Double-working-mode combustion chamber adapting to slow combustion and rotating detonation
By designing a dual-mode combustion chamber that adapts to slow combustion and rotating detonation, and adopting a coaxial double-layer casing structure and a swirler oil supply structure, stable combustion in the combustion chamber under different air intake volumes is achieved, solving the problems of the performance limit of the traditional combustion chamber and the increased weight of the rotating detonation combustion chamber, and achieving a high-efficiency, low-emission combustion effect.
Patent Information
- Application Number
- CN202510970637.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-15
- Publication Date
- 2025-10-14
AI Technical Summary
The combustion chamber performance of traditional aviation turbine-based engines has reached its theoretical limit. When the rotating detonation combustion chamber is used as the main combustion chamber, it increases the weight of the engine and cannot adapt to complex working conditions. There is a lack of the concept of a combustion chamber that combines slow combustion and rotating detonation.
A dual-mode combustion chamber adapted to slow combustion and rotating detonation is designed, including an air intake structure, a concave cavity section, a Laval nozzle section, an annular combustion chamber section and a turbine structure. A coaxial double-layer casing structure is adopted, and the switching of the two working modes is achieved through a swirler and a fuel supply structure, and combustion is organized by combining subsonic and transonic flow states.
It achieves stable combustion in the combustion chamber under different intake volumes, combines high thermodynamic efficiency with low NOx emissions, expands the working range of the combustion chamber, and reduces engine weight and length.
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Figure CN120777590A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of combustion technology, in particular to a dual working mode combustion chamber suitable for slow combustion and rotating detonation. BACKGROUND
[0002] The combustion chamber, as the core component of the propulsion machinery, has the ability to convert chemical energy into heat energy, and is the basic condition for providing power by using heat energy. Therefore, the performance level of the combustion chamber directly determines the performance of the propulsion machinery.
[0003] Combustion is very important in the thermodynamic cycle realized by the propulsion machinery. The chemical energy of the fuel is first converted into the heat energy of the working medium through chemical reaction, and then the heat energy is converted into the kinetic energy of the working medium through the expansion process of the thermodynamic cycle. The combustion process mainly has two forms: slow combustion and detonation. The present combustion chamber is formed by combining these two basic combustion forms.
[0004] Traditional aviation turbine-based engines rely on slow combustion to achieve an approximately isobaric thermodynamic cycle. The subsonic combustion wave propagates forward through thermal and mass diffusion, and the flame propagation speed is on the order of several meters per second. Its thermodynamic efficiency is limited by the theoretical limit of the Brayton cycle. After a hundred years of development, the performance of the engine based on the slow combustion mode has gradually approached the theoretical limit, and there is limited space for improvement.
[0005] In order to meet the demand for continuous improvement of the performance of aerospace propulsion devices, many researchers at home and abroad focus on new combustion technology, and detonation combustion has received widespread attention.
[0006] Detonation is a kind of super-high-speed combustion phenomenon of matter under extreme conditions, and its core feature is the propagation process of the detonation wave. This wave front propagates in layers at a super-high speed of thousands of meters per second in the explosive medium, and its physical nature is a shock wave with strong compression effect. When the front of the detonation wave impacts unreacted matter, on the one hand, the medium temperature and pressure are suddenly raised through intense compression, triggering a chain of chemical reactions instantaneously; on the other hand, the huge amount of heat energy released by the chemical reaction forms a positive feedback mechanism, continuously providing energy for the front propagation of the detonation wave. This self-sustaining wave-reaction coupling process makes the detonation wave exhibit unique two-phase characteristics - it is not only a combustion wave carrying intense energy release, but also a pressure wave driving the reaction propagation through compression. In the dynamic balance, the detonation wave maintains stable propagation, and compared with isobaric combustion, detonation combustion also has the advantages of low NOx emission.
[0007] Rotating detonation combustion chamber has been proved to be feasible and advantageous as a core component of turbine engine through existing researches. However, it cannot adapt to complex working conditions if it is only used as a main combustion chamber. When it is used as a power component of rotating detonation turbojet combined engine, the axial length of the engine is extended, and the weight of the engine is increased. Therefore, there is a need for a combustion chamber concept that can overcome the above-mentioned shortcomings. SUMMARY
[0008] The technical problem solved by the present application is to provide a dual working mode combustion chamber suitable for slow burning and rotating detonation in view of the defects involved in the background art.
