Efficient thermal protection hybrid thermodynamic cycle combined engine and control method thereof

Abstract

The invention relates to the technical field of aero-engines, and discloses an efficient thermal protection hybrid thermodynamic cycle combined engine and a control method thereof.The combined engine composed of an external rotary detonation engine and an internal turbine engine is adopted, and modal switching of the combined engine is achieved through an inlet adjusting valve and an adjustable exhaust nozzle; the working upper limit of a turbine engine can be effectively joined, power relay can be completed, so that a thrust gap is spanned, the structural design complexity is relatively low, the system stability is relatively high, and in a stress application rotating detonation mode, the reliability is high. Combustible mixtures sprayed by the rotary detonation engine are guided into the afterburner of the turbine engine through the afterburner diverter valve for detonation combustion, an original cooling device of the afterburner is used for thermal protection, and an outer casing is prevented from being damaged due to high temperature.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engines and discloses a hybrid thermodynamic cycle combined engine with high efficiency heat protection and a control method thereof. Background Art

[0002] The existing engines that can expand the flight speed range mainly include turbine-ramjet combination engines, turbine-ramjet-rocket combination engines and turbine-precooling combination engines, and their disadvantages are as follows: (1) When the existing turbine-ramjet combined power engine crosses the thrust trap, the ramjet engine has a high operating limit (usually above Ma3), so the turbine engine needs to work to above Ma3. However, the current operating range of the turbine engine is generally around Ma2.0. Therefore, this combined power mode conversion is difficult and it is difficult to cross the thrust gap range of Ma2.0~Ma3. There is a problem of "the turbine cannot go up and the ramjet cannot go down"; (2) The existing turbine-ramjet-rocket combination engine relies on rocket power assistance. In theory, it can effectively stitch the working range of the turbine and ramjet power units, complete the modal conversion process and thus cross the thrust gap. However, the introduction of rocket power leads to a significant increase in the design complexity of the combined engine structure, control laws, etc., making engineering application difficult; (3) When the existing turbine-precooler combination engine flies at high Mach numbers, it relies on the precooler to cool the high-temperature incoming air at the compressor inlet, which avoids the thrust gap in principle and enables the turbine engine to operate normally above Mach 3. However, the precooler unit is heavy and difficult to couple with the power unit for control, resulting in a significant increase in the design complexity of the combined power structure, control laws, etc., making engineering application difficult. Summary of the Invention

[0003] The purpose of the present invention is to provide a hybrid thermodynamic cycle combination engine with high efficiency and thermal protection and a control method thereof, which can effectively connect the working upper limit of the turbine engine, complete power relay, and thus bridge the thrust gap. The structural design complexity is relatively low, the system stability is high, and the thermal protection problem can be solved.

[0004] In order to achieve the above technical effects, the technical solution adopted by the present invention is: A hybrid thermodynamic cycle combined engine with high efficiency and heat protection, comprising an outer casing, an inner casing, and an outer bypass duct between the outer casing and the inner casing, the combined engine further comprising: a rotating detonation engine, the rotating detonation engine being arranged in the outer duct; a turbine engine, the turbine engine being arranged in the inner casing; A mode switching device, comprising an inlet regulating valve, an afterburner guide valve and an adjustable tail nozzle; The inlet regulating valve is provided at the front end of the inner casing and at the inlet of the outer duct, and is used to adjust the intake flow ratio of the outer duct and the inner duct; The adjustable tail nozzle is installed at the rear of the inner casing. The area between the adjustable tail nozzle and the outer casing constitutes the outer exhaust duct of the rotating detonation engine. The area inside the adjustable tail nozzle constitutes the inner exhaust duct of the turbine engine. The adjustable tail nozzle is used to adjust the ratio of the outlet area of ​​the outer exhaust duct to the inner exhaust duct. The afterburner guide valve is arranged on the inner casing, and an afterburner is provided between the turbine component of the turbine engine and the adjustable tail nozzle. The afterburner guide valve is used to form a guide flow channel when it is opened to close the flow channel of the turbine engine, and at the same time guide the combustible mixture ejected from the rotating detonation engine into the afterburner for detonation combustion.

[0005] Furthermore, the rotating detonation engine includes a detonation injection structure arranged in the outer duct; the area from the outer duct inlet to the front end of the detonation injection structure is a detonation ramjet duct; the rear end of the detonation injection structure is an outer duct rotating detonation combustion chamber, which is connected to the outer duct exhaust duct.

[0006] Furthermore, the inner casing includes a casing front section and a casing rear section, and the afterburner combustion chamber guide valve includes an adjustable inner wall and an adjustable outer wall, one end of the adjustable inner wall is hinged to the casing front section, and one end of the adjustable outer wall is hinged to the casing rear section. The adjustable inner wall and the adjustable outer wall are used to form a structure connecting the casing front section and the casing rear section when the two are closed, and to form a guide flow channel when the two are opened to close the flow channel of the turbine engine, and at the same time guide the combustible mixture ejected from the rotating detonation engine to the afterburner combustion chamber for detonation combustion.

