An electromagnetic power drive device and a pulsating heat pipe heat transfer system using the same

Abstract

The present invention provides an electromagnetic power drive device and a pulsating heat pipe heat transfer system using the device. The device includes: an electromagnetic acceleration device, a magnetic field generating device, two energized wires, and a DC power supply. The electromagnetic acceleration device includes a main body structure, graphite electrodes, an internal and external conductive channel connection member, and a sealing material. The upper cover of the electromagnetic acceleration device is a detachable structure, and the upper cover is connected to the cylindrical cavity through the sealing material. The lower cover is a non-detachable structure. Two graphite electrodes are placed in the cylindrical cavity close to the wall surface. The gap between the two electrodes is the flow channel. The internal and external conductive channel connection member placed in the hole of the upper cover is connected to the graphite electrode in the main body cavity. The system includes: a pulsating heat pipe, an electromagnetic power drive device, and a salt solution. The pulsating heat pipe is connected to the electromagnetic acceleration device through a switching valve, and the electromagnetic power drive device accelerates the salt solution in the pulsating heat pipe through a magnetic field. The present invention can control the magnitude and direction of the driving force received by the salt solution and enhance heat transfer.

Description

Technical Field

[0001] The present invention relates to the technical field of enhanced heat transfer, and particularly to an electromagnetic power driving device and a pulsating heat pipe heat transfer system applying the device. Background Art

[0002] In recent years, modern science and technology have developed by leaps and bounds. Electronic components tend to be miniaturized and integrated, which has led to a sharp increase in heat flux density. Effective and reliable thermal management has become an important factor driving the further development of society.

[0003] A pulsating heat pipe is a heat transfer device formed by bending a capillary into a snake-like structure. It has the advantages of high heat transfer efficiency, simple structure, no external power required, and low price, and has great application potential in the field of enhanced heat transfer. The pulsating heat pipe can be structurally divided into three parts: an evaporation end, an adiabatic end, and a condensation end. The operation process of the pulsating heat pipe is as follows: When the internal environment of the pulsating heat pipe is vacuum, a working fluid is injected. Due to the action of surface tension and gravity, the working fluid is randomly distributed in the pipeline in the form of gas plugs and liquid plugs. At the evaporation end of the pulsating heat pipe, the liquid working fluid absorbs heat and evaporates, and the pressure increases. At the condensation end of the pulsating heat pipe, the gaseous working fluid releases heat and condenses, and the pressure decreases. At this time, there is a saturated vapor pressure difference between the evaporation end and the condensation end, which is equivalent to giving a driving force to the working fluid in the pulsating heat pipe. When the flow resistance of the working fluid in the pipe is greater than the driving force, the pulsating heat pipe cannot start. When the flow resistance of the working fluid in the pipe is less than the driving force, the working fluid moves in a cyclic manner in the heat pipe, realizing heat exchange between the hot and cold ends. The operation process of the pulsating heat pipe involves the mutual coupling of multiple physical disciplines, such as the flow process, heat transfer process, and gas-liquid phase conversion process of the working fluid in the pipe, which leads to the uncertainty and complexity of the working fluid operation process.

[0004] The operation process of the pulsating heat pipe mainly includes two stages: a start-up operation stage and a stable operation stage. For the start-up operation stage, when the heating power is high, the driving force generated by the heat is greater than the flow resistance, and the working fluid starts to move. When the heating power is low, the driving force generated by the heat is less than the flow resistance, and the pulsating heat pipe cannot start. An external power can effectively make up for the problem of insufficient driving force generated by the heat and reduce the start-up temperature of the pulsating heat pipe. For the stable operation stage, a fast and stable unidirectional flow is beneficial to the efficient progress of the heat transfer process. However, due to the certain uncontrollability of the fluid inside the pulsating heat pipe, there are often short-term stagnation and reverse flow of the fluid during the operation process, which is not conducive to the efficient heat transfer of the pulsating heat pipe. An external power plays a positive role in the fast operation of the pulsating heat pipe and is more conducive to controlling the flow of the working fluid.

[0005] In a controllable tubular pulsating heat pipe heat transfer system with an external oscillation source in the prior art, the pulsating heat pipe of the heat transfer system is placed in a magnetic field, a liquid metal is used as an auxiliary working medium, and an electric current is applied to the liquid metal by an energized electrode in a local pipe. By controlling the Lorentz force received by the liquid metal, the pulsation frequency and amplitude of the working medium running inside the pipe are controlled.

[0006] The disadvantages of a controllable tubular pulsating heat pipe heat transfer system with an external oscillation source in the above prior art include: First, since the liquid metal is an auxiliary working medium and the content is small, it takes the liquid metal to run one week inside the pipe to reach the energized electrode to achieve acceleration, which results in a long acceleration interval period; Second, during the operation of the pulsating heat pipe, the liquid metal may slowly disperse into the working medium, and the liquid metal is evenly dispersed in the working medium in the form of fine particles, resulting in the liquid metal losing the function of forming an electric conduction loop and thus losing its effect; Third, the working medium other than the liquid metal forms a loop with the electrode, wire, and power supply, and there is a risk of electrolysis of the working medium. Summary of the Invention

[0007] An embodiment of the present invention provides an electromagnetic power driving device and a pulsating heat pipe heat transfer system applying the device to effectively improve the starting and operating performance of the pulsating heat pipe and enhance the heat transfer performance of the pulsating heat pipe.