[0009] The present application adopts the following technical solutions to solve the above technical problems: A dual working mode combustion chamber suitable for slow burning and rotating detonation, comprising an air intake structure, a cavity section, a Laval nozzle section, an annular combustion chamber section, and a turbine structure. The air intake structure comprises a ram air intake structure, a swirler, and a compressed air intake structure, wherein the ram air intake structure and the compressed air intake structure are arranged inside and outside and are connected through the swirler. The air intake structure, the cavity section, the Laval nozzle section, the annular combustion chamber section, and the turbine structure are sequentially connected. The compressed air intake structure is directly connected to the last downstream rotor of the compressor, and no guide vane is arranged therebetween, thereby directly forming a full-ring scale swirl air intake. The cavity section, the Laval nozzle section, and the annular combustion chamber section are full-ring channels with inner and outer walls integrally connected. The cavity section is supplied with air by the ram air intake structure and the compressed air intake structure. Two streams of fluid enter the annular combustion chamber section from the cavity section through the Laval nozzle section, and finally flow to the turbine structure. An adjustable ejector structure is arranged between the ram air intake structure and the swirler. An oil supply structure is arranged on the surface of the cavity section. The annular combustion chamber section is provided with an initiation structure.
[0010] As a further optimization scheme of the dual working mode combustion chamber suitable for slow burning and rotating detonation, the overall structure of the combustion chamber is a coaxial double-layer casing structure, and the outer walls of the cavity section, the Laval nozzle section, and the annular combustion chamber section are flush.
[0011] As a further optimization scheme of the dual working mode combustion chamber suitable for slow burning and rotating detonation, the oil supply structure comprises 10 fuel centrifugal nozzles.
[0012] As a further optimization scheme of the dual working mode combustion chamber suitable for slow burning and rotating detonation, the swirling direction of the swirler is the same as the air intake direction of the compressed air intake structure, and the swirling angle of the swirler is between 50° and 70°.
[0013] As a further optimization scheme of the dual working mode combustion chamber adapting to slow burning and rotating detonation, the swirler is axially connected with the cavity section, and the compressed air structure is radially connected with the cavity section.
[0014] As a further optimization scheme of the dual working mode combustion chamber adapting to slow burning and rotating detonation, the upstream tapered part and the downstream tapered part of the Laval nozzle section are both smooth curved surfaces, and the curvature radius of the upstream tapered part is greater than that of the downstream tapered part.
[0015] As a further optimization scheme of the dual working mode combustion chamber adapting to slow burning and rotating detonation, the annular channel width of the annular combustion chamber is less than that of the cavity section, and the annular channel width at the throat of the Laval nozzle section is less than that of the swirler.
[0016] As a further optimization scheme of the dual working mode combustion chamber adapting to slow burning and rotating detonation, the axial length of the annular combustion chamber section is greater than or equal to 1.5 times the average radius of the annular channel and less than or equal to 2 times the average radius of the annular channel.
[0017] Compared with the prior art, the technical scheme of the present application has the following technical effects: The present application adopts the combustion concept of hierarchical zoning, and can realize two working modes: When the air intake amount is small, the airflow in the combustion chamber presents a subsonic flow state, at this time, the recirculation zone of the cavity section and the recirculation zone of the annular combustion chamber section at the intersection step of the Laval nozzle section and the annular combustion chamber section jointly organize subsonic slow burning; When the air intake amount is large, the airflow in the combustion chamber presents a transonic flow state, the gas flows through the Laval nozzle after being fully mixed to break through the sound speed, and the rotating detonation combustion is organized in the annular combustion chamber section. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 is a structural schematic diagram of the present application.
[0019] In the figure, 1 is a ram air structure, 2 is a swirler, 3 is a compressed air structure, 4 is a cavity section, 5 is a Laval nozzle section, 6 is an annular combustion chamber section, 7 is a turbine structure, 8 is an adjustable injection structure, 9 is an oil supply structure, and 10 is an ignition structure. DETAILED DESCRIPTION
[0020] The technical scheme of the present application will be further described in detail below in combination with the drawings: The present application can be implemented in many different forms, and should not be considered limited to the embodiments described herein. On the contrary, these embodiments are provided to make the present disclosure thorough and complete, and to fully convey the scope of the present application to those skilled in the art. In the drawings, the components are enlarged for clarity.
