A high-speed aircraft precooling variable cycle combined propulsion system and operation mode

Abstract

The invention discloses a high-speed aircraft precooling variable cycle combined propulsion system and operation mode. The system includes a ramjet propulsion module, a variable cycle propulsion module and a strong precooling module; the strong precooling module is respectively connected to the ramjet propulsion module and the variable cycle propulsion module; the operation modes include a turbofan mode, a turbojet mode, a precooling turbojet mode and a ramjet mode. By adjusting the relevant valves, the propulsion system is in the turbofan mode when flying at a low Mach number, in the turbojet mode when flying at a medium and low Mach number, in the precooling turbojet mode when flying at a medium and high Mach number, and in the ramjet mode when flying at a high Mach number, thereby effectively solving the problem of insufficient thrust in the transition zone when the variable cycle engine is converted from the turbojet mode to the ramjet mode, ensuring that the aircraft propulsion system continuously, stably and efficiently works within the range of Mach numbers 0 to 6, while improving the thrust of the propulsion system in the transition zone, ensuring that the high-speed aircraft can operate effectively and reliably within the range of flight Mach numbers 0 to 6.

Description

Technical Field

[0001] The present invention relates to the technical field of hypersonic aircraft, and more specifically to a precooling variable cycle combined propulsion system for a hypersonic aircraft with a flight Mach number within the range of 0 to 6. Background Art

[0002] There is an urgent need for high-speed flight in both the military and civilian fields, and high-speed aircraft is an important development direction in the future aviation field. At present, one of the main problems plaguing high-speed flight is the propulsion system of the aircraft. As the flight speed increases, the total energy of the incoming flow continues to increase, and the energy that can be injected into the compressor is constantly decreasing; at the same time, the performance of the compressor under the supersonic incoming flow is also constantly decreasing, and it is not beneficial to use the compressor to boost the airflow; and the temperature of the cooling air used for turbine cooling is constantly increasing with the increase of the Mach number, making it more difficult to cool the turbine and combustion chamber.

[0003] To solve this problem, the Swede René Lorin proposed the ramjet engine. The ramjet engine has no rotating parts such as compressors and turbines, but only three main parts: the air inlet, the combustion chamber and the tail nozzle. It has a simple structure and light weight, and is suitable for flights above Ma=3.5. However, it cannot generate thrust when the flight speed is zero. When flying at low speeds, the performance of the ramjet engine is poor because the pressure in the air inlet is small and the pressure in the combustion chamber is low.

[0004] The variable cycle engine is a multi-design point engine that adjusts its thermodynamic cycle parameters (such as compression ratio, turbine pre-temperature, bypass ratio) by changing the geometry, size or position of some components, and changes the engine cycle working mode (turbojet mode, turbofan mode or ramjet mode), so that the engine can meet different mission requirements or adapt to a wider working range. However, when the flight Mach number is between 2.5 and 3.5, the performance of the turbojet mode is seriously reduced, and the ramjet mode cannot work efficiently, resulting in insufficient thrust and unstable operation in the transition section.

[0005] Therefore, it is an urgent problem to be solved by those skilled in the art to effectively broaden the efficient operating speed range of the turbojet engine, thereby achieving a smooth transition from the turbojet mode to the ramjet mode of the variable cycle engine, allowing the engine to maintain optimal performance over a wider speed range and greatly improving the practicality of the variable cycle propulsion system. Summary of the invention

[0006] In view of this, the present invention provides a high-speed aircraft pre-cooling variable cycle combined propulsion system, aiming to solve the above technical problems.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A high-speed aircraft precooling variable cycle combined propulsion system comprises: a ramjet propulsion module, a variable cycle propulsion module and a strong precooling module; the strong precooling module is respectively connected to the ramjet propulsion module and the variable cycle propulsion module; the strong precooling function of the strong precooling module is used to broaden the efficient working speed range of the turbojet engine.

