Low-vibration thermo-acoustic magnetohydrodynamic power generation device

Abstract

The utility model relates to the technical field of thermo-acoustic power generation, and provides a low-vibration thermo-acoustic magnetohydrodynamic power generation device which comprises a thermo-acoustic engine and a liquid metal magnetohydrodynamic power generator, and the thermo-acoustic engine comprises an engine assembly and an air reservoir; the liquid metal magnetohydrodynamic generator comprises at least two magnetohydrodynamic power generation channels, every two magnetohydrodynamic power generation channels are symmetrically arranged, one end of each magnetohydrodynamic power generation channel is connected with the engine assembly, the other end of each magnetohydrodynamic power generation channel is connected with the air reservoir, and each magnetohydrodynamic power generation channel is filled with liquid metal. A first magnet and a second magnet are arranged on the outer wall of the magnetofluid power generation channel, and at least one electrode pair is embedded in an insulating layer of the magnetofluid power generation channel and located on the channel wall parallel to the magnetic field direction. In the operation process, force generated by liquid metal flowing, magnetic field interaction and the like counteracts each other in the symmetrical direction, force balance and moment balance are achieved on the whole, and ultralow-vibration operation is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to thermoacoustic power generation technical field especially relates to a low vibration's thermoacoustic magnetic fluid power generation device. BACKGROUND

[0002] Thermoacoustic power generation technology is a new type of power generation technology that couples a thermoacoustic engine with an acoustic-electric conversion device (generator). The main acoustic-electric conversion devices currently include linear motors, piezoelectric devices, friction nanogenerators, and magnetic fluid generators.

[0003] Among them, there are mechanical moving parts (piston, motor mover, etc.) in the linear motor, which weakens the high reliability advantage of the thermoacoustic engine without mechanical moving parts; piezoelectric power generation is based on high-frequency vibration of piezoelectric devices, which is only suitable for small-scale thermoacoustic power generation scenarios, and the thermoelectric conversion efficiency is low (less than 10%); the friction nanogenerator generates electricity based on the electrostatic effect between friction materials, with low power output (less than 1W), and long-term operation between friction parts causes wear and other problems, with low reliability; the magnetic fluid generator uses the high-intensity pressure fluctuations generated by the thermoacoustic engine to drive the magnetic fluid to reciprocate in a magnetic field environment. The magnetic fluid composed of electrons and positive ions cuts the magnetic induction lines to generate induced electromotive force, outputting alternating current energy.

[0004] Compared with linear motors, piezoelectric devices, and friction nanogenerators, there are no mechanical moving parts in the magnetic fluid generator, with flexible power and high potential power generation efficiency, and it has wide applications in space power generation, wave power generation, etc. Therefore, combining the thermoacoustic engine and the liquid metal magnetic fluid generator can form a completely mechanical moving part-free magnetic fluid power generation device. Since the magnetic fluid power generation device combines the characteristics of the thermoacoustic engine and the liquid metal magnetic fluid generator, it has high reliability, long service life, high energy conversion rate, and wide energy adaptability, and therefore can be widely applied to various application scenarios with extremely high requirements for generator reliability, such as space isotope power supply, space nuclear reactor power supply, etc.

[0005] In the related art, US4599551A discloses a thermoacoustic magnetohydrodynamic generator. Periodic pressure fluctuations are generated by two opposing standing wave thermoacoustic engines, thereby driving the liquid metal magnetofluid to cut the magnetic lines to generate induced electromotive force. The system uses flat plate electrodes installed on the inner wall of the resonant tube of the standing wave engine to collect and output electric energy, realizes the direct coupling design of the thermoacoustic engine and the magnetofluid generator, and makes the overall structure relatively simple. However, the system still has the following limitations in practical application: first, since the standing wave thermoacoustic engine is based on an irreversible thermodynamic cycle, its potential efficiency is low; second, the working medium of the thermoacoustic engine and the magnetofluid generator is liquid metal, which has high design difficulty and manufacturing cost; third, the working frequency of the thermoacoustic magnetofluid power generation system reaches kHz level, which is much higher than the power frequency (50-60 Hz), which is not conducive to practical use; fourth, due to the high thermal conductivity of liquid metal, there is serious axial heat conduction loss in the thermoacoustic engine, and the system thermal efficiency is limited to a certain extent.

[0006] Therefore, CN101282074B discloses a thermoacoustic liquid magnetofluid alternating current power generation system. The system directly couples the resonant tube of the thermoacoustic engine with the opening of one end of the working pipeline of the liquid metal magnetofluid generator, so that the pressure wave generated by the oscillation of the resonant tube drives the magnetofluid to flow in the working pipeline. The working pipeline is placed between two magnetic fields, and when the magnetofluid flows in the pipeline, it cuts the magnetic lines to generate induced electromotive force and output electric energy. In this design, the thermoacoustic engine uses gas as the working medium, which significantly simplifies the engine structure and reduces the manufacturing cost compared with the traditional engine using liquid metal magnetofluid. In addition, the design of the thermoacoustic engine using gas as the driving medium effectively reduces the working frequency to close to the power frequency (50-60 Hz), which is more in line with the needs of practical power application. At the same time, since the thermal conductivity of the gas medium is much lower than that of the liquid metal medium, the axial heat conduction loss is significantly reduced, thereby improving the overall efficiency of the system. However, the thermoacoustic engine used in this system is a traditional thermoacoustic engine, which has large volume and weight, and serious loss. In addition, since the system uses a conduction type magnetofluid generator, the output current is large and the voltage is small, the power transmission loss is large, and there is great reciprocating vibration, which greatly limits the application in low vibration demand applications.

