Based on supercritical CO 2 Combined power generation system and method of LMMHD and Brayton cycle for transport

Abstract

The present invention discloses a combined power generation system and method based on supercritical CO2 transportation for LMMHD and Brayton cycle. The liquid metal working medium in the liquid metal magnetohydrodynamic power generation cycle relies on the transportation and carriage of the supercritical CO2 working medium in the supercritical CO2 Brayton cycle to achieve high-speed flow, thereby improving the liquid metal magnetohydrodynamic power generation efficiency. The supercritical CO2 working medium in the supercritical CO2 Brayton cycle is in direct contact with the high-temperature liquid metal working medium in the liquid metal magnetohydrodynamic power generation cycle, absorbs the heat of the liquid metal, and then further conducts a supercritical CO2 partial cooling Brayton cycle for power generation, improving the energy utilization efficiency of the system. In addition, the present invention can, through reasonable system layout and adjustment of corresponding valves, start the corresponding magnetohydrodynamic power generation form according to the initial flow rate of the liquid metal. When the magnetohydrodynamic power generation fails, it can also quickly switch to the traditional space nuclear power working mode for power generation, improving the anti-risk ability of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of energy recycling, mainly to a method based on supercritical CO 2 Liquid metal magnetic fluid transport (LMMHD) and Brayton cycle combined power generation system and operation method. Background Art

[0002] Compared with ordinary power systems, space nuclear power systems have the advantages of high energy density, wide power range, good maneuverability, compact system, strong environmental adaptability, etc. They can operate stably in harsh space environments and are ideal power sources for high-power space missions such as deep space exploration and space station construction. Liquid metal magnetofluid nuclear power systems use magnetic fields as a medium to directly realize the conversion of working fluid kinetic energy and output electrical energy. The advantages of high power generation efficiency, no moving parts, and closed working fluid circulation make them particularly suitable for the aerospace field. At the same time, compared with high-temperature plasma magnetofluid power generation, liquid metal magnetofluid power generation does not require high heat source temperature and has a wider range of applications.

[0003] In the principle of magnetohydrodynamic power generation, the current density J is positively correlated with the speed u, and the viscosity of liquid metal is relatively large, so it is often difficult for single-phase liquid metal to reach a high flow rate. Therefore, in the liquid metal magnetohydrodynamic power generation system, it is usually necessary to use other fluid working fluids to boost the two-phase flow method to achieve high-speed flow of liquid metal. The commonly used boosting working fluids are liquid low boiling point and conventional gas working fluids. Among them, the transport efficiency is not ideal due to the large difference in density between liquid metal and conventional gas; and the liquid low boiling point working fluid will undergo phase change and absorb a large amount of heat during transportation, which will reduce the temperature of the liquid metal during actual application, resulting in a decrease in thermoelectric conversion efficiency. When the temperature and pressure are both higher than the critical point, the substance will be in a supercritical state. The density of supercritical fluid is very close to that of liquid, and the viscosity is only slightly higher than that of gas. Compared with liquid, the diffusion coefficient of supercritical fluid is about 100 times that of liquid, and the surface tension of the fluid is about zero, showing good solubility. Considering the high density and strong diffusion properties of supercritical fluid, it has great potential in liquid metal transportation.

[0004] The present invention is based on the magnetic fluid nuclear power system, using supercritical CO 2 Substituting low-boiling-point working fluids to realize liquid metal magnetic fluid transport and power generation, due to supercritical CO 2 Direct contact heat exchange with high temperature magnetic fluid, CO with high thermodynamic properties after transportation 2 The Brayton cycle can continue to generate electricity, reducing the heat absorbed by the phase change due to the use of low-boiling-point working fluids, making full use of the energy generated by the nuclear energy of the system, and improving the overall energy utilization efficiency of the system. Secondly, through reasonable arrangement, the present invention can operate in three working modes, providing the system with risk resistance. Summary of the invention