[0009] The ramjet propulsion module comprises a first air inlet, a mode conversion valve A, a ramjet combustion chamber and a ramjet tail nozzle which are connected in sequence from front to back;

[0010] The variable cycle propulsion module comprises a second air inlet, a mode conversion valve B, a fan and a low-pressure compressor, a high-pressure compressor, a variable cycle combustion chamber, a high-pressure turbine, a low-pressure turbine and a turbine tail nozzle which are connected in sequence from front to back; the fan and the low-pressure compressor have another flow path connected to the turbine tail nozzle through a variable area duct ejector;

[0011] The strong precooling module includes a fuel pump, a fuel regulating valve A, a fuel regulating valve B and a strong precooler regulating valve respectively connected to the fuel pump, and a strong precooler; the fuel regulating valve A is connected to the ramjet combustion chamber; one flow path of the strong precooler is connected to the fuel regulating valve B and the variable cycle combustion chamber respectively, and another flow path of the strong precooler is connected in series between the mode conversion valve B and the fan and the low-pressure compressor; the strong precooler regulating valve is connected to the connecting flow path of the strong precooler and the variable cycle combustion chamber.

[0012] Through the above technical scheme, the present invention makes modifications on the basis of the variable cycle propulsion system, adds a strong precooler, combines the ramjet propulsion module, the variable cycle propulsion module and the strong precooling module, and utilizes the precooling system to broaden the efficient working speed range of the turbojet engine, thereby solving the problem of insufficient thrust in the mode switching of the variable cycle engine, and enabling the hypersonic aircraft propulsion system to operate continuously and stably in the range of Mach numbers from 0 to 6.

[0013] Preferably, in the above-mentioned high-speed aircraft precooling variable cycle combined propulsion system, the outlet flow paths of the fan and the low-pressure compressor are divided into an outer duct flow path and an inner duct flow path; the outer duct flow path is connected to the variable area duct ejector; the inner duct flow path is connected to the high-pressure compressor. The fan and the low-pressure compressor can be divided into two flow paths, the inner and outer duct flow paths, to meet the structural requirements.

[0014] The present invention provides an operation mode of a high-speed aircraft precooling variable cycle combined propulsion system, aiming to solve the above technical problems.

[0015] In order to achieve the above object, the present invention adopts the following technical solution:

[0016] An operation mode of a high-speed aircraft precooling variable cycle combined propulsion system, including a turbofan mode, a turbojet mode, a precooling turbojet mode and a ramjet mode;

[0017] When the flight Mach number of the aircraft reaches a first preset range value, the turbofan mode is entered; the ramjet propulsion module is turned off, the strong precooler does not work, the airflow enters the second air inlet, is compressed by the fan and the low-pressure compressor, flows through the variable area duct ejector and reaches the turbine tail nozzle, and flows through the high-pressure compressor and is compressed again and enters the variable cycle combustion chamber for combustion. The generated combustion gas enters the high-pressure turbine and the low-pressure turbine for expansion and work, and then reaches the turbine tail nozzle;

[0018] When the flight Mach number of the aircraft reaches a second preset range value, the turbojet mode is entered; the ramjet propulsion module is turned off, the strong precooler does not work, the airflow enters the second air inlet, is compressed by the fan and the low-pressure compressor, flows through the high-pressure compressor and is compressed again before entering the variable cycle combustion chamber for combustion, and the generated combustion gas enters the high-pressure turbine and the low-pressure turbine for expansion and work before reaching the turbine tail nozzle;

[0019] When the flight Mach number of the aircraft reaches a third preset range value, it enters the precooling turbojet mode; the ramjet propulsion module is closed, the strong precooler is working, the airflow enters the second air inlet, flows through the strong precooler for cooling, is compressed by the fan and the low-pressure compressor, flows through the high-pressure compressor for compression again, and enters the variable cycle combustion chamber; the fuel pressed by the fuel pump enters the variable cycle combustion chamber and is mixed with air for combustion after the high-temperature stagnant air is cooled by the strong precooler, and the generated combustion gas enters the high-pressure turbine and the low-pressure turbine for expansion and work, and then reaches the turbine tail nozzle;

[0020] When the flight Mach number of the aircraft reaches a fourth preset range value, the ramjet mode is entered; the variable cycle propulsion module is closed, the airflow enters the first air inlet, enters the ramjet combustion chamber for combustion, and the generated gas reaches the ramjet tail nozzle.

