A turbine-based detonation afterburner engine based on an aerodynamic center body

Abstract

Provided is a turbine-based detonation afterburner engine based on an aerodynamic center body, which is a low bypass ratio turbofan engine, comprising a compressor (1), an air intake duct (2), a main combustion chamber (3), a turbine (4), a rotating detonation afterburner combustion chamber (5), a secondary fuel and oxidant supply device (6), a duty detonator (7) and an adjustable nozzle (8). The present invention eliminates the physical inner barrel, which can avoid the problem of thermal ablation and also greatly reduce the weight of the engine structure. The adjustable aerodynamic center body design timely adjusts the width of the "aerodynamic annular combustion chamber" according to different engine working conditions; the secondary supply of fuel and oxidant can improve the detonation performance of the rotating detonation wave and can be used as a secondary afterburner. The present invention can make full use of the advantages of detonation engines and turbine engines, and is of great significance for reducing fuel consumption, increasing range, achieving higher Mach number flight, and avoiding the "thrust trap" caused by mode conversion.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engines, and in particular relates to a turbine-based detonation afterburner engine based on an aerodynamic center body. Background Art

[0002] Detonation combustion has potential advantages over existing combustors operating in the traditional deflagration mode. In theory, detonation combustion has greater heat release intensity and smaller entropy increase, which can significantly increase the pressure and temperature of the combustion products. Compared with the traditional Brayton cycle, the theoretical efficiency of the detonation-based thermodynamic cycle can be improved by nearly 20-50%. In recent years, the development of thrusters based on detonation combustion has been considered as an innovative way to improve the performance of aerospace propulsion systems. Detonation combustion is defined as an unstable process in which the average total pressure of the entire device increases and allows work to be extracted by expansion to the initial pressure.

[0003] At present, the traditional rotating detonation combustion chamber is usually composed of two concentric cylinders, respectively called the outer cylinder and the central cylinder, and the annular channel formed between them is called the annular combustion chamber. Due to its good annular structure, it is possible to combine this type of combustion chamber with a turbine engine. The main ideas include using the rotating detonation combustion chamber as the main combustion chamber to blow the turbine to do work and as an afterburner to directly provide thrust. Among them, the geometric parameters that affect the detonation wave dynamics include the width of the annular combustion chamber, the total diameter of the combustion chamber, etc.

[0004] Studies have shown that for fuels with larger cell sizes, such as kerosene and ethylene, they exhibit unstable detonation operation states when the annular combustion chamber width is small, and it is even difficult to initiate detonation combustion. And because the fuel cell size changes with the change of operating conditions such as the equivalence ratio, the stable operating range of the annular detonation combustion chamber with fixed geometric dimensions is limited. In addition, during the detonation combustion process, the excessive heat flux of the combustion products will cause the inner and outer wall temperatures to be too high, which brings new problems to the high temperature protection and cooling of the combustion chamber. Summary of the invention

[0005] In view of the problems existing in the background technology, the present invention provides a turbine-based detonation afterburner engine based on an aerodynamic center body, hereinafter referred to as a "detonation afterburner engine", which is a low bypass ratio turbofan engine, including a compressor 1, an intake duct 2, a main combustion chamber 3, a turbine 4, a duty detonator 7 and an adjustable nozzle 8; characterized in that it also includes a rotating detonation afterburner combustion chamber 5 of an aerodynamically adjustable center body, a fuel and oxidant secondary supply device 6; wherein

[0006] The compressor 1 is located at the front end of the detonation afterburner engine, and includes a low-pressure compressor 11 and a high-pressure compressor 12 located thereafter;

[0007] After passing through the low-pressure compressor 11, the first airflow flows into the inner duct 21 and is then provided to the high-pressure compressor 12; the second airflow flows into the rear afterburner 5 through the outer duct 22 outside the high-pressure compressor 12 channel;

[0008] The first airflow is further compressed by the high-pressure compressor 12 and then provided to the main combustion chamber 3;

[0009] The main combustion chamber 3 is located behind the high-pressure compressor 12;

[0010] The isobaric combustion products are expanded and work is performed by the high-pressure turbine 41 behind the main combustion chamber 3 and the low-pressure turbine 42 behind the high-pressure turbine 41 in sequence, and the work extracted by the high-pressure and low-pressure turbines is used to drive the high-pressure and low-pressure compressors to perform work respectively;

[0011] The first airflow after doing work through the inner duct 21 is used as the engine power source on the one hand, and on the other hand, the airflow is accelerated by the aerodynamic center body regulating mechanism 54 and serves as the aerodynamic center body of the subsequent detonation afterburner chamber 5; the second airflow flows through the outer duct 22 into the afterburner chamber 5 behind the low-pressure turbine 42 for detonation supercharging combustion;

[0012] The rotary detonation afterburner combustion chamber 5 comprises an outer cylinder 51, an oil passage assembly 52, a throat boss 53 and an aerodynamic center body adjustment mechanism 54;

[0013] The rotating detonation afterburner outer cylinder 51 is a cylindrical cylinder outside the engine outer duct, extending backward from the rear end of the low-pressure turbine 42 to the nozzle;

[0014] The inner wall of the outer duct 22 extends backward from the front end of the high-pressure compressor 12 to the rear end of the low-pressure turbine 42, and then continues to extend backward for a period of time. After that, the inner wall of the outer duct 22 protrudes toward the outer wall of the outer duct 22, thereby forming a throat boss 53. The throat boss 53 is in the shape of a hollow cylinder, and is fixedly connected and integrated with the inner wall of the outer duct 22 through the transition part of the throat boss 53. The transition part is between the rear end of the inner wall of the outer duct 22 and the front end of the throat boss 53, and is a circular ring structure. The axis of the circular ring coincides with the axis of the engine, and the plane of the circular ring is perpendicular to the axis of the engine; the throat boss 53 forms a concave cavity on the side facing the aerodynamic center body;