[0008] To achieve the above object, the present invention adopts the following technical solutions.

[0009] According to one aspect of the present invention, there is provided an electromagnetic power driving device, including: an electromagnetic acceleration device, a magnetic field generating device, two energized wires, and a DC power supply;

[0010] The electromagnetic acceleration device includes a main body structure, graphite electrodes, an internal and external conductive channel connection member, and a sealing material. The internal and external conductive channel connection member adopts a metal connection method, a combination connection method of metal and graphite, or a graphite connection method. The upper cover of the electromagnetic acceleration device is a detachable structure, and the upper cover is connected to the cylindrical cavity through a sealing material. Two pipes are welded on the side wall surface of the cylindrical cavity. The lower cover is a non-detachable structure. Two graphite electrodes are placed closely against the wall surface inside the cylindrical cavity. The gap between the two electrodes is a flow channel. The internal and external conductive channel connection member placed in the hole of the upper cover is connected to the graphite electrode in the main body cavity;

[0011] The magnetic field generating device generates a uniform magnetic field whose magnitude and direction can be adjusted. The electromagnetic acceleration device is placed in the magnetic field environment generated by the magnetic field generating device. One of the two current-carrying wires is connected to the positive pole of the DC power supply, and the other current-carrying wire is connected to the negative pole of the DC power supply. The other ends of the two current-carrying wires are respectively connected to the ends of the internal and external conductive channel connecting members on the electromagnetic acceleration device. The other ends of the two internal and external conductive channel connecting members are respectively in contact with the built-in graphite electrodes of the electromagnetic acceleration device. The working medium in the pulsating heat pipe is a conductive salt solution, and the electromagnetic acceleration device accelerates the salt solution in the pulsating heat pipe through the magnetic field.

[0012] Preferably, the angle between the electromagnetic acceleration device and the magnetic field generating device is in a non-parallel state, and the best angle is 90°.

[0013] Preferably, the main structure of the electromagnetic acceleration device includes a cylindrical cavity, an upper cover, a lower cover, and two pipes welded to the side wall of the cylindrical cavity. The upper cover is a detachable structure, and small holes are reserved on the cover. There are two types of small holes: one type is a hole penetrating the upper cover, and the other type is a groove not penetrating the upper cover. The hole penetrating the upper cover serves as the internal and external conductive channel, and the groove not penetrating the upper cover is used to fix the built-in graphite electrode. The upper cover is connected to the cylindrical cavity through a sealing material. The lower cover is a non-detachable structure and is welded to the main structure as a whole. On the side wall of the main cylindrical cavity, two pipes are welded. Two high-temperature resistant and high-purity graphite electrodes are placed closely against the wall in the cylindrical cavity as the conductive electrodes inside the electromagnetic acceleration device. The gap between the two conductive electrodes is the flow channel for the working medium. The internal and external conductive channel connecting members placed in the holes of the upper cover are connected to the graphite electrodes in the main cavity.

[0014] Preferably, the main structure of the electromagnetic acceleration device includes a cylindrical cavity, an upper cover, a lower cover, and two pipes welded to the side wall of the cylindrical cavity. The upper cover is a detachable structure, and small holes are reserved on the cover. There are two types of small holes: one type is a hole penetrating the upper cover, and the other type is a groove not penetrating the upper cover. The holes penetrating the upper cover are divided into two types: one type serves as the internal and external conductive channel, and the other type is used to seal the electromagnetic acceleration device. The grooves not penetrating the upper cover are divided into two types: one type is used to fix the built-in graphite electrode, and the other type is used to fix the sealing material. Through holes with the same number and consistent positions as the upper cover are reserved on the wall of the cylindrical cavity. The sealing material is placed in the grooves of the upper cover, and the main cavity and the upper cover are tightly connected together through the extrusion of the connecting members in the holes. The lower cover is a non-detachable structure and is welded to the main body as a whole. On the wall of the main cylindrical cavity, two pipes are welded. Two high-temperature resistant and high-purity graphite electrodes are placed closely against the wall of the main body in the cylindrical cavity as the conductive electrodes inside the electromagnetic acceleration device. The gap between the two electrodes is the flow channel for the working medium. The internal and external conductive channel connecting members placed in the holes of the upper cover are connected to the graphite electrodes in the main cavity.

[0015] According to another aspect of the present invention, there is provided a pulsating heat pipe heat transfer system applying the electromagnetic power driving device, including: a pulsating heat pipe and an electromagnetic power driving device. The working fluid in the pulsating heat pipe is a salt solution. The pulsating heat pipe is connected to an electromagnetic acceleration device through a switching valve. The upper end of the pulsating heat pipe is a condensation zone, the middle end is an adiabatic zone, and the lower end is an evaporation zone. The pulsating heat pipe is formed by bending a capillary tube to form a loop structure. The salt solution has electrical conductivity, and the salt solution does not undergo overall electrochemical changes in the conductive state; the electromagnetic acceleration device accelerates the salt solution in the pulsating heat pipe through a magnetic field.

