Liquid metal magnetohydrodynamic generator

Abstract

The invention relates to the technical field of generators, and discloses a liquid metal magnetohydrodynamic generator, comprising: a housing having a flowing space of liquid metal, and an inlet and an outlet communicated with the flowing space; at least one pair of magnets which are oppositely arranged and have opposite polarities form a magnetic field which is distributed along the axial direction parallel to the shell in the flowing space of the shell; the insulating flow guide assembly is arranged in the flowing space in the axial direction of the shell and is suitable for shunting the liquid metal flowing in from the inlet and cutting magnetic lines of the magnetic field towards at least two different directions; the first electrode pair and the second electrode pair oppositely penetrate through the shell, two electrodes of the first electrode pair and the second electrode pair are evenly arranged on the two sides of the insulation flow guide assembly, the parts, located outside the shell, of the positive electrode and the negative electrode of the first electrode pair are arranged in a short circuit mode, and the parts, located outside the shell, of the positive electrode and the negative electrode of the second electrode pair are connected with a load. The magnetohydrodynamic generator solves the problems that an existing magnetohydrodynamic generator is small in electrode distance and low in output voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of generators, and particularly to a liquid metal magnetohydrodynamic generator. Background Art

[0002] A liquid metal magnetohydrodynamic generator (LMMHD) is a highly efficient energy conversion device that directly generates electrical energy through the movement of a liquid metal working medium in a magnetic field. Its core principle is Faraday's law of electromagnetic induction. Due to its high power density, compact structure, and the absence of mechanical transmission components, this technology shows significant potential in areas such as wave energy generation, distributed power supply, and automotive engines. However, traditional LMMHD technology mostly uses a linear rectangular power generation channel. The electrode spacing of the rectangular power generation channel is limited, generally on the order of 10 2 10 1 m level. The external magnetic field of the liquid metal magnetohydrodynamic generator is generally generated by a permanent magnet, with a magnetic field strength of about 1T. The flow rate of the liquid metal is on the order of 10 1 m / s, resulting in a relatively low output voltage, usually on the order of 10 -1 -10 0 V level. At the same time, traditional LMMHD technology mostly uses a reciprocating type, outputting low-voltage large-current (10 3 -10 4 A level) alternating current, with poor power quality, making it difficult to meet the requirements of efficient power conversion. Moreover, the conversion efficiency (about 75%-85%) of rectifying and boosting the low-voltage large-current alternating current to 48VDC is much lower than that of boosting the low-voltage direct current to 48VDC (85%-93%). Therefore, how to effectively increase the output voltage of the liquid metal magnetohydrodynamic generator to improve the power quality is an urgent technical problem to be solved in the current liquid metal magnetohydrodynamic generator. Summary of the Invention

[0003] In view of this, the present invention provides a liquid metal magnetohydrodynamic generator to solve the problems of small electrode spacing and low output voltage in existing magnetohydrodynamic generators.

[0004] The present invention provides a liquid metal magnetohydrodynamic generator, including:

[0005] A housing having a flow space for liquid metal and an inlet and an outlet that are communicated with the flow space and are oppositely arranged;

[0006] At least one pair of magnets that are oppositely arranged and have opposite polarities, and at least one pair of magnets forms a magnetic field distributed along the axis of the housing in the flow space of the housing;

[0007] An insulating flow guiding component is axially arranged in the flow space along the housing, and is adapted to divide the liquid metal flowing in from the inlet, cut the magnetic force lines of the magnetic field in at least two different directions, and then converge and flow out through the outlet;

[0008] The first electrode pair and the second electrode pair penetrate through the housing relatively. The two electrodes of the first electrode pair and the second electrode pair are evenly arranged on both sides of the insulating flow guiding component. The positive and negative electrodes of the first electrode pair are short-circuited in the part outside the housing. The positive and negative electrodes of the second electrode pair are both connected to the load in the part outside the housing. The positive electrode of the first electrode pair is correspondingly arranged with the negative electrode of the second electrode pair, and the negative electrode of the first electrode pair is correspondingly arranged with the positive electrode of the second electrode pair to form a loop current output.