[0015] The oil circuit assembly 52 includes an oil supply pipeline and a fuel nozzle, which is located on the outer wall of the outer duct 22 facing the throat boss 53, and the oil circuit assembly 52 is fixedly connected to the outer wall of the outer duct 22; the fuel nozzle adopts a centrifugal swirl atomizing nozzle, which is evenly distributed along the circumference of the outer wall of the outer duct 22, and the spacing should not be too far;

[0016] The aerodynamic center body adjustment mechanism 54 is a convergent adjustable mechanism, including an adjustment sheet 54a, an actuator cylinder 54b and a connecting hinge 54c; the adjustment sheet 54a is movably connected to the inner wall of the inner cylinder of the outer duct 22, and multiple adjustment sheets 54a are evenly arranged along the circumferential direction on the inner wall of the inner cylinder of the outer duct 22, and the left and right sides of adjacent adjustment sheets 54a overlap and press with the adjacent adjustment sheets 54a on the left and right sides respectively; the adjustment sheet 54a is movably connected to the inner wall of the inner cylinder of the outer duct 22 in such a way that the adjustment sheet 54a can rotate in the plane formed by the adjustment sheet 54a and the engine axis; multiple adjustment sheets 54a are circumferentially arranged downstream of the low-pressure turbine, and this structure can change the outlet area of ​​the flow channel of the combustion product gas flow of the inner duct;

[0017] One end of the actuator cylinder 54b is movably connected to the inner wall of the inner tube of the outer duct 22 through a connecting hinge 54c fixed on the inner wall of the inner tube of the outer duct 22; the other end of the actuator cylinder 54b is also movably connected to the regulating plate 54a through the connecting hinge 54c; the fuel and oxidant secondary supply device 6 is located upstream of the aerodynamic center body regulating mechanism and after the turbine, specifically between the low-pressure turbine 42 and the regulating plate 54a, including the inner wall of the inner tube of the outer duct 22 uniformly arranged Multiple groups of air supply spray rods 61 and oil supply spray rods 62; for one group of air supply spray rods 61 and oil supply spray rods 62: one end of the air supply spray rod 61 is fixed on the inner wall of the inner tube of the outer duct 22, and the other end is a blind end with small air holes, and the air supply spray rod 61 is perpendicular to the inner wall of the inner tube of the outer duct 22; one end of the oil supply spray rod 62 is fixed on the inner wall of the inner tube of the outer duct 22, and the other end is equipped with an atomizing nozzle, and the oil supply spray rod 62 is perpendicular to the inner wall of the inner tube of the outer duct 22;

[0018] The duty detonator 7 is installed on the outside of the rotary detonation afterburner, on the outer wall of the outer tube of the outer duct 22, and is located within a certain distance range downstream of the boss throat. The spark plug 74 is installed at the blind end of the detonator tube 71; the outlet of the duty detonator 7 pipeline is perpendicular to the outer barrel 51, and extends parallel to the engine axis after bending backwards; an oxygen injection control valve 72, a fuel injection control valve 73 and a spark plug 74 are installed at the blind end of the duty detonator 7; the oxygen injection control valve 72 and the fuel injection control valve 73 are electromagnetic valves installed at the rear end of the duty detonator 7; a one-way valve 75 is installed at the outlet end of the duty detonator 7;

[0019] The adjustable nozzle 8 is connected to the rear of the afterburner. The adjustable nozzle 8 is located at the rear end of the outer cylinder 51 of the afterburner and is a hollow truncated cone that gradually shrinks inwards. The outlet area of ​​the adjustable nozzle 8 connected to the rear of the afterburner is adjustable.

[0020] In one embodiment of the present invention, from the low-pressure turbine 42 to the rear, the outer cylinder 51 of the rotating detonation afterburner is made of a high-temperature alloy material and is not an integral part with the front engine outer casing.

[0021] In another embodiment of the present invention, the length of the outer cylinder 51 of the rotating detonation afterburner is not less than 500 mm.

[0022] In yet another embodiment of the present invention, the radial width of the throat formed at the throat boss 53 is between 2-8 mm; the throat boss 53 extends in a direction parallel to the engine axis by a length of 5-10 mm.

[0023] In yet another embodiment of the present invention, it is characterized in that the duty detonator 7 is located 10-50 mm downstream of the boss throat.

[0024] A method for operating a turbine-based detonation afterburner engine based on an aerodynamic center body is also provided, which is based on the above-mentioned turbine-based detonation afterburner engine based on an aerodynamic center body, specifically:

[0025] After the low-pressure compressor 11, the flow channel divides the air into two streams according to the rated ratio according to the working requirements of the engine, wherein the first stream flows into the inner duct 21; the second stream also flows from the low-pressure compressor 11 through the outer duct 22 outside the high-pressure compressor 12 channel into the rear afterburner 5;

[0026] The compressed first airflow enters the main combustion chamber 3, and isobaric combustion is realized in the main combustion chamber 3, and the isobaric combustion products are output to the high-pressure turbine 41;

[0027] The isobaric combustion products are expanded and work is performed by the high-pressure turbine 41 behind the main combustion chamber 3 and the low-pressure turbine 42 behind the high-pressure turbine 41 in sequence, and the work extracted by the high-pressure and low-pressure turbines is used to drive the high-pressure and low-pressure compressors to perform work respectively;

[0028] The first airflow after doing work through the inner duct 21 is used as the engine power source on the one hand, and on the other hand, the airflow is accelerated by the aerodynamic center body regulating mechanism 54 and serves as the aerodynamic center body of the subsequent detonation afterburner chamber 5; the second airflow flows through the outer duct 22 into the afterburner chamber 5 behind the low-pressure turbine 42 for detonation supercharging combustion;