[0007] To address this, Chinese Patent Publication No. CN106533119B discloses a liquid metal magnetohydrodynamic (MHD) power generation system driven by a single-stage thermoacoustic motor. This system uses a single-stage thermoacoustic motor as the drive source, dividing the liquid metal flow channel in the MHD generator into multiple annular flow channels. Electrodes are arranged in each flow channel, and the electrodes in each flow channel are connected in series to reduce the output current and increase the output voltage. This thermoacoustic MHD system features small size and weight, high energy density, low start-up and operating temperatures, and easy utilization of output energy. However, because the liquid metal MHD generator in this system is arranged in a single tube, there is a problem of force and torque imbalance during operation, and the system experiences significant vibration and high energy loss during operation. Utility Model Content

[0008] This invention provides a low-vibration thermoacoustic magnetohydrodynamic (MHD) power generation device to solve the defects of large vibration and high energy loss in existing MHD power generation devices during operation; it achieves force balance and torque balance as a whole, effectively reduces mechanical vibration during operation, and realizes ultra-low vibration operation.

[0009] This utility model provides a low-vibration thermoacoustic magnetohydrodynamic power generation device, comprising:

[0010] A thermoacoustic engine includes an engine assembly and an air reservoir, wherein the engine assembly is used to extract acoustic power and form a traveling wave phase, and the air reservoir is used to adjust acoustic impedance and resonance conditions.

[0011] A liquid metal magnetohydrodynamic (MHD) generator includes at least two MHD power generation channels, each pair of MHD power generation channels being symmetrically arranged. One end of each MHD power generation channel is connected to the engine assembly, and the other end of each MHD power generation channel is connected to the gas reservoir. The interior of each MHD power generation channel is filled with liquid metal or liquid metal containing nano-reinforced conductive materials. The outer wall of each MHD power generation channel is provided with a first magnet and a second magnet, which are used to construct a parallel magnetic field. At least one pair of electrodes is embedded in the insulating layer of each MHD power generation channel, and the at least one pair of electrodes is located on the channel wall parallel to the direction of the magnetic field.

[0012] According to the embodiment of this utility model, the low-vibration thermoacoustic magnetohydrodynamic power generation device includes a first pipe segment, a second pipe segment, and a third pipe segment connected end to end in sequence. The second pipe segment is horizontally arranged, and the first pipe segment and the third pipe segment are vertically connected to both ends of the second pipe segment.

[0013] The first pipe segments of the two symmetrically arranged magnetohydrodynamic power generation channels overlap, the first pipe segment is connected to the engine assembly, and the second pipe segment and the third pipe segment are symmetrically arranged with the axis of the first pipe segment as the axis of symmetry;

[0014] The first magnet and the second magnet are arranged at corresponding positions of the second pipe section, and at least one pair of the electrodes is arranged at corresponding positions of the second pipe section.

[0015] According to the low-vibration thermoacoustic magnetic fluid power generation device, the cross section of the second pipe section is rectangular, and the cross sections of the first pipe section and the third pipe section are circular.

[0016] According to the low-vibration thermoacoustic magnetic fluid power generation device, at least three pairs of electrodes are embedded on the insulation layer of the magnetic fluid power generation channel, and two adjacent pairs of electrodes are arranged at intervals.

[0017] According to the low-vibration thermoacoustic magnetic fluid power generation device, three pairs of electrodes are embedded on the insulation layer of the magnetic fluid power generation channel, and two adjacent pairs of electrodes are arranged at intervals.

[0018] The negative plate of the first pair of electrodes and the positive plate of the second pair of electrodes are connected by a wire, the negative plate of the second pair of electrodes and the positive plate of the third pair of electrodes are connected by a wire, and a load is connected to the positive plate of the first pair of electrodes and the negative plate of the third pair of electrodes by a wire to form an electric circuit.

[0019] According to the low-vibration thermoacoustic magnetic fluid power generation device, an insulation plate is arranged in the magnetic fluid power generation channel, the insulation plate is located in the gap between two adjacent pairs of electrodes, and the magnetic fluid power generation channel is divided into at least three magnetic fluid sub-power generation channels by the insulation plate.

[0020] According to the low-vibration thermoacoustic magnetic fluid power generation device, the engine assembly comprises, in sequence, a main chamber temperature end heat exchanger, a regenerator, a heater, a secondary chamber temperature end heat exchanger, a resonance pipe, a feedback pipe and an acoustic capacitor.

[0021] The main chamber temperature end heat exchanger and the secondary chamber temperature end heat exchanger exchange heat with an external low-temperature heat source to form a chamber temperature end, the heater exchanges heat with an external high-temperature heat source to form a high-temperature end, and the regenerator is used to generate acoustic power.

