Liquid metal based engine pre-cooling and thermoelectric conversion method and system

Abstract

The application provides a liquid metal-based engine pre-cooling and thermoelectric conversion method and system, which comprises the following steps: connecting a liquid metal pre-cooler, a thermoelectric hot end heat exchanger, a hot end liquid metal heat exchanger and a liquid metal driving device in a head-to-tail mode to form a liquid metal loop, and connecting the liquid metal pre-cooler and a secondary pre-cooler in series; air flow is firstly cooled by the liquid metal pre-cooler, the secondary pre-cooler deeply cools the air flow passing through the liquid metal pre-cooler, and the liquid metal in the liquid metal pre-cooler is further cooled after absorbing heat by passing through the thermoelectric hot end heat exchanger; the liquid metal flowing out of the thermoelectric hot end heat exchanger enters the hot end liquid metal heat exchanger, and the liquid metal exchanges heat with a cold end fuel heat exchanger by passing through the hot end liquid metal heat exchanger. The technical scheme of the application is used to solve the technical problems of insufficient heat sink capacity, poor heat exchange capacity of the cooling medium and continuous power supply of the aircraft in the prior art.

Description

Technical Field

[0001] This invention relates to the field of engine precooling and comprehensive energy utilization technology, and in particular to an engine precooling and thermoelectric conversion method and system based on liquid metal. Background Technology

[0002] The combined pre-cooled propulsion engine is a combined engine that uses pre-cooled atmospheric air as an oxidizer to achieve the sharing of combustion components in both air-breathing and rocket modes. Combined propulsion aircraft adopt different power modes in different airspace and speed ranges, and have technical characteristics such as wide operating range and good overall economy. It is one of the ideal carriers for future reusable space transportation.

[0003] The long endurance, long distance, and high speed characteristics of spacecraft drastically increase the power demand of their onboard equipment, requiring a continuous and stable power supply. However, carrying power supply devices such as fuel cells adds extra weight. Simultaneously, high-speed aircraft generate significant heat loads during flight, such as aerodynamic friction heat, combustion chamber wall heat flux, and incoming high-temperature air. Since cryogenic fuel is the only cooling source for the aircraft, large quantities are used for cooling, leading to insufficient fuel heat sinks. Converting some of the heat load into electrical energy through thermoelectric conversion devices can provide a stable power supply and reduce the need for fuel heat sinks, which is of great significance for the development of propulsion systems for high-speed aircraft operating over long distances.

[0004] Patent document CN 101580134A provides an aircraft cooling system based on the Stirling cycle, in which the heat source is the heat flow of the combustion chamber wall, the working fluid of the Stirling heat engine is the aircraft coolant, and the fuel is the indirect coolant, which can effectively cool the engine combustion chamber and provide power supply.

[0005] Patent document CN 111828198B provides a liquid metal Rankine cycle thermoelectric conversion device for jet engines, which uses liquid metal as a coolant to cool the turbine stator blades of jet engines, solving the problem of turbine stator blade ablation caused by excessively high initial gas temperature.

[0006] The aforementioned patent documents mainly address structural heat such as combustion chamber wall heat in engines and propose corresponding comprehensive energy utilization technologies. With the development of combined-drive engine technology, the temperature of incoming air in the power unit is constantly increasing, and the heat exchanger cooling medium has insufficient heat exchange capacity. The rapid dissipation and comprehensive utilization of heat from high-temperature incoming air has become a problem that needs to be solved. Summary of the Invention

[0007] This invention provides a method and system for engine precooling and thermoelectric conversion based on liquid metal, which can solve the technical problems of insufficient heat sink capacity, poor heat exchange capacity of cooling medium and continuous power supply of high-speed aircraft in the prior art.