[0029] On the one hand, the throat boss 53 accelerates the airflow in the outer duct to the speed of sound, preventing the detonation wave from returning and causing compressor surge or detonation wave extinction; on the other hand, the throat boss 53 is conducive to the penetration and mixing of kerosene fuel at the throat; in addition, the concave cavity formed on the side of the throat boss 53 facing the aerodynamic center body induces the airflow in the rotating detonation afterburner combustion chamber to form a low-speed recirculation zone, and the formed recirculation zone can be used as an anchor point for the flame in the detonation formation stage, avoiding the detonation wave from being unable to stabilize in the combustion chamber due to the excessively high airflow velocity in the detonation stage;

[0030] The fuel nozzles are centrifugal swirl atomizing nozzles, which are evenly distributed along the circumference of the outer wall of the outer duct 22, and the spacing should not be too far to ensure that the atomizing cone areas of adjacent fuel nozzles can overlap; the fuel nozzle model and oil pressure are adjusted to ensure the penetration of kerosene within a certain range, ensuring better fuel atomization and crushing effects and fuel mixing effects;

[0031] The adjusting plate 54a is movably connected to the inner wall of the inner cylinder of the outer duct 22 in such a way that the adjusting plate 54a can rotate in the plane formed by the adjusting plate 54a and the engine axis, and the rotation angle is determined according to the detonation afterburner working equivalent ratio, working pressure, etc., and the rotation angle is controlled by the stroke of the actuator 54b; a plurality of adjusting plates 54a are circumferentially arranged downstream of the low-pressure turbine, and the mechanism is located behind the low-pressure turbine 42. After the combustion products have done work on the turbine expansion, they pass through the aerodynamic center body regulating mechanism 54 to form an aerodynamic center body, and the aerodynamic center body and the inner wall of the detonation afterburner outer cylinder 51 form an aerodynamic annular combustion chamber;

[0032] The actuator 54b is composed of a movable piston and a cylinder body. The engine adjustment system controls the stroke of the actuator by controlling the inflow and outflow of hydraulic oil. According to the change of the working state of the engine, the actuator 54b drives the adjustment plate 54a to move, thereby changing the outlet area of ​​the inner channel combustion product airflow flow channel, thereby changing the center body airflow velocity and the diameter of the pneumatic center body, so as to better match the different working states of the engine.

[0033] The air supply spray rod 61 and the oil supply spray rod 62 spray fresh oxidant and fuel perpendicularly to the axial flow direction, respectively. The oxidant and fuel are provided by the air supply and oil supply pipelines arranged along the outer cylinder wall of the inner channel of the engine respectively. When it is opened under certain working conditions where detonation is not easy and the thrust needs to be further enhanced, the fuel and oxidant secondary supply device 6 can improve the working performance of the detonation afterburner and increase the thrust;

[0034] The on-duty detonator 7 fills explosive fuel and oxygen in a small-diameter detonator tube 71, which is ignited by a spark plug 74 installed at the blind end of the detonator tube 71, forming a detonation wave that is shot into the rotary detonation afterburner to detonate the afterburner detonation wave; the fuel oxidizer is refilled and ignited according to the ignition needs; the oxygen injection control valve 72 and the fuel injection control valve 73 are manually controlled by the operator when the engine is started; the oxygen and fuel used by the detonator 7 are all from the oxygen and kerosene carried by the aircraft; the one-way valve 75 automatically opens when the pressure is higher than the rated pressure difference to prevent the pre-filled fuel and oxidizer from being ejected by the mainstream air;

[0035] The high enthalpy products generated by the adjustable nozzle 8 are discharged through the adjustable nozzle 8 connected to the afterburner, generating a high-speed airflow, thereby forming thrust; the outlet area of ​​the adjustable nozzle 8 connected to the afterburner is adjustable to enhance the adaptability of the engine under different working conditions and increase the engine thrust.

[0036] The turbine-based detonation afterburner engine of the present invention uses a turbine-based rotary detonation afterburner engine, which can effectively utilize the advantages of the rotary detonation engine such as high cycle efficiency and high-frequency continuous operation after one detonation. The detonation-based supercharged combustion is of great significance for reducing fuel consumption, increasing range, achieving higher Mach number flight, and avoiding the "thrust trap" caused by mode conversion.

[0037] The beneficial effects of the present invention are as follows:

[0038] 1. A rotating detonation engine is arranged outside the turbine engine. The detonation combustion chamber adopts nearly isochoric detonation boost combustion instead of traditional isobaric combustion, which can greatly improve efficiency, increase thrust and reduce fuel consumption.

[0039] 2. The aerodynamic center body design avoids the problems of physical center barrel ablation and thermal protection. In addition, it greatly reduces the weight of the afterburner structure, which is beneficial to improving the engine thrust-to-weight ratio.

[0040] 3. The adjustable aerodynamic center body changes the width of the aerodynamic annular combustion chamber between the aerodynamic center body and the outer cylinder, and cooperates with the adjustable nozzle to adapt to the normal detonation of the afterburner combustion chamber within different equivalence ratio ranges and obtain the best thrust.

[0041] 4. Adding fresh fuel oxidizer into the aerodynamic center body helps improve certain difficult-to-detonate conditions and can serve as a secondary boost to further increase engine thrust. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic cross-sectional structure diagram of a turbine-based detonation afterburner engine based on an aerodynamic center body according to the present invention;

[0043] Figure 2 for Figure 1 Enlarged view of the middle dotted frame A;

[0044] Figure 3 for Figure 1 Enlarged view of the dotted box B.

