Fuel injection device of central staged combustion chamber

Abstract

The present disclosure discloses a fuel injection device of a central staged combustion chamber, which includes an injector body; the injector body is annular; a plurality of nozzles are uniformly arranged on the injector body along the circumferential direction, and a fuel leakage hole is arranged between any two adjacent nozzles; the fuel leakage hole is connected to the two adjacent nozzles. The present disclosure can realize the structural integration and processing of multiple self-excited sweeping fuel nozzles with the dome of the central staged main combustion chamber under the constraint of limited space size, and increase the characteristic throat size by more than 50%.

Description

[0001] This application is a continuation application of PCT application No. PCT / CN2024 / 109836, filed on August 05, 2024, which claims priority to the Chinese patent application filed with the China Patent Office on January 02, 2024, with the application number 202410005657.0 and the title "FUEL INJECTION DEVICE OF CENTRAL STAGED COMBUSTION CHAMBER", the entire contents of which are incorporated into this application by reference.FIELD

[0002] The present disclosure relates to the technical field of aero-engines, and specifically to a fuel injection device of a central staged combustion chamber.BACKGROUND

[0003] Patent US6253782 proposes a fluid oscillator structure without feedback channels, which includes two inlets, one outlet, and one jet coupling cavity. When fluid enters the coupling cavity through the two inlets at a stable flow rate, due to the instability of the jet inside the cavity, after complex internal coupling effects and vortex evolution, the fluid is ejected from the outlet in the form of high-frequency sweeping oscillation. When the working medium is liquid, a sweeping liquid column or a fan-shaped liquid surface can be formed at the outlet. The inventor's related patent application CN113464982A first applied a dual-feedback channel self-excited sweeping liquid injection device to fuel injection in the main combustion chamber of a central staged aero-engine. By using the high-frequency dynamic sweeping effect generated by this device, the spatial dispersion uniformity of fuel in the incoming flow is significantly improved, thereby reducing the emission of pollutants such as NOx and soot, improving the temperature distortion at the outlet of the combustion chamber, and ultimately achieving the goal of enhancing engine performance. However, in practical applications, the structure disclosed in CN113464982A has the following problems.

[0004] The space where the main combustion stage is located is limited, and the space available for arranging the flow channels of the self-excited sweeping nozzles is even more limited, imposing extremely strict constraints on the size of the flow channels of the self-excited sweeping nozzles. The difference between the inner and outer radii of the bottom plate ring where the flow channels of the self-excited sweeping nozzles are arranged is generally not more than 10mm. For example, the inner diameter is generally not less than 40mm, and the outer diameter is generally not more than 60mm. At the same time, 10 to 20 fuel nozzle flow channels need to be formed on this ring. Integrating the complex flow channel structure of the dual-feedback self-excited sweeping fuel nozzles into the compact dome of the main combustion stage of the combustion chamber, while ensuring no interference with the fuel flow path and gas flow path of the pre-combustion stage and the swirling gas flow path of the main combustion stage, maintaining the overall flow structure equivalent to the original structure, and keeping the parameters such as the injection flow number and sweeping frequency of each nozzle consistent, undoubtedly poses a huge challenge to the design of the combustion chamber dome with the coupled self-excited sweeping nozzle structure.

[0005] Taking the structure disclosed in CN113464982A as an example, 12 self-excited sweeping nozzle flow channels are formed on the bottom plate ring, and the width of the ring is only 8mm, that is, the difference between the inner and outer diameters is 16mm. When a dual-feedback self-excited sweeping fuel nozzle is used, the height of the nozzle flow channel itself (from the inlet section to the outlet section) is at least 12 times its throat width. As the minimum size inside the flow channel, the throat width is generally not less than 0.5mm, so its height H is at least greater than 6mm, and generally greater than 7mm. Considering that a fuel leakage hole with a diameter of at least 3 times the throat width needs to be reserved at the inlet, and a 1mm welding contact surface needs to be reserved on the side of the flow channel close to the baffle ring, the width of the ring needs to be greater than 6 + 1.5 + 1 = 8.5mm to arrange a dual-feedback channel self-excited sweeping nozzle flow channel with a characteristic size of 0.5mm.

[0006] In order to highlight the advantages of the self-excited sweeping nozzle, the characteristic size of the inlet throat of the self-excited sweeping nozzle is generally designed to be larger, thereby reducing the number of nozzles on the basis of ensuring the atomization and dispersion effects. Moreover, the larger the size of the flow channel of the self-excited sweeping nozzle, the higher the processing dimensional accuracy, the lower the cost, and the less likely the problem of fuel coking and carbon deposition occurs. In summary, how to significantly increase the throat size without increasing the overall size of the combustion chamber dome structure, changing the position and size of the swirler, and changing the distribution of the fuel injection holes is one of the important problems to be solved urgently in this field.SUMMARY

[0007] The purpose of the present disclosure is to provide a fuel injection device of a central staged combustion chamber to solve the shortcomings in the prior art. It can realize the structural integration and processing of multiple self-excited sweeping fuel nozzles with the dome of the central staged main combustion chamber under the constraint of limited space size, and increase the characteristic throat size by more than 50%.

[0008] The present disclosure provides a fuel injection device of a central staged combustion chamber, which includes an injector body; the injector body is annular; a plurality of nozzles are uniformly arranged on the injector body along the circumferential direction, and a fuel leakage hole is arranged between any two adjacent nozzles; the fuel leakage hole is connected to the two adjacent nozzles.

[0009] For the fuel injection device of the central staged combustion chamber as described above, optionally: the injector body includes a first bottom plate, an injection plate, and a second bottom plate; the first bottom plate, the injection plate, and the second bottom plate are coaxially arranged and fixedly connected in sequence; a fuel channel is arranged on the injection plate, and the first bottom plate and the second bottom plate block the injection plate from both sides to form the nozzle and the fuel leakage hole; an annular installation groove is arranged on the first bottom plate, and the annular installation groove is connected to the fuel leakage hole.

[0010] For the fuel injection device of the central staged combustion chamber as described above, optionally: the first bottom plate and the injection plate are integrally formed, and the fuel leakage hole is directly opposite to the annular installation groove.

[0011] For the fuel injection device of the central staged combustion chamber as described above, optionally: the center of the fuel leakage hole is located on the bisector of the included angle formed by the center lines of two adjacent nozzles, and the diameter of the fuel leakage hole is more than 3 times the throat width of the nozzle.

[0012] For the fuel injection device of the central staged combustion chamber as described above, optionally: the minimum width of the channel connecting the fuel leakage hole and the nozzle is larger than the throat width of the nozzle.

[0013] For the fuel injection device of the central staged combustion chamber as described above, optionally: the nozzle is a self-excited sweeping nozzle without a feedback channel or a self-excited sweeping nozzle with dual feedback channels.

