Axisymmetric adjustable spray pipe of rotary detonation combined engine adapting to spiral shock wave incoming flow

Abstract

The invention discloses an axisymmetric adjustable spray pipe of a rotary detonation combined engine adapting to spiral shock wave incoming flow, and relates to the field of combined power engines. The jet pipe is composed of fins, a jet pipe shell, an electric push rod, balls, a graphite ring, a jet pipe outer cover, a jet pipe inner cylinder, a jet pipe inner cone and the like, an adjustable outer culvert flow channel is formed between the jet pipe outer cover and the jet pipe inner cylinder, and an outer culvert throat channel is formed in the position, with the minimum axial section area, of the flow channel; an inner culvert flow channel is formed between the spray pipe inner cylinder and the spray pipe inner cone; and the area of the throat of the outer culvert is adjusted through the push-pull action of the electric push rod. Under the working mode of the turbine, air flow is sprayed out through the inner culvert flow channel; and in the stamping mode, air flow is sprayed out through the outer culvert flow channel. In the stamping mode, the area of the throat of the outer culvert is flexibly changed through adjustment of the electric push rod, and the requirements for environment pressure and engine performance at different altitudes are met. The flow matching capacity and expansion pressure ratio adaptability of the engine are improved, and the performance of the rotating and knocking combined engine in the stamping mode is improved.

Description

Technical Field

[0001] The invention relates to the field of combined power engines, in particular to an axisymmetric adjustable nozzle of a rotating detonation combined engine adapted to a spiral shock wave incoming flow. Background Art

[0002] The rotating detonation engine (RDE) is a new type of propulsion engine that uses detonation combustion as a power source. The continuous detonation wave propagates circumferentially in the annular combustion chamber, and the high-temperature and high-pressure products of the detonation combustion are discharged axially outward to generate thrust. The rotating detonation engine has become a research hotspot in the field of aerospace propulsion at home and abroad in recent years due to its simple structure, continuous and stable thrust, and wide operating speed range.

[0003] Combined cycle engines are a type of propulsion system that combines two or more engines. They can meet the needs of efficient operation within a wide range of flight envelopes and have great technical advantages and broad application prospects. A common type of combined cycle engine is the turbine-ramjet combined cycle engine. By further combining it with RDE and replacing the conventional isobaric combustion chamber of the ramjet engine with a rotating detonation combustion chamber, a detonation-modified combined cycle power system can be obtained.

[0004] This rotating detonation combined engine has a wide operating speed range, and the engine flow, flight Mach number, and ambient pressure vary greatly. Therefore, under different operating conditions, the nozzle will face unsteady incoming flows with different shock wave angles and shock wave intensities. Based on this, an adjustable nozzle with adjustment function is designed. According to the incoming shock wave under the current working conditions, the wall configuration can be adjusted so that the shock wave can propagate in the nozzle with minimal energy loss, meeting the engine thrust performance requirements under different operating conditions. Summary of the invention

[0005] The purpose of the present invention is to provide an axially symmetrical adjustable nozzle of a rotating detonation combination engine that is adaptable to spiral shock wave flow, which can realize separate exhaust of inner and outer ducts of the combination engine, and the outer duct can be adjusted according to flight conditions to ensure engine flow matching, thereby realizing efficient and stable operation of the combination engine in a wide speed range of flight.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] The utility model discloses an axisymmetric adjustable nozzle of a rotating detonation combination engine adapted to a spiral shock wave flow, comprising a nozzle inner cone, a nozzle inner barrel, a nozzle outer cover, a nozzle shell and an electric push rod; the nozzle outer cover is slidably connected to the rear end of the nozzle shell, the electric push rod is arranged outside the nozzle shell, the fixed end of the electric push rod is connected to the nozzle shell, and the telescopic end of the electric push rod is connected to the nozzle outer cover for adjusting the position of the nozzle outer cover; the nozzle inner barrel is arranged in a cavity formed by the nozzle shell and the nozzle outer cover, and the nozzle inner barrel is connected to the inner wall of the nozzle shell; an outer duct flow channel is formed between the nozzle outer cover and the nozzle inner barrel, and an adjustable throat is formed at the minimum axial cross-section of the flow channel; the nozzle inner cone is arranged in the cavity formed by the nozzle inner barrel, and the nozzle inner cone is connected to the inner barrel wall of the nozzle inner barrel; an inner duct flow channel is formed between the nozzle inner barrel and the nozzle inner cone.

