Bimodal afterburner structure and modal adjusting method thereof

Abstract

The invention discloses a bimodal afterburner structure and a modal adjusting method thereof.The bimodal afterburner structure comprises an inner duct structure, an outer duct structure, a combustion chamber and a spray pipe, a partition plate is arranged between the inner duct structure and the outer duct structure, and a change-over valve is connected to the partition plate; one end of the combustion chamber is connected with the inner duct structure and the outer duct structure, and the other end of the combustion chamber is connected with the spray pipe. Through the design of a slow combustion / deflagration dual-mode inner and outer ring parallel structure, autonomous dual-mode switching and a dual-mode shared combustion chamber, efficient energy conversion and dynamic adjustment of the power device in a wide speed domain range are achieved, the thrust coefficient of a slow combustion mode is 0.3-0.5, the detonation mode is improved to 0.6-0.8, the flight requirement of Mach number 1-Mach number 5 can be met, and the flight speed of the power device is improved. And meanwhile, the detonation combustion heat efficiency is improved by 15% compared with a slow combustion mode, and the fuel power ratio is reduced by 15%-20%.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft engines, and in particular relates to a dual-mode afterburner combustion chamber structure and a mode adjustment method thereof. Background Art

[0002] The afterburner components of existing aircraft power mostly adopt a single slow-burn working mode, which has a narrow thrust adjustment range. It cannot adapt to the difference in thrust requirements between low-speed cruising (<1Ma) and high Mach number (>4Ma) flight conditions by relying solely on fine-tuning the fuel supply; and the combustion efficiency is limited within a wide speed range. During high-speed flight, the thermal efficiency of the slow-burn mode reaches its peak and cannot be further improved to meet the requirements of higher thrust for the combustion environment. Existing rotating detonation combustion chambers mostly adopt an independent combustion chamber design, and the detonation and slow-burn combustion chambers are arranged independently, resulting in increased weight of the entire aircraft, large space occupancy, and low energy utilization.

[0003] Therefore, a dual-mode afterburner structure and mode adjustment method are needed to connect the inner slow combustion channel and the outer ring detonation channel in parallel and share the combustion chamber, so as to reduce the structural complexity and improve the thrust output efficiency.

[0004] The patent application document with the announcement number CN118463227A discloses a structurally adjustable detonation and slow-burn dual-mode combined afterburner, which combines the two combustion modes of detonation and slow-burn and can flexibly switch between different combustion modes. However, there are the following shortcomings: 1. The patent application document is used for aviation turbofan engines, which have a narrow operating range, but is not used for ramjet and turbofan combination engines. Turbofan engines use slow-burn afterburners, and ramjet engines use detonation afterburner combustion chambers, which have a wide operating range. 2. The detonation and slow-burn afterburner combustion chambers in the patent application document share a combustion chamber. The stabilizer is located in the flow channel of the combustion chamber. The detonation wave passes through the stabilizer, resulting in large flow resistance losses and low engine propulsion efficiency. 3. There is no description of the afterburner ignition and linked flame design in the patent application document, and it is impossible to determine whether it can ensure the normal and stable operation of the afterburner.

[0005] Patent application CN116241371A discloses a gas turbine with parallel detonation combustion chambers. This design improves the overall cycle efficiency of the gas turbine and reduces overall pollutant emissions. It also addresses the problems of pure detonation combustion engines, such as difficulty starting and unstable continuous operation. However, this design, with separate detonation and slow-burn combustion chambers, increases the combustion chamber footprint. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a dual-mode afterburner combustion chamber structure and a modal adjustment method thereof. Through a rotatable rear duct modal conversion valve, the inner and outer ring flow channels are locked and opened. When the outer ring flow channel is opened, the central concave cavity inner cone and radial support plate stabilizer are used to organize the combustion of the inner channel. When the outer ring flow channel is locked, the outer ring detonation wave combustion rotation motion mode is used to work in the shared combustion chamber and nozzle components to generate stable thrust output.

