Turbine engine pre-cooling system and aircraft

Abstract

The present disclosure relates to the technical field of aircraft, and particularly provides a turbine engine pre-cooling system and an aircraft. The turbine engine pre-cooling system comprises a propulsion channel, a pre-cooler, an air turbine, a radiator, a circulating pump and an engine; the pre-cooler is located on the side of the engine close to an air inlet; the pre-cooler has a first heat exchange medium channel and an air channel; the radiator is arranged on the outside of the propulsion channel, and has a second heat exchange medium channel and a fuel channel; the second heat exchange medium channel is in communication with the first heat exchange medium channel; the air turbine is arranged in a hollow channel at the center of the pre-cooler, and the air intake direction of the air turbine is parallel to the extension direction of the air channel; the circulating pump is arranged on the radiator and connected with the air turbine, so as to drive the heat exchange medium to circulate between the first heat exchange medium channel and the second heat exchange medium channel; a valve is arranged at the air outlet of the air turbine, thereby improving the heat exchange efficiency and the working condition adaptability.

Description

Technical Field

[0001] This disclosure relates to the field of aircraft technology, and in particular to a turbine engine precooling system and an aircraft. Background Technology

[0002] The high speed of aircraft has extremely important military and civilian value, but the aerodynamic heating effect generated by aircraft during high-speed flight limits the flight limits of aircraft.

[0003] Turbine engines are a crucial component of aircraft, providing propulsion for flight. To enhance the flight speed of turbine engines, related technologies incorporate precoolers on the engine's inlet side. These precoolers cool the ram air intake, lowering its temperature to partially offset the temperature rise caused by aerodynamic heating during high-speed flight. However, the heat exchange efficiency of these precoolers is insufficient, and their adaptability to various operating conditions is poor. Summary of the Invention

[0004] To solve the above-mentioned technical problems, or at least partially solve them, this disclosure provides a turbine engine precooling system and an aircraft to improve heat exchange efficiency and operating condition adaptability.

[0005] In a first aspect, this disclosure provides a turbine engine precooling system, including a propulsion passage, a precooler, an air turbine, a radiator, a circulation pump, and an engine;

[0006] One end of the propulsion channel has an air inlet; the precooler, the air turbine, and the engine are located within the propulsion channel; the precooler is located on the side of the engine near the air inlet; the precooler is an annular structure with a hollow channel at its center, and the precooler has a first heat exchange medium channel for heat exchange medium flow and an air channel for air flow; the air turbine is disposed within the hollow channel, and the air intake direction of the air turbine is parallel to the extension direction of the air channel;

[0007] The radiator is disposed outside the propulsion channel. The radiator has a second heat exchange medium channel for the flow of heat exchange medium and a fuel channel for heat exchange with the second heat exchange medium channel. The second heat exchange medium channel is connected to the first heat exchange medium channel.

[0008] The circulating pump is mounted on the radiator and connected to the air turbine to drive the heat exchange medium to circulate between the second heat exchange medium channel and the first heat exchange medium channel when the air turbine rotates; a valve for adjusting the output power and speed of the air turbine is provided at the exhaust port of the air turbine.

[0009] Optionally, the precooler includes a first housing and a heat exchange core located within the first housing;

[0010] The heat exchange core includes multiple arc-shaped baffles, which are arranged sequentially from the inside to the outside with the center of the precooler as the center. In every three adjacent baffles, an air channel is formed between two adjacent baffles, and the first heat exchange medium channel is formed between the other two adjacent baffles.

[0011] The air passage extends along the direction from the air inlet to the engine, and the first heat exchange medium passage extends circumferentially along the heat exchange core and is perpendicular to the air passage.

[0012] Optionally, the tube wall of the propulsion channel has a clearance hole area at the position corresponding to the precooler, and at least the inlet end and the outlet end of the second heat exchange medium channel extend into the first housing through the clearance hole area, so that the inlet end of the second heat exchange medium channel is directly connected to the outlet end of the first heat exchange medium channel, and the outlet end of the second heat exchange medium channel is directly connected to the inlet end of the first heat exchange medium channel.

[0013] Optionally, the heat sink includes a second housing and a heat dissipation core located within the second housing;

[0014] The heat dissipation core has a second heat exchange medium channel and a fuel channel; the extending direction of the fuel channel is parallel to the extending direction of the air channel, and the second heat exchange medium channel is perpendicular to the fuel channel.

[0015] Optionally, the second housing is connected to the first housing, and an expansion joint is provided at the connection point.

[0016] Optionally, the outer surface of the second housing and / or the outer surface of the first housing is provided with a heat-insulating protective layer.

[0017] Optionally, the second heat exchange medium channel includes a first channel portion and a second channel portion arranged in parallel.

[0018] One end of the first channel section is connected to the outlet of the first heat exchange medium channel, the other end of the first channel section is connected to one end of the second channel section, and the other end of the second channel section is connected to the inlet of the first heat exchange medium channel, so that the second heat exchange medium channel is formed into a U-shaped channel;

[0019] The circulation pump is located at the junction of the other end of the first channel section and one end of the second channel section.

[0020] Optionally, the circulating pump is connected to the air turbine via a transmission assembly, which drives the impeller of the circulating pump to rotate when the air turbine rotates.

[0021] Optionally, the transmission assembly includes a worm and a worm wheel that are meshed together, wherein the axis of the worm is perpendicular to the axis of the worm wheel;

[0022] The worm gear is connected to the turbine shaft of the air turbine, and the worm wheel is meshed with the input shaft of the circulating pump.

