavity 21 can uniformly flow into the premixing cavity 24 through each fuel injection hole 22.

[0046] In the embodiments of the present application, the number of each fuel injection hole 22 and each air injection hole 25 is not overly limited. When the air 7 and the fuel 8 in the premixing cavity 24 can be mixed evenly, the fuel injection holes 22 and the air injection holes 25 can be set to any reasonable number according to requirements. For example: the number of fuel injection holes 22 can be any one of 6, 7, 8, 9, 10, 11, and 12; the number of air injection holes 25 can also be any one of 6, 7, 8, 9, 10, 11, and 12.

[0047] It should be noted that, when the total runoff area formed by each fuel injection hole 22 remains unchanged, the more the number of fuel injection holes 22, the smaller the diameter of the fuel injection holes 22. And the smaller the diameter of the fuel injection holes 22, the greater the processing difficulty. If the number of fuel injection holes 22 is less, it is less conducive to the uniform mixing of air 7 and fuel 8 in the premixing cavity 24. Based on this, after a large number of tests and verifications by the inventor, it is found that it is more appropriate to control the number of fuel injection holes 22 to be 6 to 12. Similarly, it is also more appropriate to control the number of air injection holes 25 to be 6 to 12.

[0048] In the embodiments of the present application, there are no excessive restrictions on the installation positions and axial center line directions of each fuel injection hole 22 and each air injection hole 25. When the air 7 and fuel 8 in the premixing cavity 24 can be mixed evenly, the positions and axial center line directions of the fuel injection holes 22 and air injection holes 25 can be set according to requirements. For example, in an embodiment of the present application, the axial center line of the main body, the axial center lines of each fuel injection hole 22, and the axial center lines of each air injection hole 25 are all parallel. The included angle between the first line segment and the second line segment is greater than or equal to 0° and less than or equal to 30°. The first line segment is longer than the second line segment. The first line segment is the connecting line segment between the first point and the second point. The second line segment is the connecting line segment between the first point and the third point. The first point is the center point of the projection of the main body on the first plane. The first plane is perpendicular to the axial center line of the main body. The second point is the center point of the projection of any one of the fuel injection holes 22 on the first plane. The third point is the center point of the projection of the air injection hole 25 closest to the fuel injection hole 22 on the first plane. That is to say, in the embodiment, the fuel injection holes 22 and the air injection holes 25 are arranged staggeredly. The staggeredly arranged fuel injection holes 22 and air injection holes 25 are conducive to the interaction between the flow fields, thereby improving the mixing of fuel and air, that is, improving the premixing uniformity.

[0049] Of course, in other embodiments of the present application, the second point can be the center point of the projection of any one of the air injection holes 25 on the first plane. The third point is the center point of the projection of the fuel injection hole 22 closest to the air injection hole 25 on the first plane.

[0050] It should be noted that, after a large number of tests and verifications by the inventor, it is found that in a limited space, if the distance between two staggered counter-jet flows is controlled between 2D and 6D, where D is the diameter of the jet hole (that is, the fuel injection hole 22 or the air injection hole 25), there will be a strong interaction between the flow fields formed by the two jet beams. Such a flow field structure can strengthen the mixing of fuel and air and improve the premixing uniformity. Based on this, in an embodiment of the present application, the diameters of the fuel injection holes 22 and the air injection holes 25 are equal. The lengths of the first line segment and the second line segment satisfy the following calculation formula:

[0051]

[0052] Wherein, D represents the diameter of the fuel injection hole 22; S1 represents the length value of the first line segment; S2 represents the length value of the second line segment; cos represents the cosine function; B represents the included angle between the first line segment and the second line segment.

[0053] In a specific embodiment of the present application, the included angle between the first line segment and the second line segment (i.e., the included angle B as shown in Figure 3 can be any one of 0°, 5°, 10°, 15°, 20°, 25° and 30°, or any degree between two adjacent degrees above. It should be noted that in this embodiment, if the included angle B is larger, then cosB is smaller. If cosB is smaller, then when the distance between the fuel injection hole 22 and the nearest air injection hole 25 is constant, the length difference between the first line segment and the second line segment can be smaller. That is to say, the fuel injection hole 22 and the air injection hole 25 can be designed relatively compactly, which is beneficial to saving the design space.

[0054] In order to further improve the mixing uniformity of the air 7 and the fuel 8, in an embodiment of the present application, as shown in Figure 4 , a radial swirler 225 is further provided in the premixing cavity 24. If the radial swirler 225 is provided in the premixing cavity 24, then the micro-premixed gas 10 in the premixing cavity 24 will form a swirl as shown in Figure 4 (i.e., the spiral dotted line as shown in Figure 4 after passing through the radial swirler 225, and the swirl is beneficial to further mixing the air 7 and the fuel 8 uniformly.

