A turbine afterburner matching system for a small turbojet engine supercharged afterburner combustion chamber

Abstract

The present invention discloses a turbine afterburner matching system for a small turbojet engine supercharged afterburner combustion chamber. The system comprises a mixing channel and a supercharged annular cavity. The mixing channel communicates with the supercharged annular cavity, and an anti-backflow unit is provided between the mixing channel and the supercharged annular cavity. The anti-backflow unit is used to control the directional flow of fluid through the mixing channel into the supercharged annular cavity. This ensures a stable front-to-rear pressure drop ratio for the turbine in the supercharged afterburner combustion chamber of the small turbojet engine, prevents premature fuel autoignition, and ensures the stability of the turbine's operating state.

Description

Technical Field

[0001] The invention relates to the field of small turbojet engines with afterburner combustion chambers, in particular to a turbine afterburner matching system of a supercharged afterburner combustion chamber of a small turbojet engine. Background Art

[0002] The afterburner is a critical component of aircraft engines. Its use significantly increases the engine's specific thrust and thrust-to-weight ratio, comprehensively improving aircraft maneuverability and expanding the flight envelope. Conventional afterburners are long and heavy, limiting further improvements in the thrust-to-weight ratio of afterburning turbine engines. However, the afterburners used in small turbojet engines have a reduced barrel length and diameter, significantly shortening the fuel's residence time in the combustion chamber. Consequently, a significant amount of fuel is burned outside the tailpipe, reducing combustion chamber performance.

[0003] Because the supercharged combustion chamber offers advantages such as increased combustion pressure, a fast combustion rate, and high combustion efficiency, it can achieve continuous supercharged combustion after a single detonation. It also operates stably at inflow velocities from subsonic to supersonic. Therefore, constructing a supercharged afterburner chamber using supercharged combustion technology can significantly shorten the chamber's structural length, significantly reduce the afterburner's structural size and weight, and significantly improve the engine's thrust-to-weight ratio. However, since supercharged combustion will generate high-frequency pressure pulsations of more than several thousand hertz at the head of the supercharged annular cavity, and the pressure pulsation amplitude is very large, it is easy to cause pressure to be transmitted back to the turbine, resulting in a decrease in the turbine pressure drop ratio and deviation from its design point, thereby causing a decrease in the turbine output power, seriously interfering with the normal operation of the turbine; in addition, the high-temperature and high-pressure combustion gas generated after the detonation wave flows back to the inlet flow channel of the supercharged annular cavity, which will also cause the injected fuel to spontaneously ignite prematurely; due to the pressure feedback and the flame feedback generated by the premature spontaneous combustion of the injected fuel, the temperature distribution design of the turbine blades is affected, the local temperature of the turbine blades increases, and the turbine performance and life are reduced; the problem of the turbine being easily affected in the supercharged afterburner combustion chamber constructed with supercharged combustion technology needs to be solved urgently. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiency in the prior art that the turbine of the supercharged afterburner combustion chamber is easily affected by detonation waves, and provide a turbine afterburner matching system of the supercharged afterburner combustion chamber of a small turbojet engine, which includes a mixing flow channel, a supercharged annular cavity and an anti-backflow unit, and the anti-backflow unit is installed between the mixing flow channel and the supercharged annular cavity; the anti-backflow unit can suppress the backflow of high-temperature and high-pressure gas generated by the detonation wave, reducing the influence of the high-temperature and high-pressure gas on the turbine, and solving the problem that the turbine in the supercharged afterburner combustion chamber constructed with supercharged combustion technology is easily affected by detonation waves.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] A turbine afterburner matching system for a supercharged afterburner combustion chamber of a small turbojet engine includes a mixing flow channel and a supercharged annular cavity. The mixing flow channel is connected to the supercharged annular cavity. An anti-backflow unit is provided at the connection between the mixing flow channel and the supercharged annular cavity. The anti-backflow unit is used to control the directional flow of fluid into the supercharged annular cavity through the mixing flow channel.

