Engine pre-cooling and thermoelectric conversion method and system based on liquid metal

Abstract

The invention provides an engine pre-cooling and thermoelectric conversion method and system based on liquid metal, and the method comprises the 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 end to end to form a liquid metal loop, and connecting the liquid metal pre-cooler with a secondary pre-cooler in series; incoming flow air firstly passes through the liquid metal precooler to be cooled for the first time, the secondary precooler is used for deeply cooling the incoming flow air flowing through the liquid metal precooler, and liquid metal in the liquid metal precooler absorbs heat and then flows through the thermoelectric hot end heat exchanger to be further cooled; liquid metal flowing out of the thermoelectric hot-end heat exchanger enters the hot-end liquid metal heat exchanger, and the liquid metal flows through the hot-end liquid metal heat exchanger to exchange heat with the cold-end fuel heat exchanger. According to the technical scheme, the technical problems that in the prior art, a high-speed aircraft is insufficient in heat sink capacity, the cooling medium heat exchange capacity is poor, and continuous power supply of the aircraft is achieved are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of engine precooling and comprehensive energy utilization, and in particular to a liquid metal-based engine precooling and thermoelectric conversion method and system. Background Art

[0002] The composite pre-cooled combined power engine is a combination engine that uses pre-cooled air in the atmosphere as an oxidant to achieve the sharing of combustion components in the air-breathing mode and the rocket mode. The combined power aircraft adopts different power modes in different airspaces and speed ranges. It has technical characteristics such as a wide operating range and good comprehensive economy. It is one of the ideal carriers for future reusable round-trip between the earth and the sky.

[0003] The long flight time, long distance, and high-speed flight characteristics of earth-to-space shuttles have led to a sharp increase in the power demand of their onboard equipment, requiring a continuous and stable power supply. However, carrying energy supply devices such as fuel cells will increase the extra weight burden. At the same time, a high-speed aircraft will generate a large amount of heat load during navigation, such as aerodynamic friction heat, heat flow on the combustion chamber wall, incoming high-temperature air, etc. Low-temperature fuel is the only cold source for the aircraft, and the amount of cooling fuel is large, facing the problem of insufficient fuel heat sink. Converting part of the heat load into electrical energy through a thermoelectric conversion device can provide a stable power supply on the one hand, and reduce the demand for fuel heat sinks on the other hand. This is of great significance to the development of power device systems for high-speed aircraft that fly for a long time and long distances.

[0004] Patent document CN 101580134A provides an aircraft cooling system based on the Stirling cycle, whose 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 an indirect coolant, which can effectively cool the engine combustion chamber and provide power supply.

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

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

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

[0008] According to one aspect of the present invention, a method for engine precooling and thermoelectric conversion based on liquid metal is provided, and the method for engine precooling and thermoelectric conversion comprises: 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 device, 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 the liquid metal precooler and the secondary precooler are connected in series; the incoming air is first cooled once through the liquid metal precooler, and the secondary precooler is cooled once. 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 flows through the thermoelectric hot-end heat exchanger for further cooling. Part 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. The liquid metal flows through the hot-end liquid metal heat exchanger and 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 again driven by the liquid metal drive device to absorb the heat of the incoming air.

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

[0010] Furthermore, the high-temperature thermoelectric material of the thermoelectric element is silicon germanium SiGe or semi-Heuchler alloy material, the medium-temperature thermoelectric material is lead-based thermoelectric material PbQ, tin telluride SnTe, germanium telluride GeTe and CoSb3-based skutterudite; 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.

[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 loop is a gallium-based alloy, a bismuth-based alloy or a sodium-potassium alloy.

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

[0015] Furthermore, the thermoelectric hot-end heat exchanger, the thermoelectric cold-end heat exchanger and the thermoelectric element are designed to conform to the curved surface.

[0016] According to another aspect of the present invention, a liquid metal-based engine precooling and thermoelectric conversion system is provided, which uses the engine precooling and thermoelectric conversion method as 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 device. 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 device, 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 respectively located on both sides of the thermoelectric element, and the liquid metal precooler and the secondary precooler are connected in series.