[0016] The electromagnetic power driving device selects an internal graphite electrode that does not undergo an electrochemical reaction with the working fluid during the power-on process. The working fluid in the pulsating heat pipe selects a conductive salt solution. Under the action of a magnetic field, the graphite electrode applies a current to the salt solution. The charges moving directionally in the salt solution are applied with a controllable and continuous external driving force. By changing the magnetic field strength and direction or the magnitude and direction of the input current, the magnitude and direction of the external driving force are controlled, thereby enhancing the startup performance and heat transfer performance of the pulsating heat pipe.

[0017] Preferably, the tube wall material of the pulsating heat pipe is any material that does not react with the salt solution.

[0018] Preferably, the working fluid is a salt solution composed of ferric sulfate and ferrous sulfate as solutes and distilled water or ultrapure water as a solvent.

[0019] During the operation of the pulsating heat pipe, by changing the magnetic field strength, current magnitude, salt solution concentration, and / or structural form, the magnitude and direction of the external driving force on the salt solution are controlled, thereby reducing the startup heating power of the pulsating heat pipe and enhancing the flow heat transfer. 8. The system according to claim 6, wherein the pulsating heat pipe is of a single-loop type or a multi-bend loop type, and the number of electromagnetic acceleration devices is one or more.

[0020] Preferably, when the number of the electromagnetic acceleration devices is one and it is located at the adiabatic end of the pulsating heat pipe, in the case that the inside of the pulsating heat pipe is in a vacuum state, a salt solution working medium is filled. The salt solution working medium is randomly distributed in the pipe in the form of gas plugs and liquid plugs. A pair of graphite electrodes is placed inside the electromagnetic acceleration device as the conductive electrodes inside the electromagnetic acceleration device. The gap between the two conductive electrodes is the flow channel for the salt solution working medium. The power input of the graphite electrodes is provided by an external DC power supply. During the operation of the pulsating heat pipe, the connection channel of the external power supply is always in an open state. When the salt solution working medium moves to the gap between the two graphite electrodes, the salt solution becomes a conductor. Under the action of the electric field force, the negative charges in the salt solution move towards the positive electrode, and the positive charges move towards the negative electrode. The directional movement of the charges forms an electric current, and the entire circuit changes from an open circuit to a closed circuit state. The salt solution working medium, the built-in graphite electrodes, and the external circuit form a closed loop. Under the action of the magnetic field, the energized working medium salt solution is accelerated and ejected under the action of an external driving force.

[0021] Preferably, when the number of the electromagnetic acceleration devices is two and they are located at the adiabatic end of the pulsating heat pipe, the polarities of the two groups of electromagnetic acceleration devices are the same, and the driving forces generated inside the heat pipe are all consistent with the flow direction of the salt solution working medium. When the salt solution working medium passes through the first electromagnetic acceleration device, it is accelerated and ejected, and the salt solution working medium that has been accelerated and ejected is further accelerated and ejected by the second electromagnetic acceleration device.

[0022] It can be seen from the technical solutions provided by the embodiments of the present invention described above that the devices and systems of the embodiments of the present invention can solve the problems of high heating power during the startup process of the pulsating heat pipe, low heat transfer performance during the operation process, and dry burning problems, can reduce the startup heating power, strengthen the flow heat transfer, and prevent dry burning. Thereby improving the startup and operation performance of the pulsating heat pipe and enhancing the heat transfer performance of the pulsating heat pipe.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description, and these will become obvious from the following description, or can be understood through the practice of the present invention. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 It is a schematic plan view of the first electromagnetic acceleration device provided by the embodiment of the present invention;

[0026] Figure 2 It is a schematic plan view of the second electromagnetic acceleration device provided by the embodiment of the present invention;

[0027] Figure 3 This is a schematic cross-sectional view of the second electromagnetic acceleration device provided by the embodiment of the present invention;

[0028] Figure 4 This is a schematic cross-sectional view of an internal and external conductive channel connection member using a metal connection method provided by the embodiment of the present invention;

[0029] Figure 5 This is a schematic cross-sectional view of an internal and external conductive channel connection member using a connection method combining metal and graphite provided by the embodiment of the present invention;

[0030] Figure 6 This is a schematic cross-sectional view of an internal and external conductive channel connection member using a graphite connection method provided by the embodiment of the present invention.

[0031] Figure 7 This is a schematic diagram of the principle of a pulsating heat pipe heat transfer system of a single electromagnetic acceleration device provided by the embodiment of the present invention;

[0032] Figure 8 This is a schematic diagram of the principle of a pulsating heat pipe heat transfer system of two electromagnetic acceleration devices provided by the embodiment of the present invention;

[0033] Description of the drawings: 1 is a magnetic field, 2 is an electromagnetic acceleration device, 3 is the main pipe of the pulsating heat pipe, 4 is the working medium, 5 is a DC power supply, 6 is a wire, 7 is the evaporation end, 8 is the adiabatic end, 9 is the condensation end, 10 is a graphite electrode, 11 is the internal and external conductive channels, 12 is a groove, 13 is a hole, 14 is a pipe, 15 is a metal rod, 16 is a sealing material 1, 17 is a metal shell, 18 is a sealing material 2, 19 is a wire channel, 20 is a sealing material. Detailed implementation manners

[0034] The following details the implementation manners of the present invention. Examples of the implementation manners are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The implementation manners described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0035] Those skilled in the art can understand that, unless specifically stated otherwise, the singular forms "a", "an", "the" and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say that an element is "connected" or "coupled" to another element, it can be directly connected or coupled to other elements, or there may also be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or coupling. The phrase "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0036] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here.

