Dual-fuel composite pre-cooling engine system based on jet flow / heat exchanger pre-cooling and using method of dual-fuel composite pre-cooling engine system

Abstract

The invention provides a dual-fuel composite pre-cooling engine system based on jet flow / heat exchanger pre-cooling and a using method of the dual-fuel composite pre-cooling engine system, and relates to the field of aircraft engine systems. An air inlet channel, a fuel pump, a precooler, a jet device, an air compressor, a main combustion chamber, a turbine, an afterburner and an exhaust nozzle sequentially form an engine main body in the axial direction. According to the system, the characteristics of jet flow precooling and heat exchanger precooling are combined, liquid ammonia / kerosene dual-fuel layout is adopted, and a cooling working medium can realize conversion of precooling working places through a control valve according to precooling requirements, so that incoming flow air in different flight states is efficiently precooled; and the problems that a heat exchanger is large in precooling weight and flow resistance and a jet device is poor in precooling heat exchange effect are effectively solved. And finally, the system gives consideration to the simple jet flow pre-cooling structure and the high efficiency of heat exchanger pre-cooling, and the pre-cooling effect and the propelling performance of the pre-cooling engine are effectively improved.

Description

Technical Field

[0001] The present invention belongs to the field of aircraft engine systems and relates to an advanced pre-cooling aviation turbine engine system, in particular to a composite pre-cooling engine system based on jet and heat exchanger cooling of incoming air suitable for a wide speed range. Background Art

[0002] Hypersonic vehicles, defined as those with flight speeds exceeding Mach 5 or 6,000 kilometers per hour, can effectively operate between the highest altitudes of conventional aircraft and the lowest orbital altitudes of satellites. Because they can reach any region of the globe within hours and possess high penetration and survivability, they can be applied in a variety of fields, including supersonic cruise missiles, hypersonic aircraft, and space shuttles. They have become a key research area in both military and civilian fields.

[0003] As the flight Mach number increases, the total intake temperature of the turbine engine rises rapidly due to aerodynamic friction. At 4 Mach, the incoming air temperature can reach above 900K. The excessively high temperature airflow at the compressor inlet will increase the power consumption of the compressor, causing the turbine engine's propulsion performance to seriously deteriorate or even fail to work normally. This problem can be effectively avoided by adopting intake precooling technology.

[0004] Existing heat exchanger-type pre-cooling engines usually use highly compact involute heat exchangers to achieve an increase in heat exchange efficiency. However, this type of pre-cooler occupies a large space, is heavy, and has a high air-side pressure loss.

[0005] The jet pre-cooling engine uses a jet device as the place to cool the air. The jet device has the characteristics of light weight, small size, simple structure, and can be put into use quickly. The traditional jet pre-cooling engine mainly uses water as the jet working fluid. As the jet flow rate increases during the pre-cooling process, the engine's specific impulse performance will drop significantly. In addition, the jet pre-cooling process belongs to downstream heat exchange, which loses some heat exchange performance.

[0006] Existing jet fuel has an autoignition point of approximately 573K and a flammability limit between 1.4-7.5 vol%. Injecting large amounts of jet fuel can cause the resulting mixture to combust in the compressor, leading to performance degradation and even engine damage. Furthermore, given the turbine inlet temperature limit, the jet fuel injection rate required to meet combustion requirements in the combustor is insufficient to meet the air cooling requirements at high Mach numbers.

[0007] Ammonia, as a common fuel, has excellent cooling performance. The phase change of liquid ammonia can provide high latent heat absorption. Ammonia will undergo a decomposition and endothermic reaction under the conditions of a catalyst and a high temperature of 500°C, which can further improve heat sinking. Summary of the Invention

[0008] In view of this, in order to solve the technical problems mentioned in the above background technology, the present invention proposes a dual-fuel composite pre-cooling engine system based on jet / heat exchanger pre-cooling and a method of using the same, by introducing a jet device to reduce the pre-cooling load borne by the pre-cooler, thereby improving the power-to-weight ratio performance of the pre-cooling component; by introducing a dual working medium layout, the combustion requirements and pre-cooling requirements during the operation of the pre-cooling engine are met, no pre-cooling is performed before zero speed to the minimum pre-cooling Mach number, and after the minimum pre-cooling Mach number, the pre-cooler and the jet device are used to achieve first-stage and second-stage cooling of the air, thereby reducing the power consumption of the compressor and improving the propulsion performance of the pre-cooling engine.