[0014] For the fuel injection device of the central staged combustion chamber as described above, optionally: when the nozzle is a self-excited sweeping nozzle without a feedback channel, the width of the channel connecting the fuel leakage hole and the nozzle gradually decreases in the direction close to the nozzle.

[0015] For the fuel injection device of the central staged combustion chamber as described above, optionally: the throat width of the nozzle is 0.4 to 0.8 mm.

[0016] For the fuel injection device of the central staged combustion chamber as described above, optionally: when the nozzle is a self-excited sweeping nozzle with dual feedback channels, the distance from the inlet of the nozzle to the inner side wall of the fuel channel is more than 1.5 times the throat width of the nozzle.

[0017] For the fuel injection device of the central staged combustion chamber as described above, optionally: the number of the nozzles is 6 to 24.

[0018] Compared with the prior art, the present disclosure can realize the structural integration and processing of multiple self-excited sweeping fuel nozzles with the dome of the central staged main combustion chamber under the constraint of limited space size. By arranging the nozzles and fuel leakage holes at intervals, that is, changing the arrangement of the nozzles and corresponding fuel leakage holes from the radial direction in the prior art to the circumferential interval arrangement, the size of the nozzles can be scaled up proportionally under the same size of the fuel injection device, so that the characteristic throat size is increased by more than 50%. In some preferred solutions, the characteristic throat size can be increased by 75%. The increase in the characteristic throat size can significantly reduce the nozzle processing cost and improve the forming accuracy of the nozzle flow channel.BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a schematic diagram of the installation structure of the injection plate and the first bottom plate proposed by the present disclosure;

[0020] FIG. 2 is a schematic diagram of the structure in FIG. 1 from another perspective;

[0021] FIG. 3 is a cross-sectional view of the injector body proposed by the present disclosure;

[0022] FIG. 4 is a schematic diagram of the nozzle distribution structure proposed in Embodiment 1 of the present disclosure;

[0023] FIG. 5 is a schematic diagram comparing the sizes of the self-excited sweeping nozzle flow channel and the fuel leakage hole between the solution in Embodiment 1 and the prior art under the same size constraint;

[0024] FIG. 6 is a schematic diagram of the fuel flow direction of the fuel leakage hole and the self-excited sweeping nozzle flow channel in Embodiment 1;

[0025] FIG. 7 is a schematic diagram of an injector with a self-excited sweeping nozzle structure without a feedback channel proposed in Embodiment 2;

[0026] FIG. 8 is a diagram of the bottom plate ring flow channel structure using self-excited sweeping nozzles with different sizes of non-feedback structures under the same constraint size;

[0027] FIG. 9 is a comparison of characteristic sizes between the existing coupling scheme and the coupling scheme of this disclosure for self-excited sweeping nozzles;

[0028] FIG. 10 is a schematic diagram of a parameterized self-excited sweeping nozzle structure without a feedback channel proposed in Embodiment 2 of the present disclosure.Explanation of reference signs:

[0029] 1-Injector body, 2-Nozzle, 3-Fuel leakage hole;

[0030] 11-First bottom plate, 12-Injection plate, 13-Second bottom plate;

[0031] 111-Annular installation groove.DETAILED DESCRIPTION

[0032] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and cannot be construed as limiting the present disclosure.Embodiment 1

[0033] Please refer to FIGS. 1 to 6. This embodiment proposes a fuel injection device of a central staged combustion chamber, which includes an injector body 1. The injector body 1 is used to connect to an external fuel channel and inject fuel into the combustion chamber.

[0034] In this embodiment, the injector body 1 is annular. In a specific implementation, the injector body 1 receives fuel from one end face and injects fuel from the outer side face.

[0035] Specifically, a plurality of nozzles 2 are uniformly arranged on the injector body 1 along the circumferential direction, and a fuel leakage hole 3 is arranged between any two adjacent nozzles 2; the fuel leakage hole 3 is connected to the two adjacent nozzles 2. Please refer to FIGS. 5 and 6. On the injector body 1, the nozzles 2 and the fuel leakage holes 3 are arranged at intervals, changing the radial arrangement of the existing nozzles 2 and fuel leakage holes 3 to the circumferential interval arrangement. This saves radial space, allows the nozzles 2 to be scaled up proportionally, and thus increases the characteristic throat size. In a certain type of structure, the throat size of the nozzle 2 can be increased from 0.4mm in the prior art to 0.7mm, increasing the throat size of the nozzle by more than 75%, which can significantly reduce the nozzle processing cost and improve the forming accuracy of the nozzle flow channel. At the same time, the size of the fuel leakage hole 3 can also be increased.

[0036] Changing the position of the fuel leakage hole 3 to between the nozzles 2 also moves the position of the fuel leakage hole 3 outward in the radial direction. The change in the radial position of the fuel leakage hole 3 can also increase the area of the fuel leakage hole 3, which is beneficial to reducing the resistance of the fuel leakage hole 3 itself to the fuel. On the other hand, moving the position of the fuel leakage hole 3 outward in the radial direction can reserve sufficient space on both the inner and outer sides of the fuel leakage hole 3 in the radial direction to connect to the main combustion stage fuel collecting cavity. It can avoid designing a stepped surface in the main combustion stage fuel collecting cavity to adapt to the fuel leakage hole 3, and can facilitate the processing of the main combustion stage fuel collecting cavity.

[0037] In a specific implementation, for the convenience of processing and manufacturing, the injector body 1 includes a first bottom plate 11, an injection plate 12, and a second bottom plate 13. That is, the injector body 1 is made by separately manufacturing the first bottom plate 11, the injection plate 12, and the second bottom plate 13 into corresponding shapes, and then welding them together to form an integral body.

[0038] The first bottom plate 11, the injection plate 12, and the second bottom plate 13 are coaxially arranged and fixedly connected in sequence. A fuel channel is arranged on the injection plate 12, and the first bottom plate 11 and the second bottom plate 13 block the injection plate 12 from both sides to form the nozzle 2 and the fuel leakage hole 3; an annular installation groove 111 is arranged on the first bottom plate 11, and the annular installation groove 111 is connected to the fuel leakage hole 3. Specifically, the first annular installation groove 111 is arranged on the side far away from the injection plate 12, and a through hole is arranged at the bottom of the first annular installation groove 111; a raised baffle ring is arranged on the side of the first bottom plate 11 close to the injection plate 12, and the baffle ring is used to block the fuel channel from the inner side when matching with the injection plate 12. Fuel enters the annular main combustion stage fuel collecting cavity through the main combustion stage fuel inlet pipe, passes through the fuel leakage hole 3 on the first bottom plate 11, and enters the two adjacent nozzles. Due to the restriction of the baffle ring, the fuel can only be injected into the main combustion stage airflow channel through the outlet of the nozzle. The first bottom plate 11 and the baffle ring can be separately processed and formed, then combined and welded for assembly, and then combined and assembled with components such as the fuel collecting cavity. In a specific implementation, the second bottom plate 13 can be a separate annular plate, or the end face of other components. That is, instead of separately processing a second bottom plate 13, the first bottom plate 11 is welded to the injection plate 12, and then connected to the end face of other components to form the injector body.