[0021] The present application can be implemented in many different forms and should not be considered limited to the form shown in the drawings. The drawings are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.
[0022] In the drawings, other engine components are added and simplified for clarity of expression, and the structural size ratio of the components of the present application is enlarged.
[0023] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "front end", "rear end", "inner side", "outer side", "upstream", "downstream" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.
[0024] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0025] As shown in Figure 1 The present application discloses a dual working mode combustion chamber suitable for slow burning and rotating detonation, comprising an air intake structure, a cavity section, a Laval nozzle section, an annular combustion chamber section, and a turbine structure. The air intake structure comprises a ram air intake structure, a swirler, and a compressed air intake structure, wherein the ram air intake structure and the compressed air intake structure are arranged inside and outside and connected through the swirler. The air intake structure, the cavity section, the Laval nozzle section, the annular combustion chamber section, and the turbine structure are connected in sequence. The compressed air intake structure is directly connected to the last downstream rotor of the compressor, and no guide vane is arranged between the two, thereby directly forming a full-ring scale swirl air intake.
[0026] The cavity section, the Laval nozzle section, and the annular combustion chamber section are full-ring channels integrally connected with the inner and outer walls, and the cavity section is supplied with air by the ram air intake structure and the compressed air intake structure. Two streams of fluid enter the annular combustion chamber section from the cavity section through the Laval nozzle section, and finally flow to the turbine structure.
[0027] The adjustable ejecting structure is arranged between the ram air intake structure and the swirler, and the surface of the cavity section is provided with a fuel supply structure.
[0028] The combustion chamber structure is a coaxial double-layer casing structure.
[0029] The cavity section, the Laval nozzle section and the outer wall of the annular combustion chamber section are flush.
[0030] The fuel supply structure comprises 10 fuel centrifugal nozzles.
[0031] The swirling direction of the swirler is the same as the air intake direction of the compressed air intake structure.
[0032] Figure 1 The swirling angle of the swirler is 70°.
[0033] The pipe diameter size of the annular combustion chamber section is constant.
[0034] The swirler is axially connected with the cavity section, and the compressed air intake structure is radially connected with the cavity section.
[0035] The axial size of the cavity section should be close to the radial size.
[0036] The upstream tapered part of the Laval nozzle section is a smooth curved surface with a larger curvature radius, and the downstream diverging part is a smooth curved surface with a smaller curvature radius.
[0037] The annular channel width of the annular combustion chamber should be smaller than the annular channel width of the cavity section.
[0038] The annular channel width at the throat of the Laval nozzle section should be smaller than the annular channel width of the swirler.
[0039] The axial length of the annular combustion chamber section should be not less than 1.5 times of the average radius of the annular channel and not more than 2 times of the average radius of the annular channel.
[0040] The application also discloses a combustion method of a dual-working-mode combustion chamber suitable for slow combustion and rotating detonation, and the specific steps of slow combustion organization are as follows. Part of the airflow flows through the swirler after being injected by the ram air intake structure, and part of the airflow flows out through the compressed air intake structure and enters the combustion chamber, and the airflow behaves as a subsonic flow state suitable for slow combustion. After the two swirls are coupled, they are blocked by the downstream solid wall of the cavity section, forming a full annular recirculation zone in the cavity area, which can mix with the fuel gas sprayed by the fuel supply structure to stabilize the flame and organize preliminary combustion.
[0041] The air intake of the ram air intake structure can naturally form a cooling gas film on the outer wall surface by centrifugation, and is mixed with the fuel gas downstream to reduce the outlet temperature.
[0042] After the subsonic airflow flows through the Laval nozzle section, a backflow area is formed at the step behind the nozzle for further combustion of the upstream incompletely combusted gas mixture.
[0043] The rotating detonation combustion organization method is as follows: with the increase of the intake air amount, the flow in the combustion chamber becomes a transonic flow, and the fully mixed gas before the annular combustion chamber section can organize rotating detonation combustion after the shock wave through the detonation organization structure.