[0007] Currently, to achieve a significant increase in engine thrust in a short period of time, aircraft engines often utilize afterburners to inject fuel into the afterburner engine, ignite, and burn the fuel into the gas or fan airflow, thereby improving aircraft maneuverability. However, due to the combustion conditions in conventional afterburners, the gas entering the afterburner is first decelerated in the diffuser and mixed with the fuel injected by the nozzle to form an oil-air mixed flow. To ensure a good distribution of fuel concentration throughout the afterburner, dozens or hundreds of centrifugal or direct current nozzles are generally used for fuel injection. These nozzles are mounted on a fuel supply ring. After the oil-air mixed flow passes through the flame stabilizer, a recirculation zone is formed, which reduces the local airflow velocity to facilitate combustion. At the same time, another portion of fuel is directly injected near the flame stabilizer to create an oil-rich zone behind the flame stabilizer, improving combustion stability. As a result, the airflow in the afterburner has low pressure and high velocity, requiring the ignited mixture to complete combustion within a longer cylinder. For small turbojet engines, the use of an afterburner requires a corresponding reduction in the diameter and length of the afterburner cylinder, significantly reducing afterburner performance. To compensate for these deficiencies, a supercharged combustion technique, such as supercharged combustion, which offers advantages such as supercharged combustion and high combustion efficiency, can be employed to construct a supercharged afterburner. This shortens the afterburner's structural length and significantly improves the engine's thrust-to-weight ratio. However, the detonation wave generated by supercharged combustion can cause pressure to be transmitted back to the turbine, reducing the turbine's pressure drop ratio and deviating from the design point. Furthermore, the high-temperature, high-pressure combustion generated by the detonation wave can also cause the injected fuel to spontaneously ignite prematurely due to the transmission back to the supercharged annular cavity inlet flow passage, thereby affecting the combustion efficiency of the supercharged afterburner. Furthermore, premature fuel spontaneous combustion can also increase the local temperature of the turbine blades. Consequently, the turbine's performance and life are affected by this high-temperature, high-pressure combustion.

[0008] In the embodiment of the present application, the supercharged afterburner combustion chamber includes a mixing flow channel and a supercharged annular cavity; the mixing flow channel is used to input an oil-gas mixture into the supercharged afterburner combustion chamber, and the supercharged annular cavity is used to detonate the oil-gas mixture. After the oil-gas mixture is detonated, a detonation wave is generated and high-temperature and high-pressure combustion gas is formed. Since the high-temperature and high-pressure combustion gas is prone to backflow in the mixing flow channel and the supercharged annular cavity, the returned high-temperature and high-pressure combustion gas will affect the working state of the turbine; in order to reduce the influence of the high-temperature and high-pressure combustion gas on the turbine, the supercharged afterburner combustion chamber is used to detonate the oil-gas mixture. The pressure-boosted combustion chamber also includes an anti-backflow unit, which is installed between the mixing flow channel and the boost annular cavity. The anti-backflow unit is used to control the fluid to flow into the boost annular cavity only through the mixing flow channel. In this way, when the detonation wave occurs, through the setting of the anti-backflow unit, the mixing flow channel and the boost annular cavity only have a one-way flow effect, and the high-temperature and high-pressure combustion gas generated by the detonation wave cannot be transmitted back to the mixing flow channel or the boost annular cavity, thereby avoiding the impact of the backflow of the detonation wave on the normal working state of the turbine.

[0009] Furthermore, it also includes a supercharged afterburner outer cylinder, a supercharged ring cavity outer ring, a supercharged ring cavity inner ring and a supercharged afterburner inner cylinder, a first channel is left between the supercharged afterburner outer cylinder and the supercharged ring cavity outer ring, a second channel is left between the supercharged afterburner inner cylinder and the supercharged ring cavity inner ring, the supercharged ring cavity outer ring is arranged outside the supercharged ring cavity inner ring, and a main channel is formed between the supercharged ring cavity outer ring and the supercharged ring cavity inner ring, and the mixing flow channel, the supercharged ring cavity and the anti-backflow unit are all located in the main channel.