[0039] The injection plate 12 is processed into a structure with the outline shape of the nozzle and the fuel channel. When welded with the first bottom plate 11 and the second bottom plate 13, the nozzle, the fuel leakage hole, and the channel connecting the nozzle and the fuel leakage hole are formed.

[0040] In specific implementation, the first bottom plate 11 and the injection plate 12 are integrally formed, and the fuel leakage hole 3 is directly opposite to the annular installation groove 111. That is, the fuel leakage hole 3 is directly connected to the annular installation groove 111.

[0041] The circumferential surface with a larger inner diameter in the annular installation groove 111 is used for positioning the outer ring of the fuel collecting cavity, and the circumferential surface with a smaller diameter of the annular installation groove 111 is used for positioning the inner ring of the fuel collecting cavity. In specific implementation, the second bottom plate 13 is located on the leeward side of the injector body 1. This design has the following advantages: first, all sides are flat, the structure is compact, and processing is convenient; second, compared with the convex positioning method, the positioning method through the annular installation groove 111 saves more space and weight; third, after the annular installation groove 111 is positioned and installed with the fuel collecting cavity, it is easier to fix and connect through welding; fourth, the space between the baffle ring of the fuel collecting cavity and the outer ring is directly connected to the fuel leakage hole, so that the fuel entering each fuel leakage hole is more uniform.

[0042] In specific implementation, the center of the fuel leakage hole 3 is located on the bisector of the included angle formed by the center lines of two adjacent nozzles 2. In specific implementation, the plane passing through the center line of the fuel leakage hole 3 and the center line of the injector body 1 is used as the symmetry plane, and the channels on both sides of the fuel leakage hole 3 are symmetrical. After the fuel enters the fuel leakage hole, its flow direction is perpendicular to the plane where the flow channel of the nozzle is located. The fluid will lose dynamic pressure dome during the process of changing its flow direction, so the speed of the fuel in the fuel leakage hole 3 should be reduced as much as possible. Assuming the width of its inlet throat is T, the depth S = T, and the fuel speed corresponding to the required flow rate is U, then the flow rate in the fuel leakage hole is UT2 / 0.785D2, and this part of the kinetic energy will be completely lost. For this reason, the diameter of the fuel leakage hole 3 is larger than 3 times the throat width of the nozzle 2. If D > 3T, the flow loss caused by the fuel leakage hole corresponds to a flow rate less than 1 / 7 of the nozzle throat flow rate, and the pressure loss is less than 1 / 49 of the ideal pressure. At this time, it can be considered that there is no impact. For the traditional self-excited sweeping nozzle, fuel needs to flow in from the lower inlet and then be ejected from the top outlet, so a fuel leakage hole is generally constructed at the inlet. However, by constructing a fuel leakage hole between adjacent nozzles and then entering the inlet part of the nozzle through a diversion channel, not only can the size of the fuel leakage hole be significantly increased, the pressure loss caused by the change of flow direction can be significantly reduced, but also the required space can be significantly saved. Taking the structure disclosed in CN113464982A as an example, under the condition that the diameter of the fuel leakage hole is greater than 4T, just by arranging the fuel leakage hole in the middle, the characteristic size of the nozzle can be increased from 0.4mm to 0.5mm, an increase of 25%. In order to further increase the characteristic size of the nozzle, a self-excited sweeping nozzle without a feedback channel can be further selected. This will be further explained in Embodiment 2. In this embodiment, a dual-feedback channel self-excited sweeping nozzle is used.

[0043] Please refer to FIGS. 5 and 6, in specific implementation, in order to ensure convenient processing and welding, for the plane where the flow channel of the self-excited sweeping nozzle is located, except for the injection outlet position, the distances W1 and W2 from the main flow channel to both sides of the outer ring and inner ring of the nozzle bottom plate must be not less than the throat width T, that is, the radial size of the baffle ring is not less than the throat width. This ensures the processability during processing, assembly, and welding. Preferably, W1 = W2> 1mm.

[0044] In order to reduce the flow loss of fuel, the minimum width of the channel connecting the fuel leakage hole 3 and the nozzle 2 is larger than the throat width of the nozzle 2. Specifically, from the fuel leakage hole to the inlet throat of the nozzle, an arc curve is used to construct the fuel flow path, and the width of the narrowest part of the flow path is H2. The distance from the nozzle inlet to the boundary of the flow path is H1, which must satisfy H2> T and H1> 1.5T. That is, the distance from the inlet of the nozzle 2 to the inner side wall of the fuel channel is more than 1.5 times the throat width of the nozzle 2. Otherwise, the two jets with opposite speeds at this position will converge and then turn 90 degrees, which will inevitably cause a significant increase in flow loss. Under the conditions that H2 is greater than T and H1 is greater than 1.5T, the flow loss at this part corresponds to a flow rate less than 1 / 10 of the nozzle throat flow rate. Preferably, when the nozzle 2 is a self-excited sweeping nozzle 2 without a feedback channel, the width of the channel connecting the fuel leakage hole 3 and the nozzle 2 gradually decreases in the direction close to the nozzle 2. In this embodiment, taking the structure disclosed in CN113464982A as an example, the throat width of the nozzle 2 is 0.5mm.

[0045] The number of the nozzles 2 is 6 to 24. In specific implementation, the number of nozzles 2 is 7, 8, 9, 10, 11, 12, 13, 14, or 15, 16, 17, 18, 19, 20, 21, 22, 23.Embodiment 2

[0046] This embodiment is a further improvement based on Embodiment 1, and the similarities will not be repeated here. Only the differences will be explained below.

[0047] Please refer to FIGS. 7 to 10. This embodiment adopts a self-excited sweeping nozzle structure without a feedback channel. The self-excited sweeping nozzle without a feedback channel includes two inlets, i.e., the two inlets in FIG. 10, one coupling cavity, and one outlet. The mutual interaction of the two jets in the coupling cavity enables self-excited sweeping jet at the outlet. Through a special design, under the same throat width, the main flow channel height H of the non-feedback channel can be reduced by 30% compared with the self-excited sweeping nozzle of the dual-feedback channel configuration, which creates extremely favorable conditions for the integration of the self-excited sweeping nozzle in the dome of the central staged combustion chamber. At the same time, under the same throat width, the operating frequency of the non-feedback channel configuration can be increased by more than 50% under the same inlet and outlet pressure drop. Under a pressure drop of 1MPa, it can reach more than 2kHz, which is far higher than the combustion pulsation frequency in the combustion chamber, and is less likely to cause combustion oscillation.