[0045] The reference numerals are described as follows:

[0046] 1 Compressor 54 Pneumatic center body adjustment mechanism

[0047] 11 Low pressure compressor 54a regulating plate

[0048] 12 High pressure compressor 54b actuator

[0049] 2 Intake duct 54c connecting hinge

[0050] 21 Internal channel 6 Fuel and oxidant secondary supply device

[0051] 22 Bypass 61 Air supply boom

[0052] 3 Main combustion chamber 62 fuel supply spray bar

[0053] 4 Turbine 7 Duty Detonator

[0054] 41 High-pressure turbine 71 Detonator

[0055] 42 Low-pressure turbine 72 Oxygen injection control valve

[0056] 5 Rotating Detonation Afterburner 73 Fuel Injection Control Valve

[0057] 51 outer cylinder 74 spark plug

[0058] 52 Oil circuit assembly 75 Check valve

[0059] 53 throat boss 8 adjustable nozzle DETAILED DESCRIPTION

[0060] In order to make the technical solution, working process and beneficial effects of the present invention clearer, Figure 1-3 , the present invention is further elaborated in more detail.

[0061] The present embodiment is a turbine-based detonation afterburner engine based on an aerodynamic center body (hereinafter referred to as "detonation afterburner engine"), which is a low bypass ratio turbofan engine, including a compressor 1, an intake duct 2, a main combustion chamber 3, a turbine 4, a rotating detonation afterburner combustion chamber 5, a secondary fuel and oxidant supply device 6, a duty detonator 7 and an adjustable nozzle 8.

[0062] The compressor 1 is located at the front end of the detonation afterburner engine, and includes a low-pressure compressor 11 and a high-pressure compressor 12 located thereafter.

[0063] After the low-pressure compressor 11, the bypass channel divides the air into two streams at a rated ratio according to the engine working requirements. The first stream flows into the inner duct 21 and is then provided to the high-pressure compressor 12; the second stream also flows from the low-pressure compressor 11 through the outer duct 22 outside the high-pressure compressor 12 channel into the rear afterburner 5.

[0064] The first air flow is further compressed by the high-pressure compressor 12 and then provided to the main combustion chamber 3 .

[0065] The main combustion chamber 3 is located behind the high-pressure compressor 12. The compressed first airflow enters the main combustion chamber 3, and isobaric combustion is realized in the main combustion chamber 3. The isobaric combustion products are output to the high-pressure turbine 41.

[0066] The isobaric combustion products expand and perform work through the high-pressure turbine 41 behind the main combustion chamber 3 and the low-pressure turbine 42 behind the high-pressure turbine 41 in turn (the isobaric combustion products blow the turbine to perform work), and the work extracted by the high and low-pressure turbines is used to drive the high and low-pressure compressors respectively (because the turbine and the compressor are coaxial, the rotation of the turbine will drive the compressor to rotate, the low-pressure turbine is coaxial with the low-pressure compressor, and the high-pressure turbine is coaxial with the high-pressure compressor) to perform work.

[0067] The high-speed airflow (first airflow) after doing work through the inner duct 21, on the one hand, serves as the engine power source; on the other hand, the high-speed airflow is accelerated by the aerodynamic center body regulating mechanism 54 and serves as the aerodynamic center body of the subsequent detonation afterburner 5. The second airflow flows through the outer duct 22 into the afterburner 5 behind the low-pressure turbine 42 for detonation supercharging combustion. Since detonation combustion has its own supercharging advantage, stable operation can be achieved without a very high pressure ratio.

[0068] like Figure 1 , 2 As shown, the rotary detonation afterburner combustion chamber 5 includes an outer cylinder 51, an oil circuit assembly 52, a throat boss 53 and an aerodynamic center body adjustment mechanism 54. The outer cylinder 51 and the oil circuit assembly 52 are well known to those skilled in the art as components of the rotary detonation afterburner combustion chamber 5 and will not be described again.

[0069] The rotating detonation afterburner outer cylinder 51 is a cylindrical cylinder outside the engine outer duct, extending backward from the rear end of the low-pressure turbine 42 to the nozzle. From the low-pressure turbine 42 to the rear, the rotating detonation afterburner outer cylinder 51 is made of high-temperature alloy material, so the rotating detonation afterburner outer cylinder 5 is not an integral part with the front engine outer shell. Due to the high efficiency of detonation combustion, the length of the rotating detonation afterburner outer cylinder 51 is not less than 500mm.

[0070] After the inner wall of the outer duct 22 extends backward from the front end of the high-pressure compressor 12 to the rear end of the low-pressure turbine 42, it continues to extend backward for a period of time, and then the inner wall of the outer duct 22 protrudes toward the outer wall of the outer duct 22, thereby forming a throat boss 53. In fact, the throat boss 53 is in the shape of a hollow cylinder, and is fixedly connected and integrated with the inner wall of the outer duct 22 through the transition part of the throat boss 53. The transition part is between the rear end of the inner wall of the outer duct 22 and the front end of the throat boss 53, and is actually a ring. The axis of the ring coincides with the axis of the engine, and the plane of the ring is perpendicular to the axis of the engine. On the one hand, the throat boss 53 accelerates the outer duct airflow to the speed of sound to prevent the detonation wave from being transmitted back to cause compressor surge or detonation wave extinction; on the other hand, the throat boss 53 is conducive to the penetration and mixing of kerosene fuel (kerosene comes from the oil circuit assembly 52, which will be described below) at the throat. The radial width of the throat formed at the throat boss 53 is between 2-8 mm (referring to the throat width, the range is between 2 and 8 mm), so that the airflow can reach weak sound speed at the lowest working flow rate. The throat boss 53 extends 5-10 mm in a direction parallel to the engine axis. If the extension length is too long, the inner cylinder will be ablated by the detonation wave and interfere with the regulation of the aerodynamic center body. In addition, the concave cavity formed on the side of the throat boss 53 facing the aerodynamic center body can induce the airflow in the rotating detonation afterburner to form a low-speed recirculation zone. The formed recirculation zone can be used as an anchor point for the flame in the detonation formation stage to avoid the detonation wave from being unable to stabilize in the combustion chamber due to the excessively high airflow velocity during the detonation stage.