[0010] In an embodiment of the present application, it also includes a supercharged afterburner outer cylinder and a supercharged afterburner inner cylinder, a first channel is left between the supercharged afterburner outer cylinder and the outer ring of the supercharged ring cavity, and a second channel is left between the supercharged afterburner inner cylinder and the inner ring of the supercharged ring cavity; thus, in an embodiment of the present application, when airflow passes through the first channel and the second channel, since the supercharged ring cavity outer ring is arranged outside the supercharged ring cavity inner ring, a main channel is formed between the supercharged ring cavity outer ring and the supercharged ring cavity inner ring and the mixing flow channel, the supercharged ring cavity and the anti-backflow unit are all installed in the main channel, the first channel and the second channel are able to dissipate heat from the components in the main channel, thereby improving the working stability of the engine.

[0011] Furthermore, the mixing flow channel includes a straight section and a convergent section, the straight section is located at the inlet of the mixing flow channel, one end of the convergent section is connected to the straight section, and the other end thereof gradually converges and is connected to the boost ring cavity.

[0012] In an embodiment of the present application, the mixing flow channel includes a straight section and a convergent section, the straight section is located at the inlet of the mixing flow channel, one end of the convergent section is connected to the straight section, and the other end thereof gradually converges and is connected to the boost annular cavity; thereby, the speed of the oil-gas mixture can be increased in the mixing flow channel through the cooperation of the convergent section and the straight section, and the boost afterburner combustion chamber can flow more oil-gas mixture in a shorter time, thereby improving the working efficiency of the boost afterburner combustion chamber; in addition, since the straight section and the convergent section reduce the pressure of the oil-gas mixture, the flow of the oil-gas mixture in the boost afterburner combustion chamber can have higher stability.

[0013] Furthermore, the anti-backflow unit includes an isolation section, which includes a plurality of wedge-shaped barbs, and the plurality of wedge-shaped barbs are connected in sequence and in the same direction. The isolation section is installed in the convergent section of the mixing channel and is used to suppress the interference of pressure fluctuations in the boost ring cavity on the fluid flow in the mixing channel.

[0014] In an embodiment of the present application, the anti-backflow unit includes an isolation section, and the isolation section includes a plurality of wedge-shaped barbs. Thus, the isolation section is installed in the convergent section of the mixing flow channel. Since the wedge-shaped barbs have little obstruction to the flow of low-pressure and high-temperature gas after the turbine flowing in the forward direction, and the wedge-shaped barbs have great obstruction to the flow of high-temperature and high-pressure gas flowing in the reverse direction; that is, through the unidirectional flowability of the fluid by the wedge-shaped structure, in the embodiment of the present application, through the isolation section including a plurality of wedge-shaped barbs, when the high-temperature and high-pressure gas generated after the detonation wave is returned to the mixing flow channel, the occurrence of the problem of the detonation wave pressure backflow affecting the turbine is suppressed.

[0015] Furthermore, the anti-backflow unit also includes a Tesla valve, which is installed at the inlet of the boost ring cavity and is used to inhibit the high-temperature and high-pressure gas from being backflowed to the intake end of the boost ring cavity.

[0016] In an embodiment of the present application, in order to achieve the unidirectional conductivity of the boost annular cavity and avoid the anti-backflow unit structure being too complicated, the anti-backflow unit also includes a Tesla valve, which is installed at the inlet of the boost annular cavity; in an embodiment of the present application, due to the unidirectional conductivity of the Tesla valve, when the high-temperature and high-pressure gas is returned to the boost annular cavity, the Tesla valve installed at the inlet of the boost annular cavity can suppress the backflow of the high-temperature and high-pressure gas, thereby suppressing the pressure backflow of the high-temperature and high-pressure gas after the detonation wave, which causes a decrease in the turbine pressure drop ratio; in addition, suppressing the backflow of the high-temperature and high-pressure gas also avoids the occurrence of problems such as premature spontaneous combustion of the fuel and the influence of the temperature of the turbine blades, and the combustion efficiency of the boost afterburner combustion chamber and the performance of the turbine are improved.