[0023] Secondly, this disclosure provides an aircraft including a turbine engine precooling system as described above.

[0024] The turbine engine precooling system and aircraft disclosed herein are configured with a precooler, an air turbine, a radiator, and a circulating pump. The precooler has a first heat exchange medium channel and an air channel, and the radiator has a second heat exchange medium channel and a fuel channel. The first and second heat exchange medium channels are connected. A circulating pump is installed on the radiator and connected to the air turbine. In this way, a portion of the air entering from the inlet of the propulsion channel enters through the air channel of the precooler, and another portion of the air entering from the inlet enters the air turbine, driving the air turbine to rotate at high speed. The air turbine cools and depressurizes this portion of air, and the circulating pump operates under the rotation drive of the air turbine, causing the heat exchange medium to circulate between the first and second heat exchange medium channels.

[0025] This allows the heat exchange medium in the first heat exchange medium channel to exchange heat with the air entering the air channel, achieving cooling of the air. The heat exchange medium, having absorbed heat, enters the second heat exchange medium channel under the action of the circulating pump, where it exchanges heat with the low-temperature fuel in the fuel channel. The heat is transferred to the low-temperature fuel, effectively utilizing the fuel as a heat sink, thus cooling the heat exchange medium. This allows for a continuous supply of low-temperature heat exchange medium to the first heat exchange medium channel, thereby improving the heat exchange efficiency between the low-temperature heat exchange medium and the air, achieving cooling of the ram air intake, and improving pre-cooling efficiency and effect. At the same time, because the heat absorbed by the heat exchange medium from the air is transferred to the fuel, the enthalpy of the fuel is increased, thereby improving engine performance.

[0026] Furthermore, by installing valves at the exhaust port of the air turbine, the valves can be flexibly adjusted according to different flight conditions, thereby flexibly controlling the output power and speed of the air turbine, and thus adjusting the speed of the circulating pump and the flow rate of the heat exchange medium. This allows for flexible adaptation to different flight conditions, ensuring that the cooling capacity provided by the precooling system matches the actual heat load, and enabling the engine to operate stably under different flight conditions.

[0027] Because the air turbine is located within the hollow channel at the center of the precooler, the structural compactness of the precooling system is improved to a certain extent, which is conducive to the miniaturization of the precooling system and, consequently, the miniaturization of the entire aircraft. Furthermore, by effectively utilizing a portion of the ram air to drive the air turbine's rotation, not only is the air turbine used to cool and depressurize this portion of air, reducing the temperature of the air entering the engine and improving heat exchange efficiency, but it also converts the pressure and thermal energy of the high-speed airflow into the mechanical energy of the circulating pump. This allows the circulating pump to drive the heat exchange medium to flow between the first and second heat exchange medium channels, eliminating the need for an additional drive unit to operate the circulating pump. In other words, the air turbine, while cooling and depressurizing the air, also drives the circulating pump, thereby reducing the size and weight of the precooling system to a certain extent.

[0028] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0029] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this disclosure and form part of the specification. They are used together with the embodiments of this disclosure to explain the disclosure and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0030] Figure 1 This is a schematic diagram of the structure of a turbine engine precooling system according to an embodiment of the present disclosure;

[0031] Figure 2 This is a schematic diagram of the overall structure of the precooler, air turbine, radiator and circulation pump in a turbine engine precooling system according to an embodiment of the present disclosure.

[0032] Figure 3 for Figure 2 Enlarged view of the structure at point I in the middle;

[0033] Figure 4 for Figure 1 Enlarged view of the structure at point I in the middle.

[0034] The components include: 1. Propulsion channel; 11. Air inlet; 12. Clearance hole area; 2. Precooler; 20. Hollow channel; 21. First shell; 22. Heat exchange core; 220. Baffle; 23. Air channel; 24. First heat exchange medium channel; 3. Air turbine; 4. Engine; 5. Radiator; 51. Fuel channel; 52. Second heat exchange medium channel; 521. First channel section; 522. Second channel section; 53. Second shell; 54. Radiator core; 6. Circulation pump; 7. Valve; 8. Transmission assembly; 81. Worm gear; 82. Worm wheel; 9. Expansion joint. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this disclosure more apparent, exemplary embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this disclosure, and not all embodiments of this disclosure. It should be understood that this disclosure is not limited to the exemplary embodiments described herein.

[0036] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below. It should be noted that the concepts of "first", "second", etc., used in this disclosure are only used to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0037] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0038] Reference Figures 1 to 4 As shown, this disclosure provides a turbine engine precooling system, including a propulsion channel 1, a precooler 2, an air turbine 3, a radiator 5, a circulation pump 6, and an engine 4.

[0039] The propulsion channel 1 has an air inlet 11 at one end. The precooler 2, air turbine 3, and engine 4 are located within the propulsion channel 1. The precooler 2 is located on the side of the engine 4 closest to the air inlet 11.

[0040] The precooler 2 is an annular structure with a hollow channel 20 at the center. The precooler 2 has a first heat exchange medium channel 24 for the flow of heat exchange medium and an air channel 23 for the flow of air.

[0041] It is understandable that the air inlet of the air passage 23 faces the air inlet 11. The air entering the air passage 23 exchanges heat with the heat exchange medium in the first heat exchange medium passage 24, cooling the air in the air passage 23. The cooled air enters the engine 4 through the air outlet of the air passage 23.