[0008] According to one aspect of the present invention, an engine precooling and thermoelectric conversion method based on liquid metal is provided. The method includes: connecting a liquid metal precooler, a thermoelectric hot-end heat exchanger, a hot-end liquid metal heat exchanger, and a liquid metal driving device end-to-end to form a liquid metal circuit; connecting a fuel storage tank, a fuel driving device, a cold-end fuel heat exchanger, and a thermoelectric cold-end heat exchanger to form a fuel flow path; the thermoelectric hot-end heat exchanger and the thermoelectric cold-end heat exchanger are respectively located on both sides of the thermoelectric element; and connecting the liquid metal precooler and a secondary precooler in series; the incoming air first undergoes primary cooling through the liquid metal precooler, and the secondary... The secondary precooler deeply cools the incoming air flowing through the liquid metal precooler. The liquid metal in the liquid metal precooler absorbs heat and then flows through the thermoelectric hot-end heat exchanger for further cooling. Some of the heat is converted into electrical energy through the thermoelectric element, and the remaining heat is dissipated through the cold end of the thermoelectric element to the thermoelectric cold-end heat exchanger. The liquid metal flowing out of the thermoelectric hot-end heat exchanger enters the hot-end liquid metal heat exchanger, where it exchanges heat with the cold-end fuel heat exchanger to further release heat. The liquid metal flowing out of the hot-end liquid metal heat exchanger returns to the liquid metal precooler under the drive of the liquid metal driving device to absorb heat from the incoming air.

[0009] Furthermore, the thermoelectric element adopts a multi-stage thermoelectric material design covering the high-temperature, medium-temperature, and near-room-temperature ranges.

[0010] Furthermore, the high-temperature thermoelectric material of the thermoelectric element is silicon germanide (SiGe) or semi-Hüssler alloy; the medium-temperature thermoelectric material is lead-based thermoelectric material (PbQ), tin telluride (SnTe), germanium telluride (GeTe), and CoSb3-based cobaltite; and the near-room-temperature thermoelectric material is bismuth telluride (Bi2Te3) or bismuth-antimony-telluride (Bi). 0.5 Sb 1.5 Te3 or magnesium-based thermoelectric material Mg3(Sb,Bi)2.

[0011] Furthermore, the secondary precooler is a shell-and-tube heat exchanger.

[0012] Furthermore, the shell-and-tube heat exchanger is filled with helium or nitrogen.

[0013] Furthermore, the liquid metal in the liquid metal circuit is a gallium-based alloy, a bismuth-based alloy, or a sodium-potassium alloy.

[0014] Furthermore, the liquid metal driven pump is an electromagnetic pump, a mechanical pump, or a peristaltic pump.

[0015] Furthermore, the thermoelectric hot-end heat exchanger, thermoelectric cold-end heat exchanger, and thermoelectric element are designed with curved surfaces conformally.

[0016] According to another aspect of the present invention, an engine precooling and thermoelectric conversion system based on liquid metal is provided, wherein the engine precooling and thermoelectric conversion system based on liquid metal uses the engine precooling and thermoelectric conversion method described above to perform engine precooling and thermoelectric conversion.

[0017] Furthermore, the engine precooling and thermoelectric conversion system includes a liquid metal precooler, a secondary precooler, a liquid metal drive device, a thermoelectric hot-end heat exchanger, a thermoelectric element, a thermoelectric cold-end heat exchanger, a cold-end fuel heat exchanger, a hot-end liquid metal heat exchanger, a fuel drive device, and a fuel storage tank. The liquid metal precooler, the thermoelectric hot-end heat exchanger, the hot-end liquid metal heat exchanger, and the liquid metal drive device are connected end to end. The fuel storage tank, the fuel drive device, the cold-end fuel heat exchanger, and the thermoelectric cold-end heat exchanger are connected in sequence. The thermoelectric hot-end heat exchanger and the thermoelectric cold-end heat exchanger are located on both sides of the thermoelectric element, and the liquid metal precooler and the secondary precooler are connected in series.