[0007] The present invention is achieved through the following technical solutions.

[0008] The present invention provides a dual-mode afterburner combustion chamber structure, which includes an inner duct structure, an outer duct structure, a combustion chamber and a nozzle. A partition is arranged between the inner duct structure and the outer duct structure, and a conversion valve is connected to the partition. One end of the combustion chamber is connected to the inner duct structure and the outer duct structure respectively, and the other end of the combustion chamber is connected to the nozzle.

[0009] Preferably, a support plate oil supply assembly, a central cone cavity and an oblique radial flame transfer groove are provided on the inner channel structure, the central cone cavity is provided at the bottom of the inner channel structure, the support plate oil supply assembly is provided at the top of the inner channel structure, one end of the oblique radial flame transfer groove is connected to the central cone cavity, and the other end of the oblique radial flame transfer groove is connected to the mounting groove where the support plate oil supply assembly is provided, and a partition is provided on the top of the support plate oil supply assembly.

[0010] Preferably, a central ignition nozzle and an air atomizing nozzle are provided on the central cone cavity, and the central ignition nozzle is located above the air atomizing nozzle.

[0011] Preferably, a central oblique incident hole is provided on the central cone cavity on a side close to the inner cone cavity, and the central oblique incident hole connects the inner cavity of the central cone cavity with the inner cone cavity.

[0012] Preferably, a support plate injection nozzle is provided on the support plate oil supply assembly.

[0013] Preferably, an oil supply pipe, an air supply pipe, a vortex finder and an ignition nozzle are provided on the outer duct structure. The oil supply pipe and the air supply pipe are arranged on the left side of the vortex finder, and the ignition nozzle is arranged on the right side of the vortex finder. One end of the oil supply pipe and the air supply pipe is connected to the vortex finder.

[0014] Preferably, the nozzle comprises a convergent section and an divergent section, one end of the convergent section is connected to the divergent section, and the other end of the convergent section is connected to the combustion chamber.

[0015] A method for adjusting the modal state of a dual-mode afterburner combustion chamber structure includes adjusting a conversion valve so that an inner duct structure and an outer duct structure are connected to a combustion chamber respectively, and adjusting the nozzle angle to achieve a process of switching between a slow combustion working mode and a deflagration working mode.

[0016] Preferably, the step of adjusting the slow combustion working mode includes: A1: Adjust the switching valve so that the outer duct structure no longer communicates with the combustion chamber, leaving only the inner duct structure in communication with the combustion chamber. When the engine is powered on, the gas flow inside the central conical cavity passes through the central oblique inlet hole into the inner conical cavity, forming a recirculation zone. The fuel sprayed from the air atomizing nozzle mixes with the gas flow and enters the recirculation zone on the inner conical cavity to form an oil-gas mixture. A2: When the engine is in afterburner and transitions to partial afterburner and full afterburner states, the support plate fuel supply assembly injects fuel through the support plate injection nozzle. The injected fuel is broken and evaporated under the action of the mainstream airflow of the engine, and then enters the support plate recirculation area at the trailing edge of the support plate fuel supply assembly to form a stable oil mist field. The central ignition nozzle releases an electric spark to ignite the oil-gas mixture in the recirculation area of ​​the inner cone cavity and the support plate recirculation area, and form a continuous and stable ignition source. At the same time, the oil-gas mixture in the recirculation area of ​​the inner cone cavity is connected and propagated with the flame of the support plate recirculation area through the oblique radial flame transfer groove, forming a main combustion area. The oil-gas mixture in the main combustion area enters the combustion chamber to continue burning.