[0008] The nozzle outer cover includes a connecting straight section, a contraction profile section and an expansion profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle outer cover and is used for sliding connection with the nozzle shell; the contraction profile section and the expansion profile section are structures that first contract and then expand from front to back (the so-called expansion and contraction are relative to the central symmetry axis of the nozzle, expansion refers to the increase in the diameter of the cross-sectional circle, and contraction refers to the decrease in the diameter of the cross-sectional circle, the same below), serving as the outer wall surface of the outer duct.

[0009] The nozzle inner cone includes a connecting straight section, an expansion profile section and a contraction profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner cone and is used for fixed connection with the nozzle inner tube; the expansion contraction profile section is a structure which expands first and then contracts from front to back, and serves as the inner wall surface of the internal flow channel.

[0010] The nozzle inner barrel includes an outer wall surface of the nozzle inner barrel and an inner wall surface of the nozzle inner barrel. The outer wall surface of the nozzle inner barrel includes a connecting straight section, an expansion profile section and a contraction profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner barrel, and is used to be fixedly connected with the nozzle shell; the expansion contraction profile section is a structure that first expands and then contracts from front to back, and serves as the inner wall surface of the outer duct. The inner wall surface of the nozzle inner barrel includes a connecting straight section, a contraction profile section and an expansion profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner barrel, and is used to be fixedly connected with the nozzle inner cone; the contraction profile section and the expansion profile section are a structure that first contracts and then expands from front to back, and serves as the outer wall surface of the inner duct.

[0011] The nozzle outer duct flow channel is formed between the nozzle outer cover and the nozzle inner tube; the nozzle inner duct flow channel is formed between the nozzle inner tube and the nozzle inner cone. Since the nozzle outer cover is a contraction-expansion profile and the outer wall surface of the nozzle inner tube is an expansion-contraction profile, the outer duct flow channel forms an adjustable throat at the lowest point of the flow channel outer wall profile and the expansion part of the flow channel inner wall profile.

[0012] The nozzle cover and the nozzle housing are connected by a guide rail for sliding, and a ball is arranged in the guide rail to reduce the friction between the nozzle cover and the nozzle housing.

[0013] A self-lubricating graphite ring is used for heat sealing between the nozzle cover and the nozzle shell. The graphite ring is arranged between the nozzle cover and the nozzle shell for heat sealing of high-temperature airflow.

[0014] An electric push rod is used between the nozzle cover and the nozzle shell for actuation.

[0015] The nozzle inner tube and the nozzle shell are connected by ribs.

[0016] The nozzle inner cone and the nozzle inner tube are connected by ribs.

[0017] Preferably, the electric push rods are evenly distributed around the outer circumference of the nozzle housing, specifically four, and each electric push rod works simultaneously to ensure smooth movement of the nozzle cover.

[0018] Preferably, the guide rail is a groove with balls, which is evenly distributed circumferentially between the nozzle shell and the nozzle cover, specifically 12 in number, with 10 balls in each guide rail to further reduce friction and improve adjustment accuracy and response speed.

[0019] Preferably, the graphite ring is made of self-lubricating material to ensure sealing performance under high-temperature airflow, while having good friction coefficient, thermal conductivity and wear resistance.

[0020] The nozzle of the present invention has two working modes: the first is that the engine is in turbine working mode, and the airflow is ejected through the inner flow channel; the second is that the engine is in ram mode, and the airflow is ejected through the outer flow channel. At this time, the area of ​​the outer throat can be changed by adjusting the electric push rod to adapt to different flight conditions and engine performance requirements.

[0021] In the ramjet mode, when the aircraft is operating at a lower altitude, the electric push rod is extended to move the nozzle cover backward, increasing the culvert throat area, improving the engine flow, and reducing the nozzle expansion ratio; when the aircraft is operating at a higher altitude, the electric push rod is shortened to move the nozzle cover forward, reducing the culvert throat area, reducing the engine flow, and increasing the nozzle expansion ratio.

[0022] The design of the nozzle follows the design criteria of the Laval nozzle, ensuring that the airflow is accelerated to the speed of sound when it flows through the smallest cross-sectional area of ​​the flow channel, and then accelerated to supersonic speed when the cross-sectional area is expanded to provide greater thrust.