[0048] In order to significantly increase the throat size without increasing the overall size of the combustion chamber dome structure, changing the position and size of the swirler, and changing the distribution of the fuel injection holes, the nozzle is further designed in this embodiment.

[0049] Please refer to FIG. 10. Specifically, this nozzle is a semicircle with a radius of R0. An expansion angle with an opening angle of α is formed from its center to the inner cavity, and two inlet channels are constructed at the intersection with the outer contour of the semicircle. Taking the edge line of the α expansion angle as the center line, translating it to both sides by J / 2 respectively, an inlet channel with a width of J is constructed. The inlet channel expands outward along the center line by a distance of L1, and the flow channel width is maintained at J1 within the distance of L1. Outside L1, the flow channel can be freely designed according to the position of the fuel leakage hole. The straight edge line of the semicircle is translated downward by H1 to form a new inner cavity boundary of the nozzle. The center line of the nozzle inner cavity is translated to both sides by T / 2 respectively, so that an outlet throat with a width of T can be constructed at the intersection of this lower boundary and the center line. An expansion angle of β is formed outward at the outlet throat, and its height is H2. Chamfering with a radius of R1 is performed at the lower boundary and the translation line. The sizes of the self-excited sweeping nozzle structure without a feedback channel must satisfy: 2 < R0 / T < 8, 0.2 < H1 / T < 4, 0.5 < H2 / T < 3, 0.5 < L1 / T < 2, 60°<α< 150°, (α - β) > 20°, and (R0 + H1 + H2) / T < 10. Under the above size constraints, the self-excited sweeping nozzle without a feedback channel can smoothly generate self-excited sweeping oscillating jet at the outlet, and at the same time, can significantly reduce the nozzle size under the same throat size constraint required by the combustion chamber dome, or significantly increase the nozzle throat size and reduce the number of nozzles under the same flow number and space size constraints.

[0050] Through the above structure, taking the structure disclosed in CN113464982A as an example, the nozzle throat size originally 0.4mm can be increased to 0.7mm. Of course, according to actual needs, it can also be scaled proportionally so that the nozzle throat size is between 0.4 and 0.8mm.

[0051] It should be noted that for the dual-feedback channel self-excited sweeping nozzle, its throat is at the inlet of the nozzle, and for the self-excited sweeping nozzle without a feedback channel, it is at the smallest part of the nozzle outlet.

[0052] It should be noted that the size marks shown in the drawings are for the convenience of reading in combination with the text part of this application, and the values therein only refer to the structure of a certain model, and do not limit the actual size of the scheme proposed in this application.

[0053] The above describes the structure, characteristics, and effects of the present disclosure in detail with reference to the embodiments shown in the drawings. The above are only preferred embodiments of the present disclosure, but the present disclosure is not limited to the implementation scope shown in the drawings. Any changes made according to the concept of the present disclosure, or modified into equivalent embodiments with equivalent changes, still do not exceed the spirit covered by the description and the drawings, and shall all be within the protection scope of the present disclosure.

Examples

embodiment 1

[0033]Please refer to FIGS. 1 to 6. This embodiment proposes a fuel injection device of a central staged combustion chamber, which includes an injector body 1. The injector body 1 is used to connect to an external fuel channel and inject fuel into the combustion chamber.

[0034] In this embodiment, the injector body 1 is annular. In a specific implementation, the injector body 1 receives fuel from one end face and injects fuel from the outer side face.

[0035]Specifically, a plurality of nozzles 2 are uniformly arranged on the injector body 1 along the circumferential direction, and a fuel leakage hole 3 is arranged between any two adjacent nozzles 2; the fuel leakage hole 3 is connected to the two adjacent nozzles 2. Please refer to FIGS. 5 and 6. On the injector body 1, the nozzles 2 and the fuel leakage holes 3 are arranged at intervals, changing the radial arrangement of the existing nozzles 2 and fuel leakage holes 3 to the circumferential interval arrangement. This saves radial sp...

embodiment 2

[0046] This embodiment is a further improvement based on Embodiment 1, and the similarities will not be repeated here. Only the differences will be explained below.

[0047]Please refer to FIGS. 7 to 10. This embodiment adopts a self-excited sweeping nozzle structure without a feedback channel. The self-excited sweeping nozzle without a feedback channel includes two inlets, i.e., the two inlets in FIG. 10, one coupling cavity, and one outlet. The mutual interaction of the two jets in the coupling cavity enables self-excited sweeping jet at the outlet. Through a special design, under the same throat width, the main flow channel height H of the non-feedback channel can be reduced by 30% compared with the self-excited sweeping nozzle of the dual-feedback channel configuration, which creates extremely favorable conditions for the integration of the self-excited sweeping nozzle in the dome of the central staged combustion chamber. At the same time, under the same throat width, the operating...

[0001] This application is a continuation application of PCT application No. PCT / CN2024 / 109836, filed on August 05, 2024, which claims priority to the Chinese patent application filed with the China Patent Office on January 02, 2024, with the application number 202410005657.0 and the title "FUEL INJECTION DEVICE OF CENTRAL STAGED COMBUSTION CHAMBER", the entire contents of which are incorporated into this application by reference.FIELD

[0002] The present disclosure relates to the technical field of aero-engines, and specifically to a fuel injection device of a central staged combustion chamber.BACKGROUND

[0003] Patent US6253782 proposes a fluid oscillator structure without feedback channels, which includes two inlets, one outlet, and one jet coupling cavity. When fluid enters the coupling cavity through the two inlets at a stable flow rate, due to the instability of the jet inside the cavity, after complex internal coupling effects and vortex evolution, the fluid is ejected from the outlet in the form of high-frequency sweeping oscillation. When the working medium is liquid, a sweeping liquid column or a fan-shaped liquid surface can be formed at the outlet. The inventor's related patent application CN113464982A first applied a dual-feedback channel self-excited sweeping liquid injection device to fuel injection in the main combustion chamber of a central staged aero-engine. By using the high-frequency dynamic sweeping effect generated by this device, the spatial dispersion uniformity of fuel in the incoming flow is significantly improved, thereby reducing the emission of pollutants such as NOx and soot, improving the temperature distortion at the outlet of the combustion chamber, and ultimately achieving the goal of enhancing engine performance. However, in practical applications, the structure disclosed in CN113464982A has the following problems.