[0022] One end of each magnetic fluid power generation channel is connected to the resonance pipe.

[0023] According to the low-vibration thermoacoustic magnetic fluid power generation device provided by the embodiment of the utility model, the engine assembly further comprises a heat buffer pipe, one end of the heat buffer pipe is connected with the heater, and the other end of the heat buffer pipe is connected with the secondary room temperature end heat exchanger.

[0024] The cross-sectional area of the primary room temperature end heat exchanger, the regenerator and the heater is greater than the cross-sectional area of any one of the heat buffer pipe, the secondary room temperature end heat exchanger and the resonance pipe.

[0025] According to the low-vibration thermoacoustic magnetic fluid power generation device provided by the embodiment of the utility model, the liquid metal comprises any one of mercury, gallium, gallium indium tin alloy and sodium potassium liquid alloy; and the nano-enhanced conductive material comprises nano-copper, silver or carbon nanotube.

[0026] According to the low-vibration thermoacoustic magnetic fluid power generation device provided by the embodiment of the utility model, the electrode is made of gold, silver, platinum, aluminum, nickel, copper, titanium or chromium, or the electrode is made of an alloy formed by at least two of gold, silver, platinum, aluminum, nickel, copper, titanium or chromium.

[0027] The low-vibration thermoacoustic magnetic fluid power generation device provided by the utility model comprises at least two magnetic fluid power generation channels, and each two magnetic fluid power generation channels are symmetrically arranged and present a regular and stable structure, so that the forces generated by the reciprocating flow of the liquid metal, the interaction of the magnetic fields and the like in the running process of the thermoacoustic magnetic fluid power generation device are mutually offset in the symmetric direction. For example, if the liquid metal generates a leftward thrust in one of the two symmetric magnetic fluid power generation channels, due to the symmetric relationship, a rightward thrust with the same size is generated in the other magnetic fluid power generation channel, so that the force balance is achieved in the whole, the mechanical vibration in the running process is effectively reduced, and the ultra-low vibration running is realized. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical scheme in the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creative labor.

[0029] Figure 1 It is a structure schematic view of the low-vibration thermoacoustic magnetic fluid power generation device provided by the embodiment of the utility model.

[0030] Figure 2 It is an internal structure schematic view of the liquid metal magnetic fluid power generation machine in the low-vibration thermoacoustic magnetic fluid power generation device provided by the embodiment of the utility model.

[0031] Figure 3 Figure 1 is an external structure schematic diagram of a liquid metal magnetohydrodynamic generator in a low-vibration thermoacoustic magnetohydrodynamic power generation device provided by an embodiment of the present application.

[0032] Figure 4 Figure 1 is an external structure schematic diagram of a liquid metal magnetohydrodynamic generator in a low-vibration thermoacoustic magnetohydrodynamic power generation device provided by an embodiment of the present application. Figure 3 Figure 1 is an external structure schematic diagram of a liquid metal magnetohydrodynamic generator in a low-vibration thermoacoustic magnetohydrodynamic power generation device provided by an embodiment of the present application.

[0033] Figure 5 Figure 1 is an external structure schematic diagram of a liquid metal magnetohydrodynamic generator in a low-vibration thermoacoustic magnetohydrodynamic power generation device provided by an embodiment of the present application.

[0034] Reference signs:

[0035] 1, thermoacoustic engine; 11, main chamber warm end heat exchanger; 12, regenerator; 13, heater; 14, thermal buffer tube; 15, secondary chamber warm end heat exchanger; 16, resonant tube; 17, feedback tube; 18, acoustic capacitor; 19, gas reservoir;

[0036] 2, liquid metal magnetohydrodynamic generator; 211, first magnet; 212, second magnet; 221, first magnetohydrodynamic sub-power generation channel; 222, second magnetohydrodynamic sub-power generation channel; 223, third magnetohydrodynamic sub-power generation channel; 231-1, positive plate of first pair of electrode pairs; 231-2, negative electrode of first pair of electrode pairs; 232-1, positive plate of second pair of electrode pairs; 232-2, negative electrode of second pair of electrode pairs; 233-1, positive plate of third pair of electrode pairs; 233-2, negative electrode of third pair of electrode pairs;

[0037] 3, magnetohydrodynamic power generation channel; 31, first pipe section; 32, second pipe section; 33, third pipe section;

[0038] 4, liquid metal. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the present application more clear, the technical scheme of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0040] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0041] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0043] Figure 1 This is a schematic diagram of a low-vibration thermoacoustic magnetohydrodynamic power generation device provided in an embodiment of this utility model. Figure 2 This is a schematic diagram of the internal structure of the liquid metal magnetohydrodynamic generator in the low-vibration thermoacoustic magnetohydrodynamic power generation device provided in this embodiment of the present invention.

[0044] See Figure 1 and Figure 2 This utility model provides a low-vibration thermoacoustic magnetohydrodynamic power generation device, including a thermoacoustic engine 1 and a liquid metal magnetohydrodynamic generator 2.

[0045] The thermoacoustic engine 1 comprises an engine assembly for extracting acoustic power and forming a traveling wave phase, and a reservoir 19 for adjusting acoustic impedance and resonance condition, and is filled with a high-pressure gas working substance such as helium, nitrogen or carbon dioxide.