[0009] To achieve the above objectives, the present invention adopts the following technical solutions: a dual-fuel composite pre-cooling engine system based on jet / heat exchanger pre-cooling, comprising an air intake, a pre-cooler, a jet device, a compressor, a main combustion chamber, a turbine, an afterburner, a tail nozzle, a liquid ammonia storage tank, and a kerosene storage tank. The air inlet, precooler, jet device, compressor, main combustion chamber, turbine, afterburner and tail nozzle are arranged in sequence from front to back, the compressor and turbine are arranged coaxially, the liquid ammonia storage tank is respectively connected to the precooler and jet device, and the kerosene storage tank is respectively connected to the precooler, jet device, main combustion chamber and afterburner.

[0010] Furthermore, the precooler is an involute precooler.

[0011] Furthermore, the jet device is nested inside the precooler, and the jet device includes a spray rod and a plurality of nozzles, and the spray rod is provided with a plurality of nozzles.

[0012] Furthermore, the liquid ammonia storage tank, the liquid ammonia pump, the first liquid ammonia regulating valve and the precooler are connected in sequence.

[0013] Furthermore, the liquid ammonia storage tank, the liquid ammonia pump, the second liquid ammonia regulating valve and the jet device are connected in sequence.

[0014] Furthermore, the kerosene storage tank, the kerosene pump, the first kerosene regulating valve and the cold fluid side inlet of the precooler are connected in sequence.

[0015] Furthermore, the kerosene storage tank, kerosene pump, second kerosene regulating valve and jet device are connected in sequence.

[0016] Furthermore, the kerosene storage tank, kerosene pump, main combustion chamber flow valve and main combustion chamber are connected in sequence.

[0017] Furthermore, the kerosene storage tank, kerosene pump, afterburner flow valve and afterburner are connected in sequence, and the kerosene is pumped by the kerosene pump to the cold fluid side inlet of the precooler, and then flows out from the cold fluid side outlet of the precooler, and is proportionally injected into the main combustion chamber and the afterburner flow valve respectively.

[0018] A method for using a composite precooling engine system based on jet / heat exchanger precooling, specifically including the following: Case 1: From zero Mach start to the minimum pre-cooling Mach number, the Mach range is 0-2 Mach. All working fluid regulating valves are in the closed state. Kerosene is pumped by the kerosene pump and flows into the main combustion chamber and afterburner according to the engine combustion requirements. The incoming air pressurized by the compressor burns with kerosene in the main combustion chamber to generate combustion gas. The combustion gas expands in the turbine to perform work, then enters the afterburner to burn again and is finally discharged from the tail nozzle. Case 2: From the lowest precooling Mach number to the higher flight Mach number, the Mach range is 2-4 Ma, the first kerosene regulating valve and the second liquid ammonia regulating valve are open, the second kerosene regulating valve and the first liquid ammonia regulating valve are closed, the liquid ammonia is pumped to the jet device by the liquid ammonia pump and ejected, the kerosene is pumped to the cold fluid side inlet of the precooler by the kerosene pump, and then flows out from the cold fluid side outlet of the precooler and is proportionally injected into the main combustion chamber and afterburner respectively through the main combustion chamber flow valve and the afterburner flow valve; the incoming air After being compressed in the intake duct, the high-temperature air is in the high-temperature range of 350-909K. This high-temperature air flows through the air-side inlet of the precooler for heat exchange. The medium-temperature air at the air-side outlet of the precooler continues to flow through the jet device and is mixed with ammonia spray. The resulting mixed gas enters the compressor inlet. The supercharged mixed gas flows into the main combustion chamber and is mixed with kerosene for combustion. The resulting high-temperature combustion gas expands in the turbine to generate work and drives the compressor to rotate. The combustion gas at the turbine outlet enters the afterburner and is burned again with kerosene. The high-temperature combustion gas at the outlet is finally discharged into the tail nozzle after expansion. Case 3: At high flight Mach number, Mach>4Ma, the second kerosene regulating valve and the first liquid ammonia regulating valve are opened, the first kerosene regulating valve and the second liquid ammonia regulating valve are in the closed state, the kerosene is partially pumped to the jet device for injection by the kerosene pump, and the rest flows into the main combustion chamber and the afterburner respectively, the liquid ammonia is pumped to the cold fluid inlet of the precooler by the liquid ammonia pump, and then injected into the main combustion chamber and the afterburner from the cold fluid outlet of the precooler; the incoming air is compressed by the air inlet and is in a high temperature zone above 909K. The air enters the precooler and the jet device in turn for cooling, and the resulting mixture enters the core components of the engine consisting of the compressor, main combustion chamber, turbine, afterburner, and tail nozzle to work normally, and is finally discharged into the atmosphere through the tail nozzle to generate thrust to propel the aircraft to navigate.