[0004] The space where the main combustion stage is located is limited, and the space available for arranging the flow channels of the self-excited sweeping nozzles is even more limited, imposing extremely strict constraints on the size of the flow channels of the self-excited sweeping nozzles. The difference between the inner and outer radii of the bottom plate ring where the flow channels of the self-excited sweeping nozzles are arranged is generally not more than 10mm. For example, the inner diameter is generally not less than 40mm, and the outer diameter is generally not more than 60mm. At the same time, 10 to 20 fuel nozzle flow channels need to be formed on this ring. Integrating the complex flow channel structure of the dual-feedback self-excited sweeping fuel nozzles into the compact dome of the main combustion stage of the combustion chamber, while ensuring no interference with the fuel flow path and gas flow path of the pre-combustion stage and the swirling gas flow path of the main combustion stage, maintaining the overall flow structure equivalent to the original structure, and keeping the parameters such as the injection flow number and sweeping frequency of each nozzle consistent, undoubtedly poses a huge challenge to the design of the combustion chamber dome with the coupled self-excited sweeping nozzle structure.

[0005] Taking the structure disclosed in CN113464982A as an example, 12 self-excited sweeping nozzle flow channels are formed on the bottom plate ring, and the width of the ring is only 8mm, that is, the difference between the inner and outer diameters is 16mm. When a dual-feedback self-excited sweeping fuel nozzle is used, the height of the nozzle flow channel itself (from the inlet section to the outlet section) is at least 12 times its throat width. As the minimum size inside the flow channel, the throat width is generally not less than 0.5mm, so its height H is at least greater than 6mm, and generally greater than 7mm. Considering that a fuel leakage hole with a diameter of at least 3 times the throat width needs to be reserved at the inlet, and a 1mm welding contact surface needs to be reserved on the side of the flow channel close to the baffle ring, the width of the ring needs to be greater than 6 + 1.5 + 1 = 8.5mm to arrange a dual-feedback channel self-excited sweeping nozzle flow channel with a characteristic size of 0.5mm.

[0006] In order to highlight the advantages of the self-excited sweeping nozzle, the characteristic size of the inlet throat of the self-excited sweeping nozzle is generally designed to be larger, thereby reducing the number of nozzles on the basis of ensuring the atomization and dispersion effects. Moreover, the larger the size of the flow channel of the self-excited sweeping nozzle, the higher the processing dimensional accuracy, the lower the cost, and the less likely the problem of fuel coking and carbon deposition occurs. In summary, how to significantly increase the throat size without increasing the overall size of the combustion chamber dome structure, changing the position and size of the swirler, and changing the distribution of the fuel injection holes is one of the important problems to be solved urgently in this field.SUMMARY

[0007] The purpose of the present disclosure is to provide a fuel injection device of a central staged combustion chamber to solve the shortcomings in the prior art. It can realize the structural integration and processing of multiple self-excited sweeping fuel nozzles with the dome of the central staged main combustion chamber under the constraint of limited space size, and increase the characteristic throat size by more than 50%.

[0008] The present disclosure provides a fuel injection device of a central staged combustion chamber, which includes an injector body; the injector body is annular; a plurality of nozzles are uniformly arranged on the injector body along the circumferential direction, and a fuel leakage hole is arranged between any two adjacent nozzles; the fuel leakage hole is connected to the two adjacent nozzles.

[0009] For the fuel injection device of the central staged combustion chamber as described above, optionally: the injector body includes a first bottom plate, an injection plate, and a second bottom plate; the first bottom plate, the injection plate, and the second bottom plate are coaxially arranged and fixedly connected in sequence; a fuel channel is arranged on the injection plate, and the first bottom plate and the second bottom plate block the injection plate from both sides to form the nozzle and the fuel leakage hole; an annular installation groove is arranged on the first bottom plate, and the annular installation groove is connected to the fuel leakage hole.

[0010] For the fuel injection device of the central staged combustion chamber as described above, optionally: the first bottom plate and the injection plate are integrally formed, and the fuel leakage hole is directly opposite to the annular installation groove.

[0011] For the fuel injection device of the central staged combustion chamber as described above, optionally: the center of the fuel leakage hole is located on the bisector of the included angle formed by the center lines of two adjacent nozzles, and the diameter of the fuel leakage hole is more than 3 times the throat width of the nozzle.

[0012] For the fuel injection device of the central staged combustion chamber as described above, optionally: the minimum width of the channel connecting the fuel leakage hole and the nozzle is larger than the throat width of the nozzle.

[0013] For the fuel injection device of the central staged combustion chamber as described above, optionally: the nozzle is a self-excited sweeping nozzle without a feedback channel or a self-excited sweeping nozzle with dual feedback channels.

[0014] For the fuel injection device of the central staged combustion chamber as described above, optionally: when the nozzle is a self-excited sweeping nozzle without a feedback channel, the width of the channel connecting the fuel leakage hole and the nozzle gradually decreases in the direction close to the nozzle.

[0015] For the fuel injection device of the central staged combustion chamber as described above, optionally: the throat width of the nozzle is 0.4 to 0.8 mm.

[0016] For the fuel injection device of the central staged combustion chamber as described above, optionally: when the nozzle is a self-excited sweeping nozzle with dual feedback channels, the distance from the inlet of the nozzle to the inner side wall of the fuel channel is more than 1.5 times the throat width of the nozzle.

[0017] For the fuel injection device of the central staged combustion chamber as described above, optionally: the number of the nozzles is 6 to 24.

[0018] Compared with the prior art, the present disclosure can realize the structural integration and processing of multiple self-excited sweeping fuel nozzles with the dome of the central staged main combustion chamber under the constraint of limited space size. By arranging the nozzles and fuel leakage holes at intervals, that is, changing the arrangement of the nozzles and corresponding fuel leakage holes from the radial direction in the prior art to the circumferential interval arrangement, the size of the nozzles can be scaled up proportionally under the same size of the fuel injection device, so that the characteristic throat size is increased by more than 50%. In some preferred solutions, the characteristic throat size can be increased by 75%. The increase in the characteristic throat size can significantly reduce the nozzle processing cost and improve the forming accuracy of the nozzle flow channel.BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a schematic diagram of the installation structure of the injection plate and the first bottom plate proposed by the present disclosure;

[0020] FIG. 2 is a schematic diagram of the structure in FIG. 1 from another perspective;

[0021] FIG. 3 is a cross-sectional view of the injector body proposed by the present disclosure;

[0022] FIG. 4 is a schematic diagram of the nozzle distribution structure proposed in Embodiment 1 of the present disclosure;

[0023] FIG. 5 is a schematic diagram comparing the sizes of the self-excited sweeping nozzle flow channel and the fuel leakage hole between the solution in Embodiment 1 and the prior art under the same size constraint;