[0055] In the embodiment of the present application, there are no restrictions on the shape and structure of the body. For example, the body can be in a straight tube shape. In an embodiment of the present application, as shown in Figure 1 and Figure 4 , the body includes an air inlet pipe 23, a premixing pipe section 26 and an outlet pipe section 29 connected in sequence along the first direction. The premixing cavity 24 is located between the air inlet pipe 23 and the premixing pipe section 26.

[0056] In this embodiment, the air inlet pipe 23 is used for the air outside the nozzle 2 to enter the inside of the nozzle 2 and then participate in the subsequent combustion. In this embodiment, there are no excessive restrictions on the size of the air inlet pipe 23. If the inner diameter of the air inlet pipe 23 is too small, the processing difficulty is high; if it is too large, the inlet air flow field will be unstable. In order to make the processing difficulty of the inner diameter of the air inlet pipe 23 small and the inlet air flow field stable, in a specific embodiment of the present application, the inner diameter of the air inlet pipe 23 can be greater than or equal to 6 mm and less than or equal to 10 mm. If the axial length of the air inlet pipe 23 is too short, a uniform and stable inlet air flow field cannot be formed; if it is too long, it is easy to occupy the space at the head of the combustion chamber. Based on this, the axial length of the air inlet pipe 23 can be greater than or equal to 25 mm and less than or equal to 100 mm.

[0057] In this embodiment, the premixing pipe section 26 is mainly used for the air 7 and the fuel 8 to be further uniformly mixed inside it. In this embodiment, there are no excessive restrictions on the size of the premixing pipe section 26, as long as the air 7 and the fuel 8 can be uniformly mixed inside it. For example: the smaller the inner diameter of the premixing pipe section 26, the higher the processing cost; the larger the inner diameter of the premixing pipe section 26, the worse the mixing uniformity. Based on this, the inner diameter of the premixing pipe section 26 can be greater than or equal to 7 mm and less than or equal to 12 mm. The shorter the axial length of the premixing pipe section 26, the worse the mixing uniformity; the longer the axial length of the premixing pipe section 26, the more it will occupy the space at the head of the combustion chamber. Based on this, the axial length of the premixing pipe section 26 can be greater than or equal to 50 mm and less than or equal to 100 mm.

[0058] In this embodiment, the outlet pipe section 29 is used to guide the micro-premixed gas 10 to flow out of the nozzle 2. In this embodiment, there are no excessive restrictions on the size of the outlet pipe section 29. For example: the inner diameter of the outlet pipe section 29 can be equal to the inner diameter of the premixing pipe section 26. In order to increase the velocity of the micro-premixed gas 10 flowing out of the nozzle 2 and avoid flashback due to too low velocity of the micro-premixed gas 10, in an embodiment of the present application, the inner diameter of the outlet pipe section 29 decreases along the first direction.

[0059] It should be clear that if the inner diameter of the outlet pipe section 29 decreases along the first direction, then when the micro-premixed gas 10 passes through the outlet pipe section 29 along the first direction, its velocity will gradually increase (the velocity when flowing out of the outlet pipe section 29 is the maximum). If the velocity of the micro-premixed gas 10 increases, the risk of flashback generated by the nozzle 2 can be reduced.

[0060] It should be noted that since the combustion speed of hydrogen is extremely fast, pure hydrogen or hydrogen-rich fuels mainly composed of hydrogen are extremely prone to boundary layer flashback. It should be clear that when a fluid (i.e., the micro-premixed gas 10) flows over an object (i.e., the outlet pipe section 29), due to the viscosity of the fluid itself, the velocity of the fluid near the surface of the object tends to zero, while the velocity of the fluid at a certain distance from the surface of the object is not affected by the viscosity of the fluid itself. This part of the fluid between the object surface (i.e., the inner wall of the outlet pipe section 29) and the fluid whose velocity is not affected by the viscosity of the fluid itself is the boundary layer. That is to say, boundary layer flashback refers to the phenomenon that the flame propagates reversely (taking the fluid flow direction as the positive direction) along the boundary layer due to the fluid flow velocity in the boundary layer being lower than the flame propagation speed.

[0061] In order to avoid boundary layer flashback in the nozzle 2, in an embodiment of the present application, as Figure 1 and Figure 4 shown, the premixed pipe section 26 is provided with a plurality of air holes 28, and each air hole 28 is distributed around the axis of the body. During use, the air outside the nozzle 2 can enter the inside of the outlet pipe section 29 through the air holes 28. As Figure 1 and Figure 4 shown, the air 7 entering the inside of the outlet pipe section 29 can reduce the boundary layer thickness, reduce the concentration of the fuel in the micro-premixed gas 10 at the inner wall of the outlet pipe section 29, and further reduce the risk of boundary layer flashback in the nozzle 2.