[0017] Furthermore, the Tesla valve includes a plurality of Tesla valve units, which are connected in sequence and distributed axially along the axis of the boost ring cavity; the Tesla valve unit includes a secondary flow channel and a main flow channel, and the secondary flow channel is paired one-to-one with the main flow channel and is connected.

[0018] In an embodiment of the present application, the Tesla valve includes a plurality of Tesla valve units, and the Tesla valve includes a plurality of secondary flow channels and a plurality of main flow channels, and the plurality of main flow channels are paired and connected with the plurality of secondary flow channels one by one to form a plurality of Tesla valve units; in an embodiment of the present application, in order to avoid the high-temperature and high-pressure gas flowing through the Tesla valve, due to improper setting of the Tesla valve units in the Tesla valve, resulting in the high-temperature and high-pressure gas still being able to be returned in the boost ring cavity, the plurality of Tesla valve units are connected in sequence and distributed axially along the axis of the boost ring cavity.

[0019] Furthermore, a flow channel selection valve capable of opening or closing the inlet air flow path of the mixing flow channel is provided at the inlet of the mixing flow channel.

[0020] In an embodiment of the present application, in order to adapt to different working states of the engine, the boost and afterburner combustion chamber also includes a flow channel selection valve, which is located at the inlet of the mixing flow channel and is used to open or close the intake air flow path of the mixing flow channel; in this way, when the engine is in different states, the boost and afterburner combustion chamber can adjust to different working states by switching the intake air flow path through the flow channel selection valve to adapt to different working states of the engine, thereby improving the working stability of the engine.

[0021] In summary, the present invention has the following beneficial effects compared with the prior art: the present application is provided with an isolation section for suppressing the return of high-temperature and high-pressure gas, which causes a decrease in the turbine pressure drop ratio and thus affects the turbine output power, and a Tesla valve for suppressing the return of the high-temperature and high-pressure gas to the inlet flow channel of the boost annular cavity, which causes the injected fuel to spontaneously ignite in advance and affects the working efficiency of the combustion chamber; in addition, by arranging the isolation section and the Tesla valve between the mixing flow channel and the boost annular cavity in the present application, the occurrence of the problem of reduced performance and life of the turbine due to the return of the high-temperature and high-pressure gas affecting the blade temperature not meeting the design value is also suppressed; thus, for the boost afterburner combustion chamber in the present application, the influence of the high-temperature and high-pressure gas on the turbine is reduced, and the working performance of the small turbojet engine is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0023] Figure 1 Schematic diagram of the boost and afterburner chamber of the present invention;

[0024] Figure 2 Schematic diagram of the wedge-shaped barb of the isolation section in the present invention;

[0025] Figure 3 Schematic diagram of the forward flow of air in the Tesla valve of the present invention;

[0026] Figure 4 Schematic diagram of reverse flow of air in the Tesla valve of the present invention;

[0027] Figure 5 Schematic diagram of the Tesla valve unit in the present invention;

[0028] Figure 6 This is a schematic diagram of the working mode of the turbocharger and afterburner turbine in the present invention;

[0029] Figure 7 This is a schematic diagram of the supercharged and afterburner working mode of the supercharged and afterburner combustion chamber of the present invention;

[0030] →Indicates the direction of gas.