[0007] A control method for a hybrid thermodynamic cycle combined engine with high efficiency and thermal protection is provided, for controlling the aforementioned hybrid thermodynamic cycle combined engine with high efficiency and thermal protection, comprising: When the operating speed of the combined engine is less than or equal to a first speed threshold, the inlet regulating valve is controlled to close the outer duct, the adjustable tail nozzle is controlled to close the outer duct exhaust duct, the rotating detonation engine is shut down, the intake air flows into the inner duct, the turbine engine is operated, and the combined engine is in turbine mode; When the operating speed of the combined engine is between a first speed threshold and a second speed threshold, and the first speed threshold is less than the second speed threshold, the inlet regulating valve is controlled to open the bypass duct, the adjustable tail nozzle opens the bypass exhaust duct, the rotating detonation engine and the turbine engine operate simultaneously, and the combined engine is in a transition mode; When the flight speed is between a second speed threshold and a third speed threshold, and the second speed threshold is less than the third speed threshold, the inlet regulating valve is controlled to close the internal duct, and the adjustable tail nozzle closes the internal exhaust duct of the turbine engine, the rotating detonation engine is operated, the turbine engine is shut down, and the combined engine is in a rotating detonation mode; When the flight speed is greater than or equal to a third speed threshold, the inlet regulating valve is controlled to close the inner duct, the adjustable inner wall and the adjustable outer wall of the afterburner guide valve are opened to form a guide flow channel, the rotating detonation engine is operated, and the combined engine is in an afterburner rotating detonation mode; wherein the adjustable inner wall closes the inner exhaust duct of the turbine engine, the adjustable outer wall blocks the outer exhaust duct, and the guide flow channel guides the combustible mixture ejected from the rotating detonation engine into the afterburner for detonation combustion; Among them, according to the flight state of the combined engine, when the combined engine is in the turbine mode, transition mode and rotating detonation mode, the preset inlet regulating valve and the adjustable tail nozzle linkage action mechanism are adopted to adjust the intake flow ratio of the outer duct and the inner duct, and at the same time, the outlet area ratio of the outer duct and the inner exhaust duct is linked and adjusted.

[0008] Furthermore, the preset method for determining the linkage action mechanism between the inlet regulating valve and the adjustable tail nozzle is: Constructing a finite element analysis model of the combined engine according to the size parameters of the combined engine; Using the finite element analysis model for simulation analysis, the total pressure at the inlet of the duct, the total temperature at the inlet of the duct, and the minimum throat area required for the duct are obtained under different flight conditions and different combinations of inlet regulating valve angles. According to the ambient back pressure in each flight state and the total pressure at the inlet of the duct under the corresponding combination conditions, the maximum Mach number of the airflow at the outlet of the duct under the corresponding combination conditions is obtained; Analyze and obtain the outlet area of ​​the outer exhaust duct under corresponding combination conditions according to the minimum throat area and the maximum Mach number; The inlet regulating valve angle, the total pressure at the duct inlet, the total temperature at the duct inlet, and the maximum Mach number of the duct outlet airflow under each combination of conditions are used as input, and the duct outlet area under the corresponding combination of conditions is used as output. An analysis function for the duct outlet area based on the inlet regulating valve angle is constructed. According to the total pressure at the inlet of the outer exhaust duct, the total temperature at the inlet of the outer exhaust duct, the maximum Mach number of the airflow at the outlet of the outer exhaust duct, and the required outlet area of ​​the outer exhaust duct of the combined engine in the state to be analyzed, the angle value of the inlet regulating valve under the state to be analyzed is obtained by using the analytical function; The actions of the inlet regulating valve and the adjustable tail nozzle are controlled according to the angle value of the inlet regulating valve in the state to be analyzed and the required outlet area of ​​the outer exhaust duct.

[0009] Furthermore, the minimum throat area required for the outer exhaust duct is The analysis obtained, among which, is the outlet area of ​​the outer exhaust duct under the corresponding combination conditions, is the design intake coefficient, is the air density, is the intake air velocity, is the total temperature at the inlet of the outer exhaust duct, is the radius of the outer casing, is the radius of the inner casing, is the length of the inlet regulating valve, is the angle of the inlet regulating valve relative to the radial cross section of the combined engine, is the design flow coefficient, is the total pressure at the inlet of the bypass exhaust duct, is the design specific flow density.

[0010] Furthermore, the maximum Mach number of the airflow at the outlet of the outer exhaust duct under the corresponding combination conditions is The analysis obtained, among which, is the maximum Mach number of the airflow at the outlet of the bypass exhaust duct, is the design specific heat ratio, is the total pressure at the inlet of the bypass exhaust duct, is the ambient back pressure under the corresponding flight state.