[0071] The oil circuit assembly 52 includes an oil supply pipeline and a fuel nozzle (this component is well known to those skilled in the art), which is located on the outer wall of the outer duct 22 facing the throat boss 53, and the oil circuit assembly 52 is fixedly connected to the outer wall of the outer duct 22. The fuel nozzle adopts a centrifugal swirl atomizing nozzle, which is evenly distributed along the circumference of the outer wall of the outer duct 22, and the spacing should not be too far to ensure that the atomization cone areas of adjacent fuel nozzles can overlap. The fuel nozzle model and oil pressure are adjusted to ensure the penetration of kerosene within a certain range, and to ensure better fuel atomization and crushing effect and fuel mixing effect.

[0072] The pneumatic center body adjustment mechanism 54 is a convergent adjustable mechanism, such as Figure 2As shown, it includes an adjusting piece 54a, an actuating cylinder 54b and a connecting hinge 54c. The adjusting piece 54a is movably connected to the inner wall of the inner cylinder of the outer duct 22. A plurality of adjusting pieces 54a are evenly arranged along the circumferential direction on the inner wall of the inner cylinder of the outer duct 22. The left and right sides of adjacent adjusting pieces 54a overlap and press with the adjacent adjusting pieces 54a on the left and right sides respectively. The adjusting piece 54a is movably connected to the inner wall of the inner cylinder of the outer duct 22 in such a way that the adjusting piece 54a can rotate in the plane formed by it and the engine axis. The rotation angle is determined according to the detonation booster working equivalent ratio, working pressure, etc., and the rotation angle is controlled by the stroke of the actuating cylinder 54b. A plurality of adjustment plates 54a are circumferentially arranged downstream of the low-pressure turbine to form a structure similar to an adjustable nozzle, which can change the outlet area of ​​the flow channel of the combustion product in the inner channel. The mechanism is located behind the low-pressure turbine 42. After the combustion products have done work on the turbine expansion, they pass through the aerodynamic center body adjustment mechanism 54 (the rotation angle of the adjustment plate 54a is related to the required aerodynamic inner cylinder diameter) to form an aerodynamic center body. The aerodynamic center body and the inner wall of the detonation afterburner outer cylinder 51 form an aerodynamic annular combustion chamber.

[0073] One end of the actuator 54b is movably connected to the inner wall of the inner tube of the outer duct 22 through a connecting hinge 54c fixed on the inner wall of the inner tube of the outer duct 22. The other end of the actuator 54b is also movably connected to the adjustment plate 54a through the connecting hinge 54c. The actuator 54b is composed of a movable piston and a cylinder body. The engine adjustment system controls the stroke of the actuator by controlling the inflow and outflow of hydraulic oil. According to the change of the engine working state, the adjustment plate 54a is driven to move by the actuator 54b to change the outlet area of ​​the inner duct combustion product airflow flow channel, thereby changing the center body airflow velocity and the pneumatic center body diameter, so as to better match the different working states of the engine. The actuator is well known to those skilled in the art and will not be described again.

[0074] The secondary supply device 6 for fuel and oxidant is located upstream of the aerodynamic center body regulating mechanism and after the turbine, specifically between the low-pressure turbine 42 and the regulating plate 54a, and includes multiple groups of air supply spray rods 61 and oil supply spray rods 62 uniformly arranged along the circumference of the inner wall of the inner tube of the outer duct 22. One group of air supply spray rods 61 and oil supply spray rods 62 is taken as an example for introduction. One end of the air supply spray rod 61 is fixed on the inner wall of the inner tube of the outer duct 22, and the other end is a blind end with small air holes. The air supply spray rod 61 is perpendicular to the inner wall surface of the inner tube of the outer duct 22. One end of the oil supply spray rod 62 is fixed on the inner wall of the inner tube of the outer duct 22, and the other end is equipped with an atomizing nozzle (the atomizing nozzle is well known to those skilled in the art and will not be described again). The oil supply spray rod 62 is perpendicular to the inner wall surface of the inner tube of the outer duct 22. The air supply spray rod 61 and the oil supply spray rod 62 spray fresh oxidant and fuel perpendicular to the axial flow direction, respectively. The oxidant and fuel are provided by the air supply and oil supply pipelines arranged along the outer cylinder wall of the inner channel of the engine. When opened under certain working conditions that are difficult to detonate and need to further enhance the thrust, the fuel and oxidant secondary supply device 6 can improve the working performance of the detonation afterburner and increase the thrust.

[0075] The duty detonator 7 is installed on the outside of the rotary detonation afterburner, on the outer wall of the outer tube of the outer duct 22, and is located within a distance of 10-50mm downstream of the boss throat. By filling the small diameter detonator tube 71 with explosive fuel and oxygen, it is ignited by the spark plug 74 installed at the blind end of the detonator tube 71, forming a detonation wave that shoots into the rotary detonation afterburner chamber to detonate the afterburner chamber detonation wave. The outlet of the duty detonator 7 pipe is perpendicular to the outer barrel 51, and bends backward and then extends in parallel (parallel to the outer tube wall of the afterburner chamber), which is consistent with the direction of the engine axis. Figure 3 As shown, an oxygen injection control valve 72, a fuel injection control valve 73 and a spark plug 74 are installed at the blind end (i.e., the rear end) of the duty detonator 7, and the fuel oxidant is refilled and ignited according to the ignition needs. Among them, the oxygen injection control valve 72 and the fuel injection control valve 73 are electromagnetic valves, which are installed at the rear end of the duty detonator 7 and are manually controlled by the operator when the engine is started. The oxygen and fuel used by the detonator 7 are all from the oxygen (generally, the aircraft will have its own) and kerosene (oxygen and kerosene enter from the far end of the detonator tube 71 through the electromagnetic valve control). A one-way valve 75 is installed at the outlet end (i.e., the front end) of the duty detonator 7, which automatically opens when the pressure is higher than the rated pressure difference to prevent the pre-filled fuel and oxidant from being ejected by the mainstream air.