[0021] Through the above technical scheme, the present invention provides four operation modes on the basis of the precooling variable cycle combined propulsion system of the high-speed aircraft, and by adjusting the relevant valves, the propulsion system is in the turbofan mode when flying at a low Mach number, in the turbojet mode when flying at a medium and low Mach number, in the precooling turbojet mode when flying at a medium and high Mach number, and in the ramjet mode when flying at a high Mach number, thereby effectively solving the problem of insufficient thrust in the transition zone when the variable cycle engine is converted from the turbojet mode to the ramjet mode, while ensuring that the aircraft propulsion system can continuously, stably and efficiently work within different Mach number ranges, and ensuring that the high-speed aircraft can operate effectively and reliably within different flight Mach number ranges.

[0022] Preferably, in the operation mode of the above-mentioned high-speed aircraft precooling variable cycle combined propulsion system, in the turbofan mode, the mode conversion valve A and the fuel regulating valve A are closed; the mode conversion valve B, the fuel regulating valve B, and the strong precooler regulating valve are opened; the variable area duct ejector is opened, and the strong precooler does not work. Through the opening and closing and operation states of the above-mentioned structure, the air flow and fuel propulsion requirements of the turbofan mode can be effectively met.

[0023] Preferably, in the operation mode of the above-mentioned high-speed aircraft precooling variable cycle combined propulsion system, in the turbojet mode, the mode conversion valve A and the fuel regulating valve A are closed; the mode conversion valve B, the fuel regulating valve B, and the strong precooler regulating valve are opened; the variable area duct ejector is closed, and the strong precooler does not work. Through the opening and closing and operation states of the above-mentioned structure, the air flow and fuel propulsion requirements of the turbojet mode can be effectively met.

[0024] Preferably, in the operation mode of the above-mentioned high-speed aircraft precooling variable cycle combined propulsion system, in the precooling turbojet mode, the mode conversion valve A, the fuel regulating valve A, and the strong precooler regulating valve are closed; the mode conversion valve B and the fuel regulating valve B are opened; the variable area duct ejector is closed, and the strong precooler is working. Through the opening and closing and operation states of the above-mentioned structure, the air flow and fuel propulsion requirements of the precooling turbojet mode can be effectively met.

[0025] Preferably, in the operation mode of the above-mentioned high-speed aircraft precooling variable cycle combined propulsion system, in the ramjet mode, the mode conversion valve B, the fuel regulating valve B, and the strong precooler regulating valve are closed; the mode conversion valve A and the fuel regulating valve A are opened; the variable area duct ejector is closed, and the strong precooler does not work. Through the opening and closing and operation states of the above-mentioned structure, the air flow and fuel propulsion requirements of the ramjet mode can be effectively met.

[0026] Preferably, in the above-mentioned operation mode of the precooling variable cycle combined propulsion system for a high-speed aircraft, the first preset range value is greater than 0 and less than or equal to 1.5; the second preset range value is greater than 1.5 and less than or equal to 2.5; the third preset range value is greater than 2.5 and less than or equal to 3.5; the fourth preset range value is greater than or equal to 3.5 and less than or equal to 6. While ensuring that the aircraft propulsion system can continuously, stably and efficiently work within the range of Mach numbers 0 to 6, the thrust of the transition zone propulsion system is improved, ensuring that the high-speed aircraft can operate effectively and reliably within the range of flight Mach numbers 0 to 6.

[0027] Preferably, in the above-mentioned operation mode of the high-speed aircraft precooling variable cycle combined propulsion system, the coolant of the strong precooler and the fuel of the fuel pump are the same working fluid. The coolant is first used as a coolant and then used as a fuel.

[0028] Preferably, in the operation mode of the above-mentioned high-speed aircraft pre-cooling variable cycle combined propulsion system, the coolant is aerospace cryogenic fuel, which can be hydrogen fuel or methane fuel.

[0029] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a high-speed aircraft precooling variable cycle combined propulsion system and operation mode, which has the following beneficial effects:

[0030] 1. The present invention makes modifications on the basis of the variable cycle propulsion system, adds a strong precooler, combines the ramjet propulsion module, the variable cycle propulsion module and the strong precooling module, and utilizes the precooling system to broaden the efficient working speed range of the turbojet engine, thereby solving the problem of insufficient thrust of the variable cycle engine mode switching, so that the hypersonic aircraft propulsion system can continuously and stably operate in the range of Mach numbers from 0 to 6.

