A main flow rotating detonation combustion chamber based on concave cavity duty

Abstract

This invention discloses a mainstream rotating detonation combustor based on cavity-based operation, belonging to the field of detonation engine technology. It includes: an outer casing; a flame tube, comprising an inner and outer flame tube with multiple cooling holes; a cavity composed of a front wall, an upper wall, and a rear wall, including two air inlets: a front air inlet and a rear air inlet; a mainstream air intake passage, including a straight section and a contraction-expansion section; a shift air intake passage; a mainstream fuel supply system, with multiple mainstream fuel nozzles evenly arranged circumferentially on the straight section of the mainstream air intake passage; and a shift fuel supply system with multiple shift fuel nozzles circumferentially installed on the front wall of the cavity. When the cavity-based mainstream rotating detonation combustor operates, it employs a functionally graded and spatially partitioned combustion organization method. The cavity subsonic combustion and mainstream detonation combustion adjust their air intake and fuel supply ratios to adapt to different operating conditions, thereby ensuring stable combustion in the combustor under wide-range conditions.

Description

Technical Field

[0001] This invention belongs to the field of detonation engine technology, specifically relating to a mainstream rotating detonation combustion chamber based on cavity monitoring. Background Technology

[0002] With the continuous development of aero-engine technology, the combustion efficiency of combustors has reached near-theoretical levels, making further performance improvements extremely difficult. Detonation combustion, due to its high thermal cycle efficiency, simple structure, and short combustion time, has become the main direction for the development of next-generation aero-engine combustors. However, aero-engine combustors need to operate efficiently and stably over a wide range, including stationary, startup, low-speed, cruise, and high-speed conditions. Conventional rotating detonation combustors have high requirements for aerodynamic and fuel supply parameters, and their efficient operating range is relatively narrow. Existing detonation combustion technology cannot yet meet the operational requirements of wide-speed-range engines, and its detonation cycle efficiency and initiation performance are not significantly advantageous at low speeds. Summary of the Invention

[0003] In order to overcome the cycle efficiency limitations of traditional subsonic isobaric combustion and broaden the application conditions of rotating detonation combustion, this invention provides a mainstream rotating detonation combustion chamber based on cavity monitoring. It adopts a combustion organization method that is functionally graded and spatially partitioned. By adjusting its air intake ratio and fuel supply ratio, it can adapt to different operating conditions and ensure stable combustion of the aircraft under a wide range of conditions.

[0004] The technical solution for realizing the present invention is: a mainstream rotating detonation combustion chamber based on cavity monitoring, comprising:

[0005] Outer casing;

[0006] The flame tube includes an inner flame tube and an outer flame tube, and multiple cooling holes are arranged on the inner flame tube and the outer flame tube, respectively.

[0007] The cavity includes the front wall, the upper wall, and the rear wall. The three structures combine to form the front air inlet and the rear air inlet, thereby enabling the cavity to receive air during shifts. The cavity is located in the upstream area of ​​the outer flame tube and is close to the main fuel supply system end and the shift fuel supply system end.

[0008] The main intake passage includes a straight section and a contraction-expansion section, and is embedded between the concave cavity and the compressor blades.

[0009] The duty air intake passage is embedded between the upper wall of the concave cavity and the outer casing.

[0010] The mainstream fuel supply system has multiple mainstream fuel supply nozzles evenly arranged circumferentially.

[0011] The duty oil supply system has multiple duty oil supply nozzles installed circumferentially on the front wall of the cavity.

[0012] According to at least one embodiment of the present invention, in the above-mentioned mainstream rotating detonation combustion chamber based on cavity duty, the cavity includes a front wall surface, an upper wall surface, and a rear wall surface, which cooperate to form a cavity, constituting an inlet and a rear inlet with a radial height difference. The subsonic airflow forms a double vortex structure in the cavity through the inlet and the rear inlet.

[0013] According to at least one embodiment of the present invention, in the above-mentioned mainstream rotating detonation combustion chamber based on cavity duty, a plurality of nozzles are uniformly arranged in the straight section of the mainstream intake channel, and the contraction and expansion section forms a high subsonic or supersonic airflow with a Mach number greater than 0.6.