[0018] This invention provides a method for engine precooling and thermoelectric conversion based on liquid metal. This method connects two precoolers—a liquid metal precooler and a secondary precooler—in series. The liquid metal precooler first cools the incoming air, fully utilizing high-grade thermal energy resources and improving energy conversion efficiency. The secondary precooler further cools the incoming air, reducing its temperature. The liquid metal precooler, based on the high thermal conductivity and good flow characteristics of liquid metal, possesses strong convective heat transfer capabilities, rapidly cooling the incoming air. This reduces the precooler's volume and simplifies the fabrication of its internal microchannel structure. Furthermore, the high boiling point of liquid metal at atmospheric pressure results in lower system pipeline pressure, reducing the proportion of high-pressure pipelines in the power unit and increasing system safety margin. Therefore, compared with the prior art, the engine precooling and thermoelectric conversion method based on liquid metal provided by the present invention utilizes a closed liquid metal circuit to transfer high-grade heat energy, resulting in high heat exchange efficiency and good stability. It can effectively solve the problems of insufficient heat exchange capacity of the cooling medium in the heat exchanger and rapid dissipation and comprehensive utilization of heat from the high-temperature incoming air in the prior art. Attached Figure Description

[0019] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0020] Figure 1 A schematic diagram of an engine precooling and thermoelectric conversion system based on liquid metal according to a specific embodiment of the present invention is shown.

[0021] The above figures include the following reference numerals:

[0022] 10. Liquid metal precooler; 11. Secondary precooler; 12. Liquid metal drive unit; 13. Thermoelectric hot-end heat exchanger; 14. Thermoelectric element; 15. Thermoelectric cold-end heat exchanger; 16. Cold-end fuel heat exchanger; 17. Hot-end liquid metal heat exchanger; 18. Fuel drive unit; 19. Fuel storage unit. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0026] like Figure 1 As shown, a specific embodiment of the present invention provides an engine precooling and thermoelectric conversion method based on liquid metal. This method includes: connecting a liquid metal precooler 10, a thermoelectric hot-end heat exchanger 13, a hot-end liquid metal heat exchanger 17, and a liquid metal driving device 12 end-to-end to form a liquid metal circuit; connecting a fuel storage tank 19, a fuel driving device 18, a cold-end fuel heat exchanger 16, and a thermoelectric cold-end heat exchanger 15 to form a fuel flow path; the thermoelectric hot-end heat exchanger 13 and the thermoelectric cold-end heat exchanger 15 are respectively located on both sides of a thermoelectric element 14; and connecting the liquid metal precooler 10 and a secondary precooler 11 in series; the incoming air first undergoes primary cooling through the liquid metal precooler 10. The secondary precooler 11 deeply cools the incoming air flowing through the liquid metal precooler 10. After absorbing heat, the liquid metal in the liquid metal precooler 10 flows through the thermoelectric hot-end heat exchanger 13 for further cooling. Part of the heat is converted into electrical energy through the thermoelectric element 14, and the remaining heat is dissipated through the cold end of the thermoelectric element 14 to the thermoelectric cold-end heat exchanger 15. The liquid metal flowing out of the thermoelectric hot-end heat exchanger 13 enters the hot-end liquid metal heat exchanger 17. The liquid metal flows through the hot-end liquid metal heat exchanger 17 and exchanges heat with the cold-end fuel heat exchanger 16 to further release heat. The liquid metal flowing out of the hot-end liquid metal heat exchanger 17 returns to the liquid metal precooler 10 under the drive of the liquid metal driving device 12 to absorb heat from the incoming air.