[0009] In the liquid metal magnetohydrodynamic generator provided by the present invention, when the liquid metal enters the flow space from the inlet of the housing, due to the arrangement of the insulating flow guiding component, it can be divided under the guidance of the insulating flow guiding component, cut the magnetic force lines of the magnetic field formed by at least one pair of magnets in at least two different directions, thereby forming at least two parallel flow fields; and because the positive and negative electrodes of the first electrode pair are short-circuited in the part outside the housing, at least two circuits are connected in series, which not only increases the distance between the positive and negative electrodes of the second electrode pair, but also uses the insulating flow guiding component to block the leakage current, so as to achieve the technical effect of improving the output voltage and output power of the magnetohydrodynamic generator even when the moving speed of the liquid metal is low.

[0010] In an optional embodiment, the insulating flow guiding component includes a radial flow guiding structure partially extending to the inlet and an axial flow guiding structure dividing the flow space along the axial section of the housing. The radial flow guiding structure is adapted to divide the liquid metal flowing in from the inlet once along the axial direction of the housing and then divide it along the radial direction. The axial flow guiding structure is adapted to divide the liquid metal divided along the radial direction along the axial direction and then converge.

[0011] The arrangement of the radial flow guiding structure and the axial flow guiding structure can divide the liquid metal first along the axial direction and then along the radial direction, and then divide it along the axial direction and finally converge. When dividing along the radial direction, the magnetic force lines of the magnetic field are cut from different directions, thereby simultaneously constructing at least two parallel flow fields and a circumferential series circuit, which has a simple structure and is easy to implement.

[0012] In an optional embodiment, the radial flow guiding structure includes a first flow guiding piece arranged parallel to the axis and a second flow guiding piece arranged along the radial direction. The axial flow guiding structure includes two third flow guiding pieces arranged at intervals. The two third flow guiding pieces are arranged parallel to the axial direction of the housing at the two opposite ends of the second flow guiding piece and are coplanar with the first flow guiding piece.

[0013] The part of the flow space near the outlet is divided by two third flow guiding vanes, thereby ensuring that the metal fluid is always in a split state before reaching the outlet, ensuring that at least two circuits are independent of each other inside the generator, and the two third flow guiding vanes and the first flow guiding vane are coplanar, which is convenient for integral processing and forming.

[0014] In an alternative embodiment, a transition taper angle is provided at the connection between the first flow guiding vane and the second flow guiding vane.

[0015] The setting of the transition taper angle results in a relatively small flow resistance when the liquid metal fluid changes from axial flow to radial flow, and the flow is smoother.

[0016] In an alternative embodiment, the outer shell includes a first cylinder, a second cylinder, and a frustum that are sequentially connected in the axial direction. The diameter of the second cylinder is larger than that of the first cylinder to form a first support portion. A first magnet is provided on the first support portion. A second support portion is provided inside the second cylinder, and a second magnet is provided on the second support portion. The polarities of the first magnet and the second magnet are opposite, and an installation space for the insulation flow guiding assembly is formed between the second magnet and the inner wall of the outer shell.

[0017] The stepped first cylinder and second cylinder provide convenience for the installation of the first magnet. Only by providing a second support portion inside the second cylinder can the second magnet be fixed, and thereby a magnetic field parallel to the axial direction of the outer shell is formed, making the structure simpler and the cost lower.

[0018] In an alternative embodiment, the second support portion is a circular iron yoke. An insulating layer is provided on the outer surface of the circular iron yoke. The second magnet is provided inside the circular iron yoke. Both the first magnet and the second magnet are annular and are correspondingly arranged.

[0019] The circular iron yoke provides support for the installation of the second magnet on the one hand, and can play an insulating role on the other hand, preventing the metal fluid from interacting with the second magnet and thus affecting the stability of the current. The annular first magnet and second magnet are more convenient for processing and installation.

[0020] In an alternative embodiment, the first flow guiding vane is provided in the first cylinder and partially extends into the second cylinder. The second flow guiding vane is provided in the second cylinder and is close to the first cylinder. The third flow guiding vane is provided in the second cylinder and is close to the frustum.

[0021] The first flow guiding vane, the second flow guiding vane, and the third flow guiding vane are sequentially arranged along the axial direction of the outer shell, cutting the flow space inside the outer shell, thereby forming at least two parallel flow fields, with a simple structure and convenient processing and installation.

[0022] In an alternative embodiment, the first flow guide vane is plate-shaped, and its length in the radial direction is equal to the inner diameter of the first cylinder. The second flow guide vane is circular, and its length in the radial direction is less than the inner diameter of the second cylinder, and it is spaced from the inner wall of the second cylinder to reserve a flow space for the liquid metal. The third flow guide vane is plate-shaped and is axially arranged at a position of the second flow guide vane close to the outlet, and is respectively in contact with the second support part and the inner wall of the second cylinder.