[0042] The radiator 5 is located outside the propulsion channel 1. The radiator 5 has a second heat exchange medium channel 52 for the flow of heat exchange medium and a fuel channel 51 for heat exchange with the second heat exchange medium channel 52. The second heat exchange medium channel 52 is connected to the first heat exchange medium channel 24.

[0043] Understandably, fuel channel 51 carries cryogenic fuel (secondary heat sink) carried by the aircraft, such as liquid hydrogen, methane, or endothermic hydrocarbon fuel.

[0044] The air turbine 3 is installed inside the hollow channel 20, and the air intake direction of the air turbine 3 is parallel to the extension direction of the air channel 23.

[0045] A circulation pump 6 is mounted on the radiator 5 and is connected to the air turbine 3 to drive the heat exchange medium to circulate between the second heat exchange medium channel 52 and the first heat exchange medium channel 24 when the air turbine 3 rotates.

[0046] Specifically, the air turbine 3 is installed at the center of the precooler 2 and is arranged coaxially with the precooler 2. The air turbine 3 may include an impeller and a turbine shaft. The impeller is located in the hollow channel 20 at the center of the precooler 2, and its blades face the air intake direction to drive rotation using the kinetic and pressure energy of the ram air.

[0047] For example, Figure 1 The dashed arrow indicates the direction of airflow. Figure 2 The dashed arrow indicates the flow direction of the heat exchange medium.

[0048] Specifically, when the ram air entering from the intake 11 enters the precooler 2, a portion of the air (e.g., the driving airflow) is diverted into the air turbine 3 at the center of the precooler 2, impacting the turbine impeller and causing it to rotate at high speed, thus cooling and depressurizing the air and simultaneously driving the circulating pump 6. The other portion of the air (e.g., the main flow) enters the air passage 23 on the periphery of the precooler 2, where it exchanges heat with the heat exchange medium flowing in the first heat exchange medium passage 24. After being rapidly cooled, the air flows out from the outlet of the air passage 23 and then enters the engine 4.

[0049] The circulating pump 6 drives the heat exchange medium to circulate between the first heat exchange medium channel 24 of the precooler 2 and the second heat exchange medium channel 52 of the radiator 5. After exchanging heat with the air in the first heat exchange medium channel 24, the heat exchange medium enters the second heat exchange medium channel 52. The heat exchange medium, having absorbed heat, undergoes cross-flow heat exchange with the low-temperature fuel in the fuel channel 51 of the radiator 5, transferring heat to the fuel in the fuel channel 51. Due to the very low initial temperature of the fuel (e.g., liquid hydrogen temperature of approximately -253°C) and its high specific heat capacity or decomposable endothermic properties, it acts as a heat sink, absorbing a large amount of heat from the heat exchange medium for subsequent use by the engine 4. As the fuel temperature rises, the heat exchange medium releases heat and its temperature decreases. The low-temperature heat exchange medium then enters the first heat exchange medium channel 24 from the second heat exchange medium channel 52, where it exchanges heat again with the air in the air channel 23, cooling the air. This cycle continues, cooling the intake air and ensuring stable operation of the engine 4, while also increasing the fuel temperature, which helps improve the performance of the engine 4.

[0050] In other words, heat is transferred from the intake air to the secondary heat sink (fuel). After absorbing heat from the pre-cooling system, the fuel's temperature rises, thus providing higher energy in subsequent combustion. Specifically, the fuel flows out from the outlet of fuel passage 51 and enters the combustion chamber of engine 4 to participate in combustion.

[0051] When hydrocarbon fuels are used, the fuel may undergo a cracking reaction at high temperatures, further absorbing heat (i.e., so-called "endothermic" fuels), which helps to improve the heat exchange efficiency of radiator 5 and the calorific value of the fuel.

[0052] The driving airflow and the mainstream airflow have the same total temperature and pressure before entering the precooler 2. Within the precooler 2, they undergo different processes: the mainstream airflow cools and depressurizes by exchanging heat with the heat exchange medium, while the driving airflow cools and depressurizes by driving the air turbine 3 to expand and perform work. These two airflows converge at the turbine outlet cone of the turbine engine 4. Because the pressure of the driving airflow is significantly lower than the mainstream pressure but higher than the ambient pressure, the air temperature discharged from the air turbine 3 is significantly lower than the mainstream temperature. This allows the driving airflow to fully utilize its heat absorption capacity to reduce the temperature of the cooling air in the turbine components of the turbine engine, thereby improving cooling capacity. Finally, with the help of the mainstream's ejection effect, the driving airflow is ejected into the tailpipe after being ejected by the mainstream, generating thrust.

[0053] For example, the heat exchange medium can be a supercritical fluid or a liquid metal that exhibits stable performance and high heat transfer efficiency at high temperatures. Supercritical fluids (such as supercritical helium, supercritical nitrogen, and supercritical carbon dioxide) possess extremely high specific heat capacity and heat transfer coefficients near their critical point, enabling them to absorb a large amount of heat under near-isothermal conditions. Furthermore, supercritical fluids do not undergo gas-liquid two-phase changes, avoiding flow instability caused by phase transitions, and are chemically stable, non-flammable, and non-explosive. Liquid metals (such as sodium-potassium alloys (NaK), gallium-indium alloys (GaIn), and lead-bismuth alloys (PbBi)) possess extremely high thermal conductivity and heat capacity, allowing them to remain liquid at high temperatures and effectively transfer heat. For instance, sodium-potassium alloys are liquid at room temperature, have a wide operating temperature range (approximately -12°C to 800°C), and exhibit thermal conductivity far superior to organic fluids.

