A centrally staged combustion chamber based on a self-excited swept oscillating fuel nozzle

Abstract

The present invention provides a centrally staged combustion chamber based on a self-excited sweeping oscillation fuel nozzle, comprising an outer shell having a cavity therein, a main combustion stage coaxially arranged with the outer shell, and a pre-combustion stage coaxially arranged with the outer shell. An annular fuel channel is used to connect multiple self-excited sweeping oscillation fuel nozzles, and the self-excited sweeping oscillation fuel nozzle is suitable for spraying oscillating oil into the primary swirl channel. The fuel is output in a fan shape through the self-excited sweeping oscillation fuel nozzle and is dispersed by the rotating flow through the swirl channel, which can greatly improve the atomization performance and spatial distribution uniformity of the fuel. At the same time, the present invention realizes a compact and miniaturized structural design by also arranging an annular fuel channel inside the main body of the main combustion stage, connecting the fuel channel to the oil pipeline and communicating with the self-excited sweeping oscillation fuel nozzle.

Description

Technical Field

[0001] The invention belongs to the technical field of central staged combustion chamber schemes for aircraft engines, and in particular relates to fuel injection and atomization technology for a main combustion chamber of a gas turbine. Background Art

[0002] The main requirement of the combustion chamber of civil aviation engines is to reduce pollution emissions, and the main requirement of the combustion chamber of military aviation engines is to increase the outlet temperature. The development trend of the combustion organization of both is to adopt a central staged combustion chamber, that is, the center of each head of the combustion chamber is the pre-combustion stage flame, and the surrounding is the main combustion stage flame, such as Figure 1 As shown. The pre-combustion stage generally includes a centrifugal pressure nozzle, one or a pair of radial swirlers. The swirler is used to improve the atomization performance of the fuel and form a non-premixed flame. The pre-combustion stage is mainly used to stabilize the flame under various engine operating conditions. The main combustion stage contains an axial swirler and a series of circumferentially evenly distributed direct fuel injection holes. The fuel of the main combustion stage is mixed with the swirling air in an annular channel to complete the process of premixing and preevaporation, and then forms the main combustion stage flame after entering the flame tube.

[0003] The main pollutants of aircraft engines include: nitrogen oxides (NOx), carbon monoxide (CO), unburned hydrocarbons (UHC) and smoke, among which the main consideration is to reduce nitrogen oxide emissions. Nitrogen oxides (NOx) are mainly controlled by thermal mechanisms. Excessive temperature in the combustion zone will cause a sharp increase in NOx emissions. Therefore, the key to the design of a low-emission combustion chamber is to reduce the equivalence ratio of the head combustion zone, while improving the uniformity of the oil-gas mixture and avoiding the occurrence of local high-temperature areas. In summary, one of the core technologies of modern low-emission combustion chambers is fast and uniform fuel mixing, thereby providing a more uniform oil-gas mixture for the flame tube.

[0004] For military high temperature rise combustors, the biggest technical challenge is to improve the uniformity of the combustor outlet temperature distribution to reduce the impact of high temperature gas on turbine blades and increase engine life. To improve the uniformity of outlet temperature distribution and reduce local high temperature areas, it is also necessary to improve the uniformity of the main combustion stage oil and gas mixing.

[0005] Therefore, the mixing of the main combustion stage fuel is the key to determining the combustion chamber emission and outlet temperature distribution. Several well-known aircraft engine combustion chambers currently available basically use simple circular hole direct injection nozzles, which mainly use the shearing effect of the direct injection liquid column generated by the circular hole nozzle and the lateral airflow to break up the fuel into atomized form, such as using wall radial injection plus auxiliary air flow, wall radial injection plus pre-film plate and pre-film injection. Pre-film injection has the problem of complex structure and difficulty in implementation on large nozzles. In the first two wall radial injection schemes, the penetration depth of the fuel is controlled by the momentum ratio. Under large working conditions, the penetration depth is large, and the mixing of the fuel and the main combustion stage swirl is more intense, but the radial distribution uniformity is still not good enough; but under small working conditions, the fuel flow is small and the momentum ratio is low, which often leads to insufficient penetration depth, affecting fuel mixing; in addition, part of the fuel is easy to adhere to the inner wall of the channel, causing coking or spontaneous combustion and backfire. Therefore, the existing fuel injections currently mainly use simple circular hole direct injection nozzles, and there is still a lot of room for improvement in the mixing uniformity of the fuel. Summary of the invention