[0019] Compared with the prior art, the dual-fuel composite pre-cooling engine system based on jet / heat exchanger pre-cooling and the method of using the same according to the present invention have the following beneficial effects: 1. The jet precooling structure used in the present invention selects a combustible working fluid as the spray. After the spray is mixed with the incoming air for heat exchange, the resulting mixed gas has a certain combustion calorific value and can undergo combustion reaction in the main combustion chamber. Compared with traditional water jet precooling, this greatly improves the specific impulse performance of the engine in the precooling mode.

[0020] 2. Limited by the maximum turbine inlet temperature, the jet working fluid cannot increase the jet flow rate indefinitely. Therefore, there is a problem of being unable to meet the pre-cooling requirements of the combustible jet at high Mach numbers. Traditional water jets, when increasing the jet flow rate, not only deteriorate the engine's specific impulse performance, but also negatively impact the combustion efficiency of the combustion chamber. Unlike traditional jet pre-cooling, the composite pre-cooling engine based on jet / heat exchanger pre-cooling described in the present invention adds a pre-cooler to the jet structure, effectively overcoming this problem. Therefore, it has pre-cooling capabilities over a wide speed range and can effectively increase the maximum Mach number of the aircraft.

[0021] 3. The precooling component of the precooling engine system in the present invention is composed of a precooler and a jet device. The lightweight and small jet device shares part of the precooling load of the precooler. Therefore, under the same precooling demand, the overall power-to-weight ratio of the precooling component can be improved, which helps to optimize the design and processing of the precooler structure.

[0022] 4. The aviation pre-cooling engine of the present invention uses a mixture of kerosene and liquid ammonia as fuel, which is different from aviation engines that use conventional fuels such as jet kerosene and methane. This significantly reduces the carbon oxide content in the engine exhaust and effectively reduces exhaust pollution. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 This is a schematic structural diagram of a dual-fuel composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to the present invention; Figure 2 This is a schematic structural diagram of the pre-cooling components of the composite pre-cooling engine system according to the present invention; In the figure: air intake duct 1, precooler 2, jet device 3, compressor 4, main combustion chamber 5, turbine 6, afterburner 7, tail nozzle 8, liquid ammonia storage tank 9, liquid ammonia pump 10, first liquid ammonia regulating valve 11, second liquid ammonia regulating valve 12, kerosene storage tank 13, kerosene pump 14, first kerosene regulating valve 15, second kerosene regulating valve 16, main combustion chamber flow valve 17, afterburner flow valve 18. DETAILED DESCRIPTION The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features therein can be combined with each other in the absence of conflict, and the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0023] See also Figure 1-2 To illustrate this embodiment, a dual-fuel composite pre-cooling engine system based on jet / heat exchanger pre-cooling includes an air intake duct 1, a pre-cooler 2, a jet device 3, a compressor 4, a main combustion chamber 5, a turbine 6, an afterburner 7, a tail nozzle 8, a liquid ammonia storage tank 9 and a kerosene storage tank 13 located in an engine casing. The air intake duct 1, pre-cooler 2, the jet device 3, the compressor 4, the main combustion chamber 5, the turbine 6, the afterburner 7 and the tail nozzle 8 are arranged in sequence from front to back, the compressor 4 and the turbine 6 are coaxially arranged, the liquid ammonia storage tank 9 is respectively connected to the pre-cooler 2 and the jet device 3, and the kerosene storage tank 13 is respectively connected to the pre-cooler 2, the jet device 3, the main combustion chamber 5 and the afterburner 7.