[0023] The first flow guide vane, the second flow guide vane and the third flow guide vane with sheet-like structures are simple in structure and can effectively divide the nearly columnar flow space. While increasing the electrode spacing, the leakage current phenomenon is effectively avoided, and the high-efficiency output of the generator is realized.

[0024] In an alternative embodiment, both the first electrode pair and the second electrode pair are copper electrodes, and insulating layers are provided on the parts in contact with the housing.

[0025] The high conductivity and good thermal stability of the copper electrodes make the electric discharge machining process more efficient, which can improve the material removal rate and shorten the machining cycle; and can maintain stable performance during the machining process, reduce the machining error caused by the change of electrode materials, and at the same time its corrosion resistance helps to extend the service life of the electrodes and improve the stability of machining quality. The setting of the insulating layer effectively reduces the mutual influence between the electrodes and the housing.

[0026] In an alternative embodiment, the liquid metal is a gallium alloy.

[0027] The conductivity of the gallium alloy is 3.2×10 6 S / m, and it has good chemical stability, which can ensure the stability of current and voltage output. Description of the Drawings

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 Schematic diagram of a liquid metal magnetohydrodynamic generator according to an embodiment of the present invention;

[0030] Figure 2 Another perspective schematic diagram of a liquid metal magnetohydrodynamic generator according to an embodiment of the present invention;

[0031] Figure 3 Axial sectional schematic diagram of a liquid metal magnetohydrodynamic generator according to an embodiment of the present invention;

[0032] Figure 4 Another perspective schematic diagram of Figure 3 ;

[0033] Figure 5 Schematic diagram of the flow direction and the current direction.

[0034] Description of the reference numerals in the drawings:

[0035] 1. Outer shell; 101. First cylinder; 102. Second cylinder; 103. Frustum; 104. First support part; 105. Second support part;

[0036] 2. Magnet; 201. First magnet; 202. Second magnet;

[0037] 3. Insulating flow guiding component; 301. Radial flow guiding structure; 3011. First flow guiding piece; 3012. Second flow guiding piece; 3013. Transition cone angle; 302. Axial flow guiding structure;

[0038] 4. First electrode pair;

[0039] 5. Second electrode pair. Detailed implementation manners

[0040] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] The following describes the embodiments of the present invention in conjunction with Figures 1 to 5 .

[0042] According to an embodiment of the present invention, a liquid metal magnetohydrodynamic generator is provided, including:

[0043] An outer shell 1, having a flow space for liquid metal and an inlet and an outlet that are communicated with the flow space, and the inlet and the outlet are oppositely arranged;

[0044] At least one pair of magnets 2 that are oppositely arranged and have opposite polarities, and at least one pair of magnets form a magnetic field distributed along the axial direction of the outer shell 1 in the flow space of the outer shell 1;

[0045] An insulating flow guiding component 3, arranged in the flow space along the axial direction of the outer shell, adapted to divide the liquid metal flowing in from the inlet, cut the magnetic field lines of the magnetic field in at least two different directions, and then flow out through the outlet after confluence;

[0046] The first electrode pair 4 and the second electrode pair 5 are arranged to penetrate through the housing 1 relatively. The two electrodes of the first electrode pair 4 and the second electrode pair 5 are evenly arranged on both sides of the insulating flow guiding component 3. The positive and negative electrodes of the first electrode pair 4 located outside the housing 1 are short-circuited. The positive and negative electrodes of the second electrode pair 5 located outside the housing 1 are both connected to the load. The positive electrode of the first electrode pair 4 is arranged corresponding to the negative electrode of the second electrode pair 5, and the negative electrode of the first electrode pair 4 is arranged corresponding to the positive electrode of the second electrode pair 5 to form a ring-shaped current output.

[0047] In this embodiment, the inlet and outlet of the housing 1 are arranged completely corresponding to each other, that is, they are distributed in sequence on the housing axis. Of course, the specific positions of the inlet and outlet are not specifically limited here, and they can also be arranged in a staggered manner, as long as they are distributed in sequence along the housing axis or parallel to the housing axis, so as to ensure that the flowing liquid metal can normally cut the magnetic force lines of the magnetic field.

[0048] The positions of the N pole and S pole of at least one pair of magnets 2 are not specifically limited here. For example, Figure 3 as shown, the S pole can be on the top and the N pole can be on the bottom, or the positions of the two can be swapped, as long as the formed magnetic field distribution direction is parallel to the housing axis and the intensity is uniform.