[0006] In order to solve at least one of the above technical problems, the present invention provides a central staged combustion chamber based on a self-excited swept oscillation fuel nozzle, in which the fan-shaped nozzles in a circle of the main combustion stage are designed with different flow rates, different oil mist angles or different sweep frequencies, etc., so as to achieve a better fuel mixing effect and suppress combustion instability. The purpose of the present invention is achieved by the following scheme:

[0007] On the one hand, the present invention provides a centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle, comprising: an outer shell having a cavity inside, a main combustion stage coaxially arranged with the outer shell, and a pre-combustion stage coaxially arranged with the outer shell; the main combustion stage is arranged inside the outer shell, a main combustion stage swirler is arranged between the main body of the main combustion stage and the inner wall surface of the outer shell, and a primary swirl channel is formed, and an annular fuel channel is also arranged inside the main body of the main combustion stage, and the fuel channel is suitable for being connected to an oil pipeline; a plurality of self-excited swept oscillation fuel nozzles connected to the fuel channel are arranged on the main body in the direction opposite to the incoming flow, and the self-excited swept oscillation fuel nozzles are suitable for spraying oscillating oil into the primary swirl channel; the pre-combustion stage comprises one or two groups of swirlers that can cause the incoming flow passing through the pre-combustion stage to rotate.

[0008] Furthermore, the pre-combustion stage includes a secondary swirler and a central swirler, and the secondary swirler and the central swirler form two swirling flows with opposite rotation directions from the incoming flow passing through the pre-combustion stage.

[0009] Furthermore, the self-excited swept oscillation fuel nozzle includes a contraction port, an oscillation cavity and a nozzle; the contraction port is connected to the fuel channel through an oil guide hole, the fuel enters the self-excited swept oscillation fuel nozzle from the oil guide hole, and after passing through the contraction port, the fuel is accelerated to enter the oscillation cavity, the contraction port is connected to one end of the oscillation cavity, and the nozzle is connected to the other end of the oscillation cavity; in the oscillation cavity, two partition bodies are symmetrically arranged with the line connecting the center points of the contraction port and the nozzle as the symmetry axis, and the two partition bodies divide the oscillation cavity into a fuel oscillation part located in the middle and two fuel reflux parts distributed on both sides.

[0010] Furthermore, the main combustion stage includes an outer interstage section and an inner interstage section; the outer interstage section includes a circular shell, the main combustion stage swirler arranged on the outer side surface of the circular shell, and an oil guide flange arranged at one end of the circular shell and extending toward the axis of the circular shell; the oil guide flange is provided with a plurality of the self-excited sweeping oscillation fuel nozzles away from the direction of the incoming flow, and the oil guide flange is also provided with a plurality of oil guide holes corresponding to the self-excited sweeping oscillation fuel nozzles; the maximum outer diameter of the inner interstage section is smaller than the inner diameter of the circular shell, and the end of the inner interstage section is suitable for abutting against the oil guide flange, thereby forming the annular fuel channel that passes through the plurality of the oil guide holes.

[0011] Furthermore, the self-excited swept oscillation fuel nozzle is a groove arranged on the surface of the oil guide flange away from the incoming flow direction, and the pre-combustion stage is provided with a circular first shielding member, which is suitable for closing the opening of the groove away from the incoming flow direction.

[0012] Further, the pre-combustion stage includes a pre-combustion stage fuel injection device, which includes a pre-combustion stage fuel nozzle, a central swirler, and a fuel nozzle mounting ring for connecting the pre-combustion stage fuel nozzle to the middle of the central swirler.

[0013] Further, the pre-combustion stage includes a front end swirl portion, which includes the first shielding member, a boss located on the surface of the first shielding member and facing the incoming flow direction, and a secondary swirler located on the surface of the boss facing the incoming flow direction.

[0014] Furthermore, the pre-combustion stage fuel injection device comprises a positioning surface for abutting against the secondary swirler, and the central swirler is arranged on a side of the positioning surface away from the secondary swirler.