[0011] Furthermore, the analysis function of the outer exhaust duct outlet area based on the inlet regulating valve angle is: , in, is the outlet area of ​​the outer exhaust duct, is the design intake coefficient, is the air density, is the intake air velocity, is the total temperature at the inlet of the outer exhaust duct, is the radius of the outer casing, is the radius of the inner casing, is the length of the inlet regulating valve, is the angle of the inlet regulating valve relative to the radial cross section of the combined engine, is the design flow coefficient, is the total pressure at the inlet of the bypass exhaust duct, is the design specific flow density, is the maximum Mach number of the airflow at the outlet of the bypass exhaust duct, is the design specific heat ratio.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a combined engine consisting of an external rotating detonation engine and an internal turbine engine, and realizes the mode switching of the combined engine through an inlet regulating valve and an adjustable tail nozzle, which can effectively connect the working upper limit of the turbine engine, complete the power relay, and thus bridge the thrust gap. The structural design complexity is relatively low and the system stability is high. Moreover, in the afterburner rotating detonation mode, the combustible mixture ejected by the rotating detonation engine is guided to the afterburner combustion chamber of the turbine engine for detonation combustion through the afterburner combustion chamber guide valve, and the original cooling device of the afterburner combustion chamber is used for thermal protection to prevent the outer casing from being damaged by high temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the combined engine in the embodiment; Figure 2 for Figure 1 An enlarged schematic diagram of the afterburner guide valve at part B in the middle; Figure 3 This is a schematic structural diagram of the combined engine in the turbine mode in the embodiment; Figure 4 This is a structural diagram of the combined engine in the transition mode in the embodiment; Figure 5 Schematic diagram of the structure of the combined engine in the embodiment in the rotating detonation mode; Figure 6 Schematic diagram of the structure of the combined engine in afterburner rotating detonation in the embodiment; Among them, 10-rotating detonation engine, 11-detonation ramjet duct, 12-detonation injection structure, 13-external rotating detonation combustion chamber, 14-external exhaust duct, 20-turbine engine, 21-intake cone, 22-inner exhaust duct, 23-afterburner combustion chamber, 31-outer casing, 32-inner casing, 41-inlet regulating valve, 42-regulating valve actuating mechanism, 43-adjustable tail nozzle, 44-nozzle actuating mechanism, 50-afterburner combustion chamber guide valve, 51-adjustable inner wall, 52-adjustable outer wall. DETAILED DESCRIPTION

[0014] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0015] Example See also Figures 1-6This embodiment provides a hybrid thermodynamic cycle combined engine with high efficiency and heat protection, comprising an outer casing 31 and an inner casing 32, and an outer bypass duct between the outer casing 31 and the inner casing 32, characterized in that the combined engine further comprises: A rotating detonation engine 10 is disposed within the outer duct, comprising a detonation ramjet duct 11, a detonation injection structure 12, and an outer duct rotating detonation combustion chamber 13; the detonation ramjet duct 11, the detonation injection structure 12, and the outer duct rotating detonation combustion chamber 13 are all disposed within the outer duct, and the outer duct rotating detonation combustion chamber 13 is in communication with the outer duct exhaust duct 14; The turbine engine 20 is disposed in the inner casing 32 and is provided with an intake cone 21 extending to the air inlet duct. The area between the intake cone 21 and the front end of the inner casing 32 is the inlet of the air inlet duct. A mode switching device, comprising an inlet regulating valve 41, an afterburner guide valve 50 and an adjustable tail nozzle 43; The inlet regulating valve 41 is provided at the front end of the inner casing 32 and at the inlet of the outer duct, and is used to adjust the intake flow ratio of the outer duct and the inner duct; The afterburner guide valve 50 is provided on the inner casing 32 and is located in the afterburner 23 of the turbine engine 20. The afterburner guide valve 50 is used to form a guide flow channel when it is opened to close the flow channel of the turbine engine 20 and guide the combustible mixture ejected from the rotating detonation engine 10 into the afterburner 23 for detonation combustion. The adjustable tail nozzle 43 is installed at the tail end of the inner casing 32. The area between the adjustable tail nozzle 43 and the outer casing 31 constitutes the outer exhaust duct 14 of the rotating detonation engine 10. The inner area of ​​the adjustable tail nozzle 43 constitutes the inner exhaust duct 22 of the turbine engine 20. The adjustable tail nozzle 43 is used to adjust the outlet area ratio of the outer exhaust duct 14 and the inner exhaust duct 22.

[0016] In this embodiment, when the combined engine is in turbine mode, the inlet regulating valve 41 closes the outer duct, the internal turbine engine 20 operates normally, and the external rotating detonation engine 10 does not operate; when the combined engine is in transition mode, the inlet regulating valve 41 is opened, allowing part of the air to enter the outer duct to supply the rotating detonation engine 10, while the remaining air enters the turbine engine 20 through the inner duct, ensuring the stable operation of the turbine engine 20. The adjustable tail nozzle 43 and the inlet regulating valve 41 act in conjunction to match different working conditions of the flow down the combustion chamber, and the internal turbine engine 20 and the external rotating detonation engine 10 operate simultaneously. When the combined engine is in ramjet rotating detonation mode, the inlet regulating valve 41 closes the outer duct, the adjustable tail nozzle 43 closes the flow path of the turbine engine, the internal turbine engine 20 does not operate, and the external rotating detonation engine 10 operates normally. When the combined engine is in afterburner rotating detonation mode, the external rotating detonation engine 10 operates normally, and the afterburner guide valve 50 opens to form a guide flow path, directing the combustible mixture ejected from the rotating detonation engine 10 to the afterburner 23 of the turbine engine 20 for detonation combustion. This embodiment utilizes a mode switching device to achieve smooth transitions between different operating states of the combined engine. The combined engine's mode switching is achieved through the inlet regulating valve 41 and the adjustable tail nozzle 43, effectively bridging the operating limit of the turbine engine 20, completing power relay and thus bridging the thrust gap.