[0023] The beneficial effects achieved by the technical solution of the present invention are:

[0024] The present invention adjusts the area of ​​the combined engine outer duct by sliding the nozzle cover, meeting the high performance requirements of the combined engine in a wide working range under the detonation ramjet mode. The basic configuration of the axisymmetric annular converging and diverging nozzle ensures the matching of the engine flow channel while achieving a simple adjustment structure and easy adjustment.

[0025] When the combined engine flies at a low Mach number, it is in turbine mode, with a narrow flight speed range and small flow rate changes. The exhaust gas from the combustion chamber is converted into thrust through the nozzle inner flow channel. When the engine works in a rotating detonation ramjet mode with a wide speed range and high Mach, the electric push rod is extended through the adjustable outer duct of the nozzle, and the nozzle cover is moved backward to increase the throat area and increase the engine flow rate, which is suitable for detonation flows with weaker shock wave intensity under low-altitude and high-speed flight; the electric push rod is shortened, and the nozzle cover is moved forward to reduce the throat area and reduce the engine flow rate, which is suitable for detonation flows with strong shock wave intensity under high-altitude flight. That is, the flow channel matching of the engine is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is an isometric schematic diagram of the present invention.

[0027] Figure 2 It is the main cross-sectional view of the present invention.

[0028] Figure 3 It is a left schematic view of the present invention.

[0029] Figure 4 Isometric diagram of the nozzle shell, nozzle inner barrel and nozzle inner cone assembly.

[0030] Figure 5 It is a schematic diagram of the specific structural identification of the inner flow channel, outer flow channel and inner barrel of the nozzle in the cross-sectional diagram.

[0031] Figure 6 A partial enlarged diagram showing the change in the throat area of ​​the outer duct.

[0032] Figure 7 This is a partial enlarged view of the sliding connection between the nozzle shell and the nozzle inner tube. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and cannot be used to limit the protection scope of the present invention.

[0034] like Figures 1 to 7As shown, the present embodiment is an axisymmetric adjustable nozzle of a rotating detonation combination engine adapted to spiral shock wave flow, comprising fins 1, a nozzle housing 2, an electric push rod 3, a ball 4, a graphite ring 5, a nozzle outer cover 6, a nozzle inner tube 7, and a nozzle inner cone 8.

[0035] The nozzle cover 6 is slidably connected to the front end of the nozzle housing 2, the electric push rod 3 is arranged outside the nozzle housing 2, the fixed end of the electric push rod 3 is connected to the nozzle housing 2, and the telescopic end of the electric push rod 3 is connected to the nozzle cover 6. Specifically, there are 4 electric push rods 3 evenly distributed in the circumference, and they are evenly distributed in the circumference of the nozzle housing 2. The nozzle cover 6 and the nozzle housing 2 are connected by a guide rail for sliding. The guide rail is a groove with balls 4. There are 12 guide rails evenly distributed in the circumference, and each guide rail is provided with 10 balls. The guide rail can reduce friction.

[0036] A self-lubricating graphite ring is used for heat sealing between the nozzle cover 6 and the nozzle housing 2. The graphite material has a low friction coefficient, good thermal conductivity, stable cross-sectional structure, softness, and wear resistance. The graphite ring can ensure the sealing of the high-temperature airflow when the nozzle is working.

[0037] The nozzle inner tube 7 is arranged in the cavity formed by the nozzle shell 2 and the nozzle outer cover 6, and the nozzle inner tube 7 is connected to the inner wall of the nozzle shell 2 through ribs, and there are 6 ribs evenly distributed in the circumference; the outer duct flow channel of the nozzle is formed between the nozzle outer cover 6 and the nozzle inner tube 7, and the outer duct throat is formed at the smallest axial cross-section of the flow channel. Since the nozzle outer cover 6 and the nozzle shell 2 can slide back and forth under the action of the electric push rod 3, the area of ​​the outer duct throat can be adjusted to adapt to the different flow requirements of the engine under different working pressures. Specifically: when the throat area needs to be adjusted, the four electric push rods 3 push and pull at the same time to make the nozzle outer cover 6 translate forward and backward, and the connection between the fixed nozzle shell 2 and the nozzle outer cover 6 is supported and moved by 12 sets of guide rails and balls. The present invention pushes and pulls the electric push rod 3 to make the nozzle cover 6 translate on the guide rail, thereby adjusting the flow rate and expansion ratio of the outer throat, achieving flow matching of the rotating detonation combination engine in a wide speed range of the ramjet mode, and adapting to changes in the expansion pressure ratio.