[0037] For the convenience of understanding the embodiments of the present invention, the following will further explain and illustrate with several specific embodiments in conjunction with the accompanying drawings, and each embodiment does not constitute a limitation to the embodiments of the present invention.

[0038] The embodiments of the present invention enhance the controllability of the working fluid of the pulsating heat pipe by increasing external power, thereby reducing the starting heating power and strengthening the flow heat transfer. Considering the flow characteristics of the working fluid during the operation of the pulsating heat pipe, an electromagnetic power driving device and a pulsating heat pipe heat transfer system using the device are disclosed. A salt solution with good electrical conductivity and no electrochemical change during the conduction process is selected as the working fluid. Under the action of a magnetic field, a current is applied to the salt solution flowing through the electromagnetic power driving device through an internal graphite electrode. Due to the action of the Lorentz force on the salt solution, a controllable and continuous external driving force is added to all the working fluid salt solution filled in the pulsating heat pipe, so as to achieve the purpose of improving the starting performance, enhancing heat transfer and preventing dry burning.

[0039] An electromagnetic power drive device provided by an embodiment of the present invention includes an electromagnetic acceleration device, a magnetic field generating device, a current-carrying wire, a DC power supply, etc. The magnetic field generating device generates a uniform magnetic field with adjustable magnitude and direction. The electromagnetic acceleration device is placed in the magnetic field environment generated by the magnetic field generating device, and the electromagnetic acceleration device accelerates the salt solution in the pulsating heat pipe through the magnetic field. One of the two current-carrying wires is connected to the positive pole of the DC power supply, and the other current-carrying wire is connected to the negative pole of the DC power supply. The other ends of the two current-carrying wires are respectively connected to the ends of the internal and external conductive channel connection members on the electromagnetic acceleration device, and the other ends of the two internal and external conductive channel connection members are respectively in contact with the built-in graphite electrodes of the electromagnetic acceleration device. The electromagnetic acceleration device is placed in a uniform magnetic field environment with adjustable magnitude and direction, and the angle between the electromagnetic acceleration device and the magnetic field generating device is in a non-parallel state, and the best angle is 90°.

[0040] (1) Structural design of the electromagnetic acceleration device

[0041] 1) The first type of electromagnetic acceleration device

[0042] The schematic plan view of the first type of electromagnetic acceleration device provided by an embodiment of the present invention is as Figure 1 shown. The electromagnetic acceleration device is composed of a main structure, graphite electrodes, internal and external conductive channel connection members, sealing materials, etc. The structural form of the electromagnetic acceleration device can be any shape such as circular, triangular, square, etc., and the material can be any substance that does not react with the operating working medium salt solution and through which the magnetic field can penetrate, such as quartz glass, ceramic, plastic, etc.

[0043] In this embodiment, the main structure of the electromagnetic acceleration device is composed of a cylindrical cavity, upper and lower lids, and two pipes welded to the side wall surface of the cylindrical cavity. The upper lid is a detachable structure, and small holes are reserved on the lid. There are two types of small holes: one type is a hole penetrating the upper lid, and the other type is a groove not penetrating the upper lid. The hole penetrating the upper lid serves as the internal and external conductive channel, and the groove not penetrating the upper lid is used to fix the built-in graphite electrode. The upper lid is connected to the cylindrical cavity through a sealing material. The lower lid is a non-detachable structure and is welded to the main body as a whole. On the side wall surface of the main body cylindrical cavity, two pipes are welded. Two high-temperature resistant high-purity graphite electrodes are placed closely against the wall surface inside the cylindrical cavity as the conductive electrodes inside the electromagnetic acceleration device, and the gap between the two electrodes is the flow channel of the operating working medium. The internal and external conductive channel connection members placed in the holes of the upper lid are connected to the graphite electrodes in the main body cavity.

[0044] 2) The second type of electromagnetic acceleration device

[0045] Figure 2 is the schematic plan view of the second type of electromagnetic acceleration device provided by an embodiment of the present invention. Figure 3It is a schematic cross-sectional view of the second electromagnetic acceleration device; in this embodiment, the main structure of the electromagnetic acceleration device is composed of a cylindrical cavity, upper and lower covers, and two pipes welded to the side wall of the cylindrical cavity. The upper cover is a detachable structure, and small holes are reserved on the cover. There are two types of small holes: one type is the holes penetrating the upper cover, and the other type is the grooves not penetrating the upper cover. The holes penetrating the upper cover are divided into two categories: one category serves as the internal and external conductive channels, and the other category is used to seal the electromagnetic acceleration device. The grooves not penetrating the upper cover are divided into two categories: one category is used to fix the built-in graphite electrode, and the other category is used to fix the sealing material. Through holes with the same number and consistent positions as the upper cover are reserved on the wall of the cylindrical cavity. The sealing material is placed in the grooves of the upper cover, and the main cavity and the upper cover are tightly connected together through the extrusion of the connecting members in the holes. At this time, the sealing material in the grooves of the upper cover is extruded and deformed to fill the entire gap, so as to achieve the purpose of sealing the electromagnetic acceleration device. The lower cover is a non-detachable structure and is welded to the main body as a whole. Two pipes are welded to the wall of the main body cylindrical cavity. Two high-temperature resistant and high-purity graphite electrodes are placed closely against the wall of the main body in the cylindrical cavity and serve as the conductive electrodes inside the electromagnetic acceleration device. The gap between the two electrodes is the flow channel for the working medium. The holes in the upper cover are used to place the connecting members of the internal and external conductive channels and connect them to the graphite electrodes in the main cavity.