[0024] FIG. 6 is a schematic diagram of the fuel flow direction of the fuel leakage hole and the self-excited sweeping nozzle flow channel in Embodiment 1;

[0025] FIG. 7 is a schematic diagram of an injector with a self-excited sweeping nozzle structure without a feedback channel proposed in Embodiment 2;

[0026] FIG. 8 is a diagram of the bottom plate ring flow channel structure using self-excited sweeping nozzles with different sizes of non-feedback structures under the same constraint size;

[0027] FIG. 9 is a comparison of characteristic sizes between the existing coupling scheme and the coupling scheme of this disclosure for self-excited sweeping nozzles;

[0028] FIG. 10 is a schematic diagram of a parameterized self-excited sweeping nozzle structure without a feedback channel proposed in Embodiment 2 of the present disclosure.Explanation of reference signs:

[0029] 1-Injector body, 2-Nozzle, 3-Fuel leakage hole;

[0030] 11-First bottom plate, 12-Injection plate, 13-Second bottom plate;

[0031] 111-Annular installation groove.DETAILED DESCRIPTION

[0032] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and cannot be construed as limiting the present disclosure.Embodiment 1

[0033] Please refer to FIGS. 1 to 6. This embodiment proposes a fuel injection device of a central staged combustion chamber, which includes an injector body 1. The injector body 1 is used to connect to an external fuel channel and inject fuel into the combustion chamber.

[0034] In this embodiment, the injector body 1 is annular. In a specific implementation, the injector body 1 receives fuel from one end face and injects fuel from the outer side face.

[0035] Specifically, a plurality of nozzles 2 are uniformly arranged on the injector body 1 along the circumferential direction, and a fuel leakage hole 3 is arranged between any two adjacent nozzles 2; the fuel leakage hole 3 is connected to the two adjacent nozzles 2. Please refer to FIGS. 5 and 6. On the injector body 1, the nozzles 2 and the fuel leakage holes 3 are arranged at intervals, changing the radial arrangement of the existing nozzles 2 and fuel leakage holes 3 to the circumferential interval arrangement. This saves radial space, allows the nozzles 2 to be scaled up proportionally, and thus increases the characteristic throat size. In a certain type of structure, the throat size of the nozzle 2 can be increased from 0.4mm in the prior art to 0.7mm, increasing the throat size of the nozzle by more than 75%, which can significantly reduce the nozzle processing cost and improve the forming accuracy of the nozzle flow channel. At the same time, the size of the fuel leakage hole 3 can also be increased.

[0036] Changing the position of the fuel leakage hole 3 to between the nozzles 2 also moves the position of the fuel leakage hole 3 outward in the radial direction. The change in the radial position of the fuel leakage hole 3 can also increase the area of the fuel leakage hole 3, which is beneficial to reducing the resistance of the fuel leakage hole 3 itself to the fuel. On the other hand, moving the position of the fuel leakage hole 3 outward in the radial direction can reserve sufficient space on both the inner and outer sides of the fuel leakage hole 3 in the radial direction to connect to the main combustion stage fuel collecting cavity. It can avoid designing a stepped surface in the main combustion stage fuel collecting cavity to adapt to the fuel leakage hole 3, and can facilitate the processing of the main combustion stage fuel collecting cavity.

[0037] In a specific implementation, for the convenience of processing and manufacturing, the injector body 1 includes a first bottom plate 11, an injection plate 12, and a second bottom plate 13. That is, the injector body 1 is made by separately manufacturing the first bottom plate 11, the injection plate 12, and the second bottom plate 13 into corresponding shapes, and then welding them together to form an integral body.

[0038] The first bottom plate 11, the injection plate 12, and the second bottom plate 13 are coaxially arranged and fixedly connected in sequence. A fuel channel is arranged on the injection plate 12, and the first bottom plate 11 and the second bottom plate 13 block the injection plate 12 from both sides to form the nozzle 2 and the fuel leakage hole 3; an annular installation groove 111 is arranged on the first bottom plate 11, and the annular installation groove 111 is connected to the fuel leakage hole 3. Specifically, the first annular installation groove 111 is arranged on the side far away from the injection plate 12, and a through hole is arranged at the bottom of the first annular installation groove 111; a raised baffle ring is arranged on the side of the first bottom plate 11 close to the injection plate 12, and the baffle ring is used to block the fuel channel from the inner side when matching with the injection plate 12. Fuel enters the annular main combustion stage fuel collecting cavity through the main combustion stage fuel inlet pipe, passes through the fuel leakage hole 3 on the first bottom plate 11, and enters the two adjacent nozzles. Due to the restriction of the baffle ring, the fuel can only be injected into the main combustion stage airflow channel through the outlet of the nozzle. The first bottom plate 11 and the baffle ring can be separately processed and formed, then combined and welded for assembly, and then combined and assembled with components such as the fuel collecting cavity. In a specific implementation, the second bottom plate 13 can be a separate annular plate, or the end face of other components. That is, instead of separately processing a second bottom plate 13, the first bottom plate 11 is welded to the injection plate 12, and then connected to the end face of other components to form the injector body.

[0039] The injection plate 12 is processed into a structure with the outline shape of the nozzle and the fuel channel. When welded with the first bottom plate 11 and the second bottom plate 13, the nozzle, the fuel leakage hole, and the channel connecting the nozzle and the fuel leakage hole are formed.

[0040] In specific implementation, the first bottom plate 11 and the injection plate 12 are integrally formed, and the fuel leakage hole 3 is directly opposite to the annular installation groove 111. That is, the fuel leakage hole 3 is directly connected to the annular installation groove 111.

[0041] The circumferential surface with a larger inner diameter in the annular installation groove 111 is used for positioning the outer ring of the fuel collecting cavity, and the circumferential surface with a smaller diameter of the annular installation groove 111 is used for positioning the inner ring of the fuel collecting cavity. In specific implementation, the second bottom plate 13 is located on the leeward side of the injector body 1. This design has the following advantages: first, all sides are flat, the structure is compact, and processing is convenient; second, compared with the convex positioning method, the positioning method through the annular installation groove 111 saves more space and weight; third, after the annular installation groove 111 is positioned and installed with the fuel collecting cavity, it is easier to fix and connect through welding; fourth, the space between the baffle ring of the fuel collecting cavity and the outer ring is directly connected to the fuel leakage hole, so that the fuel entering each fuel leakage hole is more uniform.