[0014] According to at least one embodiment of the present invention, in the above-described mainstream rotating detonation combustion chamber based on cavity monitoring, the monitoring air intake channel is arranged between the upper wall of the cavity and the outer casing, guiding air into the flame tube. The monitoring air intake channel can adjust the intake volume, flexibly controlling the operation of the combustion chamber under different operating conditions.

[0015] According to at least one embodiment of the present invention, in the above-mentioned mainstream rotating detonation combustion chamber based on cavity shift, the mainstream fuel supply system has multiple mainstream fuel supply nozzles uniformly arranged circumferentially, and fuel is injected into the mainstream intake passage through the nozzles.

[0016] According to at least one embodiment of the present invention, in the above-mentioned mainstream rotating detonation combustion chamber based on cavity duty, the duty fuel supply system has multiple duty fuel supply nozzles installed circumferentially on the front wall of the cavity, and fuel is injected into the cavity through the duty nozzles to participate in the combustion process.

[0017] The beneficial effects of this invention are as follows:

[0018] (1) The present invention relates to a mainstream rotating detonation combustor based on a concave cavity duty system, which is based on a rotating detonation combustion scheme with a single concave cavity. In low-speed conditions, only the concave cavity duty zone is supplied with fuel, while in high-speed conditions, the concave cavity duty zone and the mainstream zone are supplied with fuel simultaneously. The concave cavity subsonic combustion and detonation combustion adapt to different operating conditions by adjusting their air intake ratio and fuel supply ratio, thereby ensuring stable combustion of the aircraft under wide-range conditions. A functionally graded and spatially partitioned combustion organization method is adopted. Functionally, the fuel is divided into two levels: the duty class and the mainstream class, which are responsible for flame stability and combustion organization in low-speed conditions, as well as combustion organization in the main state, respectively. Spatially, it is divided into a concave cavity duty subsonic combustion zone and a mainstream detonation combustion zone, which respectively achieve stable combustion in low-speed and low-speed conditions and efficient combustion in the main state. The advantage of the graded combustion design is that it can achieve a wider ignition and extinguishing combustion boundary, while adapting to stable combustion under different operating conditions; while the partitioned combustion design better controls the combustion process and improves combustion efficiency.

[0019] (2) The mainstream rotating detonation combustion chamber based on cavity duty of the present invention makes full use of the high cycle efficiency brought about by detonation combustion and solves the problem of difficulty in initiation of traditional detonation combustion under low state, which is beneficial to promoting the engineering application process of detonation combustion. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the mainstream rotating detonation combustion chamber structure based on cavity monitoring according to the present invention.

[0021] Figure 2 This is a schematic diagram of the flame tube and fuel supply system of the mainstream rotating detonation combustion chamber based on cavity duty according to the present invention.

[0022] Figure 3 This is a partially enlarged view of the main intake channel of the main rotating detonation combustion chamber based on the cavity shift of the present invention.

[0023] Figure 4 This is a partially enlarged view of the flame tube of the mainstream rotating detonation combustion chamber based on cavity monitoring according to the present invention.

[0024] Figure 5 This is a schematic diagram of the combustion organization of the mainstream rotating detonation combustion chamber based on cavity monitoring according to the present invention.

[0025] Figure 6 This is a flow distribution diagram for subsonic / sonic cruise in the mainstream rotating detonation combustion chamber based on cavity monitoring, according to the present invention.

[0026] Figure 7 This is a thrust distribution diagram for the mainstream rotating detonation combustion chamber based on cavity monitoring in this invention.

[0027] Explanation of reference numerals in the attached diagram: 1-Compressor blade; 2-Shaft system; 3-Oil pipe; 4-Mainstream intake passage; 5-Stationary intake passage; 6-Mainstream fuel supply system; 7-Stationary fuel supply system; 8-Cavity; 9-Flame tube; 10-Outer casing; 11-Spark plug; 12-Cooling hole; 13-Turbine blade; 14-Inner flame tube; 15-Outer flame tube; 16-Inlet; 17-Rear intake; 18-Straight section; 19-Contraction and expansion section; 20-Cavity front wall; 21-Cavity upper wall; 22-Cavity rear wall; 23-Mainstream detonation combustion zone; 24-Cavity stationary subsonic combustion zone; 25-Pre-detonation tube; 26-Cavity inlet; 27-Cavity rear intake; 28-Mainstream intake; 29-Cavity cooling gas; 30-Mainstream cooling gas. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the above descriptions are illustrative embodiments of the invention, used only to explain the invention and to fully express the scope of the invention to those skilled in the art, and should not be construed as limiting the invention.