[0024] The air intake duct 1 is located at the front end of the engine, the precooler 2 and the jet device 3 are located between the outlet of the air intake duct 1 and the compressor inlet 4, the compressor 4, the main combustion chamber 5, the turbine 6, and the afterburner 7 are arranged in sequence in front of the tail nozzle 8, and the fuel supply system consisting of the liquid ammonia storage tank 9, the kerosene storage tank 13, the liquid ammonia pump 10, the kerosene pump 14 and various regulating valves and flow valves is located outside the engine casing.

[0025] The dual-fuel aviation composite pre-cooling engine cycle adopts a dual-fuel layout, including a high calorific value fuel (kerosene) for meeting the engine combustion requirements, and a high heat sink fuel (liquid ammonia) for meeting the cooling requirements under high Mach.

[0026] The engine combustion chamber uses kerosene / ammonia duplex fuel in different proportions to avoid the problem of pure ammonia fuel being difficult to burn. The engine's turbine 6 is coaxially arranged with the compressor 4, and the compressor 4 is driven to rotate by the expansion of the fuel gas. The high-temperature fuel gas passing through the afterburner 7 is expanded and discharged from the tail nozzle 8, converting the internal energy of the fuel gas into kinetic energy to provide thrust for the engine.

[0027] like Figure 2 As shown, the precooling components of the composite precooling engine system are composed of a precooler 2 and a jet device 3. The precooler 2 is an involute precooler, which is arranged after the outlet of the intake duct 1 and before the jet device 3, and is connected to the kerosene and liquid ammonia supply pipelines through the first kerosene regulating valve 15 and the first liquid ammonia regulating valve 11 respectively.

[0028] The precooler 2 can be coated with a catalyst that promotes an endothermic chemical reaction on the fuel within the precooler tubes. This allows the fuel to act as the primary site for the chemical endothermic reaction at high temperatures corresponding to a certain Mach number, thereby improving the overall heat sink of the cooling medium. In this embodiment, liquid ammonia serves as the cooling fluid in the precooler at high Mach numbers. The catalyst coating allows the ammonia to undergo an endothermic decomposition reaction at high temperatures, further improving heat sink.

[0029] Specifically, in the case described in this embodiment, the jet device 3 is located after the refrigerant in the precooler 2 exchanges heat with the air. In terms of structural layout, the jet device 3 can be nested inside the precooler 2, such as Figure 2 As shown, since the complete evaporation of the jet medium requires a certain vaporization distance, in this embodiment, by nesting the jet device 3 inside the precooler 2, a certain jet section length can be saved.

[0030] The jet device 3 consists of a spray bar and nozzle, connected to the kerosene and liquid ammonia supply pipelines via a second kerosene regulating valve 12 and a second liquid ammonia regulating valve 16, respectively. Under low Mach number conditions, the jet medium should be a low-boiling-point fluid, such as liquid ammonia. It is located after the precooler 2 and before the compressor 4. The jet medium at the outlet of the jet device 3 directly mixes with the incoming air flow for heat exchange, and the resulting mixed gas enters the inlet of the compressor 4. The dual-fuel aviation composite precooling engine does not perform jet or precooler 2 precooling from zero speed startup to the lowest precooling Mach number. After entering the precooling mode, jet precooling and jet / precooler 2 composite precooling are enabled according to precooling requirements.

[0031] At high Mach numbers, due to the significant increase in the total intake temperature, the pre-cooling location of kerosene / liquid ammonia working fluid can be switched by opening and closing the first and second kerosene regulating valves 11 / 12 and the first and second liquid ammonia regulating valves 15 / 16. The liquid ammonia absorbs heat through evaporation and chemical decomposition reaction in the precooler 2 to significantly reduce the air temperature, and kerosene, as a jet working fluid, absorbs heat through evaporation to further reduce the air temperature.