[0017] Preferably, the step of adjusting the deflagration working mode includes: A3: Adjust the switching valve so that the inner duct structure no longer communicates with the combustion chamber, and only the outer duct structure communicates with the combustion chamber; A4: Fuel and gas are supplied through the oil and gas supply pipes respectively. The fuel and gas are fully mixed by the vortex finder and generate a detonation wave under the condition of energy supplied by the electric spark of the ignition nozzle. The detonation wave rotates and propagates along the annular channel under the guidance of the inner cone, and continuously burns in the circumferential direction to release energy and generate thrust. During the transition phase between the slow combustion mode and the deflagration mode, the convergent and divergent sections of the nozzle will be adjusted in advance to the preset angles of the target mode.

[0018] The beneficial effects of the present invention are: The present invention proposes a dual-mode afterburner structure with an inner and outer ring parallel structure. The slow-burn and detonation afterburner combustion chambers are switched through a regulating valve. The support plate stabilizer is not arranged in the detonation afterburner combustion chamber. When the detonation afterburner is working, the flow resistance loss is small and the engine propulsion efficiency is high. Through the ignition and flame combination of the inner cone cavity, the detonation afterburner combines the flames through a continuously rotating detonation wave. Through the slow-burn / detonation dual-mode inner and outer ring parallel structure, autonomous dual-mode switching and dual-mode shared combustion chamber design, the power unit can achieve efficient energy conversion and dynamic adjustment within a wide speed range. The slow-burn mode thrust coefficient is 0.3~0.5, and the detonation mode is increased to 0.6~0.8, which can cover the flight requirements of Mach 1 to Mach 5. At the same time, the thermal efficiency of detonation combustion is improved by 15% compared with the slow-burn mode, and the fuel-to-power ratio is reduced by 15%~20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : Structural diagram of the present invention; Figure 2 : Diagram of the outer duct detonation combustion mode structure of the present invention; Figure 3 : The working principle diagram of the connotation slow combustion mode of the present invention; Figure 4 : Schematic diagram of the working principle of the outer duct detonation combustion mode of the present invention; Figure 5 : Figure 3 AA section view of the support plate oil supply assembly; Figure 6 : Figure 3 Enlarged view of area I; Figure 7 : The front view of the slow burning mode of the connotation road of the present invention; Figure 8 : A front view of the outer duct rotating detonation mode of the present invention; In the figure: 1- oil supply pipe, 2- air supply pipe, 3- vortex finder, 4- ignition nozzle, 5- support plate oil supply assembly, 51- mounting groove, 6- conversion valve, 7- central ignition nozzle, 8- air atomizing nozzle, 9- central cone cavity, 91- inner cone cavity, 10- oblique radial flame transfer groove, 11- combustion chamber, 12- convergent section, 13- divergent section, 14- support plate injection nozzle, 15- support plate recirculation zone, 16- gas flow, 17- central oblique injection hole, 18- central injection fuel, 19- rotating detonation wave, 20- partition, 21- annular channel. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0021] Example: like Figures 1 to 8 As shown, a dual-mode afterburner combustion chamber structure includes an inner duct structure, an outer duct structure, a combustion chamber 11 and a nozzle. A partition 20 is arranged between the inner duct structure and the outer duct structure. The partition 20 is rotatably connected to the conversion valve 6, and the conversion valve 6 is a rear duct mode conversion valve. One end of the combustion chamber 11 is connected to the inner duct structure and the outer duct structure respectively, and the other end of the combustion chamber 11 is connected to the nozzle.

[0022] The inner channel structure is provided with a support plate oil supply assembly 5, a center cone cavity 9 and a slanting radial flame transmission groove 10. The center cone cavity 9 is arranged at the bottom of the inner channel structure, the support plate oil supply assembly 5 is arranged at the top of the inner channel structure, the support plate oil supply assembly 5 is an integrated support plate oil supply flame stabilizing assembly, one end of the slanting radial flame transmission groove 10 is connected with the center cone cavity 9, the other end of the slanting radial flame transmission groove 10 is connected with a mounting groove 51 where the support plate oil supply assembly 5 is arranged, and a partition plate 20 is arranged at the top of the support plate oil supply assembly 5.