[0031] The names corresponding to the accompanying drawings are: 1. Mixing flow channel; 2. Isolation section; 3. Tesla valve; 4. Boost annular cavity; 5. Boost annular cavity outer ring; 6. Boost annular cavity inner ring; 7. Boost and afterburner outer cylinder; 8. Boost and afterburner inner cylinder; 9. Flow channel selection valve; 10. Gas collecting cavity; 11. Guide plate; 12. Outer oil baffle; 13. Inner oil baffle; 14. Injection rod; 15. Detonator nozzle; 16. Pneumatic plug nozzle; 17. Inner cone; 21. Wedge-shaped barb; 31. Tesla valve inlet; 32. Tesla valve outlet; 33. Inlet flow channel; 34. Secondary flow channel; 35. Main flow channel; 36. Outlet flow channel; 37. Tesla valve unit body. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0033] Example:

[0034] like Figures 1 to 7As shown, in this embodiment, it includes a mixing flow channel 1 and a boost annular cavity 4. After the mixing flow channel 1 inputs an oil-gas mixture into the boost annular cavity 4, the oil-gas mixture detonates in the boost annular cavity 4, and the gas mixture forms a detonation wave and generates high-temperature and high-pressure gas. The high-temperature and high-pressure gas with huge energy expands violently in the boost annular cavity 4, and the violently expanded high-temperature and high-pressure gas generates a pressure fluctuation in the boost annular cavity 4 that is higher than that of the mixing flow channel 1. When the high-temperature and high-pressure gas is returned, the turbine pressure drop ratio is likely to decrease, thereby reducing the turbine performance. In addition, due to the high temperature of the high-temperature and high-pressure gas fuel, it is easy for the fuel to self-ignite prematurely when it is returned, thereby reducing the combustion efficiency of the supercharged afterburner combustion chamber. Therefore, in this embodiment, in order to prevent the operation of the turbine from being affected by the returned high-temperature and high-pressure gas, the return of the high-temperature and high-pressure gas needs to be suppressed. Therefore, the supercharged afterburner combustion chamber also includes an anti-backflow unit, which is located at the connection between the mixing flow channel (1) and the supercharged annular cavity (4) and is used to control the fluid to be transferred only through the mixing flow channel 1 to the supercharged annular cavity 4. Therefore, the connected mixing flow channel 1 and the supercharged annular cavity 4 can be approximately a one-way channel. Through the setting of the anti-backflow unit, the high-temperature and high-pressure gas generated after the fluid is detonated cannot be returned, thereby avoiding the influence of the high-temperature and high-pressure gas return on the turbine, thereby improving the stability of the engine working state.

[0035] In this embodiment, in order to improve the operational stability of the various components in the boost and afterburner, the system further includes a boost and afterburner outer cylinder 7, a boost annular cavity outer ring 5, a boost annular cavity inner ring 6, and a boost and afterburner inner cylinder 8. A first channel is provided between the boost and afterburner outer cylinder 7 and the boost annular cavity outer ring 5, and a second channel is provided between the boost and afterburner inner cylinder 8 and the boost annular cavity inner ring 6. The boost annular cavity outer ring 5 is sleeved outside the boost annular cavity inner ring 6, and a main channel is formed between the boost annular cavity outer ring 5 and the boost annular cavity inner ring 6. Furthermore, this embodiment further includes a guide plate 11 and an aerodynamic plug nozzle 16. Thus, in this embodiment, after the airflow is guided by the guide plate 11 and flows into the main channel, both the first channel and the second channel receive the airflow. As such, since the dilution flow channel 1, the supercharger annular cavity 4, and the anti-passback unit are all located within the main channel, the first and second channels can dissipate heat from the components within the main channel, thereby improving the operational stability of the supercharged afterburner. Furthermore, the exhaust end of the second channel can be connected to the aerodynamic plug nozzle 16. Thus, after cooling, the airflow from the second channel can be discharged through the aerodynamic plug nozzle 16 to further power the engine.