[0044] The present application provides a dual working mode combustion chamber suitable for slow combustion and rotating detonation, air is supplied from the ram air structure and the compressed air structure, and gas is formed after oil is injected by the oil supply structure, and the air amount and the oil amount are adjusted to meet the two working modes; (1) when the air flow is small, the airflow presents a subsonic flow state, and a slow combustion combustion mechanism is adopted; (2) when the air flow is large, the airflow presents a transonic flow state, and a rotating detonation combustion mechanism is adopted. The two modes can meet the requirements of combustion stability of the combustion chamber under different working conditions, so that the combustion chamber has a wide working range.
[0045] In the slow combustion working mode, only part of the radial rotational flow is sucked into the upstream backflow area, so that the area is relatively rich in oil and oxygen, and therefore the combustion efficiency is low, resulting in a large amount of CO. In the air-rich area at the edge of the backflow area, the intermediate product can react violently with oxygen, causing local high temperature at the edge, thereby rapidly and fully combusting CO. This results in a certain amount of thermal NOx represented by NO under high temperature and rapid NOx generated by reaction with hydrocarbon radicals. However, the rapid dilution of the axial rotational flow causes the downstream secondary combustion to further consume NO, achieving a stable subsonic slow combustion working mode and finally presenting a staged combustion phenomenon with good emission performance.
[0046] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with those in the prior art, and should not be interpreted in an idealized or overly formal sense unless otherwise defined.
[0047] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. A dual-mode combustion chamber adapted to slow combustion and rotating detonation, characterized in that: It includes air intake structure, cavity section, Laval nozzle section, annular combustion chamber section, and turbine structure; The air intake structure includes a ram air intake structure, a cyclone, and a compression air intake structure, wherein the ram air intake structure and the compression air intake structure are arranged inside and outside and connected through the cyclone; The air intake structure, the concave cavity section, the Laval nozzle section, the annular combustion chamber section, and the turbine structure are connected in sequence; The compression intake structure is directly connected to the most downstream stage rotor of the compressor, and no guide vanes are provided between the two, thereby directly forming a full-ring scale swirl intake; The concave cavity section, the Laval nozzle section, and the annular combustion chamber section form a full-annular channel with inner and outer walls integrally connected. The ram air intake structure and the compression air intake structure jointly supply air to the concave cavity section. The two fluids flow from the concave cavity section through the Laval nozzle section into the annular combustion chamber section and finally flow to the turbine structure. An adjustable ejector structure is provided between the ram air intake structure and the swirler, an oil supply structure is provided on the surface of the concave cavity section, and an initiation structure is provided in the annular combustion chamber section.
2. The dual-mode combustion chamber adapted to slow combustion and rotating detonation according to claim 1, characterized in that: The combustion chamber structure as a whole is a coaxial double-layer casing structure, and the concave cavity section, the Laval nozzle section and the outer wall of the annular combustion chamber section are flush.
3. The dual-mode combustion chamber adapted to slow combustion and rotating detonation according to claim 1, characterized in that: The oil supply structure includes 10 fuel centrifugal nozzles.
4. The dual-mode combustion chamber adapted to slow combustion and rotating detonation according to claim 1, characterized in that: The swirl direction of the swirler is the same as the air intake direction of the compressed air intake structure, and the swirl angle of the swirler is between 50° and 70°.
5. The dual-mode combustion chamber adapted to slow combustion and rotating detonation according to claim 1, characterized in that: The swirler is axially connected to the concave cavity section, and the compressed air intake structure is radially connected to the concave cavity section.
6. The dual-mode combustion chamber adapted to slow combustion and rotating detonation according to claim 1, characterized in that: The upstream tapered portion and the downstream diverging portion of the Laval nozzle section are both smooth curved surfaces, and the curvature radius of the upstream tapered portion is greater than the curvature radius of the downstream diverging portion.
7. The dual-mode combustion chamber adapted to slow combustion and rotating detonation according to claim 1, characterized in that: The annular channel width of the annular combustion chamber is smaller than the annular channel width of the concave cavity section, and the annular channel width at the throat of the Laval nozzle section is smaller than the annular channel width of the swirler.
8. The dual-mode combustion chamber adapted to slow combustion and rotating detonation according to claim 1, characterized in that: The axial length of the annular combustion chamber segment is greater than or equal to 1.5 times the average radius of the annular channel and less than or equal to 2 times the average radius of the annular channel.