[0005] Purpose of the invention: In view of the shortcomings of the above-mentioned background technology, the present invention provides a supercritical CO 2 Liquid metal magnetic fluid transport and Brayton cycle combined power generation system and operation method. Ingeniously combines liquid metal magnetic fluid power generation, supercritical fluid liquid metal transport and supercritical CO 2 The Brayton cycle power generation organically combines the three to increase energy utilization, improve the power generation efficiency of the entire system, and to a certain extent improve the risk resistance of the nuclear power system.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A supercritical fluid-carried multi-stage magnetohydrodynamic power generation device includes a shell (a tungsten-copper alloy with a nuclear shielding function may be used), in which concentric and parallel supercritical fluid channels and liquid metal channels are arranged, and the supercritical fluid channel wraps the liquid metal channel; the liquid metal channel is provided with a plurality of magnetohydrodynamic power generation sections parallel to the flow direction, and the liquid metal flow cross section is equal to and parallel to the magnetohydrodynamic power generation section cross section. The size of the entire device can be adjusted according to the corresponding magnetohydrodynamic power generation and system matching.

[0008] The supercritical fluid consignment multi-stage magnetohydrodynamic power generation device includes a supercritical fluid consignment section and a magnetohydrodynamic power generation section that are spaced apart. In the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device, the supercritical fluid wraps the liquid metal and flows into the device in a concentric and parallel manner. The device is provided with a number of magnetohydrodynamic power generation sections that are parallel to the flow direction. When the entire system is in a spatial condition and moves at a uniform speed, in the supercritical consignment section, the high-speed supercritical fluid will drag the liquid metal to flow in parallel, reducing the friction between the pure liquid metal flow and the pipeline and increasing the liquid metal flow rate on the contact surface. In the magnetohydrodynamic power generation section, since the liquid metal flow cross-section is equal to and parallel to the magnetohydrodynamic power generation section cross-section, the liquid metal enters the magnetohydrodynamic power generation section to generate electricity, while the supercritical fluid flows around the magnetohydrodynamic power generation section. The above process is repeated in the device until the liquid metal flow rate drops to a specific value and then flows out.

[0009] The present invention also provides a liquid metal magnetofluid power generation system, comprising a liquid metal magnetofluid circulation loop and a supercritical fluid circulation loop, characterized in that it also comprises the above-mentioned supercritical fluid consignment multi-stage magnetofluid power generation device (5), wherein the liquid metal channel is arranged in the liquid metal magnetofluid circulation loop, and the supercritical fluid channel is arranged in the supercritical fluid circulation loop.

[0010] Furthermore, it also includes a supercritical fluid-liquid metal two-phase mixer (6), a two-phase flow magnetohydrodynamic power generation device (7), and a gas-liquid separator (8); the supercritical fluid channel outlet and the liquid metal channel outlet of the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) are respectively connected to the supercritical fluid inlet and the liquid metal inlet of the supercritical fluid-liquid metal two-phase mixer (6), the outlet of the supercritical fluid-liquid metal two-phase mixer (6) is connected to the inlet of the two-phase flow magnetohydrodynamic power generation device (7), and the outlet of the two-phase flow magnetohydrodynamic power generation device (7) is connected to the inlet of the gas-liquid separator (8); the liquid metal outlet of the gas-liquid separator (8) is connected to the liquid metal magnetohydrodynamic circulation loop, and the supercritical fluid outlet of the gas-liquid separator (8) is connected to the supercritical fluid circulation loop.

[0011] The present invention also provides a method based on supercritical CO 2 The combined power generation system of liquid metal magnetic fluid and Brayton cycle for transporting is characterized by comprising a liquid metal magnetic fluid cycle and a supercritical CO 2 Brayton power generation has two circulation loops; the liquid metal working fluid in the liquid metal magnetohydrodynamic power generation circulation loop relies on supercritical CO 2 Supercritical CO in a Brayton cycle 2 The flow is achieved by transporting the working fluid (realized by a supercritical fluid-liquid metal two-phase mixer (6)) and transporting it (realized by a supercritical fluid transport multi-stage magnetohydrodynamic power generation device (5)); supercritical CO 2 Supercritical CO in a Brayton cycle 2 The working fluid is in direct contact with the liquid metal working fluid in the liquid metal magnetohydrodynamic power generation circulation loop, and after absorbing the heat of the liquid metal, it is further partially cooled to generate electricity through the Brayton cycle.