[0036] In this embodiment, in order to achieve sufficient detonation of the oil-gas mixture in the boost annular cavity 4, the height of the boost annular cavity 4 can be 5 mm and the length can be 200 mm. In addition, in this embodiment, the mixing channel 1 serving as the channel for inputting the oil-gas mixture includes a convergent section and a straight section. The straight section is located at the entrance of the mixing channel 1. One end of the convergent section is connected to the straight section, and the other end thereof gradually converges and is connected to the boost annular cavity 4. In this way, the oil-gas mixture can increase the speed of the oil-gas mixture in the mixing channel 1 through the cooperation of the convergent section and the straight section, while reducing the pressure of the oil-gas mixture. In this embodiment, when the oil-gas mixture flows through the mixing channel 1, the speed of the oil-gas mixture increases and the pressure decreases after the oil-gas mixture passes through the straight section and the convergent section; in this way, the oil-gas mixture can flow to the boost annular cavity 4 more quickly and smoothly.

[0037] In this embodiment, the anti-backflow unit includes an isolation section 2, which is arranged in the mixing channel 1. In order to further avoid the impact of the high-temperature and high-pressure gas backflow on the turbine, the isolation section 2 can be arranged in the convergent section of the mixing channel 1 and is used to suppress the interference of pressure fluctuations in the boost annular cavity 4 on the fluid flow of the mixing channel 1; in addition, the isolation section 2 includes a plurality of wedge-shaped barbs 21 structures and the plurality of wedge-shaped barbs 21 are connected in sequence and in the same direction, so that the isolation section 2 can more accurately suppress the backflow of the high-temperature and high-pressure gas; in this embodiment, in order for the isolation section 2 to effectively suppress the backflow of the high-temperature and high-pressure gas, the number of the wedge-shaped barbs 21 can be 4, the width w of the wedge-shaped barbs 21 can be in the range of 1 / 12 of the diameter of the boost annular cavity outer ring 5, the height h can be in the range of 1 / 12 of the diameter of the boost annular cavity outer ring 5, and the inclination angle α can be in the range of 60°. Therefore, when the low-pressure and high-temperature gas after the turbine flows forward through the wedge-shaped barb 21, due to the wedge-shaped structure of the wedge-shaped barb 21, the wedge-shaped barb 21 has little flow resistance to the low-pressure and high-temperature gas flowing forward, and the low-pressure and high-temperature gas can pass through the isolation section 2 smoothly; when the high-pressure and high-temperature gas generated by the detonation wave flows back through the wedge-shaped barb 21 in the reverse direction, the high-pressure and high-temperature gas is greatly affected by the wedge-shaped barb 21 and suffers great flow resistance and pressure loss, that is, the high-pressure and high-temperature gas cannot pass through the isolation section 2 smoothly. Therefore, the isolation section 2 can effectively suppress the pressure backtransmission of the high-pressure and high-temperature gas.