[0046] 3) Connecting member of internal and external conductive channels

[0047] 1) Adopt the method of metal connection

[0048] Figure 4 It is a schematic cross-sectional view of a connecting member of internal and external conductive channels adopting the metal connection method provided by the embodiment of the present invention. Only the cross-sectional analysis of the first electromagnetic acceleration device is taken as an example. In the internal and external conductive channels of the electromagnetic acceleration device, two stainless steel rods or copper rods without magnetic conductivity pass through the holes in the upper cover, and the gaps between the holes and the metal rods are filled with sealing materials. One end of the metal rod is connected to the high-temperature resistant and high-purity graphite electrode, and it is sealed with a sealing material to prevent the metal rod from directly contacting the working medium and generating an electrochemical reaction. The other end is connected to a conductive metal without magnetic conductivity, such as a clip made of stainless steel or pure copper. A wire is connected to the other end of the clip, and the other end of the wire is connected to a DC power supply, which serves as the connection path between the graphite electrode inside the main cavity and the external power supply.

[0049] 2) Adopt the connection method combining metal and graphite

[0050] Figure 5The figure is a schematic cross-sectional view of an internal and external conductive channel connection member using a connection method combining metal and graphite provided by an embodiment of the present invention. Only the cross-sectional analysis of the first electromagnetic acceleration device embodiment is taken. The protruding graphite rod on the built-in graphite electrode has a height greater than the thickness of the upper cover and passes through the hole in the upper cover. The material is a metal cavity with non-magnetic properties, such as stainless steel or copper, etc. One end of the cavity is closed and the other end is open. It is tightly nested at the upper end of the graphite rod. The gap between the hole, the graphite rod and the metal shell is filled with a sealing material to ensure the tightness of the internal and external connections of the conductive path. The material is a metal clip with non-magnetic properties, such as stainless steel or pure copper. One end is fixed on the external metal shell and the other end is connected to a wire. The other end of the wire is connected to a DC power supply. This serves as the path for the connection between the graphite electrode inside the main cavity and the external power supply.

[0051] 3) Adopt the connection method of graphite

[0052] Figure 6 The figure is a schematic cross-sectional view of an internal and external conductive channel connection member using a graphite connection method provided by an embodiment of the present invention. Only the cross-sectional analysis of the first electromagnetic acceleration device embodiment is taken. The protruding graphite rod of the graphite electrode is of the same height as the upper cover and passes through the hole in the upper cover. At the lower end of the sealing material 16, a cavity is made inside as the nesting position of the graphite rod, and the outer wall is a smooth curved surface. At the upper end of the sealing material 16, a cavity is made inside as the external wire conductive channel 19, and the outer wall is an external thread structure. The sealing material 18 is a component in the form of a lid cap. A hole is made at the center of the lid cap as the external wire conductive channel 19. The sealing material 20 is a sealing material with a relatively soft texture. During the sealing process, the hole at the lower end of the sealing material 16 is inserted into the protruding graphite rod of the graphite electrode. The external wire first passes through the sealing material 18, then through the sealing material 20, and finally through the sealing material 16, and then contacts the graphite electrode to form a path. The sealing material 18 is screwed onto the external thread of the sealing material 16 by a threaded connection method. The sealing material 20 is placed at the top of the sealing material 16, and by squeezing the sealing material 20, it is deformed to fill the entire gap to ensure the tightness of the internal and external connections of the conductive path. One end of the wire is connected to the internal graphite electrode through the external conductive channel 19, and the other end of the wire is connected to a DC power supply. This serves as the path for the connection between the graphite electrode inside the main cavity and the external power supply.

[0053] An embodiment of the present invention also discloses a pulsating heat pipe heat transfer system applying the above electromagnetic power driving device. The system includes a pulsating heat pipe main structure and an electromagnetic power driving device, and further includes a heating end, a cooling end, and an adiabatic end. The main body of the pulsating heat pipe is formed by bending a capillary tube and is connected to an electromagnetic acceleration device through a switching valve to form a pulsating heat pipe heat transfer system. The pulsating heat pipe heat transfer system can be divided into an evaporation zone, a condensation zone, and an adiabatic zone. The positions of these three zones can be arranged according to actual needs. In the present invention, only a single-loop loop-shaped pulsating heat pipe system with the upper end of the pulsating heat pipe as the condensation zone, the middle end as the adiabatic zone, and the lower end as the evaporation zone is listed. The structural form of the pulsating heat pipe can be changed according to requirements, such as a multi-elbow structure, a three-dimensional structure, etc.; the cross-sectional shape of the pulsating heat pipe pipeline can be circular, elliptical, triangular, etc.; the material of the main body pipe wall of the pulsating heat pipe can be stainless steel or any material that does not react with the salt solution.