[0038] The nozzle inner cone 8 is arranged in the cavity formed by the nozzle inner tube 7, and the nozzle inner cone 8 is connected to the nozzle inner tube 7 through ribs, and there are 4 ribs evenly distributed in the circumferential direction; a nozzle internal flow channel is formed between the nozzle inner tube 7 and the nozzle inner cone 8, and a nozzle throat is formed at the smallest axial cross-section of the flow channel.

[0039] Specifically, the nozzle cover 6 includes a connecting straight section, a contraction profile section and an expansion profile section arranged in sequence; the connecting straight section is arranged at the front end of the nozzle cover 6, and is used to be slidably connected with the nozzle housing 2 (the front end and the rear end are relative to the fluid flow direction, and the front direction is Figure 2The contraction profile section and the expansion profile section are structures that contract first and then expand from front to back, serving as the outer wall surface of the outer duct.

[0040] The nozzle inner cone 8 includes a connecting straight section, an expansion profile section and a contraction profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner cone 8, and is used to be fixedly connected to the nozzle inner tube 7; the expansion and contraction profile section is a structure that expands first and then contracts from front to back, and serves as the inner wall surface of the internal flow channel.

[0041] The nozzle inner tube 7 includes an outer wall surface of the nozzle inner tube and an inner wall surface of the nozzle inner tube. The outer wall surface of the nozzle inner tube includes a connecting straight section, an expansion profile section and a contraction profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner tube 7, and is used to be fixedly connected with the nozzle shell 2; the expansion contraction profile section is a structure that first expands and then contracts from front to back, and serves as the inner wall surface of the outer duct. The inner wall surface of the nozzle inner tube includes a connecting straight section, a contraction profile section and an expansion profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner tube 7, and is used to be fixedly connected with the nozzle inner cone 8; the contraction profile section and the expansion profile section are a structure that first contracts and then expands from front to back, and serves as the outer wall surface of the inner duct.

[0042] like Figure 5 As shown, when the outer wall of the nozzle cover 6 and the nozzle inner tube 7 form an outer duct through which air can pass, the outer duct forms an adjustable throat at the narrowest cross-sectional area. Figure 6 As shown, when the nozzle outer cover 6 moves backward, since the inflection point of the contraction and expansion of the nozzle outer cover 6 corresponds to the expansion section of the outer duct of the nozzle inner tube 4, the throat located at the inflection point will gradually widen and the throat area will increase accordingly; conversely, when the nozzle outer cover 6 moves forward, the throat area can be reduced.

[0043] Specifically, the present invention has two working modes when working. The first working mode is the working mode of the engine in the turbine working mode, and the second working mode is the working mode of the engine in the ram mode, which are specifically described as follows:

[0044] The first working mode:

[0045] The airflow is ejected through the inner flow channel of the nozzle of the present invention to generate thrust, while the outer flow channel does not work. Specifically, when the engine is started at zero speed or running at low speed, it works in the turbine mode, the turbine core engine in the center of the engine rotates, the airflow flows through the core engine, and is discharged into the atmosphere through the compression-combustion-expansion-exhaust process and generates thrust. The nozzle of the present invention undertakes the exhaust process, and the airflow needs to be discharged from the inner flow channel. The inner flow channel is composed of the inner wall surface of the nozzle inner tube 7 and the nozzle inner cone 8, and is welded and fixed by four ribs 1 to ensure that the shape of the inner flow channel remains stable under the dynamics of the airflow. The cross-sectional area change law and the profile change law of the inner flow channel are set according to the gas dynamics. When the cross-sectional area changes from front to back, it first decreases and then increases, so as to follow the design criteria of the Laval nozzle, so that the airflow flowing through the inner flow channel is accelerated to the speed of sound at the minimum cross-sectional area, and then accelerates to the supersonic speed when the cross-sectional area is expanded, so as to provide greater thrust. At this time, all or almost all of the gas flowing through the nozzle flows through the inner flow channel, and the outer flow channel does not work.