[0029] In describing the detonation combustion chamber structure in this invention, terms such as "front," "rear," "circumferential," "radial," "top," "bottom," "inner," and "outer" refer to orientation or relative positional relationships in the accompanying drawings. These terms are used only for simplified description and do not imply that the described device or components must maintain the specific orientation, construction, and operation shown in the description. Some components in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the dimensions of the actual product; therefore, they should not be construed as limitations on the invention.

[0030] This invention proposes a combustion method coupled with subsonic combustion and detonation, employing a combustion scheme based on single-sided concave cavity standby mainstream detonation, aiming to replace the traditional swirl combustion chamber. Specifically, the airflow passes through front and rear air inlets with a height difference arranged inside the concave cavity, forming a double-vortex flow structure of main vortex and secondary vortex under the forced flow of the concave cavity structure. The secondary vortex, located on the front wall of the concave cavity, lies between the main vortex and the mainstream, effectively protecting the main vortex flow structure within the concave cavity, thus achieving a zoned combustion mode of subsonic and detonation combustion. Here, subsonic combustion occurs inside the concave cavity, while rotating detonation combustion occurs in the mainstream region. Due to the presence of the secondary vortex and the concave cavity structure, the impact of detonation waves on the flow and combustion characteristics inside the concave cavity can be reduced to a certain extent. The combustion chamber adopts a functionally graded and spatially zoned combustion organization method, dividing the fuel into a standby stage and a mainstream stage. By independently controlling the fuel gas in the concave cavity vortex combustion zone and the rotating detonation combustion zone, it adapts to different operating conditions, effectively widening the stable operating range of the combustion chamber.

[0031] When the main rotating detonation combustion chamber of the concave cavity is in operation, the intake ratio and fuel supply ratio can be adjusted to adapt to different operating conditions, thereby achieving stable combustion of the aircraft under all operating conditions, including takeoff and cruise.

[0032] Combination Figures 1 to 7 This invention provides a mainstream rotating detonation combustion chamber based on cavity monitoring, comprising:

[0033] The outer casing 10 is cylindrical and is located on the outermost side of the central axis of the combustion chamber. It mainly restricts the fluid flow area and serves as a support frame for the combustion chamber.

[0034] The flame tube 9, including the inner flame tube 14 and the outer flame tube 15, is arranged around the rotating shaft system 2 and is divided into a detonation zone and a concave vortex zone. The radius of the end face of the detonation zone is smaller than the radius of the end face of the concave vortex zone. The two are coaxially fixed and the concave vortex zone is located on the outside of the flame tube 9, close to the main oil supply system 6 and the duty oil supply system 7. Multiple cooling holes 12 are arranged on the flame tube 9.

[0035] The concave cavity 8 includes a front wall surface 20, an upper wall surface 21, and a rear wall surface 22. The three surfaces cooperate to form a cavity, which constitutes an inlet 16 and a rear inlet 17 with a radial height difference. The airflow passing through the inlet 16 and the rear inlet 17 is subsonic and forms a double vortex structure in the concave cavity 8.

[0036] The main intake channel 4 includes a straight section 18 and a contraction-expansion section 19. The main intake channel 4 is embedded between the cavity 8 and the compressor blade 1. The straight section 18 of the main intake channel 4 is evenly arranged with multiple nozzles, and the contraction-expansion section 19 forms a high subsonic airflow or a supersonic airflow.

[0037] The duty air intake passage 5 is located between the upper wall 21 of the concave cavity and the outer casing 10, guiding air into the flame tube 9. The duty air intake passage 5 can adjust the intake volume, flexibly controlling the operation of the combustion chamber under different working conditions.

[0038] The main fuel supply system 6 has multiple main fuel supply nozzles evenly arranged circumferentially, and fuel is injected into the main intake channel 4 through the nozzles.

[0039] The duty fuel supply system 7 has multiple duty fuel supply nozzles installed circumferentially on the front wall 20 of the cavity. Fuel is injected into the cavity 8 through the duty nozzles and participates in the combustion process.