[0049] The insulating flow guiding component 3 is made of plastic material. Of course, other insulating materials such as rubber can also be used. The insulating flow guiding component 3 extends from inside the inlet of the housing 1 all the way to the middle and lower part near the outlet of the housing 1. Its function is to artificially divide the flow space inside the housing 1 into at least two parts, so that the liquid metal flowing in from the inlet is at least divided into two parts, forming at least two flow channels, and the liquid metal flows in at least two flow channels without interfering with each other, cutting the magnetic force lines of the magnetic field from different directions respectively, thereby forming at least two circuits.

[0050] The housing 1 is made of stainless steel material, and the inner surface is sprayed with plastic to play an insulating role. A pair of through holes are relatively opened in the middle of the housing 1 along the radial direction. The size and shape of the through holes are the same as the cross-section of the first electrode pair 4 and the second electrode pair 5. The first electrode pair 4 and the second electrode pair 5 respectively pass through the through holes and are clamped on the opposite sides of the insulating flow guiding component 3, that is, the positive and negative electrodes of the first electrode pair 4 and the second electrode pair 5 are separated by the insulating flow guiding component 3, and the parts of the first electrode pair 4 and the second electrode pair 5 located inside the housing 1 are arranged not to contact each other. Thus, at least two circuits are connected in series through the short-circuited positive and negative electrodes of the first electrode pair 4, and the generated current is output to the load through the second electrode pair 5.

[0051] For the liquid metal magnetohydrodynamic generator provided by the present invention, when the liquid metal enters the flow space from the inlet of the outer shell 1, due to the arrangement of the insulating flow guiding component 3, it can be shunted under the guidance of the insulating flow guiding component 3 and cut the magnetic force lines of the magnetic field formed by at least a pair of magnets 2 in at least two different directions, thereby forming at least two parallel flow fields; and because the positive and negative electrodes of the first electrode pair 4 are short-circuited in the part outside the outer shell 1, and then at least two circuits are connected in series, which not only increases the distance between the positive and negative electrodes of the second electrode pair 5, but also uses the insulating flow guiding component 3 to block the leakage current, so that even when the moving speed of the liquid metal is relatively low, the output voltage and output power of the magnetohydrodynamic generator can still be increased.

[0052] In one embodiment, as Figure 3 and Figure 4 shown, the arrow direction is the flow direction of the liquid metal. The insulating flow guiding component 3 includes a radial flow guiding structure 301 partially extending to the inlet and an axial flow guiding structure 302 that divides the flow space along the axial section. The radial flow guiding structure 301 is adapted to shunt the liquid metal flowing in from the inlet along the axial direction of the outer shell first and then shunt it along the radial direction. The axial flow guiding structure 302 is adapted to continue to shunt the liquid metal shunted along the radial direction along the axial direction and then converge.

[0053] During actual processing and production, the radial flow guiding structure 301 and the axial flow guiding structure 302 can be integrally processed by cutting or other means, or can be processed separately and then fixedly connected by plugging or bonding or other means.

[0054] The settings of the radial flow guiding structure 301 and the axial flow guiding structure 302 can first shunt the liquid metal along the axial direction and then shunt it along the radial direction, and then shunt it along the axial direction and finally converge. And when shunting along the radial direction, cut the magnetic force lines of the magnetic field from different directions, thereby simultaneously constructing at least two parallel flow fields and a circumferential series circuit, with a simple structure and easy to implement.

[0055] In one embodiment, the radial flow guiding structure 301 includes a first flow guiding piece 3011 arranged parallel to the axial direction and a second flow guiding piece 3012 arranged along the radial direction. The axial flow guiding structure 302 includes two spaced third flow guiding pieces, and the two third flow guiding pieces are arranged parallel to the axial direction of the outer shell at two opposite ends of the second flow guiding piece 3012 and are coplanar with the first flow guiding piece 3011.