[0046] The second working mode:

[0047] The airflow is ejected through the outer duct of the nozzle of the present invention to generate thrust, while the inner duct does not work. Specifically, after the engine runs in the turbine mode (the nozzle is running in the first working mode) for a period of time, the aircraft is accelerated to the minimum speed requirement for the rotating detonation ramjet mode, and switches to the rotating detonation ramjet mode to improve the engine performance. At this time, the turbine core engine stops, and only the rotating detonation combustion chamber outside the core engine works. The airflow flows through the rotating detonation combustion chamber outside the core engine, and after adding fuel, the rotating detonation combustion process generates combustion gas and is discharged through the outer duct of the nozzle of the present invention. The outer duct is composed of the outer wall surface of the nozzle cover 6 and the nozzle inner tube 7, and is fixed by welding with 6 fins 1. At this time, the airflow flows entirely through the outer duct, and its cross-sectional area change law and profile change law also follow the aerodynamic design, and follow the Laval nozzle design principle of first contraction and then expansion. At this time, the airflow is an airflow with uneven circumferential velocity distribution before passing through the nozzle of the present invention, with a part of it being subsonic and the other part being supersonic. It becomes sonic at the point where the cross-sectional area of ​​the outer duct is the smallest, and becomes supersonic in the subsequent expansion section. However, the shape of the outer duct is not fixed, and its shape can be changed by the electric push rod 3 pulling the nozzle cover 6 to move, especially changing the cross-sectional area of ​​the outer duct throat, where the cross-sectional area of ​​the outer duct is the smallest. When the electric push rod 3 is controlled to shorten, the nozzle cover 6 moves forward, and the cross-sectional area of ​​the outer duct throat becomes smaller; when the electric push rod 3 is controlled to extend, the nozzle cover 6 moves backward, and the cross-sectional area of ​​the outer duct throat becomes larger.

[0048] When the aircraft is operating at a lower altitude, the ambient pressure is higher, and it is necessary to increase the outer duct throat area, increase the engine flow rate, and reduce the nozzle expansion ratio through the above method to reduce the pressure of the rotating detonation combustion chamber so that it can operate normally and at the same time match the pressure of the ejected gas with the ambient pressure; similarly, when the aircraft is operating at a higher altitude, the ambient pressure is lower, and it is necessary to reduce the outer duct throat area, reduce the engine flow rate, and increase the nozzle expansion ratio through the above method to increase the pressure of the rotating detonation combustion chamber so that it can operate normally and at the same time match the pressure of the ejected gas with the ambient pressure. The method of changing the cross-sectional area of ​​the outer duct throat is shown in the attached Figure 6 It should be noted that, according to the different relative positions of the inflection points of the profile shapes of the nozzle cover 6 and the outer wall of the nozzle inner tube 7, the forward or backward movement of the nozzle cover 6 under the action of the electric push rod 3 may cause the cross-sectional area change of the outer culvert throat to be opposite to the above conclusion, and this example is still within the scope of protection of this patent application. For example, if the shape inflection point of the profile of the nozzle cover 6 is before the shape inflection point of the profile shape of the outer wall of the nozzle inner tube 7, the shortening of the electric push rod 3 will cause the outer culvert throat area to expand, while the extension of the electric push rod 3 will cause the outer culvert throat area to decrease.

[0049] The nozzle of the present invention has a unique design and can adjust the throat area according to different working modes and flight conditions to optimize the engine performance. The nozzle includes a nozzle inner cone, a nozzle inner barrel, a nozzle outer cover, a nozzle shell and an electric push rod; an outer duct flow channel is formed between the nozzle outer cover and the nozzle inner barrel, and an outer duct throat is formed at the minimum axial cross-sectional area of ​​the flow channel; an inner duct flow channel is formed between the nozzle inner barrel and the nozzle inner cone; the nozzle outer cover can slide under the drive of the electric push rod, so that the area of ​​the outer duct throat can be adjusted. When the combined engine is in a turbine mode at low altitude and low Mach number, the exhaust of the inner duct is used to generate thrust. When the combined engine is in a rotating detonation ramjet mode at high altitude and high Mach number, the exhaust of the outer duct is used to generate thrust. For the rotating detonation combustion chamber inflow of the outer duct, the outer duct nozzle can adjust the configuration of the outer duct flow channel according to the engine operating conditions to reduce the pressure loss of the incoming spiral oblique shock wave propagating in the nozzle. At high ambient pressure, the electric push rod extends and the nozzle cover moves backward, thereby increasing the outer culvert throat area, increasing the engine flow, and reducing the nozzle expansion ratio; at low ambient pressure, the electric push rod shortens and the nozzle cover moves forward, thereby reducing the outer culvert throat area, reducing the engine flow, and increasing the nozzle expansion ratio, thereby improving the heat-to-work conversion efficiency of the rotating detonation ramjet combination engine over a wide speed range.