[0012] Furthermore, the devices in the liquid metal magnetofluid power generation circulation loop include a nuclear reaction device (1), a pressure buffer device (2), a heat exchanger (3), an electromagnetic pump (4), a supercritical fluid consignment multi-stage magnetofluid power generation device (5), a supercritical fluid-liquid metal two-phase mixer (6), a two-phase flow magnetofluid power generation device (7), and a gas-liquid separator (8); the valves in the liquid metal magnetofluid power generation circulation loop include an isolation valve 1 (k1), an isolation valve 2 (k2), an isolation valve 3 (k3), an isolation valve 4 (k4), an isolation valve 5 (k5), and an isolation valve 10 (k10), and each device and valve is connected by a pipeline with a radiation shielding function.

[0013] Furthermore, supercritical CO 2The devices in the Brayton cycle power generation cycle include a heat exchanger (3), a supercritical fluid transport multi-stage magnetohydrodynamic power generation device (5), a supercritical fluid-liquid metal two-phase mixer (6), a two-phase flow magnetohydrodynamic power generation device (7), a gas-liquid separator (8), a main turbine (9), a generator (10), a high-temperature regenerator (11), a low-temperature regenerator (12), a precooler (13), a precompressor (14), a cooler (15), a main compressor (16), a recompressor (17), and an auxiliary turbine (18); the supercritical CO 2 The valves in the Brayton cycle power generation cycle include isolation valve 6 (k6), isolation valve 7 (k7), isolation valve 8 (k8), isolation valve 9 (k9), three-way valve 11 (k11), three-way valve 12 (k12), and three-way valve 13 (k13). Pipes with radiation shielding function are used to connect the devices and valves.

[0014] Through reasonable system layout and adjustment of corresponding valves, 1) supercritical CO 2 The transported liquid metal magnetic fluid is combined with the Brayton cycle to generate electricity, 2) the traditional nuclear power system generates electricity, and two different working modes generate electricity. When the combined power generation system fails, the present invention can quickly change the working mode by adjusting the valve, start the traditional nuclear power generation mode for emergency power generation, and improve the risk resistance of the entire system.

[0015] Supercritical CO 2 The working method of the combined power generation mode of the transported liquid metal magnetic fluid and the Brayton cycle is characterized by comprising the following steps:

[0016] Step 1: Close isolation valve 1 (k1), isolation valve 2 (k2), isolation valve 4 (k4), and isolation valve 8 (k8); open isolation valve 3 (k3), isolation valve 5 (k5), isolation valve 6 (k6), isolation valve 7 (k7), isolation valve 9 (k9), isolation valve (k10), three-way valve 11 (k11), three-way valve 12 (k12), and three-way valve 13 (k13).

[0017] Step 2: The liquid metal absorbs the heat generated by the nuclear reaction in the nuclear reaction device (1) and its temperature rises. The high-temperature liquid metal enters the pressure buffer device (2) through branch a to maintain a stable flow, and then flows through branch b, isolation valve 3 (k3), branch g, isolation valve 5 (k5), and branch h in sequence to enter the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5). The high-temperature liquid metal is heated in the high-speed supercritical CO 2 The multi-stage magnetohydrodynamic power generation and heat exchange are carried out under the drag of the multi-stage magnetohydrodynamic power generation device. After the speed and temperature of the liquid metal are reduced, it enters the supercritical fluid-liquid metal two-phase mixer (6) through the branch i and the branch j and the high-speed supercritical CO 2The two-phase mixed fluid after power generation in the two-phase flow magnetohydrodynamic power generation device (7) enters the gas-liquid separator (8) through the branch l to separate the liquid metal from the supercritical CO 2 The liquid metal flows through branch m and isolation valve 10 (k9) into heat exchanger (3) and supercritical CO 2 After releasing the excess heat through heat exchange, the liquid metal is pumped through branch e and electromagnetic pump (4) and flows back to the nuclear reaction device (1) from branch f to complete the liquid metal loop circulation of the supercritical CO2 transported liquid metal magnetic fluid and Brayton cycle combined power generation mode.