[0015] Furthermore, the secondary swirler and the central swirler are in the shape of oblique teeth, and the secondary swirler and the central swirler guide the flow toward the axis of the central staged combustion chamber.

[0016] Furthermore, it also includes a second shielding member for closing the annular opening of the fuel channel facing the incoming flow direction; the second shielding member is provided with a groove suitable for connecting with the oil pipeline, and the oil in the oil pipeline is suitable for entering the fuel channel through the groove.

[0017] Furthermore, it also includes an oil delivery pipe connected to the fuel channel of the main combustion stage through a joint.

[0018] Compared with the prior art, the advantages of the present invention are: the present invention provides a central staged combustion chamber based on a self-excited sweeping oscillation fuel nozzle, comprising an outer shell having a cavity inside, a main combustion stage coaxially arranged with the outer shell, and a pre-combustion stage coaxially arranged with the outer shell. A plurality of self-excited sweeping oscillation fuel nozzles are connected by an annular fuel channel, and the self-excited sweeping oscillation fuel nozzle is suitable for spraying oscillating oil into the primary swirl channel. The fuel is output in a fan shape through the self-excited sweeping oscillation fuel nozzle and is dispersed by the rotating flow through the swirl channel, which can greatly improve the atomization performance and spatial distribution uniformity of the fuel. At the same time, since the self-excited sweeping oscillation fuel nozzle suitable for outputting oscillating oil needs to have a relatively complex cavity structure, the use of the original oil circuit will inevitably increase the structural complexity of the central staged combustion chamber. Therefore, the present invention realizes a compact and miniaturized structural design by further arranging an annular fuel channel inside the main body of the main combustion stage, connecting the fuel channel with the oil pipeline and communicating with the self-excited sweeping oscillation fuel nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0020] Figure 1 This is a schematic diagram of a conventional center staged combustion chamber;

[0021] Figure 2 The central staged combustion chamber based on the self-excited swept oscillation fuel nozzle of the present invention;

[0022] Figure 3 for Figure 2 Schematic diagram of explosion in the center staged combustion chamber;

[0023] Figure 4 for Figure 2 Cross-section of the central staged combustion chamber along the symmetry plane;

[0024] Figure 5 for Figure 4 The enlarged schematic diagram of point A in the middle;

[0025] Figure 6 for Figure 3Detailed schematic diagram of the swirl section at the middle and front end;

[0026] Figure 7 for Figure 3 Detailed schematic diagram of the middle and outer interstage sections;

[0027] Figure 8 for Figure 7 Front view of the outer interstage section;

[0028] Fig. 9 for Figure 8 The enlarged schematic diagram of point B in the middle;

[0029] Fig.10 (a) Schematic diagram of fuel injection by a straight-injection nozzle; (b) Schematic diagram of fuel injection by a self-excited sweeping oscillation fuel nozzle;

[0030] Fig.11 for Figure 3 Detailed schematic diagram of the mid-pre-combustion stage fuel injection device;

[0031] Fig.12 For air flow Figure 2 Schematic diagram of a centrally staged combustion chamber.

[0032] Among them, 1. oil pipeline; 2. outer shell; 3. front end swirl part; 31. first shielding member; 32. boss; 33. secondary swirler; 4. outer interstage section; 41. circular shell; 42. main combustion stage swirler; 43. oil guide flange; 44. oil guide hole; 45. self-excited swept oscillation fuel nozzle; 451. contraction port; 452. oscillation cavity; 453. nozzle; 454. partition body; 455. fuel reflux part; 5. inner interstage section; 6. pre-combustion stage fuel injection device; 61. pre-combustion stage fuel nozzle; 62. positioning surface; 63. central swirler; 64. guide body; 65. fuel nozzle mounting ring; 7. second shielding member; 81. fuel channel; 91. first incoming flow; 92. second incoming flow; 93. third incoming flow. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and implementations. It is to be understood that the specific implementations described herein are only used to explain the relevant content, rather than to limit the present invention. It is also necessary to explain that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings.