[0076] The afterburner is connected to an adjustable nozzle 8, whose structure and principle are similar to those of the current turbojet engine nozzle, and is composed of an adjustment mechanism and an adjustment plate (which is well known to those skilled in the art and will not be described again). The adjustable nozzle 8 is located at the rear end of the afterburner outer cylinder 51, and is a hollow truncated cone that gradually shrinks inward. The high enthalpy products generated are discharged through the afterburner connected to the adjustable nozzle 8, generating a high-speed airflow, thereby forming thrust. The outlet area of ​​the afterburner connected to the adjustable nozzle 8 is adjustable to enhance the adaptability of the engine under different working conditions and increase the engine thrust.

[0077] The present invention adopts a detonation afterburner combustion chamber and adopts nearly isochoric detonation combustion instead of isobaric combustion of a traditional afterburner combustion chamber, which can effectively improve combustion efficiency, reduce fuel consumption rate, and improve engine thrust performance; the physical inner barrel design is cancelled and an aerodynamic center body is adopted, which reduces the weight of the engine structure, increases the thrust-to-weight ratio, and avoids complex thermal protection and cooling structures; the adjustable aerodynamic center body with reactive gas and non-reactive gas, on the one hand, forms an aerodynamic "adjustable aerodynamic annular combustion chamber" with the outer barrel to increase the adaptability of the engine to different working conditions; on the other hand, fresh fuel and oxidant are injected into the aerodynamic center body, which can increase the explosiveness of the non-reactive aerodynamic center body under the detonation afterburner working condition that is difficult to start, and can be used as a secondary afterburner to further enhance the thrust.

[0078] The present invention provides a turbofan engine with a small bypass ratio and a continuous rotating detonation afterburner, comprising a low-pressure compressor, a high-pressure compressor, a linked annular isobaric combustion chamber, a high-pressure turbine and a low-pressure turbine, a rotating detonation afterburner, an adjustable nozzle, and the like. The rotating detonation afterburner also comprises an outer cylinder assembly, an oil circuit assembly, and an igniter. The outer cylinder of the rotating detonation afterburner is the outer cylinder of the engine outer duct, which extends backward from the rear position of the low-pressure turbine to the nozzle, and is made of a high-temperature resistant alloy material. The inner cylinder of the outer duct expands outward to form a throat for accelerating the airflow of the outer duct. An oil circuit and a kerosene nozzle are installed on one side of the outer cylinder corresponding to the throat, and the sprayed kerosene is mixed at the throat and enters the afterburner. The afterburner has only an outer cylinder but no physical inner cylinder. A duty igniter is installed on the outer cylinder behind the throat to detonate the injected combustible gas to form continuous rotating detonation combustion.

[0079] The present invention provides a detonation afterburner combustion chamber based on an adjustable aerodynamic center body. The adjustable aerodynamic center body design is adopted to cancel the traditional physical center cylinder. On the one hand, it avoids the problem of high-temperature heat dissipation of the center cylinder, eliminates the complicated cooling and thermal protection design, and further reduces the weight of the afterburner combustion chamber structure. On the other hand, the cancellation of the physical inner cylinder weakens the reflection of the inner wall to the detonation shock wave, which is conducive to the stable propagation of the detonation wave. In addition, the adjustable aerodynamic center body design can form a "pneumatic annular channel" with the outer cylinder. Changing the diameter of the pneumatic inner cylinder and then changing the width of the pneumatic combustion chamber by adjusting the mechanism is easier to operate than changing the diameter of the physical inner cylinder, and there are no problems such as sealing requirements.

[0080] The present invention also provides a pneumatic center body that can participate in combustion reaction or non-reaction. By controlling the secondary supply device of fuel and oxidant installed in the flow channel of the pneumatic center body, the pneumatic center body can participate in combustion gas or non-participate in combustion gas. Studies have shown that the use of a pneumatic center body with reactive gas can further broaden the detonation range compared to the non-reactive form, and can further supplement fuel for use as a secondary booster.

[0081] In addition, the present invention provides an adjustable pneumatic inner cylinder with reactive gas or non-reactive gas. The pneumatic center body adjustment mechanism is a convergent adjustable mechanism, which is composed of an adjustment plate and an actuator. The adjustment plate is similar to an adjustable nozzle form, which can change the outlet area of ​​the airflow flow channel, accelerate the post-turbine combustion gas, and form a pneumatic center body. The pneumatic center body and the outer cylinder wall of the empty cylinder afterburner form a pneumatic annular combustion chamber. According to the change of the engine working state, the adjustment plate is driven by the actuator to move to change the center body airflow velocity and the diameter of the pneumatic center body, so as to better match the different working states of the engine.

[0082] The fuel and oxidant supply device is installed upstream of the aerodynamic center body adjustment mechanism and after the turbine, and the circumferentially evenly arranged oil and air supply spray bars are used. By controlling the injection of fresh fuel and oxidant into the aerodynamic center body, the center body setting with reactive gas or non-reactive gas can be realized.