[0062] In the embodiment of the present application, the boundary layer thickness of the micro-premixed gas 10 in the outlet pipe section 29 is mainly reduced, and the concentration of the fuel in the micro-premixed gas 10 at the inner wall of the outlet pipe section 29 is reduced by blowing air 7 into the inner wall of the outlet pipe section 29 through the air holes 28. That is to say, in this embodiment, as long as the air holes 28 can achieve the above purposes. After a large number of studies by the invention, it is found that the angle between the axis of the outlet pipe section 29 and the axis of the air hole 28 (i.e., the angle A as Figure 1 shown) is greater than or equal to 15° and less than or equal to 30°, then the above purposes can be well achieved. In other words, in the embodiment of the present application, the angle between the axis of the outlet pipe section 29 and the axis of the air hole 28 can be greater than or equal to 15° and less than or equal to 30°. For example, the angle between the axis of the outlet pipe section 29 and the axis of the air hole 28 can be any one of 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29° and 30°, or any degree between the above adjacent two degrees.

[0063] It should be noted that since the outlet pipe section 29 is close to the flame, the ambient temperature where it is located is relatively high, and it is easily ablated. In order to cool the outlet pipe section 29 and thus avoid ablation of the outlet pipe section 29, in an embodiment of the present application, as Figure 4 shown, an end face plate 31 is provided on the outer wall of the outlet pipe section 29, and an impact plate 33 is provided on the outer wall of the premix pipe section 26. A cooling cavity 32 is provided between the end face plate 31 and the impact plate 33. The impact plate 33 is provided with impact cooling holes 27, and the rear ends of the impact cooling holes 27 face the end face plate 31. Each air blowing hole 28 is used to communicate the cooling cavity 32 with the inside of the outlet pipe section 29.

[0064] During use, as Figure 4 shown, the air 7 located outside the nozzle 2 can enter the cooling cavity 32 through the impact cooling holes 27. Since the rear ends of the impact cooling holes 27 face the end face plate 31, the air beam formed through the impact cooling holes 27 can directly impact on the end face plate 31. Since the temperature of the air 7 is much lower than the temperature generated during flame combustion, the air beam can cool the end face plate 31. Since the end face plate 31 is directly connected to the outlet pipe section 29, if the temperature of the end face plate 31 decreases, the temperature of the outlet pipe section 29 can also decrease. Finally, the air 7 in the cooling cavity 32 enters the inside of the outlet pipe section 29 through the air blowing holes 28.

[0065] In the embodiment of the present application, there is no limitation on the number of the cooling holes 27. For example: as Figure 4 shown, only one cooling hole 27 can be provided. Of course, the cooling holes 27 can also be provided in plurality, and the respective cooling holes 27 are distributed around the axis line of the body. Further, the respective cooling holes 27 can be evenly distributed around the axis line of the body.

[0066] In this embodiment, as Figure 4 shown, the air 7 entering the inside of the outlet pipe section 29 from the air blowing holes 28 makes two turns (the air beam formed by the impact cooling holes 27 impacts on the end face plate 31 to cause the first turn of the air 7; since the air blowing holes 28 are inclined holes, the air 7 in the cooling cavity 32 needs to make the second turn when entering the air blowing holes 28), that is, the speed of the air 7 can be greatly reduced. That is to say, the speed of the air 7 entering the inside of the outlet pipe section 29 from the air blowing holes 28 is relatively low, which can reduce the risk of boundary layer flashback formed by the nozzle 2 while avoiding disturbing the main flow of the micro-premixed gas 10 in the outlet pipe section 29, that is, avoiding destroying the subsequent combustion stability.

[0067] In an embodiment of the nozzle proposed in this application, both the air injection holes and the fuel injection holes are located outside the nozzle body. Compared with a nozzle in which the air injection holes and the fuel injection holes are located inside, it is convenient for machining, that is, the machining difficulty is small, and the machining accuracy is easy to control. Moreover, the nozzle mixes fuel and air by forming a counter-flow recirculation in the premixing cavity, and its mixing effect is less affected by the positions and sizes of the air injection holes and the fuel injection holes. That is to say, compared with a nozzle based on swirl mixing, the nozzle proposed in the embodiment of this application has lower requirements for the machining accuracy of the air injection holes and the fuel injection holes (for example: hole diameter accuracy, direction accuracy, etc.), that is, the machining cost can be reduced.