[0038] In this embodiment, the anti-backflow unit further includes a Tesla valve 3, which is installed at the inlet of the boost ring cavity 4. Thus, when the high-temperature and high-pressure gas generated by the detonation wave is backflowed, the backflow of the high-temperature and high-pressure gas is suppressed due to the unidirectional flow of the Tesla valve 3. In this embodiment, the Tesla valve 3 also includes a Tesla valve inlet 31, a Tesla valve outlet 32, an inlet flow channel 33, a secondary flow channel 34, a main flow channel 35 and an outlet flow channel 36, and the main flow channel 35 and the secondary flow channel 34 are paired to form a Tesla valve unit body 37; in order to enable the Tesla valve 3 to achieve the inhibitory effect on the backflow of the high-temperature and high-pressure gas, the Tesla valve 3 includes a plurality of Tesla valve unit bodies 37, and the plurality of Tesla valve unit bodies 37 are arranged axially along the axis of the boost annular cavity 4; one of the application scenarios of this embodiment is a small turbojet engine booster combustion chamber, so the number of the Tesla valve unit bodies 37 can be 4 and the blunt body diameter Φ of the Tesla valve unit body 37 can be 1 / 3 of the annular cavity height, the blunt body angle β can be 15°, and the flow channel width L of the main channel 35 and the secondary flow channel 34 of the Tesla valve unit body 37 can be 1 / 4 of the blunt body diameter Φ. Therefore, when the low-pressure and high-temperature gas after the turbine flows forwardly into the Tesla valve 3 from the Tesla valve inlet 31, the low-pressure and high-temperature gas after the turbine enters the Tesla valve 3 through the inlet flow channel 33 and is divided into the main flow channel 35 and the secondary flow channel 34. However, since the angle between the secondary flow channel 34 and the inlet flow channel 33 is large enough and the secondary flow channel 34 has a bend, the flow rate of the low-pressure and high-temperature gas after the turbine flowing into the main flow channel 35 is much greater than the flow rate of the gas flowing into the secondary flow channel 34. When the low-pressure and high-temperature gas after the turbine merges with the outlet flow channel 36, since the outflow angle between the main flow channel 35 and the secondary flow channel 34 is small enough, the fluid in the secondary flow channel 34 is The flow of the high-temperature, high-pressure gas hardly hinders the flow of the fluid in the main channel 35. When the high-temperature, high-pressure gas generated by the detonation wave flows back into the Tesla valve 3 and enters through the Tesla valve outlet 32, it is divided into the main channel 35 and the secondary channel 34 at the outlet channel 36. Because the angle between the secondary channel 34 and the outlet channel 36 is sufficiently small, the flow rate in the secondary channel 34 is comparable to that in the main channel 35. When the high-temperature, high-pressure gas merges with the inlet channel 33, the angle between the outflow of the main channel 35 and the secondary channel 34 is relatively large, so the flow of the fluid in the secondary channel 34 significantly hinders the flow of the fluid in the main channel 35. Therefore, in this embodiment, the boost annular cavity 4 equipped with the Tesla valve 3 is approximately a unidirectional channel, which suppresses the backflow of the detonation wave and reduces the impact of the backflow of the high-temperature, high-pressure gas on the turbine.

[0039] In this embodiment, the supercharged afterburner used in the system further includes a flow channel selector valve 9, which is located at the entrance of the dilution flow channel 1 and is used to open or close the intake air flow path of the dilution flow channel 1. Thus, by setting different intake air flow paths of the dilution flow channel 1, the operating mode of the supercharged afterburner can be changed, and the supercharged afterburner can be more accurately adapted to different operating conditions of the engine. In this embodiment, the supercharged afterburner used in the system further includes a gas manifold 10, an outer oil baffle 12, an inner oil baffle 13, a fuel injection rod 14, an inner cone 17, and a detonator nozzle 15. When the flow channel selector valve 9 is operated to change the intake air flow path of the dilution flow channel 1 in the supercharged afterburner, when the flow channel selector valve 9 is closed, the supercharged afterburner is in the turbine operating mode. Since the problem of detonation wave back propagation no longer needs to be considered, the air flow is only input through the inner cone 17. When the flow channel selection valve 9 is opened, the air flow flows into the first channel, the second channel and the main channel; at this time, the supercharged afterburner combustion chamber is in the supercharged combustion afterburner mode, and the air flow is guided by the guide plate 11. At the same time, the air collecting cavity 10 that can realize circumferential rectification of the air flow, the outer oil baffle 12 that prevents fuel splashing, the inner oil baffle 13 and the fuel injection rod 14 that provides fuel are used together to realize the operation of inputting the oil-gas mixture into the mixing flow channel 1. When the oil-gas mixture enters the mixing flow channel 1, it first enters the straight section of the mixing flow channel 1 and then enters the convergent section. In this way, the speed of the oil-gas mixture is increased and the pressure of the oil-gas mixture is reduced. In this way, when the oil-gas mixture input from the mixing flow channel 1 works through the detonating nozzle 15, since the mixing degree of the oil-gas mixture is improved, its detonation in the detonating nozzle 15 is also carried out more smoothly, and the oil-gas mixture in the supercharged annular cavity 4 is detonated and forms an explosion. The high-temperature and high-pressure gas after the combustion reaction flows through the second channel composed of the flow channel selection valve 9, the supercharged afterburner outer cylinder 7, the supercharged afterburner inner cylinder 8 and the aerodynamic plug nozzle 16. The high-temperature and high-pressure gas expands and accelerates at the aerodynamic plug nozzle 16 to generate thrust. In addition, when the high-temperature and high-pressure gas flows through the supercharged annular cavity 4, the Tesla valve 3 arranged at the inlet of the supercharged annular cavity 4 has an almost unidirectional flow effect on the high-temperature and high-pressure gas. On the one hand, it suppresses the influence of the high-temperature and high-pressure gas pressure backtransmission on the turbine pressure drop ratio. On the other hand, it suppresses the high temperature of the high-temperature and high-pressure gas generated by the detonation wave from being backtransmitted to the mixing flow channel 1, thereby avoiding the problem of premature spontaneous combustion of the injected fuel. At the same time, the isolation section 2 arranged at the convergent section of the mixing flow channel 1 can also suppress the detonation wave pressure backtransmission through a plurality of wedge-shaped barbs 21 with the same direction, thereby avoiding the problem of a reduction in the turbine pressure drop ratio and thus interference with the normal operation of the turbine.