[0023] The center cone cavity 9 is provided with a center ignition electrode 7 and an air atomizing nozzle 8, and the center ignition electrode 7 is located above the air atomizing nozzle 8.

[0024] A center slanting entry hole 17 is arranged on one side of the center cone cavity 9 close to an inner cone cavity 91, and the center slanting entry hole 17 connects the inner cavity of the center cone cavity 9 with the inner cone cavity 91.

[0025] A support plate injection nozzle 14 is arranged on the support plate oil supply assembly 5, and the support plate injection nozzle 14 is arranged on both sides of the support plate oil supply assembly 5.

[0026] The outer channel structure is provided with an oil supply pipe 1, an air supply pipe 2, a vortex generator 3 and an ignition electrode 4. The oil supply pipe 1 and the air supply pipe 2 are arranged on the left side of the vortex generator 3, the ignition electrode 4 is arranged on the right side of the vortex generator 3, and one end of the oil supply pipe 1 and the air supply pipe 2 is connected with the vortex generator 3.

[0027] The nozzle comprises a converging section 12 and a diverging section 13. One end of the converging section 12 is connected with the diverging section 13, and the other end of the converging section 12 is connected with the combustion chamber 11.

[0028] A dual-mode afterburner structure mode adjusting method, which comprises the following steps: adjusting a switching valve 6 to make the inner channel structure and the outer channel structure respectively form communication with the combustion chamber 11, and adjusting the angle of the nozzle, so as to realize the conversion process between the slow combustion working mode and the deflagration working mode.

[0029] The adjusting steps of the slow combustion working mode comprise: A1: adjusting the switching valve 6 to make the outer channel structure no longer form communication with the combustion chamber 11, and only make the inner channel structure form communication with the combustion chamber 11. When the engine afterburner is turned on, the gas flow 16 in the center cone cavity 9 passes through the center slanting entry hole 17 to the inner cone cavity 91 and forms a backflow area, the center injection fuel 18 sprayed by the air atomizing nozzle 8 is broken and evaporated under the action of the gas flow, and the oil and gas mixture is formed after the center injection fuel 18 is mixed with the gas flow 16 and enters the backflow area on the inner cone cavity 91. A2: When the engine is in boost mode and transitions to partial boost and full boost, the support plate oil supply assembly 5 sprays fuel laterally through the support plate injection nozzle 14. The injected fuel is broken and evaporated under the action of the engine mainstream airflow and then enters the support plate recirculation area 15 at the trailing edge of the support plate oil supply assembly 5 to form a stable oil mist field. The mainstream airflow refers to the internal incoming airflow, located in the mainstream channel of the support plate oil supply assembly 5, and the area formed between the partition 20 and the mounting groove 51; the central ignition nozzle 7 releases high-energy electric sparks to ignite the oil-gas mixture in the recirculation area of ​​the inner cone cavity 91 and the support plate recirculation area 15, and form a continuous and stable ignition source. At the same time, the inner cone cavity The oil and gas mixture in the recirculation zone of cavity 91 is combined and propagated through the flame of the oblique radial flame transfer groove 10 and the support plate recirculation zone 15 to form a main combustion zone. The oil and gas mixture in the main combustion zone enters the combustion chamber 11 to continue to burn. The high-temperature combustion gas generated by the combustion after the support plate oil supply assembly 5 replenishes the oil enters the combustion chamber 11 and continues to burn to increase the thermal enthalpy of the gas, and expands through the nozzle to do work and generate thrust. At the same time, in order to ensure that the change in airflow volume caused by the change in combustion parameters in the combustion chamber 11 can be better converted into airflow kinetic energy to increase the effective thrust, the flow area in the convergent section 12 and the expansion section 13 of the nozzle is adjusted by the actuator.