[0068] After introducing the nozzle proposed in the embodiment of this application, a combustion chamber proposed in the embodiment of this application will be introduced below. Specifically, the combustion chamber includes a combustion chamber casing 1, a flame tube 3, and a plurality of nozzles 2 proposed in any one of the above embodiments.

[0069] In this embodiment, as Figure 5 shown, the flame tube 3 is arranged inside the combustion chamber casing 1, and an air flow passage (a mature technology, not elaborated) is arranged between the outer wall of the flame tube 3 and the inner wall of the combustion chamber casing 1. Each nozzle 2 shares the same fuel cavity 21 and the same premixing cavity 24. The main combustion stage fuel pipe 4 is arranged in the combustion chamber casing 1, and the main combustion stage fuel pipe 4 is communicated with the fuel cavity 21. During use, fuel 8 is injected into the fuel cavity 21 through the main combustion stage fuel pipe 4, and the fuel 8 located in the fuel cavity 21 can be evenly dispersed into each nozzle 2 through each fuel injection hole 22.

[0070] It should be noted that the operating condition of the gas turbine is positively correlated with the amount of fuel injected into the combustion chamber. That is to say, if the amount of fuel injected into the combustion chamber is more, the operating condition of the gas turbine is higher; if the amount of fuel injected into the combustion chamber is less, the operating condition of the gas turbine is lower. It should be clear that since the gas turbine requires less fuel when in a low operating condition, that is, the content of fuel 8 in the lean premixed gas 10 is less, the gas turbine is extremely prone to flameout or unstable combustion when in a low operating condition; since the gas turbine requires more fuel when in a high operating condition, that is, the content of fuel 8 in the lean premixed gas 10 is more, when the gas turbine is in a high operating condition, if the fuel distribution in the flame tube 3 is uneven, more pollutants (that is, nitrogen oxides) are likely to be generated.

[0071] To solve this technical problem, in an embodiment of this application, the combustion chamber may further include a partition plate 6 and a pilot fuel pipe 5 arranged in the combustion chamber casing 1. As Figure 6As shown, the partition plate 6 is arranged in the fuel cavity 21 and the premixing cavity 24, and the partition plate 6 is used to separate the fuel cavity 21 into the main combustion stage fuel cavity 214 and the duty stage fuel cavity 215, and to separate the premixing cavity 24 into the main combustion stage cavity 244 and the duty stage cavity 245. Among them, the main combustion stage fuel pipe 4 is connected to the main combustion stage fuel cavity 214, and the duty stage fuel pipe 5 is connected to the duty stage fuel cavity 215.

[0072] When using, Figure 6 As shown, the main combustion stage fuel 81 can be injected into the main combustion stage fuel cavity 214 through the main combustion stage fuel pipe 4 to ensure that the main combustion stage fuel 81 can participate in the subsequent combustion through a part of the nozzles 2 (hereinafter referred to as the first nozzle group); the duty class fuel 82 can also be injected into the duty class fuel cavity 215 through the duty class fuel pipe 5 to ensure that the duty class fuel 82 can participate in the subsequent combustion through another part of the nozzles 2 (hereinafter referred to as the second nozzle group). If the gas turbine is in a low operating state, most of the fuel 8 can be used as the duty class fuel 82, so that the content of fuel 8 in the micro premixed gas 10 sprayed by the second nozzle group is higher, thereby avoiding the phenomenon of gas turbine flameout; if the gas turbine is in a high operating state, the fuel 8 can be evenly divided into the main combustion stage fuel 81 and the duty class fuel 82 according to a reasonable proportion, so that the content of fuel 8 in various parts of the flame tube 3 is relatively uniform, thereby reducing the pollutants generated during combustion.

[0073] In the embodiment of the combustion chamber proposed in the present application, the air nozzle and the fuel nozzle in the nozzle are both located outside the nozzle body, which is easier to machine than the nozzle with the air nozzle and the fuel nozzle located inside, that is, the machining difficulty is small and the machining accuracy is easy to control. In addition, the nozzle in the combustion chamber mixes the fuel and air by forming a counter-flow reflux in the premixing cavity, and the mixing effect is less affected by the position and size of the air nozzle and the fuel nozzle. In other words, compared with the nozzle based on swirl mixing, the nozzle proposed in the embodiment of the present application has lower requirements for the machining accuracy of the air nozzle and the fuel nozzle (for example: aperture accuracy, direction accuracy, etc.), that is, it can reduce the machining cost.