[0017] In this embodiment, the afterburner combustion chamber guide valve 50 guides the combustible mixture ejected from the rotating detonation engine 10 to the afterburner combustion chamber 23 of the turbine engine 20 for detonation combustion when the combined engine is in the afterburner rotating detonation mode, and utilizes the original cooling device of the afterburner combustion chamber 23 for thermal protection to prevent the outer casing 31 from being damaged by high temperature.

[0018] It should be noted that the inner casing 32 is further provided with a regulating valve actuating mechanism 42 to actuate the inlet regulating valve 41 for adjusting the inlet regulating valve 41; the inner casing 32 is also provided with a nozzle actuating mechanism 44 to actuate the adjustable tail nozzle 43 for adjusting the adjustable tail nozzle 43. The regulating valve actuating mechanism 42 and the nozzle actuating mechanism 44 may employ existing structures.

[0019] For further information, see Figures 1-6The inner casing 32 includes a casing front section and a casing rear section, and the afterburner guide valve 50 includes an adjustable inner wall 51 and an adjustable outer wall 52. One end of the adjustable inner wall 51 is hinged to the casing front section, and one end of the adjustable outer wall 52 is hinged to the casing rear section. The adjustable inner wall 51 and the adjustable outer wall 52 are used to form a structure connecting the casing front section and the casing rear section when the two are closed, and to form a guide flow channel when the two are opened to close the flow channel of the turbine engine 20, and at the same time guide the combustible mixture ejected from the rotating detonation engine 10 to the afterburner 23 for detonation combustion.

[0020] Specifically, the front section of the casing is provided with an adjustable inner wall actuating mechanism for driving the movement of the adjustable inner wall 51, and the rear section of the casing is provided with an adjustable outer wall actuating mechanism for driving the movement of the adjustable outer wall 52. When the afterburner guide valve 50 is in a closed state, the adjustable inner wall actuating mechanism and the adjustable outer wall actuating mechanism respectively control the closure of the adjustable inner wall 51 and the adjustable outer wall 52, forming a structure connecting the front section of the casing and the rear section of the casing. When the afterburner guide valve 50 is in an open state, the adjustable inner wall actuating mechanism and the adjustable outer wall actuating mechanism respectively control the opening of the adjustable inner wall 51 and the adjustable outer wall 52 in different directions to form a guide flow channel, wherein the adjustable inner wall 51 closes the flow channel of the turbine engine 20, and the adjustable outer wall 52 blocks the outer duct 14. The guide flow channel guides the combustible mixture ejected from the rotating detonation engine 10 to the afterburner 23 of the turbine engine 20 for detonation combustion. It should be noted that both the adjustable inner wall actuating mechanism and the adjustable outer wall actuating mechanism may adopt existing structures.

[0021] Without adding any additional external structure or volume to the combined engine, this embodiment provides an afterburner diverter valve 50 on the inner casing 32. This guide channel directs the combustible mixture ejected from the rotating detonation engine 10 to the afterburner 23 of the turbine engine 20 for detonation combustion. The afterburner 23 utilizes the existing cooling device for thermal protection, enabling the combined engine to reach a predetermined speed. If the combustible mixture ejected from the rotating detonation engine 10 detonates and combusts in the outer duct rotating detonation chamber 13, the outer casing 31 will be damaged due to insufficient cooling when the flight speed exceeds a certain threshold, unless additional cooling structures are added. However, the afterburner 23 in the inner duct has its own cooling device, and the cooling capacity of the afterburner 23 is superior to that of the outer casing 31. This embodiment, by directing the combustible mixture ejected from the rotating detonation engine 10 to the afterburner 23 of the turbine engine 20 for detonation combustion, can prevent damage to the outer casing 31 due to high temperatures.

[0022] Based on the same inventive concept, this embodiment further provides a control method for a hybrid thermodynamic cycle combined engine with high efficiency and thermal protection, which is used to control the aforementioned hybrid thermodynamic cycle combined engine with high efficiency and thermal protection, comprising: See also Figure 3 When the operating speed of the combined engine is less than or equal to a first speed threshold, the inlet regulating valve 41 is controlled to close the outer duct, the adjustable tail nozzle 43 closes the outer duct exhaust duct 14, the rotating detonation engine 10 is shut down, the intake air flows into the inner duct, the turbine engine 20 is running, and the combined engine is in turbine mode; Specifically, when the operating speed of the combined engine is less than or equal to the first speed threshold, for example, when the aircraft is in the takeoff or low-speed flight range, the internal turbine engine 20 operates normally under this flight condition, and the external rotating detonation engine 10 does not operate. At this time, the regulating valve actuator 42 and the nozzle actuator 44 respectively adjust the inlet regulating valve 41 and the adjustable tail nozzle 43 to Figure 3 State, that is, the flow path of the external rotating detonation engine 10 is closed, the outer rotating detonation combustion chamber 13 is not working, all the airflow enters the internal turbine engine 20, and the main combustion chamber and the afterburner combustion chamber 23 consume fuel to generate thrust. At this time, the turbine engine 20 provides all the power sources for the aircraft.