[0042] In specific implementation, the center of the fuel leakage hole 3 is located on the bisector of the included angle formed by the center lines of two adjacent nozzles 2. In specific implementation, the plane passing through the center line of the fuel leakage hole 3 and the center line of the injector body 1 is used as the symmetry plane, and the channels on both sides of the fuel leakage hole 3 are symmetrical. After the fuel enters the fuel leakage hole, its flow direction is perpendicular to the plane where the flow channel of the nozzle is located. The fluid will lose dynamic pressure dome during the process of changing its flow direction, so the speed of the fuel in the fuel leakage hole 3 should be reduced as much as possible. Assuming the width of its inlet throat is T, the depth S = T, and the fuel speed corresponding to the required flow rate is U, then the flow rate in the fuel leakage hole is UT2 / 0.785D2, and this part of the kinetic energy will be completely lost. For this reason, the diameter of the fuel leakage hole 3 is larger than 3 times the throat width of the nozzle 2. If D > 3T, the flow loss caused by the fuel leakage hole corresponds to a flow rate less than 1 / 7 of the nozzle throat flow rate, and the pressure loss is less than 1 / 49 of the ideal pressure. At this time, it can be considered that there is no impact. For the traditional self-excited sweeping nozzle, fuel needs to flow in from the lower inlet and then be ejected from the top outlet, so a fuel leakage hole is generally constructed at the inlet. However, by constructing a fuel leakage hole between adjacent nozzles and then entering the inlet part of the nozzle through a diversion channel, not only can the size of the fuel leakage hole be significantly increased, the pressure loss caused by the change of flow direction can be significantly reduced, but also the required space can be significantly saved. Taking the structure disclosed in CN113464982A as an example, under the condition that the diameter of the fuel leakage hole is greater than 4T, just by arranging the fuel leakage hole in the middle, the characteristic size of the nozzle can be increased from 0.4mm to 0.5mm, an increase of 25%. In order to further increase the characteristic size of the nozzle, a self-excited sweeping nozzle without a feedback channel can be further selected. This will be further explained in Embodiment 2. In this embodiment, a dual-feedback channel self-excited sweeping nozzle is used.

[0043] Please refer to FIGS. 5 and 6, in specific implementation, in order to ensure convenient processing and welding, for the plane where the flow channel of the self-excited sweeping nozzle is located, except for the injection outlet position, the distances W1 and W2 from the main flow channel to both sides of the outer ring and inner ring of the nozzle bottom plate must be not less than the throat width T, that is, the radial size of the baffle ring is not less than the throat width. This ensures the processability during processing, assembly, and welding. Preferably, W1 = W2> 1mm.

[0044] In order to reduce the flow loss of fuel, the minimum width of the channel connecting the fuel leakage hole 3 and the nozzle 2 is larger than the throat width of the nozzle 2. Specifically, from the fuel leakage hole to the inlet throat of the nozzle, an arc curve is used to construct the fuel flow path, and the width of the narrowest part of the flow path is H2. The distance from the nozzle inlet to the boundary of the flow path is H1, which must satisfy H2> T and H1> 1.5T. That is, the distance from the inlet of the nozzle 2 to the inner side wall of the fuel channel is more than 1.5 times the throat width of the nozzle 2. Otherwise, the two jets with opposite speeds at this position will converge and then turn 90 degrees, which will inevitably cause a significant increase in flow loss. Under the conditions that H2 is greater than T and H1 is greater than 1.5T, the flow loss at this part corresponds to a flow rate less than 1 / 10 of the nozzle throat flow rate. Preferably, when the nozzle 2 is a self-excited sweeping nozzle 2 without a feedback channel, the width of the channel connecting the fuel leakage hole 3 and the nozzle 2 gradually decreases in the direction close to the nozzle 2. In this embodiment, taking the structure disclosed in CN113464982A as an example, the throat width of the nozzle 2 is 0.5mm.

[0045] The number of the nozzles 2 is 6 to 24. In specific implementation, the number of nozzles 2 is 7, 8, 9, 10, 11, 12, 13, 14, or 15, 16, 17, 18, 19, 20, 21, 22, 23.Embodiment 2

[0046] This embodiment is a further improvement based on Embodiment 1, and the similarities will not be repeated here. Only the differences will be explained below.

[0047] Please refer to FIGS. 7 to 10. This embodiment adopts a self-excited sweeping nozzle structure without a feedback channel. The self-excited sweeping nozzle without a feedback channel includes two inlets, i.e., the two inlets in FIG. 10, one coupling cavity, and one outlet. The mutual interaction of the two jets in the coupling cavity enables self-excited sweeping jet at the outlet. Through a special design, under the same throat width, the main flow channel height H of the non-feedback channel can be reduced by 30% compared with the self-excited sweeping nozzle of the dual-feedback channel configuration, which creates extremely favorable conditions for the integration of the self-excited sweeping nozzle in the dome of the central staged combustion chamber. At the same time, under the same throat width, the operating frequency of the non-feedback channel configuration can be increased by more than 50% under the same inlet and outlet pressure drop. Under a pressure drop of 1MPa, it can reach more than 2kHz, which is far higher than the combustion pulsation frequency in the combustion chamber, and is less likely to cause combustion oscillation.

[0048] In order to significantly increase the throat size without increasing the overall size of the combustion chamber dome structure, changing the position and size of the swirler, and changing the distribution of the fuel injection holes, the nozzle is further designed in this embodiment.

[0049] Please refer to FIG. 10. Specifically, this nozzle is a semicircle with a radius of R0. An expansion angle with an opening angle of α is formed from its center to the inner cavity, and two inlet channels are constructed at the intersection with the outer contour of the semicircle. Taking the edge line of the α expansion angle as the center line, translating it to both sides by J / 2 respectively, an inlet channel with a width of J is constructed. The inlet channel expands outward along the center line by a distance of L1, and the flow channel width is maintained at J1 within the distance of L1. Outside L1, the flow channel can be freely designed according to the position of the fuel leakage hole. The straight edge line of the semicircle is translated downward by H1 to form a new inner cavity boundary of the nozzle. The center line of the nozzle inner cavity is translated to both sides by T / 2 respectively, so that an outlet throat with a width of T can be constructed at the intersection of this lower boundary and the center line. An expansion angle of β is formed outward at the outlet throat, and its height is H2. Chamfering with a radius of R1 is performed at the lower boundary and the translation line. The sizes of the self-excited sweeping nozzle structure without a feedback channel must satisfy: 2 < R0 / T < 8, 0.2 < H1 / T < 4, 0.5 < H2 / T < 3, 0.5 < L1 / T < 2, 60°<α< 150°, (α - β) > 20°, and (R0 + H1 + H2) / T < 10. Under the above size constraints, the self-excited sweeping nozzle without a feedback channel can smoothly generate self-excited sweeping oscillating jet at the outlet, and at the same time, can significantly reduce the nozzle size under the same throat size constraint required by the combustion chamber dome, or significantly increase the nozzle throat size and reduce the number of nozzles under the same flow number and space size constraints.