[0034] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] See the instruction manual Figure 2-3The present invention provides a central staged combustion chamber based on a self-excited sweeping oscillation fuel nozzle 45. From a functional point of view, the central staged combustion chamber mainly includes a fuel delivery pipe 1, an outer shell 2, a main combustion stage and a pre-combustion stage. From a structural point of view, the main combustion stage includes an outer interstage section 4, an inner interstage section 5 and a second shielding member 7, and the pre-combustion stage includes a front swirl section 3 and a pre-combustion stage fuel injection device 6. Figure 3 It can be seen that the outer shell 2, the front swirl portion 3, the outer interstage section 4, the inner interstage section 5, the pre-combustion stage fuel injection device 6 and the second shielding member 7 are nested or connected in sequence to form Figure 2 The central staged combustion chamber in the.

[0036] First, the present invention is described from the perspective of functional division. Figure 4 The outer shell 2 is sleeve-shaped and has a through cavity inside. Preferably, the outer shell 2 is rotationally symmetrical about the central axis. The diameter of the outer shell 2 in the direction facing the incoming flow is larger than the diameter in the direction away from the incoming flow, so that the outer shell 2 can increase the flow velocity of the incoming flow to a certain extent.

[0037] The main combustion stage and the pre-combustion stage are coaxial with the outer shell 2, that is, coaxial with the central axis. The diameter of the main body of the main combustion stage is smaller than the inner diameter of the outer shell 2, so that a primary swirl channel is defined between the surface of the main body of the main combustion stage and the inner wall of the outer shell 2. The main combustion stage also includes a main combustion stage swirler 42 suitable for being arranged in the primary swirl channel. See the attached Fig.12 After the first incoming flow 91 passes through the main combustion stage swirler 42, it will generate a rotation along the first direction.

[0038] See attached Figure 5 , an annular fuel channel 81 is also provided inside the main body of the main combustion stage. Specifically, the inner wall and the outer wall of the main body are arranged at intervals to form a sandwich structure, and the space in the middle is the fuel channel 81. A plurality of self-excited sweeping oscillation fuel nozzles 45 are provided on the side of the main body facing away from the incoming flow. Preferably, the plurality of self-excited sweeping oscillation fuel nozzles 45 are evenly arranged along the circumference of the axis. One end of the fuel channel 81 should be connected to the oil pipeline 1, and the other end should be connected to the plurality of self-excited sweeping oscillation fuel nozzles 45. Therefore, after the oil in the oil pipeline 1 enters the fuel channel 81, it quickly spreads along the annular fuel channel 81 to fill the entire channel, and evenly enters the self-excited sweeping oscillation fuel nozzle 45 from the connection between the fuel channel 81 and the self-excited sweeping oscillation fuel nozzle 45.

[0039] The self-excited swept oscillating fuel nozzle 45 is suitable for spraying oscillating oil into the primary swirl channel. The high-speed swirl generated at the rear of the main combustion stage swirler 42 can quickly disperse the oil after encountering the fan-shaped oil generated by the self-excited swept oscillating fuel nozzle 45. In order to further mix the oil and gas, the pre-combustion stage usually also includes a swirler that rotates the incoming flow. Thereby, the oil and the incoming gas can be further mixed.

[0040] See attached Fig.12 The pre-combustion stage includes a secondary swirler 33 and a central swirler 63. The second incoming flow 92 will generate a second direction of rotation after entering the secondary swirler 33; the third incoming flow 93 will generate a third direction of rotation after entering the central swirler 63. When the second direction and the third direction are opposite, the air can be further mixed with the pre-combustion stage oil.

[0041] See attached Fig. 9 The self-excited swept oscillation fuel nozzle 45 includes a contraction port 451, an oscillation cavity 452 and a nozzle 453; the contraction port 451 is connected to the fuel channel 81 through an oil guide hole 44, the fuel enters the self-excited swept oscillation fuel nozzle 45 from the oil guide hole 44, and after passing through the contraction port 451, the fuel is accelerated to enter the oscillation cavity 452, the contraction port 451 is connected to one end of the oscillation cavity 452, and the nozzle 453 is connected to the other end of the oscillation cavity 452.