[0054] For example, a suitable heat exchange medium can be selected according to the specific requirements of the aircraft. For instance, aircraft using liquid hydrogen as fuel can use supercritical helium or nitrogen as the heat exchange medium, taking advantage of their low-temperature characteristics similar to liquid hydrogen. Aircraft using hydrocarbon fuel as propellant can use liquid metal as the heat exchange medium to withstand the higher temperature of the precooler 2.

[0055] For example, since the impeller of the air turbine 3 is in direct contact with high-temperature and high-pressure air, the material can be a nickel-based alloy or a ceramic matrix composite to withstand high temperature and high centrifugal loads. The turbine blades can be designed with film cooling or thermal barrier coatings to further improve heat resistance, thereby enabling the precooling system to operate reliably for a long time in extreme temperature environments.

[0056] Combination Figure 1 and Figure 4 As shown, a valve 7 for adjusting the output power and speed of the air turbine 3 is also provided at the exhaust port of the air turbine 3.

[0057] By adjusting the exhaust flow and back pressure of the air turbine 3 through valve 7, the output power and speed of the air turbine 3 can be controlled. This allows for easy adjustment of the speed of the circulating pump 6 and the flow rate of the heat exchange medium. Consequently, the cooling capacity of the precooling system can be adjusted in real time according to the flight Mach number and the operating conditions of the engine 4, better matching the cooling requirements under different operating conditions to adapt to different flight conditions. This ensures that the cooling capacity provided by the precooling system matches the actual heat load, enabling the aircraft to fly stably at high speeds.

[0058] Specifically, by adjusting the opening of valve 7, the resistance at the outlet of air turbine 3 can be controlled, the flow rate and back pressure of exhaust from air turbine 3 can be adjusted, and the turbine expansion ratio and output power can be adjusted, thereby changing the speed of circulating pump 6, so as to achieve the purpose of adjusting the flow rate of heat exchange medium.

[0059] For example, valve 7 can be a rotatable opening and closing structure. Valve 7 can be specifically located on the confluence pipe between the exhaust port of the air turbine 3 and the main outlet of the precooler 2. When valve 7 is closed, the air turbine back pressure increases, the expansion ratio decreases, the turbine output power decreases, the speed of the circulating pump 6 decreases, and the flow rate of the heat exchange medium decreases. Conversely, when valve 7 is opened, the air turbine back pressure decreases, the expansion ratio increases, the turbine output power increases, the pump speed increases, and the flow rate of the heat exchange medium increases. Therefore, by controlling valve 7, the cooling capacity of the precooling system can be flexibly adjusted.

[0060] In practice, valve 7 can be connected to a controller on the aircraft, which can then control the opening and closing of valve 7 to adjust its degree of opening. Alternatively, a separate controller can be used to control valve 7.

[0061] During hypersonic vehicle flight, the intake air temperature and required precooling amount of engine 4 change with variations in Mach number and engine operating conditions. By adjusting the opening of valve 7, the outlet temperature of precooler 2 can be maintained within a set range, avoiding both excessive cooling that wastes energy and insufficient cooling that could cause engine 4 to overheat. For example, when the vehicle is flying at a lower Mach number, the intake air temperature is relatively low, and the required precooling amount is small. In this case, valve 7 can be closed slightly to reduce the flow rate of circulating pump 6 and decrease the circulation of heat exchange medium, thereby reducing the heat exchange capacity of precooler 2. Conversely, when the vehicle accelerates to a higher Mach number, the intake air temperature rises sharply. Valve 7 should be opened wider to increase the pump flow rate, enhance cooling, and ensure that the intake air temperature is sufficiently reduced.

[0062] For example, the impeller and casing materials of the circulating pump 6 can be selected according to the type of heat exchange medium. For instance, stainless steel or nickel-based alloys can be used when conveying liquid metals, and aluminum alloys or titanium alloys can be used when conveying supercritical fluids to reduce weight. The internal seals of the pump are made of high-temperature resistant fluororubber or metal bellows to prevent leakage of the heat exchange medium, thus enabling the precooling system to operate reliably for a long time in extreme temperature environments.

[0063] For example, the impeller of the air turbine 3, since it is in direct contact with high-temperature and high-pressure air, can be made of nickel-based alloys or ceramic matrix composites to withstand high temperatures and high centrifugal loads. The turbine blades can be designed with film cooling or thermal barrier coatings to further improve heat resistance, enabling the precooling system to operate reliably for a long time in extreme temperature environments.

[0064] The turbine engine precooling system provided in this embodiment comprises a precooler 2, an air turbine 3, a radiator 5, and a circulating pump 6. The precooler 2 has a first heat exchange medium channel 24 and an air channel 23, and the radiator 5 has a second heat exchange medium channel 52 and a fuel channel 51. The first heat exchange medium channel 24 and the second heat exchange medium channel 52 are connected. The circulating pump 6 is installed on the radiator 5 and connected to the air turbine 3. Thus, a portion of the air entering from the air inlet 11 of the propulsion channel 1 enters through the air channel 23 of the precooler 2, and another portion of the air entering from the air inlet 11 enters the air turbine 3, driving the air turbine 3 to rotate at high speed. The air turbine 3 cools and depressurizes this portion of air, and the circulating pump 6 operates under the rotational drive of the air turbine 3, causing the heat exchange medium to circulate between the first heat exchange medium channel 24 and the second heat exchange medium channel 52.