[0031] 2. The present invention provides four operation modes based on the precooling variable cycle combined propulsion system of the high-speed aircraft. By adjusting the relevant valves, the propulsion system is in the turbofan mode when flying at a low Mach number, in the turbojet mode when flying at a medium and low Mach number, in the precooling turbojet mode when flying at a medium and high Mach number, and in the ramjet mode when flying at a high Mach number, thereby effectively solving the problem of insufficient thrust in the transition zone when the variable cycle engine is converted from the turbojet mode to the ramjet mode, ensuring that the aircraft propulsion system can continuously, stably and efficiently work in the Mach number range of 0 to 6, while improving the thrust of the propulsion system in the transition zone, ensuring that the high-speed aircraft can operate effectively and reliably in the flight Mach number range of 0 to 6. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0033] Figure 1 The accompanying drawing is a schematic diagram of the structure provided by the present invention.

[0034] in:

[0035] 10- Ram propulsion module;

[0036] 101- first air intake;

[0037] 102-mode conversion valve A;

[0038] 103-ramjet combustion chamber;

[0039] 104-ramjet tail nozzle;

[0040] 20- variable cycle propulsion module;

[0041] 201- Second air intake;

[0042] 202-mode conversion valve B;

[0043] 203- Fan and low-pressure compressor;

[0044] 204- High pressure compressor;

[0045] 205- variable area duct ejector;

[0046] 206- variable cycle combustion chamber;

[0047] 207-high pressure turbine;

[0048] 208- low pressure turbine;

[0049] 209-turbine tail nozzle;

[0050] 30-strong pre-cooling module;

[0051] 301-Fuel pump;

[0052] 302-Fuel regulating valve A;

[0053] 303- fuel regulating valve B;

[0054] 304-Strong precooler regulating valve;

[0055] 305-Strong precooler. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Embodiment 1:

[0058] See attached Figure 1The embodiment of the present invention discloses a high-speed aircraft precooling variable cycle combined propulsion system, comprising: a ramjet propulsion module 10, a variable cycle propulsion module 20 and a strong precooling module 30; the strong precooling module 30 is respectively connected to the ramjet propulsion module 10 and the variable cycle propulsion module 20; the strong precooling function of the strong precooling module 30 is used to broaden the efficient working speed range of the turbojet engine.

[0059] The ramjet propulsion module 10 comprises a first air inlet 101, a mode conversion valve A 102, a ramjet combustion chamber 103 and a ramjet tail nozzle 104 which are connected in sequence from front to back;

[0060] The variable cycle propulsion module 20 includes a second air inlet 201, a mode conversion valve B202, a fan and a low-pressure compressor 203, a high-pressure compressor 204, a variable cycle combustion chamber 206, a high-pressure turbine 207, a low-pressure turbine 208 and a turbine tail nozzle 209, which are connected in sequence from front to back; the fan and the low-pressure compressor 203 has another flow path connected to the turbine tail nozzle 209 through a variable area duct ejector 205;

[0061] The strong precooling module 30 includes a fuel pump 301, and a fuel regulating valve A302, a fuel regulating valve B303 and a strong precooler regulating valve 304 respectively connected to the fuel pump 301, and a strong precooler 305; the fuel regulating valve A302 is connected to the ramjet combustion chamber 103; one flow path of the strong precooler 305 is respectively connected to the fuel regulating valve B303 and the variable cycle combustion chamber 206, and another flow path of the strong precooler 305 is connected in series between the mode conversion valve B202 and the fan and the low-pressure compressor 203; the strong precooler regulating valve 304 is connected to the connecting flow path between the strong precooler 305 and the variable cycle combustion chamber 206.

[0062] In order to further optimize the above technical solution, the outlet flow path of the fan and the low-pressure compressor 203 is divided into an outer duct flow path and an inner duct flow path; the outer duct flow path is connected to the variable area duct ejector 205; and the inner duct flow path is connected to the high-pressure compressor 204.