[0030] The step of adjusting the deflagration working mode includes: A3: Adjust the switching valve 6 so that the inner duct structure no longer communicates with the combustion chamber 11, and only the outer duct structure communicates with the combustion chamber 11; A4: Fuel and gas are supplied respectively in a specific ratio through the oil supply pipe 1 and the gas supply pipe 2 according to the required force. The fuel and gas are fully mixed through the vortex finder 3. There are 18 vortex finders 3 evenly distributed in the circumferential direction. During operation, the oil and gas mixture premixed by a single vortex finder 3 is triggered by the high-energy spark released by the ignition nozzle 4 to generate a high-pressure and high-temperature detonation wave. The single detonation wave is guided by the inner cone (the structure formed by the inner cone cavity 9 after the conversion valve 6 is adjusted in this step) and propagates at high speed along the annular channel 21 to form a rotating detonation wave 19. During the propagation process, the annular channel 21 guides the detonation wave to rotate stably to avoid stagnation or flameout. The area of ​​the annular channel 21 is Figure 4 The area from the ignition nozzle 4 in the axial position to the central concave cavity 9. Controlling the stability of the detonation wave during this process is a difficult issue. Since the rotating detonation wave 19 is easily interrupted or disturbed due to changes in local conditions, the detonation wave control measures include: optimizing the number and spacing of the vortex finders 3, the axial distance between the ignition nozzles 4 and the vortex finders 3, and the number and axial distribution of the ignition nozzles 4 according to actual needs; the high-pressure, high-temperature airflow directly impacts the combustion chamber 11. The rotating detonation wave 19, through the coordinated action of the combustion chamber 11 and the nozzle, ensures that the detonation wave energy is efficiently converted into kinetic energy, pushing the gas out of the nozzle to generate thrust.

[0031] During the transition between slow-burn and deflagration modes, transitional interference may occur. Specifically, residual gas may cause detonation at the moment of transition. In this case, a rapid purge valve can be installed within the internal flow passage of the combustion chamber 11 to remove residual gas before switching between combustion modes. Subsequently, a mode switch request is triggered by flight conditions (e.g., Mach number, thrust demand) or sensor feedback (pressure, temperature). The switching valve 6, driven by an actuator, rotates to initiate the mode switch. During the transition between slow-burn and deflagration modes, all fuel supply / ignition mechanisms are temporarily shut down to ensure interference between the two modes. The nozzle's convergent section 12 and divergent section 13 are pre-adjusted to the preset angles for the target mode, minimizing thrust fluctuations caused by the mode switch.

[0032] This application is applicable to aero-engines that are a combination of ramjet and turbofan.

Claims

1. A dual-mode afterburner structure, characterized by: The invention comprises an inner duct structure, an outer duct structure, a combustion chamber (11) and a nozzle, wherein a partition (20) is provided between the inner duct structure and the outer duct structure, and a switching valve (6) is connected to the partition (20). One end of the combustion chamber (11) is connected to the inner duct structure and the outer duct structure respectively, and the other end of the combustion chamber (11) is connected to the nozzle.

2. The dual-mode afterburner structure according to claim 1, characterized in that: A support plate oil supply assembly (5), a central cone cavity (9) and an oblique radial flame transmission groove (10) are provided on the inner channel structure. The central cone cavity (9) is provided at the bottom of the inner channel structure, and the support plate oil supply assembly (5) is provided at the top of the inner channel structure. One end of the oblique radial flame transmission groove (10) is connected to the central cone cavity (9), and the other end of the oblique radial flame transmission groove (10) is connected to the mounting groove (51) where the support plate oil supply assembly (5) is provided. A partition plate (20) is provided on the top of the support plate oil supply assembly (5).

3. The dual-mode afterburner structure according to claim 2, characterized in that: A central ignition nozzle (7) and an air atomizing nozzle (8) are provided on the central cone cavity (9), and the central ignition nozzle (7) is located above the air atomizing nozzle (8).