[0040] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A turbine afterburner matching system for a small turbojet engine supercharged afterburner combustion chamber, comprising a mixing flow channel (1) and a supercharged annular cavity (4), characterized in that: The mixing flow channel (1) is in communication with the boost annular cavity (4), and an anti-backflow unit is provided at the connection between the mixing flow channel (1) and the boost annular cavity (4), and the anti-backflow unit is used to control the directionality of the fluid flowing into the boost annular cavity (4) through the mixing flow channel (1); The anti-backflow unit further comprises a Tesla valve (3), which is installed at the inlet of the boost annular cavity (4) and is used to inhibit the high-temperature and high-pressure gas from being backflowed to the intake end of the boost annular cavity (4); The Tesla valve (3) comprises a plurality of Tesla valve units (37), wherein the plurality of Tesla valve units (37) are connected in sequence and distributed axially along the axis of the boost ring cavity (4); The Tesla valve unit (37) includes a secondary flow channel (34) and a primary flow channel (35), and the secondary flow channel (34) is paired with the primary flow channel (35) and is in communication with each other. A flow channel selection valve (9) capable of opening or closing the air inlet path of the mixing flow channel (1) is provided at the inlet of the mixing flow channel (1).

2. The turbine afterburner matching system of a small turbojet engine supercharged afterburner combustion chamber according to claim 1, characterized in that: It also includes a supercharged afterburner outer cylinder (7), a supercharged ring cavity outer ring (5), a supercharged ring cavity inner ring (6) and a supercharged afterburner inner cylinder (8), a first channel is left between the supercharged afterburner outer cylinder (7) and the supercharged ring cavity outer ring (5), a second channel is left between the supercharged afterburner inner cylinder (8) and the supercharged ring cavity inner ring (6), the supercharged ring cavity outer ring (5) is sleeved outside the supercharged ring cavity inner ring (6), a main channel is formed between the supercharged ring cavity outer ring (5) and the supercharged ring cavity inner ring (6), and the mixing flow channel (1), the supercharged ring cavity (4) and the anti-backflow unit are all located in the main channel.

3. The turbine afterburner matching system of a small turbojet engine supercharged afterburner combustion chamber according to claim 1, characterized in that: The mixing flow channel (1) comprises a straight section and a convergent section, wherein the straight section is located at the inlet of the mixing flow channel (1), one end of the convergent section is connected to the straight section, and the other end thereof gradually converges and is connected to the boosting annular cavity (4).

4. The turbine afterburner matching system of a small turbojet engine supercharged afterburner combustion chamber according to claim 3, characterized in that: The anti-backflow unit comprises an isolation section (2), the isolation section (2) comprises a plurality of wedge-shaped barbs (21), the plurality of wedge-shaped barbs (21) are connected in sequence and have the same orientation, the isolation section (2) is installed in the convergent section of the mixing channel (1) and is used to suppress the interference of pressure fluctuations in the boost annular cavity (4) on the fluid flow of the mixing channel (1).

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