Claims

1. A turbine-based detonation afterburner engine based on an aerodynamic center body, hereinafter referred to as a "detonation afterburner engine", is a low bypass ratio turbofan engine, comprising a compressor (1), an air intake duct (2), a main combustion chamber (3), a turbine (4), a duty detonator (7) and an adjustable nozzle (8); characterized in that: It also comprises a rotary detonation afterburner combustion chamber (5) having an aerodynamically adjustable center body, and a secondary supply device for fuel and oxidant (6); wherein The compressor (1) is located at the front end of the detonation afterburner engine, and comprises a low-pressure compressor (11) and a high-pressure compressor (12) located thereafter; After passing through the low-pressure compressor (11), the first airflow flows into the inner duct (21) and is then supplied to the high-pressure compressor (12); after passing through the low-pressure compressor (11), the second airflow flows into the rear afterburner (5) through the outer duct (22) outside the channel of the high-pressure compressor (12); The first airflow is further compressed by the high-pressure compressor (12) and then provided to the main combustion chamber (3); The main combustion chamber (3) is located behind the high pressure compressor (12); The isobaric combustion products are sequentially expanded through a high-pressure turbine (41) behind the main combustion chamber (3) and a low-pressure turbine (42) behind the high-pressure turbine (41) to perform work, and the work extracted by the high-pressure and low-pressure turbines is used to drive the high-pressure and low-pressure compressors to perform work respectively; The first airflow after doing work through the inner duct (21) serves as the engine power source on the one hand, and on the other hand, the airflow is accelerated by the aerodynamic center body regulating mechanism (54) and serves as the aerodynamic center body of the subsequent detonation afterburner combustion chamber (5); the second airflow flows through the outer duct (22) into the afterburner combustion chamber (5) behind the low-pressure turbine (42) for detonation supercharging combustion; The rotary detonation afterburner combustion chamber (5) comprises an outer cylinder (51), an oil circuit assembly (52), a throat boss (53) and a pneumatic center body adjustment mechanism (54); The rotating detonation afterburner outer cylinder (51) is a cylindrical cylinder outside the engine outer duct, and extends backward from the rear end of the low-pressure turbine (42) to the nozzle; The inner wall of the outer duct (22) extends backward from the front end of the high-pressure compressor (12) to the rear end of the low-pressure turbine (42), and then continues to extend backward for a period of time. Then, the inner wall of the outer duct (22) protrudes toward the outer wall of the outer duct (22), thereby forming a throat boss (53). The throat boss (53) is in the shape of a hollow cylinder, and is fixedly connected and integrated with the inner wall of the outer duct (22) through a transition portion of the throat boss (53). The transition portion is between the rear end of the inner wall of the outer duct (22) and the front end of the throat boss (53), and is a circular ring structure. The axis of the circular ring coincides with the axis of the engine, and the plane of the circular ring is perpendicular to the axis of the engine. The throat boss (53) forms a concave cavity on the side facing the aerodynamic center body. The oil circuit assembly (52) comprises an oil supply pipeline and a fuel nozzle, and is located on the outer cylinder wall of the outer duct (22) facing the throat boss (53). The oil circuit assembly (52) is fixedly connected to the outer cylinder wall of the outer duct (22). The fuel nozzles are centrifugal swirl atomizing nozzles, and are evenly distributed along the circumference of the outer cylinder wall of the outer duct (22), and the spacing should not be too far. The aerodynamic center body adjustment mechanism (54) is a convergent adjustable mechanism, comprising an adjustment plate (54a), an actuator cylinder (54b) and a connecting hinge (54c); the adjustment plate (54a) is movably connected to the inner wall of the inner cylinder of the outer duct (22), and a plurality of adjustment plates (54a) are evenly arranged circumferentially on the inner wall of the inner cylinder of the outer duct (22), and the left and right sides of adjacent adjustment plates (54a) overlap and press with the adjacent adjustment plates (54a) on the left and right sides respectively; the adjustment plate (54a) is movably connected to the inner wall of the inner cylinder of the outer duct (22) in such a way that the adjustment plate (54a) can rotate in a plane formed by the adjustment plate (54a) and the engine axis; a plurality of adjustment plates (54a) are circumferentially arranged downstream of the low-pressure turbine, and this structure can change the outlet area of ​​the flow channel of the combustion product gas flow of the inner duct; One end of the actuator cylinder (54b) is movably connected to the inner wall of the inner cylinder of the outer duct (22) through a connecting hinge (54c) fixed on the inner wall of the inner cylinder of the outer duct (22); the other end of the actuator cylinder (54b) is also movably connected to the regulating plate (54a) through the connecting hinge (54c); the fuel and oxidant secondary supply device (6) is located upstream of the pneumatic center body regulating mechanism and after the turbine, specifically between the low-pressure turbine (42) and the regulating plate (54a), and includes a plurality of A plurality of groups of air supply spray rods (61) and oil supply spray rods (62); for one group of the air supply spray rods (61) and the oil supply spray rods (62): one end of the air supply spray rod (61) is fixed on the inner wall of the inner tube of the outer duct (22), and the other end is a blind end with a small air hole on the blind end, and the air supply spray rod (61) is perpendicular to the inner wall surface of the inner tube of the outer duct (22); one end of the oil supply spray rod (62) is fixed on the inner wall of the inner tube of the outer duct (22), and the other end is equipped with an atomizing nozzle, and the oil supply spray rod (62) is perpendicular to the inner wall surface of the inner tube of the outer duct (22); The on-duty detonator (7) is installed on the outside of the rotary detonation afterburner, on the outer wall of the outer tube of the outer duct (22), and is located within a certain distance range downstream of the boss throat. The spark plug (74) is installed at the blind end of the detonator tube (71); the outlet of the pipe of the on-duty detonator (7) is perpendicular to the outer barrel (51), and extends parallel to the engine axis after bending backwards; an oxygen injection control valve (72), a fuel injection control valve (73) and a spark plug (74) are installed at the blind end of the on-duty detonator (7); wherein the oxygen injection control valve (72) and the fuel injection control valve (73) are electromagnetic valves installed at the rear end of the on-duty detonator (7); a one-way valve (75) is installed at the outlet end of the on-duty detonator (7); The afterburner chamber is connected to an adjustable nozzle (8), which is located at the rear end of the afterburner chamber outer cylinder (51) and is a hollow truncated cone that gradually contracts inwards; the outlet area of ​​the afterburner chamber is adjustable.

2. The turbine-based detonation afterburner engine based on an aerodynamic center body according to claim 1, characterized in that: From the low-pressure turbine (42) to the rear, the outer cylinder (51) of the rotary detonation afterburner is made of a high-temperature alloy material and is not an integral part with the front engine outer casing.