[0056] Since the flow direction of the liquid metal changes from axial to radial after being split by the first flow guide vane 3011 and the second flow guide vane 3012, there is a possibility of re-confluence at the junction of the two radial flow channels. In this case, at the confluence of the flow field, due to magnetic field attenuation and potential difference, leakage current is generated, that is, a circulating current is generated between the positive and negative electrodes of the first electrode pair 4, increasing the internal loss of the generator and reducing the output power. To avoid the occurrence of the above situation, in this embodiment, a third flow guide vane is respectively arranged at the junction of the two radial flow channels to divide the part of the flow space close to the outlet, thereby ensuring that the metal fluid is always in a split state before reaching the outlet, ensuring that at least two circuits are independent of each other inside the generator and are connected in series through external short-circuiting, effectively avoiding the leakage current phenomenon, and the two third flow guide vanes and the first flow guide vane 3011 are arranged coplanarly, which is convenient for integral processing and forming.

[0057] In one embodiment, a transition taper angle 3013 is provided at the connection of the first flow guide vane 3011 and the second flow guide vane 3012.

[0058] As Figure 4 shown, an arc-shaped transition taper angle 3013 is provided at the bottom of the first flow guide vane 3011. Since the first flow guide vane 3011 and the second flow guide vane 3012 are basically perpendicular to each other, the flow resistance of the liquid metal fluid is relatively large when changing from axial flow to radial flow. In this embodiment, the arc-shaped transition taper angle 3013 is used to connect with the second flow guide vane 3012, avoiding the problem of relatively large flow resistance caused by right-angle transition and making the flow smoother. The angle of the transition taper angle 3013 should not be too large, and it is preferably 5°-10°, so as to prevent the cross-sectional area of the flow channel for the liquid metal to change from axial to radial from being too small, the flow resistance from being too large, and the flow loss from being too large, which affects the output voltage and output power of the generator.

[0059] In one embodiment, the outer shell 1 includes a first cylinder 101, a second cylinder 102 and a frustum 103 that are sequentially connected in communication along the axial direction. The diameter of the second cylinder 102 is larger than that of the first cylinder 101 to form a first support portion 104. A first magnet 201 is provided on the first support portion 104. A second support portion 105 is provided inside the second cylinder 102. A second magnet 202 is provided on the second support portion 105. The polarities of the first magnet 201 and the second magnet 202 are opposite. An installation space for the insulating flow guide assembly 3 is formed between the second magnet 202 and the inner wall of the outer shell 1.

[0060] The first cylinder 101, the second cylinder 102 and the frustum 103 can be integrally processed and formed, or can be fixed by welding. The first cylinder 101 and the second cylinder 102 are connected and fixed through the annular first support portion 104, thereby forming a stepped shape. The axial height of the first cylinder 101 is greater than the axial height of the first magnet 201 to ensure the stability of installation. The second support portion 105 can be fixed inside the second cylinder 102 through the third flow guide piece, and can be specifically realized by plugging and fixing, welding and fixing, etc., and no specific limitation is made here.

[0061] Of course, the shape of the outer shell 1 can also be other shapes, such as a cylinder, or small cylinders at both ends and a large cylinder in the middle, or frustums at both ends and a cylinder in the middle. At this time, the installation of the first magnet 201 needs to be adaptively adjusted, and corresponding fixing structures are set. No specific limitation is made on the shape of the outer shell 1 here.

[0062] The setting of the stepped first cylinder 101 and the second cylinder 102 provides convenience for the installation of the first magnet 201, and only one second support portion 105 needs to be arranged inside the second cylinder 102 to fix the second magnet 202, and thereby a magnetic field parallel to the axis of the outer shell is formed, making the structure simpler and the cost lower.

[0063] In one embodiment, the second support portion 105 is a circular iron yoke, and an insulating layer is provided on the outer surface of the circular iron yoke. The second magnet 202 is arranged inside the circular iron yoke. Both the first magnet 201 and the second magnet 202 are annular and are correspondingly arranged.

[0064] The circular iron yoke is a hollow structure, and the insulating layer on the outer surface can be realized by spraying plastic, or can also be realized by pasting and covering an insulating film, and no specific limitation is made here. The inner diameters of both the first magnet 201 and the second magnet 202 are the same as the outer diameter of the first cylinder 101, and the outer diameters of both the first magnet 201 and the second magnet 202 are smaller than the inner diameter of the second cylinder 102 to reserve a flow space for the liquid metal inside the outer shell 1. The second support portion 105 can also be other shell structures with an insulating layer on the outer surface, such as a cuboid or a cube, etc. Both the first magnet 201 and the second magnet 202 in this embodiment are annular, thereby generating a uniformly distributed magnetic field in a circle. The liquid metal cuts the magnetic force lines simultaneously from different circumferential directions, and the generated current is large and stable. In addition, the first magnet 201 and the second magnet 202 can also be multiple pairs of spaced magnets, such as strip magnets, U-shaped magnets, etc., as long as it is ensured that a uniform magnetic field covering the flow field can be generated, so that the liquid metal can cut the magnetic force lines from different directions.