[0040] In an optional embodiment of the mainstream rotating detonation combustor based on cavity monitoring of the present invention, the coexistence of subsonic combustion and mainstream detonation combustion in cavity monitoring is the innovation of this invention. Specifically, the fuel and air entering the combustion chamber are regulated and controlled to form two functional combustion zones within the flame tube: a cavity-monitored subsonic combustion zone 24 and a mainstream detonation combustion zone 23. The combustion organization function is divided into cavity-monitored subsonic combustion and mainstream detonation combustion. The specific regulation and control of the fuel and air are as follows: the airflow enters the combustion chamber after being pressurized by the compressor blades 1, and is divided into a mainstream airflow and a cavity-monitored airflow. The mainstream airflow is rectified from the mainstream fuel supply channel 4 through the straight section 18, and then accelerated through the contraction and expansion section 19 to form a high subsonic or supersonic airflow. The cavity-monitored airflow enters from the inlet and outlet of the cavity 8, and then mixes within the cavity before entering the mainstream channel. The fuel supply system is divided into two parts: the mainstream fuel supply system 6 and the cavity standby fuel supply system 7. Mainstream fuel supply is injected through the fuel pipe 3 in the straight section 18, where it mixes with the mainstream fuel flow. After passing through the contraction and expansion section 19, the fuel-air mixture enters the flame tube 9 and undergoes detonation combustion. Cavity standby fuel supply is injected near the inlet of the cavity 8 on the front wall 20 of the cavity. The injected fuel droplets mix with the inlet air of the cavity 8 and then undergo subsonic combustion. The high-temperature gas flow after combustion enters the turbine blades 13 through the mainstream channel outlet to perform work, and transfers some of the work to the compressor blades 1 to maintain engine operation. During ignition, a spark plug 11 is placed on the upper wall 21 of the cavity. The electric spark releases a spark with 2-10J of energy, igniting the combustible mixture and forming a stable subsonic flame in the recirculation zone of the cavity 8. The pre-detonation tube 25 is arranged on the wall of the inner flame tube 14, igniting the mainstream oil-gas mixture in the flame tube 9 to form circumferential mainstream detonation combustion. The pre-burned high-temperature gas in the concave cavity 8 enters the flame tube 9 and mixes with the mainstream oil-gas mixture, promoting mainstream detonation combustion. When the concave-controlled mainstream rotating detonation combustion chamber is operating, oil-gas parameters are graded through the concave control and mainstream flow. Simultaneously, the concave-controlled subsonic combustion zone 24 and the mainstream detonation combustion zone 23 are spatially partitioned, enabling graded and partitioned combustion. The concave-controlled mainstream rotating detonation combustion chamber of this invention, due to the special structure and position design of the concave-controlled subsonic combustion zone 24 and the mainstream detonation combustion zone 23, ensures that the airflow state and flame stability in the concave vortex combustion zone are almost unaffected by the flow in the rotating detonation combustion zone, thereby improving ignition performance and widening the flame stability range.

[0041] like Figure 6As shown, in an optional embodiment of the mainstream rotating detonation combustor based on cavity monitoring of the present invention, the coexistence of subsonic combustion and mainstream detonation combustion under cavity monitoring is the innovation of this invention. Adjusting the airflow in the combustor allows for flow matching under different flight conditions, including cavity inlet air 26, cavity rear inlet air 27, mainstream inlet air 28, cavity cooling air 29, and mainstream cooling air 30. The following describes the technical solution in detail with two typical states; it should be noted that the present invention is not limited to these specific embodiments. The flow distribution during subsonic cruise is as follows: the main combustion zone mainstream intake 28 accounts for 33% of the total air volume, the flame tube cooling air 30 accounts for 10%, the cavity inlet intake 26 accounts for 27%, the cavity rear intake 27 accounts for 20%, and the cavity cooling air 29 accounts for 10%, with film cooling as the cooling method. During supersonic cruise, the flow distribution is as follows: the main combustion zone mainstream intake 28 accounts for 55% of the total air volume, the flame tube cooling air 30 accounts for 7%, the cavity inlet intake 26 accounts for 17%, the cavity rear intake 27 accounts for 13%, and the cavity cooling air 29 accounts for 8%. During implementation, by increasing the fuel flow rate in the cavity 8, it achieves rich combustion, which to some extent increases the combustion and cracking effect of the subsonic combustion in the cavity on the fuel. The unburned fuel-air mixture enters the mainstream detonation combustion zone 23 with the airflow, which to some extent improves the combustion efficiency of the mainstream detonation combustion zone 23.