[0027] This configuration provides a method for engine precooling and thermoelectric conversion based on liquid metal, which connects two precoolers—a liquid metal precooler and a secondary precooler—in series. The liquid metal precooler first cools the incoming air, fully utilizing high-grade thermal energy resources and improving energy conversion efficiency. The secondary precooler further cools the incoming air, reducing its temperature. The liquid metal precooler, based on the high thermal conductivity and good flow characteristics of liquid metal, possesses strong convective heat transfer capabilities, rapidly cooling the incoming air. This reduces the precooler's volume and simplifies the fabrication of its internal microchannel structure. Furthermore, the high boiling point of liquid metal at atmospheric pressure results in lower system pipeline pressure, reducing the proportion of high-pressure pipelines in the power unit and increasing system safety margin. Therefore, compared with the prior art, the engine precooling and thermoelectric conversion method based on liquid metal provided by the present invention utilizes a closed liquid metal circuit to transfer high-grade heat energy, resulting in high heat exchange efficiency and good stability. It can effectively solve the problems of insufficient heat exchange capacity of the cooling medium in the heat exchanger and rapid dissipation and comprehensive utilization of heat from the high-temperature incoming air in the prior art.

[0028] Furthermore, in this invention, to maximize power generation, the thermoelectric element 14 can be designed with multi-stage thermoelectric materials in the high-temperature-medium-near-room-temperature range. With this configuration, the thermoelectric device employs a multi-stage thermoelectric material design, resulting in high thermoelectric conversion efficiency over a wide temperature range, providing ample energy supply to the aircraft and reducing fuel heat sink load.

[0029] As a specific embodiment of the present invention, the high-temperature thermoelectric material of the thermoelectric element 14 is silicon germanide SiGe or semi-Hüssler alloy material, the medium-temperature thermoelectric material is lead-based thermoelectric material PbQ, tin telluride SnTe, germanium telluride GeTe and CoSb3-based cobaltite; the near-room temperature thermoelectric material is bismuth telluride Bi2Te3, bismuth antimony telluride Bi0.5Sb1.5Te3 or magnesium-based thermoelectric material Mg3(Sb,Bi)2.

[0030] Furthermore, in this invention, the secondary precooler 11 is a shell-and-tube heat exchanger. As a specific embodiment of this invention, the shell-and-tube heat exchanger is filled with helium or nitrogen. The thermoelectric hot-end heat exchanger 13, the thermoelectric cold-end heat exchanger 15, and the thermoelectric element 14 are designed with curved surfaces conformally and distributed within the spacecraft structure, reducing additional space occupancy.

[0031] Furthermore, in this invention, the liquid metal has a high boiling point at normal pressure, resulting in lower system pipeline pressure, which reduces the proportion of high-pressure pipelines in the power unit and increases the system safety margin. As a specific embodiment of this invention, the liquid metal in the liquid metal circuit is a gallium-based alloy, a bismuth-based alloy, or a sodium-potassium alloy.

[0032] Furthermore, in order to drive the liquid metal to circulate and absorb heat repeatedly in the liquid metal circuit, a liquid metal drive pump is required. As a specific embodiment of the present invention, the liquid metal drive pump is an electromagnetic pump, a mechanical pump, or a peristaltic pump.

[0033] Furthermore, in this invention, in order to reduce additional space occupation, the thermoelectric hot-end heat exchanger 13, the thermoelectric cold-end heat exchanger 15 and the thermoelectric element 14 are designed with curved conformal surfaces.

[0034] According to another aspect of the present invention, an engine precooling and thermoelectric conversion system based on liquid metal is provided, which uses the engine precooling and thermoelectric conversion method described above to perform engine precooling and thermoelectric conversion.

[0035] This configuration provides an engine precooling and thermoelectric conversion system based on liquid metal, which connects two precoolers—a liquid metal precooler and a secondary precooler—in series. The liquid metal precooler first cools the incoming air, fully utilizing high-grade thermal energy resources and improving energy conversion efficiency. The secondary precooler further cools the incoming air, reducing its temperature. The liquid metal precooler, based on the high thermal conductivity and good flow characteristics of liquid metal, possesses strong convective heat transfer capabilities, rapidly cooling the incoming air. This allows for a reduction in precooler volume and simplifies the fabrication of the internal microchannel structure. Furthermore, the high boiling point of liquid metal at atmospheric pressure results in lower system pipeline pressure, reducing the proportion of high-pressure pipelines in the power unit and increasing system safety margin. Therefore, compared with the prior art, the engine precooling and thermoelectric conversion system based on liquid metal provided by the present invention utilizes a closed liquid metal circuit to transfer high-grade heat energy, resulting in high heat exchange efficiency and good stability. It can effectively solve the problems of insufficient heat exchange capacity of the cooling medium in the heat exchanger and rapid dissipation and comprehensive utilization of heat from the high-temperature incoming air in the prior art.