[0046] The engine assembly is a device for converting thermal energy into high-intensity acoustic energy, i.e. when a proper temperature gradient and acoustic field exist in a pipe, acoustic oscillation is spontaneously generated to convert thermal energy into mechanical energy in the form of acoustic waves. The engine assembly is based on a reversible Stirling cycle, has no mechanical moving parts, and has high operation reliability, long service life and high potential thermal efficiency.

[0047] The engine assembly comprises, in sequence, a primary chamber temperature end heat exchanger 11, a regenerator 12, a heater 13, a secondary chamber temperature end heat exchanger 15, a resonant pipe 16, a feedback pipe 17 and an acoustic capacitor 18; the primary chamber temperature end heat exchanger 11 and the secondary chamber temperature end heat exchanger 15 exchange heat with an external low-temperature heat source to form a chamber temperature end, the heater 13 exchanges heat with an external high-temperature heat source to form a high-temperature end, and the regenerator 12 is used to generate acoustic power.

[0048] In addition, the engine assembly further comprises a thermal buffer pipe 14, one end of the thermal buffer pipe 14 being connected to the heater 13, and the other end of the thermal buffer pipe 14 being connected to the secondary chamber temperature end heat exchanger 15; the cross-sectional areas of the primary chamber temperature end heat exchanger 11, the regenerator 12 and the heater 13 are all greater than the cross-sectional areas of the thermal buffer pipe 14, the secondary chamber temperature end heat exchanger 15 and the resonant pipe 16, and such arrangement can reduce the oscillation speed of the gas working substance in the regenerator 12, reduce viscous loss and improve energy conversion efficiency.

[0049] In other words, the primary chamber temperature end heat exchanger 11 is located above the regenerator 12, and functions to remove heat from the regenerator 12 and cool the gas working substance to establish a temperature gradient on the regenerator 12. The regenerator 12 is located below the primary chamber temperature end heat exchanger 11, and is usually made of a stainless steel pipe filled with a stainless steel wire mesh, and is a key component for generating and strengthening the thermoacoustic effect. The thermoacoustic effect here generates or enhances acoustic power. The heater 13 functions to provide a high-temperature heat source at the other end of the regenerator 12 relative to the primary chamber temperature end heat exchanger 11, and together with the ambient temperature at the primary chamber temperature end heat exchanger 11 forms a temperature gradient on the regenerator 12 to provide power for engine operation. The thermal buffer pipe 14 is located between the heater 13 and the secondary chamber temperature end heat exchanger 15, the upper half of the thermal buffer pipe 14 is a straight pipe, the lower half of the thermal buffer pipe 14 is a tapered pipe, and the inner surface of the thermal buffer pipe 14 needs to be polished. The thermal buffer pipe 14 functions to thermally isolate the heater 13 from the secondary chamber temperature end heat exchanger 15, reduce heat leakage from the high-temperature end heat exchanger to the secondary chamber temperature end heat exchanger 15, maintain the temperature gradient and enable acoustic power to be transmitted outward from the high-temperature region of the engine.

[0050] The sub-chamber temperature end heat exchanger 15 is located below the thermal buffer tube 14, and the sub-chamber temperature end heat exchanger 15 adopts a structure similar to that of the main-chamber temperature end heat exchanger 11, and the sub-chamber temperature end heat exchanger 15 functions to reduce the temperature of the gas transmitting acoustic power, so as to facilitate acoustic power extraction and provide power for the magneto fluid generator. The feedback tube 17 functions to provide a path for the traveling wave component, and simultaneously functions as an acoustic sensing component. The acoustic capacitor 18 is a cavity with a large volume, and together with the feedback tube 17, realizes the traveling wave phase at one end of the main-chamber temperature end heat exchanger 11. The resonant tube 16 functions to provide an infinite space with continuously changing acoustic impedance.

[0051] In the embodiment of the utility model, the sub-chamber temperature end heat exchanger 15 is connected with the feedback tube 17 and the resonant tube 16 through a tee pipe; the feedback tube 17 is sequentially connected with each part of the pipe to form a path, and the acoustic capacitor 18 spans the left and right branches of the loop; the resonant tube 16 is connected with the liquid metal magneto fluid generator 2 through a tapered pipe.

[0052] The liquid metal magneto fluid generator 2 comprises at least two magneto fluid power generation channels 3, which can be understood as pipe bodies, and each two magneto fluid power generation channels 3 are symmetrically arranged, one end of each magneto fluid power generation channel 3 is connected with an engine assembly, the other end of each magneto fluid power generation channel 3 is connected with an air reservoir 19, and the inside of each magneto fluid power generation channel 3 is filled with liquid metal 4, the outer wall of the magneto fluid power generation channel is provided with a first magnet 211 (i.e. an upper magnet) and a second magnet 212 (i.e. a lower magnet), and the first magnet 211 and the second magnet 212 are both permanent magnets such as magnets, which are used for constructing a parallel magnetic field. At least one pair of electrodes is embedded on the insulating layer of the magneto fluid power generation channel 3, and the at least one pair of electrodes is located on the channel wall parallel to the magnetic field direction. In this way, the electrodes can effectively collect the current generated by the movement of the liquid metal in the magnetic field, and the power generation efficiency is improved.