[0065] The circular iron yoke, firstly, plays the role of guiding and concentrating magnetic flux; secondly, provides support for the installation of the second magnet 202; thirdly, due to the setting of the insulating layer on the outer surface, it can play an insulating role; fourthly, blocks the contact between the liquid metal fluid and materials such as the magnetic steel of the second magnet 202, preventing chemical reactions between the liquid metal and the magnetic steel and other materials, and playing a role in protecting the second magnet 202. The annular first magnet 201 and the second magnet 202 are more convenient for processing and installation. When installing the first magnet 201, only need to set the hollow part of the first magnet 201 on the outer wall of the first cylinder 101.

[0066] In one embodiment, the first flow guide piece 3011 is arranged in the first cylinder 101 and partially extends into the second cylinder 102, the second flow guide piece 3012 is arranged in the second cylinder 102 and is close to the first cylinder 101, and the third flow guide piece is arranged in the second cylinder 102 and is close to the frustum 103.

[0067] The first flow guide piece 3011, the second flow guide piece 3012 and the third flow guide piece are arranged in sequence along the axial direction of the housing. The top end of the first flow guide piece 3011 is lower than the top end of the first cylinder 101. The first flow guide piece 3011, the second flow guide piece 3012 and the third flow guide piece are integrally close to the inlet of the housing 1 to cut the flow space inside the housing 1, so that the liquid metal is immediately shunted after entering the housing 1, thereby forming at least two parallel flow fields. The structure is simple and convenient for processing and installation. Of course, the third flow guide piece can also extend into the frustum 103 for further shunting, as long as it is ensured that the liquid metal converges before reaching the outlet. However, at this time, since the inner wall of the frustum 103 is an arc surface, the processing difficulty and the installation and fixation difficulty of the third flow guide piece both increase.

[0068] In one embodiment, the first flow guide piece 3011 is plate-shaped, and the length along the radial direction is equal to the inner diameter of the first cylinder 101. The second flow guide piece 3012 is circular, and the length along the radial direction is less than the inner diameter of the second cylinder 102, and is spaced from the inner wall of the second cylinder 102 to reserve a flow space for the liquid metal. The third flow guide piece is plate-shaped and is arranged axially at a position of the second flow guide piece 3012 close to the outlet, and is respectively in contact with the second support portion 105 and the inner wall of the second cylinder 102. The positions where the third flow guide piece is in contact with the second support portion 105 and the second cylinder 102 are both arc-shaped to ensure the connection sealing performance and thus ensure the shunting effect.

[0069] The radial length of the first flow guide vane 3011 is equal to the inner diameter of the first cylinder 101, that is, both ends of the length of the first flow guide vane 3011 are in contact with the inner wall of the first cylinder 101 to ensure complete separation. Moreover, the first flow guide vane 3011 is arranged at the center of the second flow guide vane 3012 to evenly divide the flow space inside the housing 1. The size of the second flow guide vane 3012 is the same as the size of the upper surface of the circular yoke, so as to just fit on the upper surface of the circular yoke. The axial length of the third flow guide vane is slightly greater than the axial height of the circular yoke, that is, the end close to the outlet extends beyond the lower surface of the circular yoke, thus playing a certain guiding role.

[0070] The first flow guide vane 3011, the second flow guide vane 3012 and the third flow guide vane in sheet structure are simple in structure, convenient for processing, and can meet the purpose of effectively dividing the nearly columnar flow space. While increasing the electrode spacing, the leakage current phenomenon is effectively avoided, and the high-efficiency output of the generator is realized.

[0071] Certainly, the first flow guide vane 3011 can also be in the shape of a cross, a T-shape, etc. to simultaneously divide the liquid metal into multiple paths. At this time, the number of the third flow guide vanes is also correspondingly increased to ensure the independence of multiple flow channels.

[0072] In one embodiment, both the first electrode pair 4 and the second electrode pair 5 are copper electrodes, and insulating layers are provided on the parts in contact with the housing 1.