[0032] The fuel supply side inlets of the main combustion chamber 5 and the afterburner combustion chamber 7 are provided with flow regulating valves, which achieve proper distribution of the fuel flow in each combustion chamber by controlling the flow condition valve opening; the fuel flow injected in each combustion chamber is determined by calculating the injection working fluid flow and calorific value in the jet device.

[0033] This embodiment provides an operating mode of a composite pre-cooling engine system based on jet and heat exchanger pre-cooling, which transitions from zero Mach start to flight conditions above Mach 4. The specific operating process is as follows: Before starting from zero Mach to the minimum pre-cooling Mach number (0-2 Mach), all working fluid regulating valves are in the closed state. Kerosene is pumped by the kerosene pump 14 and flows into the main combustion chamber 5 and the afterburner 7 according to the engine combustion requirements. The incoming air pressurized by the compressor 4 burns with the kerosene in the main combustion chamber 5 to generate combustion gas. The combustion gas expands through the turbine 6 to perform work, then enters the afterburner 7 to burn again and is finally discharged from the nozzle 8. At the lowest precooling Mach number to the higher flight Mach number (2-4 Mach), the first kerosene regulating valve 15 and the second liquid ammonia regulating valve 12 are opened, the second kerosene regulating valve 16 and the first liquid ammonia regulating valve 11 are closed, the liquid ammonia is pumped by the liquid ammonia pump 10 to the ejection device 3 for ejection, the kerosene is pumped by the kerosene pump 14 to the cold fluid side inlet of the precooler 2, and then flows out from the cold fluid side outlet of the precooler 2 and is proportionally injected into the main combustion chamber 5 and the afterburner 7 respectively through the main combustion chamber flow valve 17 and the afterburner flow valve 18; the incoming air After being compressed by the intake duct 1, the air is in a high-temperature range of 350-909K. This high-temperature air flows through the air-side inlet of the precooler 2 for heat exchange. The medium-temperature air at the air-side outlet of the precooler 2 continues to flow through the jet device 3 and is mixed with ammonia spray. The resulting mixed gas enters the inlet of the compressor 4. The supercharged mixed gas flows into the main combustion chamber 5 and is mixed with kerosene for combustion. The resulting high-temperature combustion gas expands through the turbine 6 to generate work, driving the compressor 4 to rotate. The combustion gas at the outlet of the turbine 6 enters the afterburner 7 and is combusted again with kerosene. The high-temperature combustion gas at the outlet is finally discharged into the tail nozzle 8 after expansion. At high flight Mach numbers (above 4 Ma), the second kerosene regulating valve 16 and the first liquid ammonia regulating valve 11 are open, and the first kerosene regulating valve 15 and the second liquid ammonia regulating valve 12 are closed. Kerosene is partially pumped to the jet device 3 by the kerosene pump 14 for injection, and the rest flows into the main combustion chamber 5 and the afterburner 7 respectively. Liquid ammonia is pumped to the cold fluid inlet of the precooler 2 by the liquid ammonia pump 10, and then injected into the main combustion chamber 5 and the afterburner 7 from the cold fluid outlet of the precooler 2; the incoming air is compressed by the air inlet 1 and is in a high temperature zone above 909K. The air enters the precooler 2 and the jet device 3 in turn for cooling, and the resulting mixed gas enters the core components of the engine consisting of the compressor 4, the main combustion chamber 5, the turbine 6, the afterburner 7, and the tail nozzle 8 to work normally, and is finally discharged into the atmosphere through the tail nozzle 8 to generate thrust to propel the aircraft to fly.

[0034] Different from the existing jet precooling aircraft engine system, the composite precooling engine system based on jet and heat exchanger precooling mentioned in this embodiment uses kerosene / liquid ammonia as a dual working fluid as coolant and fuel, and the precooler structure can bear a certain precooling load to avoid overheating of the combustion chamber caused by excessive jet. Therefore, the system has better cooling and propulsion performance and a wide operating range.