[0065] This allows the heat exchange medium in the first heat exchange medium channel 24 to exchange heat with the air entering the air channel 23, achieving cooling of the air. The heat exchange medium that has absorbed heat enters the second heat exchange medium channel 52 from the first heat exchange medium channel 24 under the action of the circulating pump 6, where it exchanges heat with the low-temperature fuel in the fuel channel 51. The heat is transferred to the low-temperature fuel, effectively utilizing the fuel as a heat sink, thus achieving cooling of the heat exchange medium. This allows for a continuous supply of low-temperature heat exchange medium to the first heat exchange medium channel 24, thereby improving the heat exchange efficiency between the low-temperature heat exchange medium and the air, achieving cooling of the ram air intake, and improving pre-cooling efficiency and effect. At the same time, since the heat absorbed by the heat exchange medium from the air is transferred to the fuel, the enthalpy of the fuel is increased, thereby improving engine performance.

[0066] Furthermore, by installing valve 7 at the exhaust port of air turbine 3, valve 7 can be flexibly adjusted according to different flight conditions, thereby flexibly controlling the output power and speed of air turbine 3, and thus realizing the adjustment of the speed of circulating pump 6 and the flow rate of heat exchange medium. This allows for flexible adaptation to different flight conditions, ensuring that the cooling capacity provided by the precooling system matches the actual heat load, and enabling the engine to operate stably under different flight conditions.

[0067] Because the air turbine 3 is located within the hollow channel 20 at the center of the precooler 2, the structural compactness of the precooling system is improved to a certain extent, which is conducive to the miniaturization of the precooling system and, consequently, the miniaturization of the entire aircraft. Furthermore, by effectively utilizing a portion of the ram air to drive the air turbine 3, not only is the air turbine 3 used to cool and depressurize this portion of air, reducing the temperature of the air entering the engine 4 and improving heat exchange efficiency, but it also converts the pressure and thermal energy of the high-speed airflow into the mechanical energy of the circulating pump 6. This allows the circulating pump 6 to drive the heat exchange medium to flow between the first heat exchange medium channel 24 and the second heat exchange medium channel 52, eliminating the need for an additional drive device for the circulating pump 6. In other words, the air turbine 3, while cooling and depressurizing the air, also drives the circulating pump 6, thereby reducing the size and weight of the precooling system to a certain extent.

[0068] Combination Figures 1 to 3 As shown, in some embodiments, the precooler 2 includes a first housing 21 and a heat exchange core 22 located within the first housing 21.

[0069] The heat exchange core 22 includes multiple arc-shaped baffles 220. The baffles 220 are arranged in a series of intervals from the inside to the outside with the center of the precooler 2 as the center. In every three adjacent baffles 220, an air passage 23 is formed between two adjacent baffles 220, and a first heat exchange medium passage 24 is formed between the other two adjacent baffles 220.

[0070] The air passage 23 extends along the direction from the air inlet 11 to the engine 4, and the first heat exchange medium passage 24 extends circumferentially along the heat exchange core 22 and is perpendicular to the air passage 23.

[0071] Reference Figure 1 and Figure 2 As shown, for example, the cross-section of the partition 220 is specifically an arc, and the first heat exchange medium channel 24 is specifically formed in an Ω-like shape. These Ω-like first heat exchange medium channels 24 are arranged sequentially from the inside to the outside with the central axis of the precooler 2 as the center. This makes the entire first heat exchange medium channel 24 have a large surface area to volume ratio, which can enhance the heat exchange between the heat exchange medium and the air, improve the heat exchange performance per unit volume, and further improve the heat exchange efficiency.

[0072] As described above, the first heat exchange medium channel 24, which is similar to an Ω shape, is arranged radially, opposite to the airflow direction (axial direction). Figure 1 The direction indicated by the dashed arrow at the intermediate precooler 2 is perpendicular, allowing air to sweep laterally across the first heat exchange medium channel 24 during axial flow, thereby obtaining a higher convective heat transfer coefficient.

[0073] For example, the first housing 21 and the partition 220 may be made of high-temperature resistant alloys (such as stainless steel or titanium alloy) to withstand high-temperature and high-pressure airflow.

[0074] The coaxial structure of the air turbine 3 located at the center of the precooler 2 allows the Ω-shaped flow channel to be arranged around the turbine channel, making full use of the central space and further improving the system compactness.

[0075] In some embodiments, the tube wall of the propulsion channel 1 has a clearance hole area 12 at the position corresponding to the precooler 2. At least the inlet end of the second heat exchange medium channel 52 and the outlet end of the second heat exchange medium channel 52 extend into the first housing 21 through the clearance hole area 12, so that the inlet end of the second heat exchange medium channel 52 is directly connected to the outlet end of the first heat exchange medium channel 24, and the outlet end of the second heat exchange medium channel 52 is directly connected to the inlet end of the first heat exchange medium channel 24.

[0076] By directly connecting the first heat exchange medium channel 24 and the second heat exchange medium channel 52 to form an integral module without the need for additional long pipe connections, this pipeless design greatly shortens the circulation path of the heat exchange medium, reduces pressure loss and heat loss, reduces the space and weight occupied by pipes, and thus reduces the space and weight occupied by the precooling system, meeting the requirements of airborne environment for miniaturization and lightweighting.