[0018] The technical solution of the present invention is applied to provide a method for engine precooling and thermoelectric conversion based on liquid metal, in which two groups of precoolers, a liquid metal precooler and a secondary precooler, are connected in series. The liquid metal precooler first cools the incoming air, which can make full use of high-grade thermal energy resources and improve energy conversion efficiency; the secondary precooler deeply cools the incoming air flowing through the liquid metal precooler to further reduce the temperature of the incoming air; the liquid metal precooler used in this method has a strong convective heat exchange capacity based on the high thermal conductivity and good flow characteristics of liquid metal, and can quickly cool the incoming air, which can reduce the volume of the precooler and reduce the difficulty of processing the internal microchannel structure; in addition, the boiling point of liquid metal is high under normal pressure, and the system pipeline pressure is low, which can reduce the proportion of high-pressure pipelines in the power unit and improve the system safety margin. Therefore, compared with the prior art, the liquid metal-based engine precooling and thermoelectric conversion method provided by the present invention utilizes a closed liquid metal loop to transfer high-grade thermal energy, has high heat exchange efficiency and good stability, and can effectively solve the problems of insufficient heat exchange capacity of the cooling medium of the heat exchanger in the prior art, and rapid dissipation and comprehensive utilization of heat from high-temperature incoming air. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

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

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

[0022] 10. Liquid metal precooler; 11. Secondary precooler; 12. Liquid metal drive device; 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 device; 19. Fuel storage tank. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0026] like Figure 1 As shown, according to a specific embodiment of the present invention, a liquid metal-based engine precooling and thermoelectric conversion method is provided, and the engine precooling and thermoelectric conversion method comprises: connecting the liquid metal precooler 10, the thermoelectric hot end heat exchanger 13, the hot end liquid metal heat exchanger 17 and the liquid metal driving device 12 end to end to form a liquid metal circuit, connecting the fuel storage tank 19, the fuel driving device 18, the cold end fuel heat exchanger 16 and the 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 the thermoelectric element 14, and the liquid metal precooler 10 is connected in series with the secondary precooler 11; the incoming air is first cooled by the liquid metal precooler 10. The secondary precooler 11 deeply cools the incoming air flowing through the liquid metal precooler 10. The liquid metal in the liquid metal precooler 10 absorbs heat and 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 to the thermoelectric cold-end heat exchanger 15 through the cold end of the thermoelectric element 14; the liquid metal flowing out of 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 again under the drive of the liquid metal driving device 12 to absorb the heat of the incoming air.

[0027] By applying this configuration, a method for engine precooling and thermoelectric conversion based on liquid metal is provided, in which two sets of precoolers, a liquid metal precooler and a secondary precooler, are connected in series. The liquid metal precooler first cools the incoming air, which can make full use of high-grade thermal energy resources and improve energy conversion efficiency; the secondary precooler deeply cools the incoming air flowing through the liquid metal precooler to further reduce the temperature of the incoming air; the liquid metal precooler used in this method has a strong convective heat transfer capacity based on the high thermal conductivity and good flow characteristics of liquid metal, and can quickly cool the incoming air, which can reduce the volume of the precooler and reduce the difficulty of processing the internal microchannel structure; in addition, the boiling point of liquid metal is high at normal pressure, and the system pipeline pressure is low, which can reduce the proportion of high-pressure pipelines in the power unit and improve the system safety margin. Therefore, compared with the prior art, the liquid metal-based engine precooling and thermoelectric conversion method provided by the present invention utilizes a closed liquid metal loop to transfer high-grade thermal energy, has high heat exchange efficiency and good stability, and can effectively solve the problems of insufficient heat exchange capacity of the cooling medium of the heat exchanger in the prior art, and rapid dissipation and comprehensive utilization of heat from high-temperature incoming air.

[0028] Furthermore, in the present invention, in order to maximize the power generation, the thermoelectric element 14 can be designed with a multi-level thermoelectric material in the high temperature-medium temperature-near room temperature range. In this configuration, the thermoelectric device is designed with a multi-level thermoelectric material, and the thermoelectric conversion efficiency is high in a wide temperature range, which can provide sufficient energy supply for the aircraft and reduce the 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 germanium SiGe or semi-Heuchler alloy material, the medium-temperature thermoelectric material is lead-based thermoelectric material PbQ, tin telluride SnTe, germanium telluride GeTe and CoSb3-based skutterudite; 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] In addition, in the present invention, the secondary precooler 11 is a shell and tube heat exchanger. As a specific embodiment of the present 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 in a curved conformal manner and are distributed in the aircraft structure space, which can reduce the additional space occupation.