[0050] Through the above structure, taking the structure disclosed in CN113464982A as an example, the nozzle throat size originally 0.4mm can be increased to 0.7mm. Of course, according to actual needs, it can also be scaled proportionally so that the nozzle throat size is between 0.4 and 0.8mm.

[0051] It should be noted that for the dual-feedback channel self-excited sweeping nozzle, its throat is at the inlet of the nozzle, and for the self-excited sweeping nozzle without a feedback channel, it is at the smallest part of the nozzle outlet.

[0052] It should be noted that the size marks shown in the drawings are for the convenience of reading in combination with the text part of this application, and the values therein only refer to the structure of a certain model, and do not limit the actual size of the scheme proposed in this application.

[0053] The above describes the structure, characteristics, and effects of the present disclosure in detail with reference to the embodiments shown in the drawings. The above are only preferred embodiments of the present disclosure, but the present disclosure is not limited to the implementation scope shown in the drawings. Any changes made according to the concept of the present disclosure, or modified into equivalent embodiments with equivalent changes, still do not exceed the spirit covered by the description and the drawings, and shall all be within the protection scope of the present disclosure.

Examples

embodiment 1

[0033]Please refer to FIGS. 1 to 6. This embodiment proposes a fuel injection device of a central staged combustion chamber, which includes an injector body 1. The injector body 1 is used to connect to an external fuel channel and inject fuel into the combustion chamber.

[0034] In this embodiment, the injector body 1 is annular. In a specific implementation, the injector body 1 receives fuel from one end face and injects fuel from the outer side face.

[0035]Specifically, a plurality of nozzles 2 are uniformly arranged on the injector body 1 along the circumferential direction, and a fuel leakage hole 3 is arranged between any two adjacent nozzles 2; the fuel leakage hole 3 is connected to the two adjacent nozzles 2. Please refer to FIGS. 5 and 6. On the injector body 1, the nozzles 2 and the fuel leakage holes 3 are arranged at intervals, changing the radial arrangement of the existing nozzles 2 and fuel leakage holes 3 to the circumferential interval arrangement. This saves radial sp...

embodiment 2

[0046] This embodiment is a further improvement based on Embodiment 1, and the similarities will not be repeated here. Only the differences will be explained below.

[0047]Please refer to FIGS. 7 to 10. This embodiment adopts a self-excited sweeping nozzle structure without a feedback channel. The self-excited sweeping nozzle without a feedback channel includes two inlets, i.e., the two inlets in FIG. 10, one coupling cavity, and one outlet. The mutual interaction of the two jets in the coupling cavity enables self-excited sweeping jet at the outlet. Through a special design, under the same throat width, the main flow channel height H of the non-feedback channel can be reduced by 30% compared with the self-excited sweeping nozzle of the dual-feedback channel configuration, which creates extremely favorable conditions for the integration of the self-excited sweeping nozzle in the dome of the central staged combustion chamber. At the same time, under the same throat width, the operating...

Claims

1. A fuel injection device of a central staged combustion chamber, comprising: an injector body (1), which is annular;a plurality of nozzles (2), which are uniformly arranged on the injector body (1) along the circumferential direction, and a fuel leakage hole (3), which is arranged between any two adjacent nozzles (2), and the fuel leakage hole (3) is connected to the two adjacent nozzles (2).

2. The fuel injection device of a central staged combustion chamber according to claim 1, wherein the injector body (1) comprises a first bottom plate (11), an injection plate (12), and a second bottom plate (13);the first bottom plate (11), the injection plate (12), and the second bottom plate (13) are coaxially arranged and fixedly connected in sequence;a fuel channel is arranged on the injection plate (12), and the first bottom plate (11) and the second bottom plate (13) block the injection plate (12) from both sides to form the nozzle (2) and the fuel leakage hole (3);an annular installation groove (111) is arranged on the first bottom plate (11), and the annular installation groove (111) is connected to the fuel leakage hole (3).

3. The fuel injection device of a central staged combustion chamber according to claim 2, wherein the first bottom plate (11) and the injection plate (12) are integrally formed, and the fuel leakage hole (3) is directly opposite to the annular installation groove (111).

4. The fuel injection device of a central staged combustion chamber according to claim 3, wherein a center of the fuel leakage hole (3) is located on a bisector of an included angle formed by center lines of two adjacent nozzles (2), and a diameter of the fuel leakage hole (3) is more than 3 times a throat width of the nozzle (2).

5. The fuel injection device of a central staged combustion chamber according to claim 1, wherein a minimum width of a channel connecting the fuel leakage hole (3) and the nozzle (2) is larger than a throat width of the nozzle (2).

6. The fuel injection device of a central staged combustion chamber according to claim 1, wherein the nozzle (2) is a self-excited sweeping nozzle (2) without a feedback channel or a self-excited sweeping nozzle (2) with dual feedback channels.

7. The fuel injection device of a central staged combustion chamber according to claim 6, wherein when the nozzle (2) is a self-excited sweeping nozzle (2) without a feedback channel, a width of a channel connecting the fuel leakage hole (3) and the nozzle (2) gradually decreases in a direction close to the nozzle (2).

8. The fuel injection device of a central staged combustion chamber according to claim 7, wherein a throat width of the nozzle (2) is 0.4 to 0.8 mm.

9. The fuel injection device of a central staged combustion chamber according to claim 6, wherein when the nozzle (2) is a self-excited sweeping nozzle with dual feedback channels, a distance from an inlet of the nozzle (2) to an inner side wall of the fuel channel is more than 1.5 times the throat width of the nozzle (2).

10. The fuel injection device of a central staged combustion chamber according to claim 1, wherein a number of the nozzles (2) is 6 to 24.

11. The fuel injection device of a central staged combustion chamber according to claim 2, wherein a number of the nozzles (2) is 6 to 24.

12. The fuel injection device of a central staged combustion chamber according to claim 3, wherein a number of the nozzles (2) is 6 to 24.

13. The fuel injection device of a central staged combustion chamber according to claim 4, wherein a number of the nozzles (2) is 6 to 24.

14. The fuel injection device of a central staged combustion chamber according to claim 5, wherein a number of the nozzles (2) is 6 to 24.

15. The fuel injection device of a central staged combustion chamber according to claim 6, wherein a number of the nozzles (2) is 6 to 24.

16. The fuel injection device of a central staged combustion chamber according to claim 7, wherein a number of the nozzles (2) is 6 to 24.

17. The fuel injection device of a central staged combustion chamber according to claim 8, wherein a number of the nozzles (2) is 6 to 24.

18. The fuel injection device of a central staged combustion chamber according to claim 9, wherein a number of the nozzles (2) is 6 to 24.

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