[0042] The oscillation cavity 452 has two partitions 454 symmetrically arranged with the line connecting the center points of the contraction port 451 and the nozzle 453 as the axis of symmetry. The two partitions 454 divide the oscillation cavity 452 into a gas oscillation portion in the middle and two fuel return portions 455 distributed on both sides. The fuel return portions 455 form a feedback channel. The partition 454 is in an "L" shape, and the two right-angled sides of the partition 454 and the two side walls of the oscillation cavity 452 form the fuel return portion 455. The bottom side of the "L" shape is close to the contraction port 451. When the fuel passes through the partition 454, it diffuses toward the vertical side of the partition 454 and forms a vortex. The vortices on both sides are difficult to be completely equal, so there must be a vortex with stronger rotation, which causes the main fuel to deflect to the side of the vortex with stronger rotation, and further strengthens the strength of the vortex on this side, while weakening the vortex strength on the other side. At the same time, since the main fuel flows close to one side, the pressure at the outlet of the fuel return section 455 close to this side is relatively low. When the main fuel passes through the inlet of the fuel return section 455, due to the effect of the pressure difference, more oil will flow from the fuel return section 455 on this side to the return section outlet, and compensate for the pressure there, pushing the mainstream there to leave the vortex on this side. When the main fuel deflects to the other side at a larger angle, the vortex on the other side will have an advantage in rotation intensity, causing the main fuel to be quickly attracted to the other side. Repeating the above process, a high-frequency oscillating jet is output at the nozzle 453.

[0043] The nozzle 453 is connected to the oscillation cavity 452 through a throat hole. Specifically, the setting of the throat hole can shrink the fluid diffused in the first oscillation cavity. Since the main fluid has already swung in the oscillation cavity 452, the jet ejected from the throat hole will continue the direction of the main fluid in the oscillation cavity 452. The outer end of the nozzle 453 is larger than the connection end with the throat hole, specifically forming a trumpet-shaped opening. Consistent with the nozzle 453, the trumpet-shaped opening can increase the space for airflow swing.

[0044] Generally, the degree of uniformity of the mixture of fuel and air will determine the degree of sufficiency and quality of combustion. The self-excited sweeping oscillation fuel nozzle 45 can spread the fuel in a larger space and mix it evenly with the air under the action of high-speed lateral airflow, thereby effectively improving the combustion efficiency. The use of direct fuel atomization leads to low fuel injection efficiency (attached Fig.10 a), while the swing fuel injection method usually requires the introduction of a mechanical control structure or an electromagnetic control mechanism, which increases the complexity of the engine. The present invention creatively introduces a self-excited sweep oscillation fuel nozzle 45, which generates a high-frequency sweep oscillation oil output (attached) by using a self-excited oscillation cavity under the injection of high-pressure oil. Fig.10 b) without adding mechanical motion structure or electromagnetic structure.

[0045] See attached Figure 3 In order to facilitate machining and assembly, the main combustion stage includes an outer interstage section 4, an inner interstage section 5 and a second shielding member 7, and the center stage includes a front end swirl portion 3 and a pre-combustion stage fuel injection device 6.

[0046] See attached Figure 7-8 , the outer stage section 4 includes a circular shell 41, the main combustion stage swirler 42 arranged on the outer side of the circular shell 41, and an oil guide flange 43 arranged at one end of the circular shell 41 and extending toward the axis of the circular shell 41. Since the above structure is relatively simple, the structural component can be obtained directly by casting and machining. At the same time, in the direction in which the oil guide flange 43 deviates from the incoming flow, the self-excited sweeping oscillation fuel nozzle 45 can be directly processed on the surface according to the shape by milling, and the self-excited sweeping oscillation fuel nozzle 45 is presented as a groove. And oil guide holes 44 corresponding to the number of the self-excited sweeping oscillation fuel nozzles 45 are opened at the end of the self-excited sweeping oscillation fuel nozzle 45 by a drilling machine.

[0047] See attached Figure 3 The purpose of the inner interstage section 5 is to form the inner wall surface of the main combustion stage. It does not need other auxiliary functional structures, so it has a regular, cylindrical main structure. The maximum outer diameter of the inner interstage section 5 is smaller than the inner diameter of the circular shell 41, and the end of the inner interstage section 5 is suitable for abutting against the oil guide flange 43, thereby forming a circular ring-shaped fuel channel 81 that penetrates the plurality of oil guide holes 44.