[0073] The high conductivity and good thermal stability of the copper electrodes make the electro-discharge machining process more efficient, which can improve the material removal rate and shorten the machining cycle. Moreover, stable performance can be maintained during the machining process, reducing the machining error caused by the change of electrode materials. At the same time, its corrosion resistance helps to extend the service life of the electrodes and improve the stability of machining quality. The setting of the insulating layer effectively reduces the mutual influence between the electrodes and the housing 1. Certainly, the first electrode pair 4 and the second electrode pair 5 can also be electrodes made of other materials, which are not specifically limited here. The parts of the first electrode pair 4 and the second electrode pair 5 in contact with the housing 1 can form an insulating layer by means of spraying.

[0074] In one embodiment, the liquid metal is a gallium alloy.

[0075] The conductivity of the gallium alloy is 3.2×10 6 S / m, and it has good chemical stability, which can ensure the stability of current and voltage output. In addition, the liquid metal can also be mercury and sodium-potassium alloy, which are not specifically limited here.

[0076] The gallium alloy in the normal temperature liquid state flows into the flow space from the inlet of the outer shell 1 under the drive of wave energy. Initially, it flows unidirectionally along the axis of the outer shell. When it encounters the first guide vane 3011, it is shunted. After passing through the transition cone angle 3013 of the first guide vane 3011 and the second guide vane 3012, it changes to flow radially along the outer shell 1. When passing through the magnetic field formed by the first magnet 201 and the second magnet 202, it cuts the magnetic force lines and generates an electric current. As Figure 5 shown, the solid line is the flow direction of the liquid metal, and the dotted line is the current direction. Since the positive and negative electrodes of the first electrode pair 4 are short-circuited, the electric currents generated by the two parallel flow fields are connected in series to form a circular flowing loop current, which is a DC generator. Furthermore, the distance between the second electrode pair 5 is increased to the circumference of the entire second cylinder 102, effectively increasing the electrode distance. Moreover, the first guide vane 3011, the second guide vane 3012, and the third guide vane block the leakage current. Even when the moving speed of the gallium alloy is relatively low, it can still increase the output voltage and output power of the magnetohydrodynamic generator. After the gallium alloy flows through the second guide vane 3012, it changes to axial flow. At this time, it is still divided by the third guide vane and then converges after passing through the third guide vane, and finally flows out of the outlet of the outer shell 1.

[0077] The liquid metal magnetohydrodynamic generator of this embodiment, under the drive of an external driving device, such as wave energy drive, directly connects the inlet of the outer shell to the wave energy drive structure. The input pressure is 5 MPa - 10 MPa, the inlet diameter is 0.1 m - 0.5 m, the electrode distance is 0.3 m - 1.55 m, the lengths of the first electrode pair and the second electrode pair along the axis of the outer shell are 0.01 m - 0.015 m, the flow speed of the liquid metal is 20 m / s - 30 m / s, the magnetic field generated by the first magnet and the second magnet in the flow channel is 1 T, the liquid metal is gallium alloy, and the conductivity is 3.2×10 6 S / m. The output voltage of this magnetohydrodynamic generator reaches the level of 5 V - 50 V, and the output power can reach the level of 100 kW.

[0078] After setting the insulating guide component, when the input pressure is 5 MPa, the inlet diameter is 0.1 m, the electrode distance is 0.3 m, the lengths of the first electrode pair and the second electrode pair along the axis of the outer shell are 0.01 m, the flow speed of the liquid metal is 20 m / s, the magnetic field generated by the first magnet and the second magnet in the flow channel is 1 T, the liquid metal is gallium alloy, and the conductivity is 3.2×10 6 S / m. The output voltage of this magnetohydrodynamic generator reaches 5 V, and the output power can reach 34.56 kW.

[0079] When the insulating current guiding component is not set, when the input pressure is 5 MPa, the inlet diameter is 0.1 m, the electrode spacing is 0.3 m, the lengths of the first electrode pair and the second electrode pair along the axial direction of the housing are 0.01 m, the flow velocity of the liquid metal is 20 m / s, the magnetic field generated by the first magnet and the second magnet in the flow channel is 1 T, the liquid metal is gallium alloy, and the conductivity is 3.2×10 6 S / m, the maximum output voltage of this magnetohydrodynamic generator reaches 3.412 V, and the output power is 134.84 W.