[0074] It should be clear that in this application, only the combustion chamber and nozzle applied to a gas turbine are used as an example to illustrate the various embodiments in this application, which does not mean that the combustion chamber or nozzle proposed in this application can only be applied to a gas turbine. It should be understood that the combustion chamber and nozzle proposed in this application can be applied to any suitable application scenario, for example: the combustion chamber and nozzle proposed in this application can be applied to an aircraft engine or an automobile engine, etc.

[0075] Although embodiments of the present application have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A nozzle (2), characterized in that, Comprising: A tubular body; A cavity front baffle (241) and a cavity rear baffle (242) sequentially arranged on the outer wall of the body along a first direction; the first direction is parallel to the axis of the body and points from the front end to the rear end of the body; a premixing cavity (24) is arranged between the cavity front baffle (241) and the cavity rear baffle (242), and the premixing cavity (24) is communicated with the interior of the body; the cavity front baffle (241) is provided with a plurality of fuel injection holes (22), and each fuel injection hole (22) is distributed around the axis of the body; the cavity rear baffle (242) is provided with a plurality of air injection holes (25), and each air injection hole (25) is distributed around the axis of the body.

2. The nozzle (2) according to claim 1, characterized in that, A fuel cavity cover plate (211) is further arranged on the outer wall of the body; the cavity front baffle (241) is located between the fuel cavity cover plate (211) and the cavity rear baffle (242); a fuel cavity (21) is arranged between the fuel cavity cover plate (211) and the cavity front baffle (241).

3. The nozzle (2) according to claim 1, characterized in that, The body comprises an air inlet pipe (23), a premixing pipe section (26) and an outlet pipe section (29) sequentially connected along the first direction; the premixing cavity (24) is located between the air inlet pipe (23) and the premixing pipe section (26).

4. The nozzle (2) according to claim 3, characterized in that, The inner diameter of the outlet pipe section (29) decreases along the first direction.

5. The nozzle (2) according to claim 4, characterized in that, An end face plate (31) is arranged on the outer wall of the outlet pipe section (29); an impact plate (33) is arranged on the outer wall of the premixing pipe section (26); a cooling cavity (32) is arranged between the end face plate (31) and the impact plate (33); the impact plate (33) is provided with impact cooling holes (27); the premixing pipe section (26) is provided with a plurality of air blowing holes (28), each air blowing hole (28) is distributed around the axis of the body, and each air blowing hole (28) is used for communicating the cooling cavity (32) and the interior of the outlet pipe section (29).

6. The nozzle (2) according to claim 5, characterized in that, The included angle between the axis of the outlet pipe section (29) and the axis of the air blowing hole (28) is greater than or equal to 15° and less than or equal to 30°.

7. The nozzle (2) according to any one of claims 1 to 6, characterized in that, The axis line of the body, the axis lines of each fuel injection hole (22), and the axis lines of each air injection hole (25) are all parallel; the included angle between the first line segment and the second line segment is greater than or equal to 0° and less than or equal to 30°; the first line segment is longer than the second line segment; the first line segment is the connecting line segment between the first point and the second point; the second line segment is the connecting line segment between the first point and the third point; the first point is the center point of the projection of the body on the first plane; the first plane is perpendicular to the axis line of the body; the second point is the center point of the projection of any one of the air injection holes (25) on the first plane; the third point is the center point of the projection of the fuel injection hole (22) closest to the air injection hole (25) on the first plane; or, the second point is the center point of the projection of any one of the fuel injection holes (22) on the first plane; the third point is the center point of the projection of the air injection hole (25) closest to the fuel injection hole (22) on the first plane.

8. The nozzle (2) according to claim 7, characterized in that, The diameters of the fuel injection holes (22) and the air injection holes (25) are equal; the lengths of the first line segment and the second line segment satisfy the following calculation formula: where D represents the diameter of the fuel injection hole (22); S1 represents the length value of the first line segment; S2 represents the length value of the second line segment; cos represents the cosine function; B represents the included angle between the first line segment and the second line segment.

9. The nozzle (2) according to any one of claims 1 to 6, characterized in that, A radial swirler (225) is further provided in the premixing cavity (24).

10. A combustion chamber, characterized in that, Including: A combustion chamber casing (1) and a flame tube (3); the flame tube (3) is arranged inside the combustion chamber casing (1), and an air flow passage is arranged between the outer wall of the flame tube (3) and the inner wall of the combustion chamber casing (1); A plurality of nozzles (2) as described in any one of claims 1 to 9; each nozzle (2) shares the same fuel cavity (21) and the same premixing cavity (24); A main combustion stage fuel pipe (4) is arranged on the combustion chamber casing (1), and the main combustion stage fuel pipe (4) is communicated with the fuel cavity (21).

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