[0050] The above embodiments are only preferred embodiments of the present invention and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An axisymmetric adjustable nozzle of a rotating detonation combined engine adapted to spiral shock wave flow, characterized in that: The invention comprises a nozzle inner cone (8), a nozzle inner barrel (7), a nozzle outer cover (6), a nozzle housing (2) and an electric push rod (3); the nozzle outer cover (6) is slidably connected to the rear end of the nozzle housing (2), the electric push rod (3) is arranged outside the nozzle housing (2), the fixed end of the electric push rod (3) is connected to the nozzle housing (2), and the telescopic end of the electric push rod (3) is connected to the nozzle outer cover (6); the nozzle inner barrel (7) is arranged in a cavity formed by the nozzle housing (2) and the nozzle outer cover (6), and the outer wall surface of the nozzle inner barrel (7) is connected to the nozzle housing (2); the nozzle inner cone (8) is arranged in a cavity formed by the nozzle inner barrel (7), and the nozzle inner cone (8) is connected to the inner wall surface of the nozzle inner barrel (7).

2. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: The nozzle outer cover (6) comprises a connecting straight section, a contraction profile section and an expansion profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle outer cover (6) and is used for sliding connection with the nozzle shell (2); the contraction profile section and the expansion profile section are structures that first contract and then expand from front to back, and serve as the outer wall surface of the outer duct.

3. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: The nozzle inner cone (8) comprises a connecting straight section, an expansion profile section and a contraction profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner cone (8) and is used for being fixedly connected to the nozzle inner tube (7); the contraction profile section and the expansion profile section are structures that expand first and then contract from front to back, and serve as the inner wall surface of the internal flow channel.

4. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: The nozzle inner tube (7) comprises two wall surfaces, an inner wall surface and an outer wall surface; the outer wall surface of the nozzle inner tube (7) comprises a connecting straight section, an expansion profile section and a contraction profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner tube (7) and is used for being fixedly connected to the nozzle shell (2); the contraction profile section and the expansion profile section are structures that first expand and then contract from front to back, and serve as the inner wall surface of the outer duct; the inner wall surface of the nozzle inner tube (7) comprises a connecting straight section, a contraction profile section and an expansion profile section which are arranged in sequence; the connecting straight section is arranged at the front end of the nozzle inner tube (7) and is used for being fixedly connected to the nozzle inner cone (8); the contraction profile section and the expansion profile section are structures that first contract and then expand from front to back, and serve as the outer wall surface of the inner duct.

5. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: The nozzle cover (6) and the nozzle housing (2) are connected in a sliding manner by means of a guide rail, wherein a ball bearing is arranged in the guide rail.

6. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: A self-lubricating graphite ring is used to perform heat sealing between the nozzle cover (6) and the nozzle housing (2).

7. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: An electric push rod (3) is used to actuate the nozzle cover (6) and the nozzle housing (2).

8. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: The nozzle inner tube (7) and the nozzle shell (2) are fixedly connected by ribs, that is, the two sides of the ribs are respectively welded to the nozzle inner tube (7) and the nozzle shell (2).

9. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: The nozzle inner cone (8) and the nozzle inner barrel (7) are fixedly connected by ribs, that is, the two sides of the ribs are respectively welded to the nozzle inner cone (8) and the nozzle inner barrel (7).

10. The axisymmetric adjustable nozzle of the rotating detonation combined engine adapted to the spiral shock wave flow as claimed in claim 1, characterized in that: The nozzle has two working modes: the first is that the engine is in turbine working mode and the airflow is ejected through the inner flow channel; the second is that the engine is in ram mode and the airflow is ejected through the outer flow channel. At this time, the area of ​​the outer throat can be changed by adjusting the electric push rod to adapt to different flight conditions and engine performance requirements.

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