[0077] In some embodiments, the radiator 5 includes a heat dissipation core 54 and a second housing 53 located outside the heat dissipation core 54. The heat dissipation core 54 has a second heat exchange medium channel 52 and a fuel channel 51. The extending direction of the fuel channel 51 is parallel to the extending direction of the air channel 23, and the second heat exchange medium channel 52 is perpendicular to the fuel channel 51.

[0078] The material of radiator 5 can be selected based on the type of fuel; it should be corrosion-resistant and low-temperature resistant, such as stainless steel or aluminum alloy.

[0079] By arranging the second heat exchange medium channel perpendicular to the fuel channel 51, the heat exchange effect is further improved.

[0080] In some embodiments, the second housing 53 is connected to the first housing 21, and an expansion joint 9 is provided at the connection.

[0081] By incorporating expansion joints 9, thermal expansion and contraction and deformation caused by temperature changes and mechanical vibrations are absorbed, ensuring the sealing of the connection and the reliability of the structure.

[0082] The expansion joint 9 has a certain axial expansion and contraction capacity, which can absorb the relative displacement caused by the temperature difference between the precooler 2 and the radiator 5, thereby relieving thermal stress. At the same time, the expansion joint 9 can also play a vibration reduction role, reducing the impact of engine 4 vibration or airflow pulsation on the connection seal.

[0083] Expansion joint 9 may be made of metal bellows, and the material of expansion joint 9 may be selected from metals that are resistant to low and high temperatures (such as stainless steel or Inconel alloy) to adapt to the temperature range of the precooling system.

[0084] Considering that the precooler 2 and radiator 5 operate in a low-temperature zone (the temperature of the heat exchange medium may be as low as -150°C), and the temperature of the fuel can rise to several hundred degrees after absorbing heat in the high-temperature zone, there may be a large heat exchange with the surrounding environment. Based on this, in some embodiments, a heat insulation protective layer (not shown in the figure) is provided on the outer surface of the second housing 53 and / or the outer surface of the first housing 21.

[0085] This design ensures that most of the heat absorbed by the precooler 2 is transferred to the secondary fuel heat sink, thus improving the system's thermodynamic efficiency. Furthermore, the insulation layer protects both the precooler 2 and the radiator 5.

[0086] The heat insulation and protective layer can be an aerogel layer, which is a lightweight porous material with extremely low thermal conductivity (less than 0.01 W / (m·K)) and good high temperature resistance and flame retardant properties.

[0087] For example, the thickness of the aerogel layer can be controlled between 0.1 mm and 1 mm, which can effectively block heat conduction between the precooler 2 and the heat sink 5 without significantly increasing the connection thickness and weight.

[0088] Of course, other high-temperature insulation materials, such as ceramic fiber felt and porous ceramic matrix composites, can also be used in other implementation methods, as long as they meet the requirements of low thermal conductivity and certain structural strength, in order to reduce heat leakage to the environment.

[0089] In some embodiments, the second heat exchange medium channel 52 includes a first channel portion 521 and a second channel portion 522 arranged in parallel. One end of the first channel portion 521 is connected to the outlet of the first heat exchange medium channel 24, the other end of the first channel portion 521 is connected to one end of the second channel portion 522, and the other end of the second channel portion 522 is connected to the inlet of the first heat exchange medium channel 24, so that the second heat exchange medium channel 52 is formed as a U-shaped channel.

[0090] By designing the heat exchange medium flow channel of radiator 5 as U-shaped, perpendicular to the flow direction of the secondary heat sink (e.g., fuel), heat transfer is enhanced. Moreover, the U-shaped flow channel significantly increases the heat exchange area within a limited volume, thereby improving the heat transfer performance per unit volume.

[0091] Specifically, the circulating pump 6 is located at the connection between the other end of the first channel section 521 and one end of the second channel section 522.

[0092] This allows the heat exchange medium to be cooled in the first half of the radiator 5, then enter the circulating pump 6, where it is pressurized and then redirected to the second half of the radiator 5 for further cooling, before being sent back to the precooler 2, completing one cycle.

[0093] The circulating pump 6 is installed at the turning point of the flow channel of the radiator 5, thus forming a compact heat exchange medium loop between the front and rear halves of the radiator 5. This pipeless, integrated design greatly shortens the circulation path of the heat exchange medium, reduces pressure and heat losses, and saves space and weight.

[0094] For example, the precooler 2 and the radiator 5 can be integrally formed using additive manufacturing (3D printing) technology.

[0095] Reference Figure 1 and Figure 2 As shown, in some embodiments, a transmission assembly 8 is also included, which is connected between the air turbine 3 and the circulation pump 6. The transmission assembly 8 is used to drive the impeller of the circulation pump 6 to rotate when the air turbine 3 rotates. This arrangement makes the operation of the circulation pump 6 more stable and reliable.

[0096] In some embodiments, the transmission assembly 8 may specifically include a worm 81 and a worm wheel 82 that are meshed together, with the axis of the worm 81 perpendicular to the axis of the worm wheel 82. The worm 81 is connected to the turbine shaft of the air turbine 3, and the worm wheel 82 is meshed with the input shaft of the circulating pump 6.

[0097] In other words, the circulating pump 6 is driven by the air turbine 3 through a vertical gear shaft system-transmission assembly 8. The turbine shaft of the air turbine 3 is connected to the input shaft of the circulating pump 6 through the transmission assembly 8, transmitting the rotational power of the turbine to the pump.