[0023] See also Figure 4 When the operating speed of the combined engine is between a first speed threshold and a second speed threshold, and the first speed threshold is less than the second speed threshold, the inlet regulating valve 41 is controlled to open the bypass duct, and the adjustable tail nozzle 43 opens the bypass exhaust duct 14. The rotating detonation engine 10 and the turbine engine 20 operate simultaneously, and the combined engine is in a transition mode. Specific, concrete, such as Figure 4 As shown, when the operating speed of the combined engine is between the first speed threshold and the second speed threshold, the internal turbine engine 20 is at the upper limit of operation under this flight condition, and its performance gradually decreases, but it can still maintain the normal flight of the aircraft. The external rotating detonation engine 10 starts to work, and the rotating detonation engine 10 and the turbine engine 20 run simultaneously, and the combined engine is in a transition mode. At this time, as shown in FIG. Figure 4As shown, according to the preset linkage action mechanism of the inlet regulating valve 41 and the adjustable tail nozzle 43, the regulating valve actuating mechanism 42 controls the inlet regulating valve 41 to gradually open the outer duct, and the angle of the inlet regulating valve 41 relative to the radial cross-section of the combined engine gradually becomes smaller, the air intake area of ​​the inner duct is reduced, and the airflow entering the turbine inlet duct gradually decreases. At this time, the working state of the internal turbine engine 20 gradually decreases; due to the increase in the air intake area of ​​the outer duct, the airflow entering the detonation ramjet duct 11 gradually increases, and part of the airflow enters the detonation ramjet duct 11, and the outer duct rotating detonation combustion chamber 13 starts to be connected and work, and the nozzle actuating mechanism 44 adjusts the adjustable tail nozzle 43 to open the outer duct exhaust duct 14 and deflect to a predetermined position to match the working state of the different incoming flow combustion chambers. At this time, the external rotating detonation engine 10 and the internal turbine engine 20 jointly provide a power source for the aircraft.

[0024] See also Figure 5 When the flight speed is between the second speed threshold and the third speed threshold, and the second speed threshold is less than the third speed threshold, the inlet regulating valve 41 is controlled to close the internal duct, and at the same time, the adjustable tail nozzle 43 closes the internal exhaust duct 22 of the turbine engine 20, the rotating detonation engine 10 is running, the turbine engine 20 is shut down, and the combined engine is in the rotating detonation mode; Specifically, when the flight speed is between the second speed threshold and the third speed threshold, that is, when the aircraft further accelerates to a higher flight Mach number, under the incoming flow conditions of this state, the internal turbine engine 20 can no longer work normally to provide effective thrust under this flight condition, and the external rotating detonation engine 10 works normally. At this time, the regulating valve actuating mechanism 42 controls the inlet regulating valve 41 to actuate to Figure 5 position, and the nozzle actuator 44 is linked to adjust the nozzle to Figure 5 Position, that is, the inlet regulating valve 41 completely closes the turbine inlet, and at the same time the wall of the adjustable tail nozzle 43 completely closes the outlet of the afterburner 23, the internal turbine engine 20 stops working, and all airflow enters the external rotating detonation engine 10, and the external rotating detonation combustion chamber 13 consumes fuel to generate thrust, providing the entire power source for the aircraft; See also Figure 6 When the flight speed is greater than or equal to a third speed threshold, the inlet regulating valve 41 is controlled to close the inner duct, and the adjustable inner wall 51 and the adjustable outer wall 52 of the afterburner guide valve 50 are opened to form a guide flow channel. The rotating detonation engine 10 is operated, and the combined engine is in the afterburner rotating detonation mode; the adjustable inner wall 51 closes the inner exhaust duct 22 of the turbine engine 20, and the adjustable outer wall 52 blocks the outer exhaust duct 14. The guide flow channel guides the combustible mixture ejected from the rotating detonation engine 10 into the afterburner 23 for detonation combustion; Specifically, when the flight speed exceeds the third speed threshold, i.e., when the aircraft accelerates further, to facilitate efficient thermal protection of the outer casing 31, the combustible mixture ejected from the rotating detonation engine 10 is directed into the afterburner 23 to initiate detonation combustion. The afterburner 23's existing cooling system is utilized for thermal protection, preventing overheating and damage to the outer casing 31. At this point, the adjustable inner wall actuator controls the adjustable inner wall 51 to move inward from the engine, cooperating with the inlet regulating valve 41 to seal the inner turbine engine 20. Simultaneously, the adjustable outer wall actuator controls the adjustable outer wall 52 to move outward, forming a guide flow path that directs the airflow from the outer shroud rotating detonation chamber 13 into the afterburner 23 to re-initiate detonation combustion. Simultaneously, the nozzle actuator 44 controls the adjustable tail nozzle 43 to move outward, appropriately changing the nozzle area ratio. This allows the high-temperature, high-pressure airflow generated by the afterburner 23 to expand and accelerate through the inner exhaust duct 22, generating thrust. The outer exhaust duct 14 then ceases operation.