[0053] That is, the liquid metal magneto fluid generator 2 comprises at least two magneto fluid power generation channels 3 made of insulating materials, and each two magneto fluid power generation channels 3 are symmetrically arranged, and present a regular and stable structure. One end of each magneto fluid power generation channel 3 is tightly connected with an engine assembly, and the engine assembly provides a power source for the whole system, so that the magneto fluid can flow smoothly in the magneto fluid power generation channel 3. The other end of each magneto fluid power generation channel 3 is connected with an air reservoir 19, and the air reservoir 19 plays an important role in adjusting the acoustic impedance and resonance condition in the system.

[0054] The inside of each magnetic fluid power channel 3 is filled with liquid metal 4 or liquid metal 4 containing nano-enhanced conductive materials, the liquid metal 4 including any one of mercury, gallium, gallium-indium-tin alloy and sodium-potassium liquid alloy; the nano-enhanced conductive materials including nano-copper, silver or carbon nanotubes. The liquid metal 4 has good conductivity and fluidity and can generate current under the action of a magnetic field. The parallel magnetic field provides conditions for the directional motion of the charged particles in the liquid metal 4, thereby realizing the conversion of electric energy.

[0055] Compared with the gallium-indium-tin liquid metal working medium commonly used in existing thermoacoustic magnetic fluid power generation devices, the liquid metal 4 of the embodiment of the utility model adopts low-density NaK alloy to replace the traditional gallium-indium-tin alloy, and uniformly distributes copper nanoparticles, carbon nanotubes and other conductive enhancement materials in the magnetic fluid of the NaK alloy, thereby significantly reducing the magnetic fluid density while maintaining high conductivity, thereby improving the flexibility, stability and power generation efficiency of system operation.

[0056] It can be understood that the low-vibration thermoacoustic magnetic fluid power generation device provided by the embodiment of the utility model comprises at least two magnetic fluid power channels 3, and each two magnetic fluid power channels 3 are symmetrically arranged, and have a regular and stable structure, so that the forces and torques generated by the liquid metal flow, magnetic field interaction and the like in the running process of the thermoacoustic magnetic fluid power generation device are mutually offset in the symmetric direction. For example, for two symmetric magnetic fluid power channels 3, if the liquid metal 4 generates a leftward thrust in one of the magnetic fluid power channels 3, due to the symmetry, a rightward thrust with the same size will be generated in the other magnetic fluid power channel 3, so that the forces are balanced as a whole, the mechanical vibration in the running process is effectively reduced, and ultra-low vibration operation is realized.

[0057] It should be noted that the embodiment of the utility model needs to ensure the consistency of the internal structure of each magnetic fluid power channel 3, including the length, inner diameter, curvature and cross-sectional area of the pipeline and the flow distribution of the liquid metal 4, the parameters of the magnetic field generator and the like.

[0058] Taking the magnetic field generator as an example, if the magnetic field intensity and direction distribution in the two symmetrically distributed magnetic fluid power channels 3 are inconsistent, the liquid metal will be subjected to uneven force, and then unbalanced force and torque will be generated. When the internal structure of the magnetic fluid power channel 3 is consistent, the motion state of the liquid metal 4 in each magnetic fluid power channel 3 is similar, and the electromagnetic force, fluid resistance and the like generated are also similar, which helps to maintain the balance of force and torque.

[0059] Therefore, the magnetic field around each MHD power generation channel 3 can be controlled to ensure the uniformity and stability of the magnetic field. The uniformity of the magnetic field can be achieved by using a high-precision magnetic field generator, such as a superconducting magnet or an optimized arrangement of conventional permanent magnets. Avoiding non-uniform magnetic fields ensures that the liquid metal 4 is subjected to uniform forces, resulting in balanced electromagnetic forces.

[0060] In addition, a feedback control system can be used to adjust the parameters of the magnetic field generator in real time when the external environment changes (such as temperature, electromagnetic field interference, etc.), ensuring the stability of the magnetic field and thus maintaining the stability of the forces acting on the liquid metal 4, which helps to maintain the balance of forces and torques.

[0061] In addition, an effective flow control system for the liquid metal 4 can be established to ensure the balanced flow of the liquid metal 4 in each MHD power generation channel 3. For example, a combination of flow sensors and regulating valves can be used to monitor and adjust the flow of the liquid metal 4 in real time. When the flow of the liquid metal 4 is balanced, the electromagnetic forces generated by the liquid metal 4 in the magnetic field are also relatively balanced, which is conducive to achieving the balance of forces and torques.

[0062] Continuing to refer to Figure 1 In some embodiments of the present application, the MHD power generation channel 3 includes a first pipe segment 31, a second pipe segment 32, and a third pipe segment 33 connected end-to-end in sequence, the second pipe segment 32 is horizontally arranged, and the first pipe segment 31 and the third pipe segment 33 are vertically connected at both ends of the second pipe segment 32 to form a structure similar to a "U" shape; the first pipe segments 31 of the two symmetrically arranged MHD power generation channels 3 coincide, the first pipe segment 31 is connected to the engine assembly, and the second pipe segment 32 and the third pipe segment 33 are symmetrically arranged with the axis of the first pipe segment 31 as the axis of symmetry.