[0048] Furthermore, the length direction of the self-excited swept oscillation fuel nozzle 45 is distributed along the radial direction of the oil guide flange 43, and the oil guide hole 44 needs to be arranged at the end of the self-excited swept oscillation fuel nozzle 45. In order to ensure the rapid distribution of the oil, the diameter of the main part of the inner interstage section 5 is larger than the diameter of the contact part of the inner interstage section 5 and the oil guide flange 43, forming a step shape.

[0049] See attached Figure 6 The front end swirl portion 3 includes the first shielding member 31, a boss 32 located on the surface of the first shielding member 31 and facing the incoming flow direction, and a secondary swirler 33 located on the surface of the boss 32 facing the incoming flow direction. Figure 5 The first shielding member 31 is suitable for closing the opening of the groove away from the incoming flow direction, so that the oil can only enter the self-excited sweeping oscillation fuel nozzle 45 through the oil guide hole 44 and be sprayed out from the nozzle 453 of the self-excited sweeping oscillation fuel nozzle 45.

[0050] It is worth noting that the first shielding member 31, the boss 32 and the secondary cyclone 33 are all circular channels. The middle part is free of air to facilitate the smooth passage of the airflow of the secondary cyclone 33 and the central cyclone 63. The secondary cyclone 33 is processed by a milling machine to form a helical tooth structure, thereby achieving the guidance of the airflow rotation direction.

[0051] See attached Fig.11 , a pre-combustion stage fuel injection device 6, the pre-combustion stage fuel injection device 6 includes a positioning surface 62 for abutting against the secondary swirler 33, a central swirler 63 arranged on the side of the positioning surface 62 away from the secondary swirler 33, a pre-combustion stage fuel nozzle 61 located on the side of the central swirler 63 facing the incoming flow direction, and a guide body 64. Specifically, the pre-combustion stage fuel nozzle 61 is connected to the central swirler 63 through a fuel nozzle mounting ring 65. The pre-combustion stage fuel nozzle 61 is connected to another oil pipeline in the direction facing the incoming flow, and the oil is sprayed toward the middle of the central swirler 63 through the middle through hole of the pre-combustion stage fuel nozzle 61. The oil sprayed by the pre-combustion stage fuel nozzle 61 will be fully dispersed and mixed when it encounters the rotating airflow output by the central swirler.

[0052] The central swirler 63 and the guide body 64 are respectively located on the two side surfaces of the positioning surface 62. The central swirler 63, the positioning surface 62 and the guide body 64 are all annular structures. The helical tooth structure on the central swirler 63 is obtained by milling. After the incoming flow passes through the central swirler 63, it converges to the center of the central swirler 63 and flows to the end of the central staged combustion chamber through the guide. The guide body 64 can separate the rotating airflow generated by the secondary swirler 33 and the central swirler 63 first. After the two rotating airflows rotate stably, they collide and mix together, and the mixing degree of oil and air is further improved.

[0053] See attached Figure 3 The second shielding member 7 is provided with a notch suitable for connecting with the oil delivery pipe 1, and the oil in the oil delivery pipe 1 is suitable for entering the fuel channel 81 through the notch. The oil delivery pipe 1 is connected to the fuel channel 81 of the main combustion stage through a joint.

[0054] The fuel of the present invention is output in a fan shape through the self-excited sweeping oscillating fuel nozzle 45, and is dispersed by the rotating flow passing through the swirl channel, which can greatly improve the atomization performance and spatial distribution uniformity of the fuel. At the same time, since the self-excited sweeping oscillating fuel nozzle 45 suitable for outputting oscillating oil needs to have a more complex cavity structure, the use of the original oil circuit will inevitably increase the structural complexity of the central staged combustion chamber. From the perspective of processing and manufacturing, the present invention decomposes the components of the central staged combustion chamber into several easy-to-process modules, realizes the connection between the fuel channel 81 and the oil pipeline 1 and the self-excited sweeping oscillating fuel nozzle 45, and does not increase the complexity of the system. Compared with the existing central staged combustion chamber, the central staged combustion chamber of the present invention also has the characteristics of compact structure and miniaturization.

[0055] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, unless they are contradictory.