[0025] Compared to conventional annular channel rotating detonation combustors, the combined engine of this embodiment, when operating in afterburner rotating detonation mode, transforms the rotating detonation wave formation channel from an annular shape to a hollow barrel shape due to the introduction of the ramjet airflow into the afterburner 23. The high-temperature, high-pressure airflow forms a localized recirculation zone at the head of the hollow barrel combustor, locally heating the injected combustible mixture and accelerating the evaporation of the liquid fuel in the combustible mixture, forming a more uniform combustible mixture layer and facilitating the stable propagation of the rotating detonation wave. At this point, all power for the aircraft is provided by the afterburner 23 operating in the ramjet detonation mode.

[0026] Furthermore, according to the flight state of the combined engine, when the combined engine is in the turbine mode, the transition mode, and the rotating detonation mode, the preset linkage mechanism of the inlet regulating valve 41 and the adjustable tail nozzle 43 is adopted to adjust the intake flow ratio of the outer duct and the inner duct, and simultaneously to adjust the outlet area ratio of the outer duct exhaust duct 14 and the inner duct exhaust duct 22. Specifically, the method for determining the preset linkage mechanism of the inlet regulating valve 41 and the adjustable tail nozzle 43 is as follows: Constructing a finite element analysis model of the combined engine according to the size parameters of the combined engine; The finite element analysis model is used for simulation analysis to obtain the total pressure at the inlet of the outer duct 14, the total temperature at the inlet of the outer duct 14, and the minimum throat area required for the outer duct 14 under different flight conditions and different combinations of inlet regulating valve 41 angles; According to the ambient back pressure in each flight state and the total pressure at the inlet of the outer exhaust duct 14 under the corresponding combination conditions, the maximum Mach number of the airflow at the outlet of the outer exhaust duct 14 under the corresponding combination conditions is obtained; According to the minimum throat area and the maximum Mach number, the outlet area of ​​the outer exhaust duct 14 under the corresponding combination conditions is analyzed and obtained; Taking the angle of the inlet regulating valve 41, the total pressure at the inlet of the duct 14, the total temperature at the inlet of the duct 14, and the maximum Mach number of the airflow at the outlet of the duct 14 under each combination of conditions as input, and the outlet area of ​​the duct 14 under the corresponding combination of conditions as output, an analytical function for the outlet area of ​​the duct 14 based on the angle of the inlet regulating valve 41 is constructed; According to the total pressure at the inlet of the outer duct 14 of the combined engine under the state to be analyzed, the total temperature at the inlet of the outer duct 14, the maximum Mach number of the airflow at the outlet of the outer duct 14, and the required outlet area of ​​the outer duct 14, the angle value of the inlet regulating valve 41 under the state to be analyzed is obtained by using the analytical function analysis; The actions of the inlet regulating valve 41 and the adjustable tail nozzle 43 are controlled according to the angle value of the inlet regulating valve 41 in the state to be analyzed and the required outlet area of ​​the outer duct 14 .

[0027] Furthermore, the minimum throat area required for the outer exhaust duct 14 is The analysis obtained, among which, is the outlet area of ​​the outer exhaust duct 14 under the corresponding combination conditions, is the design intake coefficient, is the air density, is the intake air velocity, is the total temperature at the inlet of the outer exhaust duct 14, is the radius of the outer casing 31, is the radius of the inner casing 32, is the length of the inlet regulating valve 41, is the angle of the inlet regulating valve 41 relative to the radial cross section of the combined engine, is the design flow coefficient, is the total pressure at the inlet of the outer exhaust duct 14, is the design specific flow density.

[0028] Furthermore, the maximum Mach number of the airflow at the outlet of the outer exhaust duct 14 under the corresponding combination conditions is obtained by The analysis obtained, among which, is the maximum Mach number of the airflow at the outlet of the outer exhaust duct 14, is the design specific heat ratio, is the total pressure at the inlet of the outer exhaust duct 14, is the ambient back pressure under the corresponding flight state.

[0029] Furthermore, the analysis function of the outlet area of ​​the outer exhaust duct based on the angle of the inlet regulating valve 41 is: , in, is the outlet area of ​​the outer exhaust duct 14, is the design intake coefficient, is the air density, is the intake air velocity, is the total temperature at the inlet of the outer exhaust duct 14, is the radius of the outer casing 31, is the radius of the inner casing 32, is the length of the inlet regulating valve 41, is the angle of the inlet regulating valve 41 relative to the radial cross section of the combined engine, is the design flow coefficient, is the total pressure at the inlet of the outer exhaust duct 14, is the design specific flow density, is the maximum Mach number of the airflow at the outlet of the outer exhaust duct 14, It should be noted that the design intake coefficient, design flow coefficient, design specific flow density, and design specific heat ratio are all commonly used empirical coefficients and can be selected within a certain range.