[0054] Under the action of a magnetic field, an internal graphite electrode that does not undergo an electrochemical reaction with the working medium during the energization process is selected, and a current is applied to the salt solution of the working medium with good electrical conductivity inside the pulsating heat pipe and that does not undergo an electrochemical change itself during the conduction process. At this time, the charges moving in a specific direction in the salt solution are affected by the Lorentz force, which is equivalent to being applied a controllable and continuous external driving force. By changing the magnetic field strength and direction or the magnitude and direction of the input current, precise control of the magnitude and direction of the external driving force can be achieved, thereby enhancing the startup performance and heat transfer performance of the pulsating heat pipe.

[0055] Arrangement of the electromagnetic power driving device in the system

[0056] 1) One electromagnetic power driving device

[0057] The number and position of the electromagnetic acceleration device can be placed according to actual needs. In the present invention, only the case where the number of electromagnetic acceleration devices is one and the placement position is at the adiabatic end is shown, and the other cases are not shown one by one.

[0058] Figure 7Schematic diagram of the implementation principle of a pulsating heat pipe heat transfer system with a single electromagnetic acceleration device provided by an embodiment of the present invention. When the inside of the pulsating heat pipe is in a vacuum, a salt solution working medium is filled. At this time, the working medium is randomly distributed in the pipe in the form of gas plugs and liquid plugs. A pair of graphite electrodes are placed inside the electromagnetic acceleration device as the internal conductive electrodes, and the gap between the two electrodes is the flow channel for the working medium. The power input of the built-in graphite electrodes is provided by an external DC power supply. During the operation of the pulsating heat pipe, the connection channel of the external power supply is always in an open state. In the entire circuit, since there is a gap between the two graphite electrodes inside the electromagnetic acceleration device, the circuit is in an open circuit state. When the salt solution working medium moves to the gap between the two graphite electrodes, it fills the middle gap, and the salt solution becomes a conductor. Under the action of the electric field force, the negative charges in the salt solution move towards the positive electrode, and the positive charges move towards the negative electrode. The directional movement of the charges forms an electric current, and the entire circuit changes from an open circuit to a closed circuit state. At this time, the salt solution working medium, the built-in graphite electrodes, and the external circuit form a closed loop. Under the action of the magnetic field, the energized working medium salt solution is accelerated and ejected under the action of the Lorentz force.

[0059] 2) Two electromagnetic power driving devices

[0060] Figure 8 Schematic diagram of the implementation principle of a pulsating heat pipe heat transfer system with two electromagnetic acceleration devices provided by an embodiment of the present invention. The number and position of the electromagnetic acceleration devices can be placed according to actual needs. This system only shows the case where the number of electromagnetic acceleration devices is two and the placement position is at the adiabatic end, and other cases are not shown one by one. Compared with the heat transfer system with a single electromagnetic acceleration device, it is only a difference in the number of electromagnetic acceleration devices.

[0061] Since the polarities of the two groups of electromagnetic acceleration devices are the same, the driving forces generated inside the heat pipe are all in the same direction as the flow direction of the working medium. When the working medium salt solution passes through the first electromagnetic acceleration device, it is accelerated and ejected. At this time, the salt solution that has been accelerated and ejected is ejected by the second electromagnetic acceleration device again. This is the process of secondary acceleration.

[0062] During the operation of the pulsating heat pipe, the physical properties of the working medium have a great impact on its operating performance. There are two requirements for the selection of the working medium in the present invention: First, it has good electrical conductivity. Second, the working medium does not undergo electrochemical changes as a whole in the conductive state, such as a mixed solution of ferric salt and ferrous salt, Fe2(SO4)3 and FeSO4, Fecl3 and Fecl2, etc., or a ferric salt solution. Solutions that meet the above two requirements can be used. This embodiment only analyzes the salt solution composed of ferric sulfate and ferrous sulfate as the solute and distilled water or ultrapure water as the solvent.

[0063] Analysis of the ionization of the salt solution:

[0064] Fe2(SO4)3 = 2Fe 3+ + 3SO4 2- ①

[0065] FeSO4 = Fe 2+ + SO4 2- ②

[0066] H2O = H + + OH - ③

[0067] Analysis of the electrolysis of the salt solution when the current is low:

[0068] Cathode: Fe 3+ + e - = Fe 2+ ④

[0069] Anode: Fe 2+ - e - = Fe 3+ ⑤

[0070] Analysis of the electrolysis of the salt solution when the current is high:

[0071] Cathode: 2H + + 2e - = H2↑ ⑥

[0072] Anode: 4OH - - 4e - = 2H2O + O2↑⑦

[0073] In the mixed solution of ferric salt and ferrous salt, Fe2(SO4)3 ionizes into Fe 3+ and SO4 2- two kinds of ions, FeSO4 ionizes into Fe 2+ and SO4 2- two kinds of ions, H2O ionizes into H + and OH - two kinds of ions. At this time, there are Fe 3+ , Fe 2+ , SO4 2- , H + , OH - five kinds of ions in the mixed salt solution, and the five kinds of ions are evenly distributed in the pulsating heat pipe. Due to the oxidizing property Fe 3+ > H + > Fe 2+ , and the reducing property Fe 2+ > OH - > Fe 3+ , at the initial stage of the electrolysis of the salt solution, the cathode Fe 3+ gains electrons and becomes Fe 2+ , the anode Fe2+ Lose electrons to become Fe 3+ , at low current, the electrolysis reaction is relatively slow. Due to the oscillation of the working fluid in the pulsating heat pipe, Fe 2+ and Fe 3+ ions are rapidly exchanged between the cathode and the anode, and the exchange rate of ions is greater than the electrolysis rate. At this time, Fe 2+ and Fe 3+ ions in the solution are always in a uniform distribution state, and the conversion of iron ions can maintain an equilibrium state. However, at high current, the reaction is intense, and the oscillation of the working fluid in the pulsating heat pipe cannot timely make the Fe 2+ and Fe 3+ ions in the solution maintain a uniform distribution state. The exchange rate of ions is less than the electrolysis rate. At this time, iron ions cannot be exchanged with each other in time. The cathode is only Fe 2+ , H + , OH - , and the anode is only Fe 3+ , H + , OH - , resulting in H + , OH - beginning to participate in the electrochemical reaction to generate oxygen and hydrogen. During the use of this mixed salt solution, it is necessary to strictly control the magnitude of the current below the critical current to avoid excessive current causing H + , OH - to participate in the electrochemical reaction.

[0074] The magnitude of the Lorentz force exerted on the working fluid salt solution, that is, the magnitude of the external driving force, is greatly related to the magnitude of the applied current, the magnetic field strength, the area, the salt solution concentration, etc. During the operation of the pulsating heat pipe, control the current within a reasonable range, and control the external driving force by changing the magnetic field strength, the salt solution concentration, the structural form, etc., so as to meet the requirements of the magnitude and direction of the required external driving force, thereby achieving the purpose of reducing the start-up heating power of the pulsating heat pipe and enhancing the flow and heat transfer.

[0075] In summary, the embodiment of the present invention provides a pulsating heat pipe heat transfer system assisted by electromagnetic power. By controlling the magnitude and direction of the current input to the graphite electrode pair inside the electromagnetic acceleration device and the magnitude and direction of the external magnetic field, the magnitude and direction of the Lorentz force, that is, the driving force, exerted on the internal working fluid of the pulsating heat pipe are further controlled, thereby improving the start-up and operation performance of the pulsating heat pipe and enhancing the heat transfer performance of the pulsating heat pipe. The present invention has the advantages of relatively simple structural design, common and low-cost materials used, simple manufacturing process, and easy operation and maintenance, which is beneficial to reducing the cost of the heat transfer system.

[0076] The electromagnetic power drive device of the present invention is applicable to the field of enhanced heat transfer with requirements such as high heat flux density, compact space, high operating stability, and low energy consumption, such as large-scale integrated circuits, microelectronic chips, aerospace vehicles, waste heat recovery, solar energy systems, etc.

[0077] Those of ordinary skill in the art can understand that the drawings are only schematic diagrams of an embodiment, and the modules or processes in the drawings are not necessarily essential for implementing the present invention.

[0078] From the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present invention, in essence, or the part that makes a contribution to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0079] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiments, since they are basically similar to the method embodiments, the description is relatively simple. For the relevant parts, reference can be made to the partial description of the method embodiments. The device and system embodiments described above are only illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative work.

[0080] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A pulsating heat pipe heat transfer system of an electromagnetic power drive device, characterized in that, Comprising: A pulsating heat pipe and an electromagnetic power driving device; The electromagnetic power driving device includes: an electromagnetic acceleration device, a magnetic field generating device, two current-carrying wires, and a DC power supply; The electromagnetic acceleration device includes a main body structure, graphite electrodes, internal and external conductive channel connecting members, and sealing materials. The internal and external conductive channel connecting members adopt a metal connection method, a combination connection method of metal and graphite, or a graphite connection method. The upper cover of the electromagnetic acceleration device is a detachable structure, and the upper cover is connected to the cylindrical cavity through a sealing material. Two pipes are welded on the side wall of the cylindrical cavity. The lower cover is a non-detachable structure. Two graphite electrodes are placed closely against the wall inside the cylindrical cavity. The gap between the two electrodes is the flow channel. The internal and external conductive channel connecting members placed in the holes of the upper cover are connected to the graphite electrodes in the main body cavity; The magnetic field generating device generates a uniform magnetic field whose magnitude and direction can be adjusted. The electromagnetic acceleration device is placed in the magnetic field environment generated by the magnetic field generating device. One of the two current-carrying wires is connected to the positive pole of the DC power supply, and the other current-carrying wire is connected to the negative pole of the DC power supply. The other ends of the two current-carrying wires are respectively connected to the ends of the internal and external conductive channel connecting members on the electromagnetic acceleration device. The other ends of the two internal and external conductive channel connecting members are respectively in contact with the built-in graphite electrodes of the electromagnetic acceleration device; The working fluid in the pulsating heat pipe is a salt solution. The pulsating heat pipe is connected to the electromagnetic acceleration device through a switching valve. The upper end of the pulsating heat pipe is the condensation zone, the middle end is the adiabatic zone, and the lower end is the evaporation zone. The pulsating heat pipe is bent by a capillary to form a loop structure. The salt solution has electrical conductivity, and the salt solution does not undergo electrochemical changes as a whole in the conductive state; the electromagnetic acceleration device accelerates the salt solution in the pulsating heat pipe through a magnetic field; The electromagnetic power driving device selects built-in graphite electrodes that do not undergo electrochemical reactions with the working fluid during the power-on process. The working fluid in the pulsating heat pipe selects a conductive salt solution. Under the action of the magnetic field, the graphite electrodes apply an electric current to the salt solution. The charges moving directionally in the salt solution are applied a controllable and continuous external driving force. By changing the magnetic field strength and direction or the magnitude and direction of the input current, the magnitude and direction of the external driving force are controlled, thereby enhancing the startup performance and heat transfer performance of the pulsating heat pipe.