[0056] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0057] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle, characterized in that: It comprises: an outer shell having a cavity inside, a main combustion stage coaxially arranged with the outer shell, and a pre-combustion stage coaxially arranged with the outer shell; The main combustion stage is arranged inside the outer shell, a main combustion stage swirler is arranged between the main combustion stage body and the inner wall surface of the outer shell, and a primary swirl channel is formed, and an annular fuel channel is also arranged inside the main combustion stage body, and the fuel channel is suitable for connecting with the oil pipeline; the main body is provided with a plurality of self-excited sweeping oscillating fuel nozzles connected with the fuel channel in the direction opposite to the incoming flow, and the self-excited sweeping oscillating fuel nozzles are suitable for spraying oscillating oil into the primary swirl channel; The main combustion stage includes an outer interstage section and an inner interstage section; The outer stage section comprises a circular shell, and an oil guide flange provided at one end of the circular shell and extending toward the axis of the circular shell; the oil guide flange is provided with a plurality of the self-excited sweeping oscillation fuel nozzles in a direction away from the incoming flow, and the oil guide flange is also provided with a plurality of oil guide holes corresponding to the self-excited sweeping oscillation fuel nozzles; The maximum outer diameter of the inner interstage section is smaller than the inner diameter of the circular shell, and the end of the inner interstage section is suitable for abutting against the oil guide flange, thereby forming the annular fuel channel that is connected to the plurality of oil guide holes; The self-excited sweeping oscillation fuel nozzle comprises a contraction port, an oscillation cavity and a nozzle; The contraction port is connected to the fuel channel through an oil guide hole, the fuel enters the self-excited sweep oscillation fuel nozzle from the oil guide hole, and after passing through the contraction port, the fuel is accelerated to enter the oscillation cavity, the contraction port is connected to one end of the oscillation cavity, and the nozzle is connected to the other end of the oscillation cavity; The oscillation cavity is symmetrically provided with two partitions with the line connecting the central points of the contraction port and the nozzle as the symmetry axis, and the two partitions divide the oscillation cavity into a fuel oscillation part located in the middle and two fuel return parts distributed on both sides; the nozzle is connected to the oscillation cavity through a throat hole, the outer end of the nozzle is larger than the connection end with the throat hole, and forms a trumpet-shaped opening, so as to output a high-frequency oscillating jet at the nozzle and form a fan-shaped oil liquid; The self-excited sweep oscillation fuel nozzle is a groove arranged on the surface of the oil guide flange away from the incoming flow direction, and the pre-combustion stage is provided with a circular ring-shaped first shielding member, which is suitable for closing the opening of the groove away from the incoming flow direction; The main combustion stage also includes a second shielding member for closing the annular opening of the fuel channel facing the incoming flow direction; the second shielding member is provided with a groove suitable for connecting to the oil pipeline, and the oil in the oil pipeline is suitable for entering the fuel channel through the groove.

2. A centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle as claimed in claim 1, characterized in that: The pre-combustion stage comprises one or two sets of swirlers capable of imparting rotation to the incoming flow through the pre-combustion stage.

3. A centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle as claimed in claim 2, characterized in that: The pre-combustion stage includes a secondary swirler and a central swirler, and the secondary swirler and the central swirler form two swirling flows with opposite rotation directions from the incoming flow passing through the pre-combustion stage.

4. A centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle as claimed in any one of claims 1 to 3, characterized in that: The outer inter-stage section includes the main combustion stage swirler disposed on the outer side surface of the circular shell.

5. A centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle as claimed in claim 4, characterized in that: The pre-combustion stage includes a pre-combustion stage fuel injection device, which includes a pre-combustion stage fuel nozzle, a central swirler, and a fuel nozzle mounting ring for connecting the pre-combustion stage fuel nozzle to the middle of the central swirler.

6. A centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle as claimed in claim 5, characterized in that: The pre-combustion stage includes a front end swirl portion, which includes the first shielding member, a boss located on the surface of the first shielding member and facing the incoming flow direction, and a secondary swirler located on the surface of the boss facing the incoming flow direction.

7. A centrally staged combustion chamber based on a self-excited swept oscillation fuel nozzle as claimed in claim 6, characterized in that: The pre-combustion stage fuel injection device comprises a positioning surface for abutting against the secondary swirler, The central cyclone is arranged on a side of the positioning surface away from the secondary cyclone.

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