[0035] Different from the existing heat exchanger precooling aircraft engine system, the composite precooling engine system based on jet and heat exchanger precooling mentioned in this embodiment has a precooling component composed of a precooler and a jet device. The lightweight and small jet device bears a certain precooling load, thereby improving the power-to-weight ratio of the overall precooling component under certain precooling requirements. Therefore, this structure helps to optimize the structural design and processing difficulty of the highly compact precooler.

[0036] The combustion that occurs in the engine's combustion chamber uses a mixture of kerosene and liquid ammonia as fuel, so the carbon oxide content in the combustion reactants will be significantly lower than that of hydrocarbon fuels, which helps reduce exhaust pollution.

[0037] The present invention combines the two pre-cooling structures of jet and heat exchanger and the dual-fluid engine layout, and refers to the existing jet pre-cooling system and heat exchanger pre-cooling system to establish a composite pre-cooling engine system based on jet and heat exchanger pre-cooling. It solves the problem of limited pre-cooling performance due to avoiding combustion chamber overheating in combustible jet pre-cooling, and provides optimization ideas for the phenomenon of high difficulty in pre-cooler design and processing in existing heat exchanger pre-cooling. The system of the present invention not only has excellent cooling and propulsion performance, but also has the characteristics of low carbon emissions of exhaust gas. During the process of increasing the flight speed of an air-breathing aircraft, the total temperature of the inlet air rises rapidly after being compressed in the air inlet. In order to achieve pre-cooling of the intake air, the system of the present invention opens the first kerosene regulating valve between the kerosene pump and the precooler after reaching the minimum pre-cooling Mach number (2Ma), so that the kerosene passes into the cold fluid side of the precooler and exchanges heat with the high-temperature airflow on the air side of the precooler. The high-temperature kerosene at the outlet of the cold fluid side of the precooler is then passed into the combustion chambers of each stage for combustion; at the same time, the second liquid ammonia regulating valve between the liquid ammonia pump and the jet device is opened, and the medium-temperature airflow at the outlet of the air side of the precooler is further cooled by the ammonia jet. The formed mixed gas enters the gas generator composed of the compressor and the combustion chamber and generates high-temperature and high-pressure gas. After entering the turbine for expansion, the gas is mixed with kerosene in the afterburner and burned again. The high-temperature gas is finally discharged through the tail nozzle to generate thrust.

[0038] The embodiments of the present invention disclosed above are intended only to illustrate the present invention. The embodiments do not describe all details in detail, nor do they limit the present invention to the specific embodiments described. Numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. A composite pre-cooling engine system based on jet / heat exchanger pre-cooling, characterized by: It includes an air inlet (1), a precooler (2), a jet device (3), a compressor (4), a main combustion chamber (5), a turbine (6), an afterburner (7), a tail nozzle (8), a liquid ammonia storage tank (9) and a kerosene storage tank (13). The air inlet (1), precooler (2), jet device (3), compressor (4), main combustion chamber (5), turbine (6), afterburner (7), and tail nozzle (8) are arranged in sequence from front to back, the compressor (4) and turbine (6) are coaxially arranged, the liquid ammonia storage tank (9) is respectively connected to the precooler (2) and the jet device (3), and the kerosene storage tank (13) is respectively connected to the precooler (2), the jet device (3), the main combustion chamber (5), and the afterburner (7).

2. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 1, characterized in that: The precooler (2) is an involute precooler.

3. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 1, characterized in that: The jet device (3) is nested inside the precooler (2), and the jet device (3) comprises a spray bar and a plurality of nozzles, wherein the spray bar is provided with the plurality of nozzles.

4. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 1, characterized in that: The liquid ammonia storage tank (9), the liquid ammonia pump (10), the first liquid ammonia regulating valve (11) and the precooler (2) are connected in sequence.

5. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 4, characterized in that: The liquid ammonia storage tank (9), the liquid ammonia pump (10), the second liquid ammonia regulating valve (12) and the jet device (3) are connected in sequence.

6. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 5, characterized in that: The kerosene storage tank (13), the kerosene pump (14), the first kerosene regulating valve (15) and the cold fluid side inlet of the precooler (2) are connected in sequence.

7. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 6, characterized in that: The kerosene storage tank (13), the kerosene pump (14), the second kerosene regulating valve (16) and the jet device (3) are connected in sequence.

8. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 7, characterized in that: The kerosene storage tank (13), the kerosene pump (14), the main combustion chamber flow valve (17) and the main combustion chamber (5) are connected in sequence.

9. The composite pre-cooling engine system based on jet / heat exchanger pre-cooling according to claim 8, characterized in that: The kerosene storage tank (13), kerosene pump (14), afterburner flow valve (18) and afterburner (7) are connected in sequence. The kerosene is pumped by the kerosene pump (14) to the cold fluid side inlet of the precooler (2), then flows out from the cold fluid side outlet of the precooler (2), and is proportionally injected into the main combustion chamber (5) and the afterburner (7) through the main combustion chamber flow valve (17) and the afterburner flow valve (18).

10. A method for using the composite precooling engine system based on jet / heat exchanger precooling according to claims 1-9, characterized in that: Specifically, the following situations are included: Case 1: Before starting from zero Mach to the minimum pre-cooling Mach number, the Mach range is 0-2 Mach, all working fluid regulating valves are in the closed state, kerosene is pumped by the kerosene pump (14), and flows into the main combustion chamber (5) and the afterburner (7) according to the engine combustion requirements. The incoming air pressurized by the compressor (4) burns with the kerosene in the main combustion chamber (5) to generate combustion gas, which expands and performs work through the turbine (6), then enters the afterburner (7) to burn again and is finally discharged from the tail nozzle (8); Case 2: From the lowest pre-cooling Mach number to the higher flight Mach number, the Mach range is 2-4 Mach, the first kerosene regulating valve (15) and the second liquid ammonia regulating valve (12) are open, the second kerosene regulating valve (16) and the first liquid ammonia regulating valve (11) are closed, the liquid ammonia is pumped by the liquid ammonia pump (10) to the jet device (3) for ejection, and the kerosene is pumped by the kerosene pump (14) to the cold fluid side inlet of the pre-cooler (2), and then flows out from the cold fluid side outlet of the pre-cooler (2), and is proportionally injected into the main combustion chamber (5) and the afterburner (7) through the main combustion chamber flow valve (17) and the afterburner flow valve (18). ); the incoming air is in a high temperature range of 350-909K after being compressed by the air inlet (1), and the high temperature air flows through the air side inlet of the precooler (2) for heat exchange, and the medium temperature air at the air side outlet of the precooler (2) continues to flow through the jet device (3) and is mixed with the ammonia spray, and the resulting mixed gas enters the inlet of the compressor (4), and the pressurized mixed gas flows into the main combustion chamber (5) and is mixed with kerosene for combustion, and the resulting high temperature combustion gas is expanded by the turbine (6) to drive the compressor (4) to rotate, and the gas at the outlet of the turbine (6) enters the afterburner (7) and burns again with the kerosene, and the outlet high temperature combustion gas finally enters the tail nozzle (8) and is expanded and discharged; Case 3: At high flight Mach number, Mach>4Ma, the second kerosene regulating valve (16) and the first liquid ammonia regulating valve (11) are open, the first kerosene regulating valve (15) and the second liquid ammonia regulating valve (12) are closed, the kerosene is partially pumped to the jet device (3) by the kerosene pump (14) for injection, and the rest flows into the main combustion chamber (5) and the afterburner (7), respectively. The liquid ammonia is pumped to the cold fluid inlet of the precooler (2) by the liquid ammonia pump (10), and then the precooler (2) is cooled. ) The cold fluid outlet is injected into the main combustion chamber (5) and the afterburner (7); the incoming air is compressed by the air inlet (1) and is in a high temperature zone above 909K. The air enters the precooler (2) and the jet device (3) in turn for cooling. The resulting mixed gas enters the core components of the engine consisting of the compressor (4), the main combustion chamber (5), the turbine (6), the afterburner 7, and the tail nozzle (8) to work normally, and is finally discharged into the atmosphere through the tail nozzle (8) and generates thrust to propel the aircraft to navigate.

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