4. The dual-mode afterburner structure according to claim 2, characterized in that: A central oblique incident hole (17) is provided on the central cone cavity (9) on a side close to the inner cone cavity (91), and the central oblique incident hole (17) connects the inner cavity of the central cone cavity (9) and the inner cone cavity (91).

5. The dual-mode afterburner structure according to claim 2, characterized in that: The support plate oil supply assembly (5) is provided with a support plate injection nozzle (14).

6. The dual-mode afterburner structure according to claim 1, characterized in that: An oil supply pipe (1), an air supply pipe (2), a vortex finder (3) and an ignition nozzle (4) are provided on the outer duct structure. The oil supply pipe (1) and the air supply pipe (2) are provided on the left side of the vortex finder (3), and the ignition nozzle (4) is provided on the right side of the vortex finder (3). One end of the oil supply pipe (1) and the air supply pipe (2) are connected to the vortex finder (3).

7. The dual-mode afterburner structure according to claim 1, characterized in that: The nozzle comprises a convergent section (12) and an expansion section (13), one end of the convergent section (12) is connected to the expansion section (13), and the other end of the convergent section (12) is connected to the combustion chamber (11).

8. A method for adjusting the structural modality of a dual-mode afterburner according to any one of claims 1 to 7, characterized in that: The invention includes adjusting the conversion valve (6) so that the inner duct structure and the outer duct structure are connected to the combustion chamber (11) respectively, and adjusting the nozzle angle to realize the process of switching between the slow combustion working mode and the deflagration working mode.

9. A method for adjusting the structural modality of a dual-mode afterburner according to claim 8, characterized in that: The adjustment steps of the slow combustion working mode include: A1: Adjust the switching valve (6) so that the outer duct structure no longer communicates with the combustion chamber (11), and only the inner duct structure communicates with the combustion chamber (11). When the engine is powered on, the gas flow (16) inside the central conical cavity (9) passes through the central oblique injection hole (17) to the inner conical cavity (91) and forms a recirculation zone. The fuel sprayed from the air atomizing nozzle (8) mixes with the gas flow (16) and enters the recirculation zone on the inner conical cavity (91) to form an oil-gas mixture. A2: When the engine boost is switched to the partial boost and full boost state, the support plate oil supply assembly (5) injects fuel through the support plate injection nozzle (14). The injected fuel is broken and evaporated under the action of the engine mainstream airflow and then enters the support plate recirculation area (15) at the trailing edge of the support plate oil supply assembly (5) to form a stable oil mist field. The central ignition nozzle (7) releases an electric spark to ignite the oil-gas mixture in the recirculation area of ​​the inner cone cavity (91) and the support plate recirculation area (15), and forms a continuous and stable ignition source. At the same time, the oil-gas mixture in the recirculation area of ​​the inner cone cavity (91) is connected and spread through the flame of the oblique radial flame transfer groove (10) and the support plate recirculation area (15), forming a main combustion area. The oil-gas mixture in the main combustion area enters the combustion chamber (11) and continues to burn.

10. The method for adjusting the structural mode of a dual-mode afterburner according to claim 8, wherein: The step of adjusting the deflagration working mode includes: A3: Adjust the switching valve (6) so that the inner duct structure no longer communicates with the combustion chamber (11), and only the outer duct structure communicates with the combustion chamber (11); A4: Fuel and gas are supplied through the fuel supply pipe (1) and the gas supply pipe (2) respectively. The fuel and gas are fully mixed through the vortex finder (3) and generate a detonation wave under the condition of energy supplied by the electric spark of the ignition nozzle (4). The detonation wave rotates and propagates along the annular channel (21) under the guidance of the inner cone, and continuously burns in the circumferential direction to release energy and generate thrust; During the transition phase between the slow combustion working mode and the deflagration working mode, the convergent section (12) and the divergent section (13) of the nozzle are adjusted in advance to the preset angles of the target mode.

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