[0063] Embodiment 2:

[0064] See attached Figure 1 Based on Example 1, the embodiment of the present invention discloses a high-speed aircraft precooling variable cycle combined propulsion system having operating modes including a turbofan mode, a turbojet mode, a precooling turbojet mode and a ramjet mode.

[0065] Embodiment 3:

[0066] See attached Figure 1 , based on Example 2, the embodiment of the present invention further defines the specific information of the turbofan mode:

[0067] When the flight Mach number of the aircraft reaches the first preset range value, it enters the turbofan mode; the ramjet propulsion module 10 is closed, the strong precooler 305 does not work, the airflow enters the second air inlet 201, is compressed by the fan and the low-pressure compressor 203, flows through the variable area duct ejector 205 and reaches the turbine tail nozzle 209, and flows through the high-pressure compressor 204 for compression again and enters the variable cycle combustion chamber 206 for combustion. The generated combustion gas enters the high-pressure turbine 207 and the low-pressure turbine 208 to expand and do work before reaching the turbine tail nozzle 209.

[0068] In turbofan mode, the mode conversion valve A102 and the fuel regulating valve A302 are closed; the mode conversion valve B202, the fuel regulating valve B303 and the strong precooler regulating valve 304 are opened; the variable area duct ejector 205 is opened, and the strong precooler 305 does not work.

[0069] The first preset range value is greater than 0 and less than or equal to 1.5.

[0070] In order to further optimize the above technical solution, the coolant of the strong precooler 305 and the fuel of the fuel pump 301 are the same working fluid.

[0071] In order to further optimize the above technical solution, the coolant is aerospace cryogenic fuel, which can be hydrogen fuel or methane fuel.

[0072] The working principle of this embodiment is:

[0073] When the flight speed is low and the flight Mach number is within the first preset range, that is, between 0 and 1.5, the turbofan mode is entered. At this time, the mode conversion valve A102 is closed, the fuel regulating valve A302 is closed, the ramjet propulsion module is closed, and no air is circulated; the mode conversion valve B202 is opened, the fuel regulating valve B303 is opened, the strong precooler regulating valve 304 is opened, the variable area duct ejector 205 is opened, and its area gradually decreases with the increase of the flight Mach number, the variable cycle propulsion module works, and the strong precooler 305 does not work; the air flows through the second air inlet 201 and the strong precooler 305, and the fan and the low pressure After being compressed by the compressor 203, the air is divided into two paths. One path flows into the turbine tail nozzle 209 through the outer flow channel, and the other path flows into the high-pressure compressor 204 through the inner flow channel and is compressed again. Finally, the air enters the variable cycle combustion chamber 206 from the air inlet of the variable cycle combustion chamber 206. The fuel is pressed out by the fuel pump 301, flows through the strong precooler regulating valve 304, and then enters the variable cycle combustion chamber 206 from the fuel inlet of the variable cycle combustion chamber 206. The combustion gas and air are burned in the variable cycle combustion chamber 206, and the generated combustion gas expands and performs work in the low-pressure turbine 208 and the high-pressure turbine 209 respectively, and is finally discharged from the turbine tail nozzle 209 to generate thrust.

[0074] Embodiment 4:

[0075] See attached Figure 1 , the embodiment of the present invention further defines the specific information of the turbojet mode on the basis of embodiment 2:

[0076] When the flight Mach number of the aircraft reaches the second preset range value, it enters the turbojet mode; the ramjet propulsion module 10 is closed, the strong precooler 305 does not work, the airflow enters the second air inlet 201, is compressed by the fan and the low-pressure compressor 203, flows through the high-pressure compressor 204 and is compressed again before entering the variable cycle combustion chamber 206 for combustion. The generated combustion gas enters the high-pressure turbine 207 and the low-pressure turbine 208, expands and does work, and then reaches the turbine tail nozzle 209.

[0077] In turbojet mode, the mode conversion valve A102 and the fuel regulating valve A302 are closed; the mode conversion valve B202, the fuel regulating valve B303 and the strong precooler regulating valve 304 are opened; the variable area duct ejector 205 is closed, and the strong precooler 305 does not work.

[0078] The second preset range value is greater than 1.5 and less than or equal to 2.5.