[0098] Specifically, the worm 81 is connected to the end of the turbine shaft, and a worm wheel 82 meshes with it on the input shaft of the circulating pump 6. The axes of the worm 81 and the worm wheel 82 are perpendicular to each other, thereby realizing the conversion of power from the axial output of the turbine to the radial input of the pump.

[0099] The worm gear 82 and worm 81 transmission has advantages such as compact structure, large transmission ratio, and good self-locking performance. For example, by using a 1:5 transmission ratio, the high speed of the turbine can be reduced and the torque increased to drive the circulating pump 6 to operate within a suitable speed range. Titanium alloy Ti-6Al-4V can be selected. This material has high strength, low density, and high temperature resistance, and can work reliably for a long time in the high-temperature environment of turbine exhaust.

[0100] The worm 81 and worm wheel 82 can be located inside the housing, which can be filled with high-temperature grease. Sealing devices (such as mechanical seals or labyrinth seals) are provided at the points where the turbine shaft and pump shaft exit the housing to prevent high-temperature gas or dust from entering the gearbox, while keeping the grease from leaking out.

[0101] Furthermore, the materials can also be nickel-based superalloys that maintain high strength and dimensional stability within a temperature range of -50℃ to 800℃. Nickel-based alloys exhibit excellent creep and oxidation resistance at high temperatures, while remaining brittle at low temperatures, making them ideal for the wide temperature range of precooling systems. In addition, solid lubricants (such as molybdenum disulfide coatings) are integrated into the gear meshing surfaces to provide lubrication at high temperatures and reduce friction and wear. Solid lubrication avoids the problem of traditional lubricating oil evaporation and failure at high temperatures, ensuring smooth gear operation even in turbine exhaust environments at 800℃.

[0102] It should be noted that, in addition to the transmission method of worm gear 82 and worm 81, other forms of vertical transmission mechanisms can also be used in other implementations, such as bevel gear transmission, magnetic coupling transmission, or belt / chain transmission, as long as they can achieve the function of transmitting the power of air turbine 3 to circulation pump 6.

[0103] For example, when using magnetic coupling transmission, the mechanical seal can be eliminated, and the torque of the turbine shaft can be transmitted to the pump shaft through the magnetic field, thereby achieving contactless transmission and improving the system's sealing performance and reliability. When using belt or chain transmission, elastic elements can be used to buffer vibration, but the aging problem of the belt at high temperatures must be considered. If necessary, high-temperature resistant metal belts or ceramic chains can be selected.

[0104] The precooling system provided in this embodiment operates as follows during hypersonic vehicle flight: When the vehicle flies at high Mach numbers, the high-temperature, high-pressure air (e.g., airflow above 1000°C) captured by the intake is divided into two streams and enters the precooling system. One stream enters the outer channel of the precooler 2, exchanges heat with the low-temperature heat exchange medium inside the precooler 2, and is rapidly cooled to a temperature acceptable to the turbine engine 4 (e.g., around -50°C) before flowing out of the precooler 2 and entering the compressor of the engine 4 through a pipe. The other driving airflow enters the hollow channel 20 in the center of the precooler 2, impacting the impeller of the air turbine 3 and causing it to rotate at high speed. The shaft power output by the air turbine 3 is transmitted to the circulation pump 6 through a vertical gear shaft system-worm gear structure, driving the circulation pump 6 to operate. The circulation pump 6 pressurizes the low-temperature heat exchange medium from the radiator 5 and sends it into the precooler 2. The heat exchange medium absorbs heat from the mainstream air in the Ω-shaped channel of the precooler 2, its own temperature rises, and then it flows out of the precooler 2 and into the radiator 5. In radiator 5, the high-temperature heat exchange medium flows along the U-shaped channel, exchanging heat with the low-temperature fuel flowing axially, transferring heat to the fuel. After releasing heat, the heat exchange medium cools down and becomes a low-temperature liquid or high-pressure fluid again, returning from the first half of radiator 5 to the circulation pump 6, and then entering the precooler 2 after passing through the second half of radiator 5, completing the cycle.

[0105] Meanwhile, the fuel, having absorbed heat, reaches a higher temperature and, after leaving radiator 5, is introduced into the combustion chamber of engine 4 for combustion. The additional heat it carries increases the enthalpy of the fuel, contributing to improved engine 4 performance. After the air turbine 3 drives the pump, its exhaust temperature and pressure are significantly reduced. The flow and pressure are regulated by control valve 7, and the exhaust gas enters the turbine engine 4's drum cavity. It passes through the CCA heat exchanger to cool the turbine cooling air (fully utilizing its low temperature). Then, at the turbine outlet cone, the main stream is injected into the tailpipe to generate some thrust. In this way, most of the energy carried by the driving airflow is converted into the pump's mechanical energy to maintain the heat exchange medium circulation, while the remaining pressure energy is also fully utilized, avoiding thrust loss caused by direct emission. Throughout the process, the controller adjusts the opening of control valve 7 in real time based on the engine 4 inlet temperature and flight conditions, thereby changing the output power of air turbine 3 and the flow rate of circulation pump 6, dynamically matching the cooling capacity of the pre-cooling system to the engine 4's requirements. For example, when the aircraft decelerates or climbs to a higher altitude, causing the intake air temperature to decrease, valve 7 is closed to reduce the pump flow and prevent overcooling; conversely, when the aircraft accelerates or encounters higher heat loads, valve 7 is opened to increase the pump flow and enhance the cooling effect. Through this closed-loop control, the intake air temperature of engine 4 is precisely controlled within the design range, ensuring the safe and efficient operation of engine 4 while avoiding unnecessary energy consumption.