3. The turbine-based detonation afterburner engine based on an aerodynamic center body according to claim 1, characterized in that: The length of the outer cylinder (51) of the rotary detonation afterburner is not less than 500 mm.

4. The turbine-based detonation afterburner engine based on an aerodynamic center body according to claim 1, characterized in that: The radial width of the throat formed at the throat boss (53) is between 2 and 8 mm; the throat boss (53) extends in a direction parallel to the engine axis by a length of 5 to 10 mm.

5. The turbine-based detonation afterburner engine based on an aerodynamic center body according to claim 1, characterized in that: The on-duty detonator (7) is located 10-50 mm downstream of the boss throat.

6. A method for operating a turbine-based detonation afterburner engine based on an aerodynamic center body, which is based on the turbine-based detonation afterburner engine based on an aerodynamic center body as claimed in claim 1, characterized in that: After the low-pressure compressor (11), the flow splitting passage divides the air into two streams according to the rated ratio according to the working requirements of the engine, wherein the first stream flows into the inner duct (21); the second stream also flows from the low-pressure compressor (11) through the outer duct (22) outside the high-pressure compressor (12) passage into the rear afterburner (5); The compressed first airflow enters the main combustion chamber (3), isobaric combustion is achieved in the main combustion chamber (3), and isobaric combustion products are output to the high-pressure turbine (41); The isobaric combustion products are sequentially expanded through a high-pressure turbine (41) behind the main combustion chamber (3) and a low-pressure turbine (42) behind the high-pressure turbine (41) to perform work, and the work extracted by the high-pressure and low-pressure turbines is used to drive the high-pressure and low-pressure compressors to perform work respectively; The first airflow after doing work through the inner duct (21) serves as the engine power source on the one hand, and on the other hand, the airflow is accelerated by the aerodynamic center body regulating mechanism (54) and serves as the aerodynamic center body of the subsequent detonation afterburner combustion chamber (5); the second airflow flows through the outer duct (22) into the afterburner combustion chamber (5) behind the low-pressure turbine (42) for detonation supercharging combustion; On the one hand, the throat boss (53) accelerates the airflow in the outer duct to the speed of sound, thereby preventing the detonation wave from being transmitted back and causing compressor surge or detonation wave extinction; on the other hand, the throat boss (53) is conducive to the penetration and mixing of kerosene fuel at the throat; in addition, the concave cavity formed on the side of the throat boss (53) facing the aerodynamic center body induces the airflow in the rotating detonation afterburner combustion chamber to form a low-speed recirculation zone, and the formed recirculation zone can be used as an anchor point for the flame in the detonation formation stage, thereby preventing the detonation wave from being unable to stabilize in the combustion chamber due to excessively high airflow speed in the detonation stage; The fuel nozzles are centrifugal swirl atomizing nozzles, which are evenly distributed along the circumference of the outer cylinder wall of the outer duct (22), and the spacing should not be too far to ensure that the atomizing cone areas of adjacent fuel nozzles can overlap; the fuel nozzle model and oil pressure are adjusted to ensure that the penetration of kerosene within a certain range is achieved, ensuring better fuel atomization and crushing effects and fuel mixing effects; The regulating plate (54a) is movably connected to the inner wall of the inner cylinder of the outer duct (22) in such a way that the regulating plate (54a) can rotate in a plane formed by the regulating plate (54a) and the engine axis, and the rotation angle is determined according to the detonation afterburner working equivalent ratio, working pressure, etc., and the rotation angle is controlled by the stroke of the actuator (54b); a plurality of regulating plates (54a) are circumferentially arranged downstream of the low-pressure turbine, and the mechanism is located behind the low-pressure turbine (42). After the combustion products have completed the work of expanding the turbine, they pass through the aerodynamic center body regulating mechanism (54) to form an aerodynamic center body, and the aerodynamic center body and the inner wall of the outer cylinder (51) of the detonation afterburner combustion chamber form an aerodynamic annular combustion chamber; The actuator (54b) is composed of a movable piston and a cylinder body. The engine adjustment system controls the stroke of the actuator by controlling the inflow and outflow of hydraulic oil. According to the change of the working state of the engine, the actuator (54b) drives the adjustment plate (54a) to move, thereby changing the outlet area of ​​the flow channel of the combustion product gas flow in the inner channel, thereby changing the flow velocity of the center body gas flow and the diameter of the pneumatic center body, so as to better match the different working states of the engine. The air supply spray rod (61) and the oil supply spray rod (62) spray fresh oxidant and fuel respectively perpendicularly to the axial flow direction, and the oxidant and fuel are respectively provided by air supply and oil supply pipelines arranged along the outer cylinder wall of the inner channel of the engine; when opened under certain working conditions that are difficult to detonate and working conditions that require further thrust enhancement, the fuel and oxidant secondary supply device (6) can improve the working performance of the detonation afterburner and increase the thrust; The on-duty detonator (7) fills explosive fuel and oxygen in a small diameter detonator tube (71), which is ignited by a spark plug (74) installed at the blind end of the detonator tube (71), forming a detonation wave that is injected into the rotary detonation afterburner, thereby detonating the afterburner detonation wave; the fuel oxidant is refilled and ignited according to the ignition requirements; the oxygen injection control valve (72) and the fuel injection control valve (73) are manually controlled by the operator when the engine is started; the oxygen and fuel used by the detonator 7 are both from the oxygen and kerosene carried by the aircraft; the one-way valve (75) automatically opens when the pressure is higher than the rated pressure difference, so as to prevent the pre-filled fuel and oxidant from being ejected by the mainstream air; The high enthalpy product generated by the adjustable nozzle (8) is discharged through the adjustable nozzle (8) connected to the afterburner, generating a high-speed airflow, thereby forming thrust; the outlet area of ​​the adjustable nozzle (8) connected to the afterburner is adjustable, so as to enhance the adaptability of the engine under different working conditions and increase the engine thrust.

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