[0079] In order to further optimize the above technical solution, the coolant of the strong precooler 305 and the fuel of the fuel pump 301 are the same working fluid.

[0080] In order to further optimize the above technical solution, the coolant is aerospace cryogenic fuel, which can be hydrogen fuel or methane fuel.

[0081] The working principle of this embodiment is:

[0082] On the basis of Example 3, the flight speed of the aircraft gradually increases, and when the flight Mach number reaches the second preset range value, that is, between 1.5 and 2.5, the turbojet mode is entered. At this time, on the basis of the turbofan mode, the variable area duct ejector 205 is closed, and the air flows through the second air inlet 201 and the strong precooler 305. After being compressed by the fan and the low-pressure compressor 203, it directly flows into the high-pressure compressor 204 instead of flowing into the outer duct, and the remaining cycle steps are consistent with the turbofan mode.

[0083] Embodiment 5:

[0084] See attached Figure 1 , based on Example 2, the embodiment of the present invention further defines the specific information of the pre-cooling turbojet mode:

[0085] When the flight Mach number of the aircraft reaches the third preset range value, it enters the pre-cooled turbojet mode; the ramjet propulsion module 10 is closed, the strong precooler 305 is working, the airflow enters the second air inlet 201, flows through the strong precooler 305 for cooling, and is compressed by the fan and the low-pressure compressor 203, flows through the high-pressure compressor 204 for compression again, and then enters the variable cycle combustion chamber 206. The fuel pressed by the fuel pump 301 enters the variable cycle combustion chamber 206 and is mixed with air and burned after the high-temperature stagnant air is cooled by the strong precooler 305. The generated combustion gas enters the high-pressure turbine 207 and the low-pressure turbine 208, expands and does work, and then reaches the turbine tail nozzle 209.

[0086] In the precooling turbojet mode, the mode conversion valve A102, the fuel regulating valve A302, and the strong precooler regulating valve 304 are closed; the mode conversion valve B202 and the fuel regulating valve B303 are opened; the variable area duct ejector 205 is closed, and the strong precooler 305 is working.

[0087] The third preset range value is greater than 2.5 and less than or equal to 3.5.

[0088] In order to further optimize the above technical solution, the coolant of the strong precooler 305 and the fuel of the fuel pump 301 are the same working fluid.

[0089] In order to further optimize the above technical solution, the coolant is aerospace cryogenic fuel, which can be hydrogen fuel or methane fuel.

[0090] The working principle of this embodiment is:

[0091] On the basis of Example 4, the flight speed of the aircraft is relatively high, and when the flight Mach number reaches the third preset range value, that is, between 2.5 and 3.5, it enters the pre-cooling turbojet mode. At this time, based on the turbojet mode, the strong precooler regulating valve 304 is closed, and the strong precooler 305 starts to work. Since the stagnation temperature of the air in the second air inlet 201 is relatively high, it needs to be cooled in the strong precooler 305 and then flow into the rear; the fuel pressed out by the fuel pump 301 needs to first be used as a coolant to cool the air in the strong precooler 305, and then flow into the variable cycle combustion chamber 206, and the remaining cycle steps are all consistent with the turbojet mode.

[0092] In the case of this embodiment, when the aircraft uses hydrogen as fuel and flies at Ma=4 at H=25km, the system is in the third working mode, the hydrogen circulation flow is 0.42kg / s, at this time, only the second air inlet 201 flows into the air, the air flow is 1kg / s, and the total temperature and total pressure after passing through the second air inlet 201 are 930K and 387.058kPa respectively. After passing through the strong precooler 305, the air enters the fan with a total pressure ratio of 1.6 and the low-pressure compressor 203 and the high-pressure compressor 204 to be compressed, and then mixed with the fuel hydrogen in the variable cycle combustion chamber 206 to ignite, and then expand and work in the high-pressure turbine 207 and the low-pressure turbine 208, and finally accelerates the expansion in the turbine tail nozzle 209, generating a thrust of 1.2kN, which is 0.4kN greater than the thrust generated by the turbojet mode without precooling.