[0042] like Figure 7 As shown, in low-speed conditions (idle speed, subsonic cruise), the cavity combustion zone is the primary combustion zone, providing the main thrust and distributing a large amount of airflow. As the flight conditions gradually increase (supersonic cruise and maximum aerodynamic load), the proportion of thrust provided by the cavity combustion zone gradually decreases, and the rotating detonation combustion zone gradually takes over, eventually providing most of the thrust requirements.

[0043] The specification describes the examples of the present invention in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually.

[0044] The technical solution of the present invention has been described above through preferred embodiments. Obviously, the protection scope of the present invention is not limited to these specific embodiments. Equivalent modifications and substitutions made by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A mainstream rotating detonation combustion chamber based on cavity monitoring, characterized in that, include: Outer casing (10); The flame tube (9) includes an inner flame tube (14) and an outer flame tube (15), and multiple cooling holes (12) are arranged on the inner flame tube (14) and the outer flame tube (15); The cavity (8) includes the front wall (20), the upper wall (21), and the rear wall (22). The three structures are combined to form the front air inlet (16) and the rear air inlet (17), thereby realizing the on-call air intake of the cavity. The cavity (8) is located in the upstream area of ​​the outer flame tube (15) and is close to the main fuel supply system (6) and the on-call fuel supply system (7). The main intake passage (4) includes a straight section (18) and a contraction and expansion section (19). The main intake passage (4) is embedded between the cavity (8) and the compressor blade (1). Duty air intake channel (5), the duty air intake channel (5) is embedded between the upper wall surface (21) of the concave cavity and the outer casing (10); The mainstream oil supply system (6) has multiple mainstream oil supply nozzles evenly arranged in the circumferential direction; The duty oil supply system (7) has multiple duty oil supply nozzles installed circumferentially on the front wall surface (20) of the cavity; Multiple nozzles are evenly arranged on the straight section (18) of the main intake channel (4), and the contraction and expansion section (19) forms a high subsonic airflow or a supersonic airflow. The main fuel supply system (6) has multiple main fuel supply nozzles evenly arranged in the circumference, and fuel is injected into the main intake channel (4) through the nozzles.

2. The mainstream rotating detonation combustion chamber based on cavity monitoring according to claim 1, characterized in that: The concave cavity (8) includes the front wall surface (20), the upper wall surface (21), and the rear wall surface (22). The three surfaces cooperate to form a cavity, which constitutes the front air inlet (16) and the rear air inlet (17) with a radial height difference. The airflow through the front air inlet (16) and the rear air inlet (17) is subsonic and forms a double vortex structure in the concave cavity (8).

3. The mainstream rotating detonation combustion chamber based on cavity monitoring according to claim 2, characterized in that: The front air inlet (16) and rear air inlet (17) of the concave cavity can be either slit air inlet, discrete hole air inlet, or a combination thereof. That is, the front air inlet (16) is slit air inlet and the rear air inlet (17) is discrete hole air inlet, or the front air inlet (16) is discrete hole air inlet and the rear air inlet (17) is slit air inlet.

4. The mainstream rotating detonation combustion chamber based on cavity monitoring according to claim 3, characterized in that: The duty air intake channel (5) is located between the upper wall (21) of the concave cavity and the outer casing (10), guiding air into the flame tube (9). The duty air intake channel (5) can adjust the air intake volume and flexibly control the operation of the combustion chamber under different working conditions.

5. The mainstream rotating detonation combustion chamber based on cavity monitoring according to claim 1, characterized in that: The mainstream fuel supply nozzle types include at least one of centrifugal nozzles, direct-injection nozzles, and pneumatically assisted nozzles.

6. The mainstream rotating detonation combustion chamber based on cavity monitoring according to claim 1, characterized in that: The duty fuel supply system (7) has multiple duty fuel supply nozzles installed circumferentially on the front wall (20) of the cavity. Fuel is injected into the cavity (8) through the duty fuel supply nozzles and participates in the combustion process.

7. The mainstream rotating detonation combustion chamber based on cavity monitoring according to claim 6, characterized in that: The type of on-duty oil supply nozzle includes at least one of centrifugal nozzle, direct-fire nozzle, and pneumatically assisted nozzle.

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