[0080] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A liquid metal magnetohydrodynamic generator, characterized in that Comprising: A housing (1) having a flow space for liquid metal and an inlet and an outlet that are communicatively arranged with the flow space, the inlet and the outlet being oppositely arranged; At least a pair of oppositely arranged magnets (2) with opposite polarities, at least a pair of the magnets (2) forming a magnetic field distributed along the axis of the housing in the flow space of the housing (1); An insulating flow guiding assembly (3) arranged in the flow space along the axis of the housing, adapted to divide the liquid metal flowing in from the inlet, cut the magnetic force lines of the magnetic field in at least two different directions, and then flow out through the outlet after confluence; A first electrode pair (4) and a second electrode pair (5) penetrating the housing (1) relatively, two electrodes of the first electrode pair (4) and the second electrode pair (5) being evenly arranged on both sides of the insulating flow guiding assembly (3), and the positive and negative electrodes of the first electrode pair (4) outside the housing (1) being short-circuited, the positive and negative electrodes of the second electrode pair (5) outside the housing (1) being connected to a load, and the positive electrode of the first electrode pair (4) being correspondingly arranged with the negative electrode of the second electrode pair (5), the negative electrode of the first electrode pair (4) being correspondingly arranged with the positive electrode of the second electrode pair (5) to form a ring-shaped current output.

2. The liquid metal magnetohydrodynamic generator according to claim 1, wherein The insulating flow guiding assembly (3) includes a radial flow guiding structure (301) partially extending to the inlet and an axial flow guiding structure (302) for dividing the flow space along the axial section, the radial flow guiding structure (301) being adapted to divide the liquid metal flowing in from the inlet once along the axis of the housing and then divide it radially, and the axial flow guiding structure (302) being adapted to divide the liquid metal divided radially along the axis and then confluence.

3. The liquid metal magnetohydrodynamic generator according to claim 2, wherein The radial flow guiding structure (301) includes a first flow guiding piece (3011) arranged parallel to the axis and a second flow guiding piece (3012) arranged radially, and the axial flow guiding structure (302) includes two spaced third flow guiding pieces arranged parallel to the axis of the housing at two opposite ends of the second flow guiding piece (3012) and coplanar with the first flow guiding piece (3011).

4. The liquid metal magnetohydrodynamic generator according to claim 3, wherein A transition cone angle (3013) is provided at the connection of the first flow guiding piece (3011) and the second flow guiding piece (3012).

5. The liquid metal magnetohydrodynamic generator according to claim 3, wherein The housing (1) includes a first cylinder (101), a second cylinder (102) and a frustum (103) communicatively arranged in sequence along the axis, the diameter of the second cylinder (102) being larger than that of the first cylinder (101) to form a first support portion (104), a first magnet (201) being provided on the first support portion (104), a second support portion (105) being provided inside the second cylinder (102), a second magnet (202) being provided on the second support portion (105), the first magnet (201) and the second magnet (202) having opposite polarities, and an installation space for the insulating flow guiding assembly (3) being formed between the second magnet (202) and the inner wall of the housing (1).

6. The liquid metal magnetohydrodynamic generator according to claim 5, characterized in that, The second support part (105) is a circular yoke, an insulating layer is provided on the outer surface of the circular yoke, the second magnet (202) is arranged inside the circular yoke, and both the first magnet (201) and the second magnet (202) are annular and are arranged correspondingly.

7. The liquid metal magnetohydrodynamic generator according to claim 5, characterized in that The first current guide piece (3011) is arranged in the first cylinder (101) and partially extends into the second cylinder (102), the second current guide piece (3012) is arranged in the second cylinder (102) and is arranged close to the first cylinder (101), and the third current guide piece is arranged in the second cylinder (102) and is arranged close to the frustum (103).

8. The liquid metal magnetohydrodynamic generator according to claim 7, wherein, The first current guide piece (3011) is plate-shaped, the length in the radial direction is equal to the inner diameter of the first cylinder (101), the second current guide piece (3012) is circular, the length in the radial direction is less than the inner diameter of the second cylinder (102), and is arranged at an interval from the inner wall of the second cylinder (102) to reserve a flow space for the liquid metal. The third current guide piece is plate-shaped, is arranged axially at a position of the second current guide piece (3012) close to the outlet, and is respectively in contact with the second support part (105) and the inner wall of the second cylinder (102).

9. The liquid metal magnetohydrodynamic generator according to any one of claims 1-8, characterized in that, Both the first electrode pair (4) and the second electrode pair (5) are copper electrodes, and insulating layers are provided on the parts in contact with the housing (1).

10. The liquid metal magnetohydrodynamic generator according to any one of claims 1-8, characterized in that, The liquid metal is a gallium alloy.

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