[0093] Embodiment 6:

[0094] See attached Figure 1 , based on Example 2, the embodiment of the present invention further defines the specific information of the stamping mode:

[0095] When the flight Mach number of the aircraft reaches a fourth preset range value, the ramjet mode is entered; the variable cycle propulsion module 20 is closed, the airflow enters the first air inlet 101, enters the ramjet combustion chamber 103 for combustion, and the generated gas reaches the ramjet tail nozzle 104.

[0096] In the ramming mode, the mode conversion valve B202, the fuel regulating valve B303, and the strong precooler regulating valve 304 are closed; the mode conversion valve A102 and the fuel regulating valve A302 are opened; the variable area duct ejector 205 is closed, and the strong precooler 305 does not work.

[0097] The fourth preset range value is greater than or equal to 3.5 and less than or equal to 6.

[0098] In order to further optimize the above technical solution, the coolant of the strong precooler 305 and the fuel of the fuel pump 301 are the same working fluid.

[0099] In order to further optimize the above technical solution, the coolant is aerospace cryogenic fuel, which can be hydrogen fuel or methane fuel.

[0100] The working principle of this embodiment is:

[0101] On the basis of Example 5, when the flight Mach number of the aircraft reaches the fourth preset range value, that is, between 3.5 and 6, it enters the ramjet mode, at which time the mode conversion valve A102 is opened, the fuel regulating valve A302 is opened, and the ramjet propulsion module works; the mode conversion valve B202 is closed, the fuel regulating valve B303 is closed, the strong precooler regulating valve 304 is closed, the variable cycle propulsion module is closed, and the strong precooler 305 does not work; the air does not enter the turbine propulsion system, but enters the ramjet combustion chamber 103 through the first air inlet 101 to burn and generate high-temperature combustion gas, which is finally discharged from the ramjet tail nozzle 104 to generate thrust.

[0102] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0103] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-speed aircraft precooling variable cycle combined propulsion system, It is characterized in that include: A ramjet propulsion module (10), a variable cycle propulsion module (20) and a strong precooling module (30); the strong precooling module (30) is respectively connected to the ramjet propulsion module (10) and the variable cycle propulsion module (20); the strong precooling function of the strong precooling module (30) is used to broaden the efficient working speed range of the turbojet engine; The ramjet propulsion module (10) comprises a first air inlet (101), a mode conversion valve A (102), a ramjet combustion chamber (103) and a ramjet tail nozzle (104) which are sequentially connected from front to back; The variable cycle propulsion module (20) comprises a second air inlet (201), a mode conversion valve B (202), a fan and a low-pressure compressor (203), a high-pressure compressor (204), a variable cycle combustion chamber (206), a high-pressure turbine (207), a low-pressure turbine (208) and a turbine tail nozzle (209) which are sequentially connected from front to back; the fan and the low-pressure compressor (203) have another flow path connected to the turbine tail nozzle (209) through a variable area duct ejector (205); The strong precooling module (30) comprises a fuel pump (301), a fuel regulating valve A (302), a fuel regulating valve B (303) and a strong precooler regulating valve (304) respectively connected to the fuel pump (301), and a strong precooler (305); the fuel regulating valve A (302) is connected to the ramjet combustion chamber (103); a flow path of the strong precooler (305) is respectively connected to the fuel regulating valve B (303) and the variable cycle combustion chamber (206), and another flow path of the strong precooler (305) is connected in series between the mode conversion valve B (202) and the fan and the low-pressure compressor (203); the strong precooler regulating valve (304) is connected to the connecting flow path between the strong precooler (305) and the variable cycle combustion chamber (206).

2. A high-speed aircraft precooling variable cycle combined propulsion system according to claim 1, It is characterized in that The outlet flow paths of the fan and the low-pressure compressor (203) are divided into an outer duct flow path and an inner duct flow path; the outer duct flow path is connected to the variable area duct ejector (205); and the inner duct flow path is connected to the high-pressure compressor (204).

3. An operation mode of the high-speed aircraft precooling variable cycle combined propulsion system according to any one of claims 1-2, It is characterized in that It has turbofan mode, turbojet mode, pre-cooled turbojet mode and ramjet mode.