[0036] Furthermore, in this invention, in order to realize engine precooling and thermoelectric conversion, the engine precooling and thermoelectric conversion system can be configured to include a liquid metal precooler 10, a secondary precooler 11, a liquid metal drive device 12, a thermoelectric hot-end heat exchanger 13, a thermoelectric element 14, a thermoelectric cold-end heat exchanger 15, a cold-end fuel heat exchanger 16, a hot-end liquid metal heat exchanger 17, a fuel drive device 18, and a fuel storage tank 19. The liquid metal precooler 10, the thermoelectric hot-end heat exchanger 13, the hot-end liquid metal heat exchanger 17 and the liquid metal drive device 12 are connected end to end. The fuel storage tank 19, the fuel drive device 18, the cold-end fuel heat exchanger 16 and the thermoelectric cold-end heat exchanger 15 are connected in sequence. The thermoelectric hot-end heat exchanger 13 and the thermoelectric cold-end heat exchanger 15 are respectively located on both sides of the thermoelectric element 14. The liquid metal precooler 10 and the secondary precooler 11 are connected in series.

[0037] To gain a further understanding of the present invention, the following description is provided in conjunction with... Figure 1 The present invention provides a detailed description of the engine precooling and thermoelectric conversion method and system based on liquid metal.

[0038] like Figure 1As shown in the figure, a liquid metal-based engine cooling and thermoelectric conversion system is provided according to a specific embodiment of the present invention. The system includes a liquid metal precooler 10, a secondary precooler 11, a liquid metal drive device 12, a thermoelectric hot-end heat exchanger 13, a thermoelectric element 14, a thermoelectric cold-end heat exchanger 15, a cold-end fuel heat exchanger 16, a hot-end liquid metal heat exchanger 17, a fuel drive device 18, and a fuel storage tank 19. The liquid metal precooling system consists of the liquid metal precooler 10, the liquid metal drive device 12, the thermoelectric hot-end heat exchanger 13, and the hot-end liquid metal heat exchanger 17, connected by metal pipes. The system is filled with liquid metal to form a closed-loop circulation circuit. The liquid metal in the circuit is a gallium-based alloy, a bismuth-based alloy, or a sodium-potassium alloy. The fuel storage tank 19, the fuel drive device 18, the cold-end fuel heat exchanger 16, and the thermoelectric cold-end heat exchanger 15 constitute a fuel flow path, in which the fuel is liquid hydrogen or hydrocarbon. The thermoelectric hot-end heat exchanger 13 and the thermoelectric cold-end heat exchanger 15 are located on both sides of the thermoelectric element 14. The thermoelectric element 14 adopts a multi-stage thermoelectric material design in the high-temperature, medium-temperature, and near-room-temperature ranges to achieve efficient energy extraction under large temperature differences. The high-temperature thermoelectric material is silicon germanide (SiGe) or half-Heusler alloy; the medium-temperature thermoelectric material is lead-based thermoelectric material PbQ (Q = S, Se, Te), tin telluride (SnTe), germanium telluride GeTe, or CoSb3-based cobaltite; and the near-room-temperature thermoelectric material is bismuth telluride (Bi2Te3), bismuth antimony telluride (Bi0.5Sb1.5Te3), or magnesium-based thermoelectric material Mg3(Sb,Bi)2. The thermoelectric element adopts a curved design and is connected to the aircraft structure, distributed on the aircraft structural platform.