2. The system according to claim 1, wherein The angle between the electromagnetic acceleration device and the magnetic field generating device is in a non-parallel state, and the best angle is 90°.

3. The system according to claim 1, wherein The main structure of the electromagnetic acceleration device includes a cylindrical cavity, an upper cover, a lower cover, and two pipes welded to the side wall of the cylindrical cavity. The upper cover is a detachable structure with small holes reserved on the cover. The small hole types include two categories: one is a hole penetrating the upper cover, and the other is a groove not penetrating the upper cover. The hole penetrating the upper cover serves as an internal and external conductive channel, and the groove not penetrating the upper cover is used to fix the built-in graphite electrode. The upper cover is connected to the cylindrical cavity through a sealing material. The lower cover is a non-detachable structure and is welded to the main structure as a whole. On the side wall of the main cylindrical cavity, two pipes are welded. Two high-temperature resistant and high-purity graphite electrodes are placed closely against the wall in the cylindrical cavity and serve as conductive electrodes inside the electromagnetic acceleration device. The gap between the two conductive electrodes is the flow channel for the working medium. The internal and external conductive channel connecting member placed in the hole of the upper cover is connected to the graphite electrode in the main cavity.

4. The system according to claim 1, wherein The main structure of the electromagnetic acceleration device includes a cylindrical cavity, an upper cover, a lower cover, and two pipes welded to the side wall of the cylindrical cavity. The upper cover is a detachable structure with small holes reserved on the cover. The small hole types include two categories: one is a hole penetrating the upper cover, and the other is a groove not penetrating the upper cover. The holes penetrating the upper cover are divided into two categories: one serves as an internal and external conductive channel, and the other is used to seal the electromagnetic acceleration device. The grooves not penetrating the upper cover are divided into two categories: one is used to fix the built-in graphite electrode, and the other is used to fix the sealing material. Through holes with the same number and consistent positions as the upper cover are reserved on the wall of the cylindrical cavity. The sealing material is placed in the groove of the upper cover, and the main cavity and the upper cover are tightly connected together through the extrusion of the connecting member in the hole. The lower cover is a non-detachable structure and is welded to the main body as a whole. On the wall of the main cylindrical cavity, two pipes are welded. Two high-temperature resistant and high-purity graphite electrodes are placed closely against the wall of the main body in the cylindrical cavity and serve as conductive electrodes inside the electromagnetic acceleration device. The gap between the two electrodes is the flow channel for the working medium. The internal and external conductive channel connecting member placed in the hole of the upper cover is connected to the graphite electrode in the main cavity.

5. The system according to claim 1, wherein The tube wall material of the pulsating heat pipe is any material that does not react with the salt solution.

6. The system according to claim 1, wherein The working medium is a salt solution composed of ferric sulfate and ferrous sulfate as solutes and distilled water or ultrapure water as solvents. During the operation of the pulsating heat pipe, the magnitude and direction of the external driving force on the salt solution are controlled by changing the magnetic field strength, current magnitude, salt solution concentration, and / or structural form, thereby reducing the starting heating power of the pulsating heat pipe and enhancing the flow heat transfer.

7. The system according to claim 1, characterized in that, The pulsating heat pipe is of a single-loop type or a multi-bend loop type, and the number of the electromagnetic acceleration devices is one or more.

8. The system according to claim 1, wherein When the number of the electromagnetic acceleration devices is one and it is located at the adiabatic end of the pulsating heat pipe, in the case that the inside of the pulsating heat pipe is vacuum, a salt solution working medium is filled. The salt solution working medium is randomly distributed in the pipe in the form of gas plugs and liquid plugs. A pair of graphite electrodes is placed inside the electromagnetic acceleration device as the conductive electrodes inside the electromagnetic acceleration device. The gap between the two conductive electrodes is the flow channel for the salt solution working medium. The power input of the graphite electrodes is provided by an external DC power supply. During the operation of the pulsating heat pipe, the connection channel of the external power supply is always in an open state. When the salt solution working medium moves to the gap between the two graphite electrodes, the salt solution becomes a conductor. Under the action of the electric field force, the negative charges in the salt solution move towards the positive electrode, and the positive charges move towards the negative electrode. The directional movement of the charges forms an electric current, and the whole circuit changes from an open circuit to a closed circuit state. The salt solution working medium, the built-in graphite electrodes, and the external circuit form a closed loop. Under the action of the magnetic field, the energized working medium salt solution is accelerated and ejected under the action of an external driving force.

9. The system according to claim 1, wherein When the number of the electromagnetic acceleration devices is two and they are located at the adiabatic end of the pulsating heat pipe, the polarities of the two groups of electromagnetic acceleration devices are the same, and the driving forces generated inside the heat pipe are all consistent with the flow direction of the salt solution working medium. The salt solution working medium is accelerated and ejected when passing through the first electromagnetic acceleration device, and the salt solution working medium that has been accelerated and ejected is further accelerated and ejected by the second electromagnetic acceleration device.

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