[0030] In this embodiment, the ratio of the intake flow rate entering the outer duct and the inner duct is adjusted by the inlet regulating valve 41, and the outlet area ratio of the outer duct exhaust duct and the inner duct is adjusted by the adjustable tail nozzle 43 to match the working state of the main combustion chamber and the afterburner combustion chamber of the turbine engine, and at the same time match the working state of the outer duct rotating detonation combustion chamber. Through the linkage of the adjustable tail nozzle 43 and the inlet regulating valve 41, the intake flow rate and combustion chamber state of the turbine engine 20 and the rotating detonation engine 10 reach the preset state, thereby reducing the fuel consumption of the combined engine and improving the propulsion efficiency of the combined engine.

[0031] Compared with the existing turbine-ramjet combination engine, the combination engine of the present invention has a lower connection lower limit of the external rotating detonation combustion chamber, which can effectively connect with the working upper limit of the turbine engine 20, complete the power relay and thus bridge the thrust gap.

[0032] Compared with the existing turbine-ramjet-rocket combination engine, the combination engine of the present invention has fewer power units. In terms of the effect of bridging the thrust gap, the structural design complexity is relatively low, the structure and control laws are relatively simple, the system reliability is higher, and the feasibility of engineering application is greater.

[0033] Compared with the existing turbine-precooling engine, the combined engine of the present invention does not need to additionally consider the coupling problem between the precooling unit and the power unit. The structural design complexity is relatively low, the structure and control laws are relatively simple, the system reliability is higher, and the feasibility of engineering application is greater.

[0034] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements 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 hybrid thermodynamic cycle combined engine with high efficiency and heat protection, comprising an outer casing (31) and an inner casing (32), and an outer bypass duct between the outer casing (31) and the inner casing (32), characterized in that: The combined engine further comprises: A rotating detonation engine (10), the rotating detonation engine (10) being arranged in the outer duct; a turbine engine (20), the turbine engine (20) being disposed in the inner casing (32); A mode switching device, the mode switching device comprising an inlet regulating valve (41), an afterburner guide valve (50) and an adjustable tail nozzle (43); The inlet regulating valve (41) is provided at the front end of the inner casing (32) and located at the inlet of the outer duct, and is used to adjust the intake flow ratio of the outer duct and the inner duct; The adjustable tail nozzle (43) is installed at the rear of the inner casing (32), the area between the adjustable tail nozzle (43) and the outer casing (31) constitutes the outer exhaust duct (14) of the rotating detonation engine (10), the inner area of ​​the adjustable tail nozzle (43) constitutes the inner exhaust duct (22) of the turbine engine (20), and the adjustable tail nozzle (43) is used to adjust the ratio of the outlet area of ​​the outer exhaust duct (14) and the inner exhaust duct (22); The afterburner guide valve (50) is arranged on the inner casing (32), and an afterburner (23) is arranged between the turbine component of the turbine engine (20) and the adjustable tail nozzle (43). The afterburner guide valve (50) is used to form a guide flow channel when it is opened to close the flow channel of the turbine engine (20) and at the same time guide the combustible mixture ejected by the rotating detonation engine (10) into the afterburner (23) for detonation combustion.

2. The hybrid thermodynamic cycle combined engine with high efficiency and heat protection according to claim 1, characterized in that: The rotary detonation engine (10) includes a detonation injection structure (12) arranged in the outer duct; the area from the outer duct inlet to the front end of the detonation injection structure (12) is a detonation ramjet duct (11); the rear end of the detonation injection structure (12) is an outer duct rotary detonation combustion chamber (13), which is connected to the outer duct exhaust duct (14).

3. The hybrid thermodynamic cycle combined engine with high efficiency and heat protection according to claim 1, characterized in that: The inner casing (32) includes a casing front section and a casing rear section, and the afterburner combustion chamber guide valve (50) includes an adjustable inner wall (51) and an adjustable outer wall (52), one end of the adjustable inner wall (51) is hinged to the casing front section, and one end of the adjustable outer wall (52) is hinged to the casing rear section. The adjustable inner wall (51) and the adjustable outer wall (52) are used to form a structure connecting the casing front section and the casing rear section when the two are closed, and to form a guide flow channel when the two are opened to close the flow channel of the turbine engine (20) and at the same time guide the combustible mixture ejected by the rotating detonation engine (10) to the afterburner combustion chamber (23) for detonation combustion.