[0039] In the operation of the liquid metal-based engine cooling and thermoelectric conversion system, incoming air with a temperature exceeding 1200K first passes through the liquid metal precooler 10. After sufficient heat exchange between the liquid metal and the incoming air, it is heated to at least 1000K. Then, it flows through a closed-loop circulation pipeline to the thermoelectric hot-end heat exchanger 13, releasing heat to below 1000K. At this point, some of the heat is converted into electrical energy by the thermoelectric element 14, while the remaining heat is dissipated through the cold end of the thermoelectric element to the thermoelectric cold-end heat exchanger, providing secondary preheating for the fuel. Subsequently, the liquid metal flows through the hot-end liquid metal heat exchanger 17 and the cold-end fuel heat exchanger 16 for heat exchange, further releasing heat and cooling to near room temperature, providing primary preheating for the fuel. Finally, the liquid metal returns to the liquid metal precooler via the liquid metal drive device 12 to absorb heat from the incoming air for the next cycle.

[0040] The liquid metal precooler 10 and the secondary precooler 11 work in series. After the incoming air is cooled by the liquid metal precooler 10, the temperature is still above 1000K. Then it flows through the secondary precooler 11 for deep cooling. The secondary precooler 11 adopts a shell-and-tube heat exchanger and is filled with helium or nitrogen cooling medium.

[0041] In summary, this invention provides a method and system for engine cooling and thermoelectric conversion based on liquid metal. The system consists of two precoolers, a liquid metal precooler and a secondary precooler, operating in series. The liquid metal precooler first cools the incoming air, fully utilizing high-grade thermal energy resources and improving energy conversion efficiency. The secondary precooler further cools the incoming air, reducing its temperature. Based on the high thermal conductivity and good flow characteristics of liquid metal, the liquid metal precooler possesses strong convective heat transfer capabilities, rapidly cooling the incoming air and reducing the precooler's volume and the difficulty of fabricating the internal microchannel structure. The high boiling point of liquid metal at atmospheric pressure results in lower system pipeline pressure, reducing the proportion of high-pressure pipelines in the power unit and increasing system safety margin. The thermoelectric devices employ a multi-stage thermoelectric material design, achieving high thermoelectric conversion efficiency over a wide temperature range, providing ample energy supply to the aircraft and reducing fuel heat sink load. The thermoelectric devices and heat exchangers are designed with curved conformal surfaces and distributed within the aircraft's structural space, minimizing additional space occupation. Therefore, this invention has significant advantages in the field of high-speed aircraft propulsion technology, especially in the field of engine precooling and comprehensive energy utilization. Compared with existing technologies, the liquid metal thermoelectric conversion system provided by this invention designs an integrated precooling and power generation system based on liquid metal. It utilizes a closed liquid metal loop to transfer high-grade heat energy, resulting in high heat exchange efficiency and good stability. By employing a multi-stage thermoelectric material design, it maximizes power generation and effectively solves the problems of insufficient heat exchange capacity of the cooling medium in existing heat exchangers and the rapid dissipation and comprehensive utilization of heat from high-temperature incoming air.

[0042] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0043] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for engine precooling and thermoelectric conversion based on liquid metal, characterized in that, The engine precooling and thermoelectric conversion method includes: The liquid metal precooler (10), thermoelectric hot-end heat exchanger (13), hot-end liquid metal heat exchanger (17) and liquid metal drive device (12) are connected end to end to form a liquid metal circuit. The fuel storage device (19), fuel drive device (18), cold-end fuel heat exchanger (16) and thermoelectric cold-end heat exchanger (15) are connected to form a fuel flow passage. The thermoelectric hot-end heat exchanger (13) and the thermoelectric cold-end heat exchanger (15) are located on both sides of the thermoelectric element (14). The liquid metal precooler (10) and secondary precooler (11) are connected in series. The incoming air first passes through the liquid metal precooler (10) for primary cooling. The secondary precooler (11) further cools the incoming air flowing through the liquid metal precooler (10). After absorbing heat, the liquid metal in the liquid metal precooler (10) flows through the thermoelectric hot end heat exchanger (13) for further cooling. Part of the heat is converted into electrical energy through the thermoelectric element (14), and the remaining heat is dissipated through the cold end of the thermoelectric element (14) to the thermoelectric cold end heat exchanger (15). Liquid metal flowing out from the thermoelectric hot end heat exchanger (13) enters the hot end liquid metal heat exchanger (17), and the liquid metal flows through the hot end liquid metal heat exchanger (17) to exchange heat with the cold end fuel heat exchanger (16) to further release heat; The liquid metal flowing out of the hot-end liquid metal heat exchanger (17) returns to the liquid metal precooler (10) under the drive of the liquid metal drive device (12) to absorb the heat from the incoming air.