[0063] The first magnet 211 and the second magnet 212 are arranged at positions corresponding to the second pipe segment 32, and at least one pair of electrodes is arranged at positions corresponding to the second pipe segment 32.

[0064] When the thermoacoustic MHD power generation device is in operation, the two symmetrically arranged MHD power generation channels 3 generate a leftward thrust in one of the MHD power generation channels 3 and an equal-sized rightward thrust in the other MHD power generation channel 3. The forces generated by the flow of the liquid metal 4 and the interaction of the magnetic field cancel each other out in the symmetric direction, thereby achieving overall force balance and effectively reducing mechanical vibration during operation, achieving ultra-low vibration operation.

[0065] The first pipe segment 31, the second pipe segment 32, and the third pipe segment 33 can be arranged in sections and connected by flanges or other connecting elements. Alternatively, the first pipe segment 31, the second pipe segment 32, and the third pipe segment 33 can be arranged as an integrally formed structure.

[0066] Continuing to refer to Figure 1In some embodiments of the utility model, the shape of the cross section of the second pipe section 32 is rectangular, and the shape of the cross section of the first pipe section 31 and the third pipe section 33 is circular.

[0067] The cross section of the second pipe section 32 is designed as a rectangle, which can provide a larger plane area, help the magnetic fluid to be more evenly distributed and flow in the pipe, and create good conditions for subsequent electromagnetic interaction.

[0068] Unlike the shape of the cross section of the second pipe section 32, the shape of the cross section of the first pipe section 31 and the third pipe section 33 is circular, which has a low flow resistance in fluid mechanics, and can ensure that the magnetic fluid maintains a relatively stable flow rate and flow when entering and leaving the second pipe section 32, so as to reduce energy loss.

[0069] Among them, the first pipe section 31 and the second pipe section 32, and the second pipe section 32 and the third pipe section 33 can be connected by variable cross section pipes.

[0070] Continue to refer to Figure 1 In some embodiments of the utility model, at least three pairs of electrode pairs are embedded on the insulation layer of the magnetic fluid power generation channel, and the two adjacent electrode pairs are arranged at intervals. Among the two adjacent electrode pairs, the negative plate of one electrode pair and the positive plate of the other electrode pair are connected in series by a wire, and the load is connected to the positive plate of the first electrode pair and the negative plate of the last electrode pair through the wire.

[0071] That is, the multi-layer flow channel electrically insulated and divided electric series structure used in the magnetic fluid power generation channel can be equivalent to a plurality of generators connected in series, which can improve the problems of large current, low voltage loss and inconvenience of use of the traditional thermoacoustic magnetic fluid power generation device.

[0072] Figure 3 It is the external structure schematic diagram of the liquid metal magnetic fluid generator in the low-vibration thermoacoustic magnetic fluid power generation device provided by the embodiments of the utility model. Figure 4 It is Figure 3 The cross-sectional view along line A-A.

[0073] Refer to Figure 3 And Figure 4 The inside of the magnetic fluid power generation channel is provided with an insulating plate, the insulating plate is located in the gap between the two adjacent electrode pairs, the insulating plate divides the magnetic fluid power generation channel 3 into at least three magnetic fluid sub-power generation channels, and each electrode pair is located on both sides of the corresponding magnetic fluid sub-power generation channel.

[0074] The embodiment takes three-layer rectangular MHD sub-power generation channels as an example for illustration. The three-layer rectangular MHD sub-power generation channels are sequentially arranged from top to bottom as the first MHD sub-power generation channel 221, the second MHD sub-power generation channel 222 and the third MHD sub-power generation channel 223. Each of the rectangular MHD sub-power generation channels is provided with a pair of flat plate electrodes, and the MHD sub-power generation channels are filled with liquid metal 4, and the total volume of the liquid metal 4 is less than the total volume of the two symmetrically arranged MHD power generation channels 3.

[0075] The three-layer rectangular MHD sub-power generation channels are equally spaced in the vertical direction (i.e. the height direction of the MHD power generation channel 3), and the magnetic field B passes through all the layers of the MHD sub-power generation channels in the vertical direction; each pair of electrodes is located on both sides of the corresponding layer of the rectangular MHD sub-power generation channel, and each pair of electrodes includes two flat plate electrodes. The flat plate electrodes are thin plates made of conductive materials, and the materials of the flat plate electrodes can be selected from gold, silver, platinum, aluminum, nickel, copper, titanium, chromium and other metal conductors, or the flat plate electrodes are made of an alloy formed by at least two of gold, silver, platinum, aluminum, nickel, copper, titanium or chromium.

[0076] The length of each flat plate electrode is equal to the length of each rectangular MHD sub-power generation channel, and the height of each flat plate electrode is equal to the height of each rectangular MHD sub-power generation channel. In each rectangular MHD sub-power generation channel, the two opposite surfaces of the two flat plate electrodes are in contact with the liquid metal, and the two opposite surfaces are connected to the external circuit.