4. A method for controlling a hybrid thermodynamic cycle combined engine with high efficiency and thermal protection, for controlling a hybrid thermodynamic cycle combined engine with high efficiency and thermal protection as claimed in any one of claims 1 to 3, characterized in that: include: When the operating speed of the combined engine is less than or equal to a first speed threshold, the inlet regulating valve (41) is controlled to close the outer duct, the adjustable tail nozzle (43) closes the outer duct exhaust duct (14), the rotating detonation engine (10) is shut down, the intake air flows into the inner duct, the turbine engine (20) is operated, and the combined engine is in turbine mode; When the operating speed of the combined engine is between a first speed threshold and a second speed threshold, and the first speed threshold is less than the second speed threshold, the inlet regulating valve (41) is controlled to open the bypass duct, the adjustable tail nozzle (43) opens the bypass exhaust duct (14), the rotating detonation engine (10) and the turbine engine (20) operate simultaneously, and the combined engine is in a transition mode; When the flight speed is between a second speed threshold and a third speed threshold, and the second speed threshold is less than the third speed threshold, the inlet regulating valve (41) is controlled to close the inner duct, and at the same time, the adjustable tail nozzle (43) closes the inner exhaust duct (22) of the turbine engine (20), the rotating detonation engine (10) is operated, the turbine engine (20) is shut down, and the combined engine is in a rotating detonation mode; When the flight speed is greater than or equal to a third speed threshold, the inlet regulating valve (41) is controlled to close the inner duct, the adjustable inner wall (51) and the adjustable outer wall (52) of the afterburner guide valve (50) are opened to form a guide flow channel, the rotating detonation engine (10) is operated, and the combined engine is in an afterburner rotating detonation mode; wherein the adjustable inner wall (51) closes the inner exhaust duct (22) of the turbine engine (20), the adjustable outer wall (52) blocks the outer exhaust duct (14), and the guide flow channel guides the combustible mixture ejected from the rotating detonation engine (10) to the afterburner (23) for detonation combustion; According to the flight state of the combined engine, when the combined engine is in the turbine mode, the transition mode and the rotating detonation mode, the preset linkage action mechanism of the inlet regulating valve (41) and the adjustable tail nozzle (43) is adopted to adjust the intake flow ratio of the outer duct and the inner duct, and at the same time, the outlet area ratio of the outer duct exhaust duct (14) and the inner duct exhaust duct (22) is linked and adjusted.

5. The hybrid thermodynamic cycle combined engine control method according to claim 4, characterized in that: The method for determining the preset linkage action mechanism between the inlet regulating valve (41) and the adjustable tail nozzle (43) is: Constructing a finite element analysis model of the combined engine according to the size parameters of the combined engine; The finite element analysis model is used to perform simulation analysis to obtain the total pressure at the inlet of the outer duct (14), the total temperature at the inlet of the outer duct (14), and the minimum throat area required for the outer duct (14) under different flight states and different inlet regulating valve (41) angle combinations; According to the ambient back pressure in each flight state and the total pressure at the inlet of the outer exhaust duct (14) under the corresponding combination conditions, the maximum Mach number of the airflow at the outlet of the outer exhaust duct (14) under the corresponding combination conditions is obtained; According to the minimum throat area and the maximum Mach number, an outlet area of ​​the outer exhaust duct (14) under corresponding combination conditions is analyzed and obtained; Taking the angle of the inlet regulating valve (41), the total pressure at the inlet of the outer duct (14), the total temperature at the inlet of the outer duct (14), and the maximum Mach number of the airflow at the outlet of the outer duct (14) under each combination condition as input, and the outlet area of ​​the outer duct (14) under the corresponding combination condition as output, an analysis function of the outlet area of ​​the outer duct (14) based on the angle of the inlet regulating valve (41) is constructed; According to the total pressure at the inlet of the outer exhaust duct (14) of the combined engine in the state to be analyzed, the total temperature at the inlet of the outer exhaust duct (14), the maximum Mach number of the airflow at the outlet of the outer exhaust duct (14), and the required outlet area of ​​the outer exhaust duct (14), the angle value of the inlet regulating valve (41) in the state to be analyzed is obtained by using the analytical function analysis; According to the angle value of the inlet regulating valve (41) in the state to be analyzed and the required outlet area of ​​the outer duct (14), the actions of the inlet regulating valve (41) and the adjustable tail nozzle are controlled.

6. The hybrid thermodynamic cycle combined engine control method according to claim 5, characterized in that: The minimum throat area required for the outer exhaust duct (14) is The analysis obtained, among which, is the outlet area of ​​the outer exhaust duct (14) under the corresponding combination conditions, is the design intake coefficient, is the air density, is the intake air velocity, is the total temperature at the inlet of the outer exhaust duct (14), is the radius of the outer casing (31), is the radius of the inner casing (32), is the length of the inlet regulating valve (41), is the angle of the inlet regulating valve (41) relative to the radial cross section of the combined engine, is the design flow coefficient, is the total pressure at the inlet of the outer exhaust duct (14), is the design specific flow density.

7. The hybrid thermodynamic cycle combined engine control method according to claim 6, characterized in that: The maximum Mach number of the outlet airflow of the outer exhaust duct (14) under the corresponding combination conditions is obtained by The analysis obtained, among which, is the maximum Mach number of the airflow at the outlet of the outer exhaust duct (14), is the design specific heat ratio, is the total pressure at the inlet of the outer exhaust duct (14), is the ambient back pressure under the corresponding flight state.

8. The hybrid thermodynamic cycle combined engine control method according to claim 7, characterized in that: The outlet area analysis function of the outer exhaust duct (14) based on the angle of the inlet regulating valve (41) is: in, is the outlet area of ​​the outer exhaust duct (14), is the design intake coefficient, is the air density, is the intake air velocity, is the total temperature at the inlet of the outer exhaust duct (14), is the radius of the outer casing (31), is the radius of the inner casing (32), is the length of the inlet regulating valve (41), is the angle of the inlet regulating valve (41) relative to the radial cross section of the combined engine, is the design flow coefficient, is the total pressure at the inlet of the outer exhaust duct (14), is the design specific flow density, is the maximum Mach number of the airflow at the outlet of the outer exhaust duct (14), is the design specific heat ratio.

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