2. The engine precooling and thermoelectric conversion method based on liquid metal according to claim 1, characterized in that, The thermoelectric element (14) is designed with multi-stage thermoelectric materials in the high-temperature-medium-near-room temperature range.

3. The engine precooling and thermoelectric conversion method based on liquid metal according to claim 2, characterized in that, The high-temperature thermoelectric material of the thermoelectric element (14) is silicon germanide SiGe or semi-Hüssler alloy; the medium-temperature thermoelectric material is lead-based thermoelectric material PbQ, tin telluride SnTe, germanium telluride GeTe and CoSb3 cobaltite; and the near-room temperature thermoelectric material is bismuth telluride Bi2Te3, bismuth antimony telluride Bi... 0.5 Sb 1.5 Te3 or magnesium-based thermoelectric material Mg3(Sb,Bi)2.

4. The engine precooling and thermoelectric conversion method based on liquid metal according to claim 3, characterized in that, The secondary precooler (11) is a shell-and-tube heat exchanger.

5. The engine precooling and thermoelectric conversion method based on liquid metal according to claim 4, characterized in that, The shell-and-tube heat exchanger is filled with helium or nitrogen.

6. The engine precooling and thermoelectric conversion method based on liquid metal according to any one of claims 1 to 5, characterized in that, The liquid metal in the liquid metal circuit is a gallium-based alloy, a bismuth-based alloy, or a sodium-potassium alloy.

7. The engine precooling and thermoelectric conversion method based on liquid metal according to claim 6, characterized in that, The liquid metal drive device is an electromagnetic pump, a mechanical pump, or a peristaltic pump.

8. The engine precooling and thermoelectric conversion method based on liquid metal according to claim 7, characterized in that, The thermoelectric hot-end heat exchanger (13), the thermoelectric cold-end heat exchanger (15), and the thermoelectric element (14) are designed with curved surfaces conformally.

9. An engine precooling and thermoelectric conversion system based on liquid metal, characterized in that, The liquid metal-based engine precooling and thermoelectric conversion system uses the engine precooling and thermoelectric conversion method as described in any one of claims 1 to 8 to perform engine precooling and thermoelectric conversion.

10. The engine precooling and thermoelectric conversion system based on liquid metal according to claim 9, characterized in that, The engine precooling and thermoelectric conversion system includes a liquid metal precooler (10), a secondary precooler (11), a liquid metal drive device (12), a thermoelectric hot-end heat exchanger (13), a thermoelectric element (14), a thermoelectric cold-end heat exchanger (15), a cold-end fuel heat exchanger (16), a hot-end liquid metal heat exchanger (17), a fuel drive device (18), and a fuel storage tank (19). The liquid metal precooler (10), the thermoelectric hot-end heat exchanger (13), and the hot-end... The liquid metal heat exchanger (17) is connected end to end to the liquid metal drive device (12). The fuel storage device (19), the fuel drive device (18), the cold end fuel heat exchanger (16) and the thermoelectric cold end heat exchanger (15) are connected in sequence. The thermoelectric hot end heat exchanger (13) and the thermoelectric cold end heat exchanger (15) are located on both sides of the thermoelectric element (14). The liquid metal precooler (10) and the secondary precooler (11) are connected in series.

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