[0077] In other words, the liquid metal MHD generator 2 includes a first magnet 211 (i.e. an upper magnet), a second magnet 212 (i.e. a lower magnet) and at least N layers of rectangular MHD sub-power generation channels. The first magnet 211 (i.e. the upper magnet), the at least N layers of rectangular MHD sub-power generation channels and the second magnet 212 (i.e. the lower magnet) are arranged along the height direction of the MHD power generation channel 3, wherein N is a positive integer ≥ 3. Each layer of the rectangular MHD sub-power generation channel is provided with a pair of flat plate electrodes.

[0078] The positive plate of the first plate electrode pair and the negative electrode of the Nth plate electrode pair are connected with the load respectively; the plate electrodes in the adjacent two rectangular MHD sub-power generation channels are connected in series through wires; the connection mode is that the negative electrode of the first plate electrode pair and the positive plate of the second plate electrode pair are connected through wires, the negative electrode of the second plate electrode pair and the positive plate of the third plate electrode pair are connected through wires, and so on, the negative electrode of the (N-1)th plate electrode pair and the positive plate of the Nth plate electrode pair are connected through wires.

[0079] When the rectangular MHD sub-power generation channel is provided with three layers, the corresponding electrode pairs are provided with three pairs; the positive plate 231-1 of the first electrode pair and the negative electrode 233-2 of the third electrode pair are connected with the load respectively; the negative electrode 231-2 of the first electrode pair and the positive plate 232-1 of the second electrode pair are connected through wires, and the negative electrode 232-2 of the second electrode pair and the positive plate 233-1 of the third electrode pair are connected through wires. The current conduction path is: the negative electrode 233-2 of the third electrode pair, liquid metal 4, the positive plate 233-1 of the third electrode pair, the negative electrode 232-2 of the second electrode pair, liquid metal 4, the positive plate 232-1 of the second electrode pair, the negative electrode 231-2 of the first electrode pair, liquid metal 4, the positive plate 231-1 of the first electrode pair, the load, the negative electrode 233-2 of the third electrode pair, forming an electric circuit.

[0080] The working process of the low-vibration thermoacoustic MHD power generation device is as follows:

[0081] The heater 13 of the thermoacoustic engine 1 absorbs the heat of the high-temperature heat source outside to form a high-temperature end, the main chamber temperature end heat exchanger 11 exchanges heat with the circulating cooling water outside to form a room temperature end, so that a temperature gradient is established in the regenerator 12.

[0082] When the temperature gradient of the regenerator 12 exceeds the critical temperature gradient, the thermoacoustic engine 1 starts to work, the gas is self-excited to produce reciprocating oscillation of pressure fluctuation, and the regenerator 12 continuously converts the heat energy of the high-temperature heat source outside into sound work (mechanical energy). The propagation direction of the sound work is along the positive direction of the temperature gradient, and is first transmitted to the thermal buffer tube 14 and the secondary room temperature end heat exchanger 15. After the sound work passes through the room temperature end heat exchanger 15, it is transmitted in two directions: part of the sound work passes through the resonant tube 16 and reaches the electrically insulated pipe of the two magnetohydrodynamic power generation channels 3 arranged symmetrically, pushes the liquid metal 4 in the electrically insulated pipe to reciprocate in the horizontal direction in the rectangular magnetohydrodynamic sub-power generation channel, cuts the magnetic induction lines and generates electric power output. The remaining sound work is transmitted to the main room temperature end heat exchanger 11 along the feedback tube 17 and the acoustic capacitor 18, is amplified again through the regenerator 12, is circulated and reciprocated, and continuously converts the heat source heat into electric energy output.

[0083] The feedback tube 17 and the acoustic capacitor 18 can adjust the sound field in the loop where the thermoacoustic engine 1 is located, so that the traveling wave component in the regenerator 12 absolutely dominates, and the starting temperature and viscous loss of the thermoacoustic engine 1 are reduced.

[0084] Figure 5 It is the working principle schematic diagram of the low-vibration thermoacoustic magnetohydrodynamic power generation device provided by the embodiment of the utility model.

[0085] Referring to Figure 5 When the liquid metal 4 reciprocates along the length direction of the rectangular magnetohydrodynamic sub-power generation channel, the liquid metal 4 cuts the magnetic induction lines to generate an induced electromotive force. Under the uniform magnetic field intensity, the induced electromotive forces generated in the adjacent two rectangular magnetohydrodynamic sub-power generation channels are the same in direction and size; the current passes through the electrode pairs in the rectangular magnetohydrodynamic sub-power generation channel and is output, according to the right-hand rule, the induced current generated in the direction along the width direction of the rectangular magnetohydrodynamic power generation channel is perpendicular to the magnetic force direction, and the positive and negative charges are gathered on the positive plate and the negative plate of each electrode pair, respectively.