[0106] The precooling system of this disclosure solves the problems of low heat exchange efficiency, bulky system, and poor adaptability to operating conditions in existing precooling technologies. Utilizing a ductless integrated layout and advanced air turbine drive technology, the system significantly reduces size and weight, and enables flexible adjustment of the heat exchange medium circulation. Under the extreme conditions of hypersonic flight, this system can efficiently reduce the intake air temperature of engine 4 to a level that the turbine engine 4 can withstand, thereby improving propulsion efficiency, protecting the hot-end components of engine 4, and extending their lifespan. This powerful precooling system can be widely applied to various hypersonic vehicles, including hypersonic aircraft, spaceplanes, and reusable launch vehicles, providing them with reliable thermal management support, and has significant military and civilian value.

[0107] While ensuring high heat exchange efficiency, the system's size and weight have been significantly reduced, and flexible adjustment of the heat exchange medium flow rate has been achieved, providing an efficient and reliable pre-cooling solution for the turbine engines of hypersonic vehicles.

[0108] This disclosure also provides an aircraft including a turbine engine precooling system.

[0109] The turbine engine precooling system in this embodiment has the same specific structure and implementation principle as the turbine engine precooling system provided in the above embodiments, and can bring the same or similar technical effects. For details, please refer to the description of the above embodiments, which will not be repeated here.

[0110] The above description is merely an embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features disclosed in this disclosure that have similar functions.

[0111] While specific embodiments of this disclosure have been described in detail by way of example, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A turbine engine precooling system, characterized in that, This includes the propulsion channel, precooler, air turbine, radiator, circulation pump, and engine; One end of the propulsion channel has an air inlet; the precooler, the air turbine, and the engine are located within the propulsion channel; the precooler is located on the side of the engine near the air inlet; the precooler is an annular structure with a hollow channel at its center, and the precooler has a first heat exchange medium channel for heat exchange medium flow and an air channel for air flow; the air turbine is disposed within the hollow channel, and the air intake direction of the air turbine is parallel to the extension direction of the air channel; The radiator is disposed outside the propulsion channel. The radiator has a second heat exchange medium channel for the flow of heat exchange medium and a fuel channel for heat exchange with the second heat exchange medium channel. The second heat exchange medium channel is connected to the first heat exchange medium channel. The circulating pump is mounted on the radiator and connected to the air turbine to drive the heat exchange medium to circulate between the second heat exchange medium channel and the first heat exchange medium channel when the air turbine rotates; a valve for adjusting the output power and speed of the air turbine is provided at the exhaust port of the air turbine. The precooler includes a first housing and a heat exchange core located within the first housing; The heat exchange core includes multiple arc-shaped baffles, which are arranged sequentially from the inside to the outside with the center of the precooler as the center. In every three adjacent baffles, an air channel is formed between two adjacent baffles, and the first heat exchange medium channel is formed between the other two adjacent baffles. The air passage extends along the direction from the air inlet to the engine, and the first heat exchange medium passage extends circumferentially along the heat exchange core and is perpendicular to the air passage. The tube wall of the propulsion channel has a clearance hole area at the position corresponding to the precooler. At least the inlet end and the outlet end of the second heat exchange medium channel extend into the first housing through the clearance hole area, so that the inlet end of the second heat exchange medium channel is directly connected to the outlet end of the first heat exchange medium channel, and the outlet end of the second heat exchange medium channel is directly connected to the inlet end of the first heat exchange medium channel. The radiator includes a second housing and a heat dissipation core located within the second housing; The heat dissipation core has a second heat exchange medium channel and a fuel channel; the extending direction of the fuel channel is parallel to the extending direction of the air channel, and the second heat exchange medium channel is perpendicular to the fuel channel.

2. The turbine engine precooling system according to claim 1, characterized in that, The second housing is connected to the first housing, and an expansion joint is provided at the connection point.

3. The turbine engine precooling system according to claim 1, characterized in that, The outer surface of the second housing and / or the outer surface of the first housing are provided with a heat-insulating protective layer.

4. The turbine engine precooling system according to any one of claims 1 to 3, characterized in that, The second heat exchange medium channel includes a first channel section and a second channel section arranged in parallel. One end of the first channel section is connected to the outlet of the first heat exchange medium channel, the other end of the first channel section is connected to one end of the second channel section, and the other end of the second channel section is connected to the inlet of the first heat exchange medium channel, so that the second heat exchange medium channel is formed into a U-shaped channel; The circulating pump is located at the junction of the other end of the first channel section and one end of the second channel section.

5. The turbine engine precooling system according to any one of claims 1 to 3, characterized in that, The circulating pump is connected to the air turbine via a transmission assembly, which drives the impeller of the circulating pump to rotate when the air turbine rotates.

6. The turbine engine precooling system according to claim 5, characterized in that, The transmission assembly includes a worm and a worm wheel that are meshed together, and the axis of the worm is perpendicular to the axis of the worm wheel; The worm gear is connected to the turbine shaft of the air turbine, and the worm wheel is meshed with the input shaft of the circulating pump.

7. An aircraft, characterized in that, Includes the turbine engine precooling system as described in any one of claims 1 to 6.

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