[0031] Furthermore, in the present invention, the boiling point of liquid metal is high under normal pressure, and the system pipeline pressure is low, which can reduce the proportion of high-pressure pipelines in the power device and improve the system safety margin. As a specific embodiment of the present invention, the liquid metal in the liquid metal loop is a gallium-based alloy, a bismuth-based alloy or a sodium-potassium alloy.

[0032] In addition, in order to drive the liquid metal to circulate back and forth in the liquid metal loop to absorb heat, a liquid metal driving pump is required to drive it. As a specific embodiment of the present invention, the liquid metal driving pump is an electromagnetic pump, a mechanical pump or a peristaltic pump.

[0033] Furthermore, in the present invention, in order to reduce the additional space occupied, the thermoelectric hot-end heat exchanger 13 , the thermoelectric cold-end heat exchanger 15 and the thermoelectric element 14 are designed to be conformal to the curved surface.

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

[0035] By applying this configuration, a liquid metal-based engine precooling and thermoelectric conversion system is provided, which connects two sets of precoolers, a liquid metal precooler and a secondary precooler, in series. The liquid metal precooler first cools the incoming air, which can make full use of high-grade thermal energy resources and improve energy conversion efficiency; the secondary precooler deeply cools the incoming air flowing through the liquid metal precooler to further reduce the temperature of the incoming air; the liquid metal precooler used in this system has a strong convective heat exchange capacity based on the high thermal conductivity and good flow characteristics of liquid metal, and can quickly cool the incoming air, which can reduce the volume of the precooler and reduce the difficulty of processing the internal microchannel structure; in addition, liquid metal has a high boiling point at normal pressure, and the system pipeline pressure is low, which can reduce the proportion of high-pressure pipelines in the power unit and improve the system safety margin. Therefore, compared with the prior art, the liquid metal-based engine precooling and thermoelectric conversion system provided by the present invention utilizes a closed liquid metal loop to transfer high-grade thermal energy, has high heat exchange efficiency and good stability, and can effectively solve the problems of insufficient heat exchange capacity of the cooling medium of the heat exchanger in the prior art, and rapid dissipation and comprehensive utilization of heat from high-temperature incoming air.

[0036] Further, in the present 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 device 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 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 respectively located on both sides of the thermoelectric element 14, and the liquid metal precooler 10 and the secondary precooler 11 are connected in series.

[0037] In order to further understand the present invention, the following Figure 1 The liquid metal-based engine precooling and thermoelectric conversion method and system provided by the present invention are described in detail.

[0038] like Figure 1As shown, according to a specific embodiment of the present invention, a liquid metal-based engine cooling and thermoelectric conversion system is provided, which includes a liquid metal precooler 10, a secondary precooler 11, a liquid metal driving 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 driving device 18, and a fuel storage 19. The liquid metal precooling system is composed of a liquid metal precooler 10, a liquid metal driving device 12, a thermoelectric hot end heat exchanger 13 and a hot end liquid metal heat exchanger 17, which are connected by metal pipes and filled with liquid metal to form a closed circulation flow loop. The liquid metal in the loop is a gallium-based alloy, a bismuth-based alloy or a sodium-potassium alloy. The fuel storage 19, the fuel driving device 18, the cold end fuel heat exchanger 16 and the thermoelectric cold end heat exchanger 15 form a fuel flow path, and the fuel in the path is liquid hydrogen or hydrocarbon. 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 thermoelectric element 14 adopts a multi-level thermoelectric material design of high temperature, medium temperature and near room temperature to achieve efficient energy extraction under large temperature difference. The high temperature thermoelectric material is silicon germanium (SiGe) or half-Heusler alloy material, the medium temperature thermoelectric material is lead-based thermoelectric material PbQ (Q = S, Se, Te), tin telluride (SnTe), germanium telluride GeTe or CoSb3-based skutterudite, 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 to connect with the aircraft structure and is distributed on the aircraft structure platform.

[0039] During the operation of the liquid metal-based engine cooling and thermoelectric conversion system, the incoming air with a temperature exceeding 1200K first passes through the liquid metal precooler 10. After the liquid metal and the incoming air have undergone sufficient heat exchange, they are heated to no less than 1000K. Then, they flow through the thermoelectric hot end heat exchanger 13 through a closed circulation pipeline, releasing heat to below 1000K. At this time, part of the heat is converted into electrical energy through the thermoelectric element 14, and the remaining heat is dissipated to the thermoelectric cold end heat exchanger through the cold end of the thermoelectric element, which is a secondary preheating of the fuel. Subsequently, the liquid metal flows through the hot end liquid metal heat exchanger 17 and exchanges heat with the cold end fuel heat exchanger 16, further releasing heat and cooling to a range close to room temperature, which is a primary preheating of the fuel. Finally, the liquid metal returns to the liquid metal precooler through the liquid metal drive device 12 to absorb the heat of 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, and then it flows through the secondary precooler 11 for deep cooling. The secondary precooler 11 adopts a shell and tube heat exchanger filled with helium or nitrogen cooling medium.