[0086] Compared with the existing thermoacoustic magnetohydrodynamic power generation device, the volume of the thermoacoustic engine 1 in the thermoacoustic magnetohydrodynamic power generation device is small, the energy density is high, the vibration starting and operation temperature are low, and the utilization of the medium and low temperature heat source is suitable. Meanwhile, due to the symmetric double "U" type magnetohydrodynamic power generation channel design, the inertial force of the fluid working medium is symmetrically distributed along the movement direction of the two "U" type magnetohydrodynamic power generation channels 3, the inertial force of the fluid working medium in one "U" type magnetohydrodynamic power generation channel 3 is offset by the reverse inertial force generated by the fluid working medium in another "U" type magnetohydrodynamic power generation channel 3, the thermoacoustic magnetohydrodynamic power generation device can realize good force balance and torque balance during operation, the system vibration is low, the output characteristics are improved, and the demand of the power equipment can be better met. And the thermoacoustic magnetohydrodynamic power generation device provided by the embodiment of the utility model has the advantages of compact structure, no mechanical moving parts, high reliability, low vibration, high potential efficiency and the like, and has wide application prospect in the fields of solar energy utilization, biomass energy utilization, waste heat utilization, extreme environment power generation and the like.

[0087] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the utility model, and not to limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.

Claims

1. A low-vibration thermoacoustic magnetohydrodynamic power generation device, characterized in that, include: A thermoacoustic engine includes an engine assembly and an air reservoir, wherein the engine assembly is used to extract acoustic power and form a traveling wave phase, and the air reservoir is used to adjust acoustic impedance and resonance conditions. A liquid metal magnetohydrodynamic (MHD) generator includes at least two MHD power generation channels, each pair of MHD power generation channels being symmetrically arranged. One end of each MHD power generation channel is connected to the engine assembly, and the other end of each MHD power generation channel is connected to the gas reservoir. The interior of each MHD power generation channel is filled with liquid metal or liquid metal containing nano-reinforced conductive materials. The outer wall of each MHD power generation channel is provided with a first magnet and a second magnet, which are used to construct a parallel magnetic field. At least one pair of electrodes is embedded in the insulating layer of each MHD power generation channel, and the at least one pair of electrodes is located on the channel wall parallel to the direction of the magnetic field.

2. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to claim 1, characterized in that, The magnetohydrodynamic power generation channel includes a first pipe segment, a second pipe segment, and a third pipe segment connected end to end in sequence. The second pipe segment is horizontally arranged, and the first pipe segment and the third pipe segment are vertically connected to both ends of the second pipe segment. The first pipe segments of the two symmetrically arranged magnetohydrodynamic power generation channels overlap, the first pipe segment is connected to the engine assembly, and the second pipe segment and the third pipe segment are symmetrically arranged with the axis of the first pipe segment as the axis of symmetry; The first magnet and the second magnet are located at positions corresponding to the second tube segment, and at least one pair of the electrodes are located at positions corresponding to the second tube segment.

3. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to claim 2, characterized in that, The second pipe segment has a rectangular cross-section, while the first and third pipe segments both have circular cross-sections.

4. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to claim 1, characterized in that, At least three pairs of electrodes are embedded in the insulating layer of the magnetohydrodynamic power generation channel, with adjacent pairs of electrodes spaced apart; and in the two adjacent pairs of electrodes, the negative plate of one pair of electrodes and the positive plate of the other pair of electrodes are connected in series by a wire, and the load is connected to the positive plate of the first pair of electrodes and the negative plate of the last pair of electrodes by a wire.

5. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to claim 4, characterized in that, Three pairs of electrodes are embedded in the insulating layer of the magnetohydrodynamic power generation channel, with adjacent pairs of electrodes spaced apart. The negative plate of the first electrode pair is connected to the positive plate of the second electrode pair by a wire, and the negative plate of the second electrode pair is connected to the positive plate of the third electrode pair by a wire; the load is connected to the positive plate of the first electrode pair and the negative plate of the third electrode pair by a wire to form an electrical circuit.

6. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to claim 4, characterized in that, An insulating plate is provided inside the magnetohydrodynamic power generation channel. The insulating plate is located in the gap between two adjacent pairs of electrodes. The insulating plate divides the magnetohydrodynamic power generation channel into at least three magnetohydrodynamic sub-channels. Each pair of electrodes is located on both sides of the corresponding magnetohydrodynamic sub-channel.

7. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to any one of claims 1 to 6, characterized in that, The engine assembly includes a main room temperature heat exchanger, a regenerator, a heater, a secondary room temperature heat exchanger, a resonant tube, a feedback tube, and an acoustic capacitor connected in sequence. The main room temperature heat exchanger and the secondary room temperature heat exchanger exchange heat with the external low temperature heat source to form a room temperature end, and the heater exchanges heat with the external high temperature heat source to form a high temperature end. The regenerator is used to generate acoustic power. One end of each of the magnetohydrodynamic power generation channels is connected to the resonant tube.

8. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to claim 7, characterized in that, The engine assembly also includes a heat buffer tube, one end of which is connected to the heater and the other end of which is connected to the sub-room temperature end heat exchanger. The cross-sectional areas of the main room temperature heat exchanger, the regenerator, and the heater are all greater than the cross-sectional area of ​​any one of the heat buffer tube, the secondary room temperature heat exchanger, and the resonant tube.

9. The low-vibration thermoacoustic magnetohydrodynamic power generation device according to any one of claims 1 to 6, characterized in that, The liquid metal includes any one of mercury, gallium, gallium-indium-tin alloy, and sodium-potassium liquid alloy; the nano-reinforced conductive material includes copper nanotubes, silver nanotubes, or carbon nanotubes.

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