4. The operation mode of the high-speed aircraft precooling variable cycle combined propulsion system according to claim 3, Features: When the flight Mach number of the aircraft reaches a first preset range value, the turbofan mode is entered; the ramjet propulsion module (10) is turned off, the strong precooler (305) is not working, the airflow enters the second air inlet (201), is compressed by the fan and the low-pressure compressor (203), flows through the variable area duct ejector (205) and reaches the turbine tail nozzle (209), and flows through the high-pressure compressor (204) and is compressed again before entering the variable cycle combustion chamber (206) for combustion. The generated combustion gas enters the high-pressure turbine (207) and the low-pressure turbine (208), expands and performs work, and then reaches the turbine tail nozzle (209); When the flight Mach number of the aircraft reaches a second preset range value, the turbojet mode is entered; the ramjet propulsion module (10) is turned off, the strong precooler (305) is not working, the airflow enters the second air inlet (201), is compressed by the fan and the low-pressure compressor (203), flows through the high-pressure compressor (204) and is compressed again before entering the variable cycle combustion chamber (206) for combustion, and the generated combustion gas enters the high-pressure turbine (207) and the low-pressure turbine (208) for expansion and work before reaching the turbine tail nozzle (209); When the flight Mach number of the aircraft reaches a third preset range value, the precooling turbojet mode is entered; the ramjet propulsion module (10) is closed, the strong precooler (305) is in operation, the airflow enters the second air inlet (201), flows through the strong precooler (305) for cooling, is compressed by the fan and the low-pressure compressor (203), flows through the high-pressure compressor (204) for compression again, and enters the variable cycle combustion chamber (206); the fuel pressed by the fuel pump (301) enters the variable cycle combustion chamber (206) after the high-temperature stagnant air is cooled by the strong precooler (305) to mix with the air and burn, and the generated combustion gas enters the high-pressure turbine (207) and the low-pressure turbine (208) to expand and do work, and then reaches the turbine tail nozzle (209); When the flight Mach number of the aircraft reaches a fourth preset range value, the ramjet mode is entered; the variable cycle propulsion module (20) is closed, the airflow enters the first air inlet (101), enters the ramjet combustion chamber (103) for combustion, and the generated combustion gas reaches the ramjet tail nozzle (104).

5. The operation mode of the high-speed aircraft precooling variable cycle combined propulsion system according to claim 4, It is characterized in that In the turbofan mode, the mode conversion valve A (102) and the fuel regulating valve A (302) are closed; the mode conversion valve B (202), the fuel regulating valve B (303), and the strong precooler regulating valve (304) are opened; the variable area duct ejector (205) is opened, and the strong precooler (305) does not work.

6. The operation mode of the high-speed aircraft precooling variable cycle combined propulsion system according to claim 4, It is characterized in that In the turbojet mode, the mode conversion valve A (102) and the fuel regulating valve A (302) are closed; the mode conversion valve B (202), the fuel regulating valve B (303) and the strong precooler regulating valve (304) are opened; the variable area duct ejector (205) is closed, and the strong precooler (305) does not work.

7. The operation mode of the high-speed aircraft precooling variable cycle combined propulsion system according to claim 4, It is characterized in that In the precooling turbojet mode, the mode conversion valve A (102), the fuel regulating valve A (302), and the strong precooler regulating valve (304) are closed; the mode conversion valve B (202) and the fuel regulating valve B (303) are opened; the variable area duct ejector (205) is closed, and the strong precooler (305) is working.

8. The operation mode of the high-speed aircraft precooling variable cycle combined propulsion system according to claim 4, It is characterized in that In the ramming mode, the mode conversion valve B (202), the fuel regulating valve B (303), and the strong precooler regulating valve (304) are closed; the mode conversion valve A (102) and the fuel regulating valve A (302) are opened; the variable area duct ejector (205) is closed, and the strong precooler (305) does not work.

9. The operation mode of the high-speed aircraft precooling variable cycle combined propulsion system according to any one of claims 4 to 8, It is characterized in that The first preset range value is greater than 0 and less than or equal to 1.5; the second preset range value is greater than 1.5 and less than or equal to 2.5; the third preset range value is greater than 2.5 and less than or equal to 3.5; the fourth preset range value is greater than or equal to 3.5 and less than or equal to 6.

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