[0041] In summary, the present invention provides a method and system for engine cooling and thermoelectric conversion based on liquid metal, in which two groups of precoolers, a liquid metal precooler and a secondary precooler, work in series. The liquid metal precooler first cools the incoming air, which can make full use of high-grade thermal energy resources and improve energy conversion efficiency. The secondary precooler deeply cools the incoming air flowing through the liquid metal precooler to further reduce the temperature of the incoming air. The liquid metal precooler has a strong convective heat transfer capacity based on the high thermal conductivity and good flow characteristics of the liquid metal, and can quickly cool the incoming air, which can reduce the volume of the precooler and reduce the difficulty of processing the internal microchannel structure. The liquid metal has a high boiling point under normal pressure, and the system pipeline pressure is low, which can reduce the proportion of high-pressure pipelines of the power unit and improve the system safety margin. The thermoelectric device adopts a multi-stage thermoelectric material design, and the thermoelectric conversion efficiency is high in a wide temperature range, which can provide sufficient energy supply for the aircraft and reduce the fuel heat sink load. The thermoelectric device and the heat exchanger are designed in a curved conformal manner and distributed in the aircraft structure space, which can reduce the additional space occupation. Therefore, the present invention has significant advantages in the field of high-speed aircraft power plant technology, especially in the field of engine precooling and comprehensive energy utilization technology. Compared with the prior art, the liquid metal thermoelectric conversion system provided by the present invention designs an integrated system of precooling and power generation based on liquid metal, uses a closed liquid metal loop to transfer high-grade thermal energy, has high heat exchange efficiency and good stability, adopts a multi-stage thermoelectric material design, maximizes power generation, and can effectively solve the problems of insufficient heat exchange capacity of the heat exchanger cooling medium in the prior art, and rapid dissipation and comprehensive utilization of heat from high-temperature incoming air.

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

[0043] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A liquid metal-based engine precooling and thermoelectric conversion method, characterized in that: The engine precooling and thermoelectric conversion method comprises: The liquid metal precooler (10), the thermoelectric hot end heat exchanger (13), the hot end liquid metal heat exchanger (17) and the liquid metal driving device (12) are connected end to end to form a liquid metal circuit, and the fuel storage device (19), the fuel driving device (18), the cold end fuel heat exchanger (16) and the thermoelectric cold end heat exchanger (15) are connected 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 the thermoelectric element (14), and the liquid metal precooler (10) and the 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) performs deep cooling on the incoming air flowing through the liquid metal precooler (10), the liquid metal in the liquid metal precooler (10) absorbs heat and then 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), 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) is driven by the liquid metal driving device (12) to return to the liquid metal precooler (10) to absorb the heat of the incoming air.

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

3. The method for engine precooling and thermoelectric conversion based on liquid metal according to claim 2, characterized in that: The high-temperature thermoelectric material of the thermoelectric element (14) is silicon germanium SiGe or semi-Heuchler alloy material; the medium-temperature thermoelectric material is lead-based thermoelectric material PbQ, tin telluride SnTe, germanium telluride GeTe and CoSb3-based skutterudite; 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 method for engine precooling and thermoelectric conversion based on liquid metal according to claim 3, characterized in that: The secondary precooler (11) is a shell and tube heat exchanger.

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

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

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

8. The liquid metal-based engine precooling and thermoelectric conversion method 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 to conform to the curved surface.

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 according to any one of claims 1 to 8 to perform engine precooling and thermoelectric conversion.

10. The liquid metal-based engine precooling and thermoelectric conversion system according to claim 9, characterized in that: The engine precooling and thermoelectric conversion system comprises a liquid metal precooler (10), a secondary precooler (11), a liquid metal driving 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 driving device (18), and a fuel storage device (19). The liquid metal heat exchanger (17) is connected end to end with the liquid metal driving device (12); the fuel storage device (19), the fuel driving 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); and the liquid metal precooler (10) and the secondary precooler (11) are connected in series.

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