[0018] Step 3: High-speed supercritical CO 2 From branch A, through isolation valve 6 (k6), branch B and isolation valve 7 (k7), branch C, it enters the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) to consign liquid metal for power generation and absorbs part of the heat, and then enters the supercritical fluid-liquid metal two-phase mixer (6) through branch D and isolation valve 9 (k9) to mix with the low-speed liquid metal, pushing the liquid metal from branch k into the two-phase flow magnetohydrodynamic power generation device (7) for power generation. During the mixing and power generation process, supercritical CO 2 The temperature of the supercritical CO2 with high thermodynamic energy increases as it continues to absorb heat. After separation through branch l, it enters the gas-liquid separator (8). 2 The supercritical CO2 flows from branch F into the main turbine (9) to perform work, driving the generator (10) to generate electricity. The temperature and pressure of the supercritical CO2 are reduced after the work is completed. 2 The exhaust gas enters the high-temperature regenerator (11) through branch G and the low-temperature regenerator (12) through branch H to release the residual heat, and then enters the precooler (13) through branch I to reduce the temperature, and then enters the pre-compressor (14) through branch J for pre-compression. After the pre-compression is completed, most of the CO is discharged through the three-way valve 11 (k11) of branch R. 2 It enters the main cooler (15) from branch L to cool down, enters the main compressor through branch M to increase the pressure after compression, enters the low-temperature regenerator (12) through branch N to absorb low-temperature waste heat, and at the same time, another part of the supercritical CO2 passes through the three-way valve 11 (k11) from branch R to 2 The liquid metal is directly recompressed in the recompressor (17) through the branch line P, and a part of it enters the heat exchanger (3) from the branch line S through the three-way valve 12 (k12) through the branch line Q to provide cooling for the liquid metal, and the other part passes through the branch line R and the three-way valve 13 (k13) to absorb the low-temperature waste heat of the supercritical CO in the low-temperature regenerator (12). 2The supercritical fluid is transported by the multi-stage magnetohydrodynamic power generation device (5) and the supercritical fluid-liquid metal two-phase mixer (6) to provide transport and transportation for the liquid metal, thus completing the supercritical CO 2 Supercritical CO transported by liquid metal magnetic fluid and Brayton cycle combined power generation mode 2 Partially cooled Brayton circuit cycle.

[0019] Step 4: A portion of the supercritical CO flows from branch Q through three-way valve 12 (k12) 2 , enters the heat exchanger (3) from branch S, cools the liquid metal that is about to enter the nuclear reactor (1) and absorbs the residual heat in the liquid metal after the magnetic fluid generates electricity. The supercritical CO 2 After the temperature is increased, it enters the auxiliary turbine (18) through the branch V to drive the generator (10) to generate electricity. After the work is completed, it passes through the branch G and releases the supercritical CO 2 The air flows converge and enter the low-temperature regenerator (12) together to release low-temperature waste heat, thereby completing heat recovery of the liquid metal.

[0020] Step 5: If the liquid metal flowing out of the nuclear reactor (1) has a flow rate too low to enter the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) to achieve consignment power generation, adjust the supercritical CO 2 The first step of the working method of the combined power generation mode of the transported liquid metal magnetic fluid and the Brayton cycle is: close the isolation valve 1 (k1), isolation valve 2 (k2), isolation valve 4 (k4), close the isolation valve 5 (k5), isolation valve 6 (k6), isolation valve 7 (k7), isolation valve 8 (k8), isolation valve 9 (k9); open the isolation valve 3 (k3), isolation valve (k10), three-way valve 11 (k11), three-way valve 12 (k12), three-way valve 13 (k13). The liquid metal from branch g passes through the isolation valve 4 (k4) and the supercritical CO from branch A. 2 The liquid directly enters the supercritical fluid-liquid metal two-phase mixer (6) through the isolation valve 8 (k8). The above steps are performed simultaneously when the system is running.

[0021] The working method of the conventional nuclear power system power generation mode is characterized by comprising the following steps:

[0022] Step 1: Close isolation valve 3 (k3) and isolation valve 10 (k10), three-way valve 11 closes P branch, three-way valve 12 (k12) closes Q branch, and three-way valve closes U branch; open isolation valve 1 and isolation valve 2.

[0023] Step 2: The liquid metal absorbs the heat released by the nuclear reaction from the nuclear reactor (1), passes through branch a, is buffered in the pressure buffer device (2), and then passes through branch b, isolation valve 1 (k1), branch c, isolation valve 2 (k2), and branch d to enter the heat exchanger (3), where it transfers the heat to the low-temperature supercritical CO 2 After the temperature of the liquid metal drops, it enters the electromagnetic pump (4) through branch e to pump the liquid metal back to the nuclear reactor (1) from branch f, completing the liquid metal loop circulation of the traditional nuclear power system power generation mode.

[0024] Step 3: Supercritical CO 2 It enters the heat exchanger (3) from branch S to absorb the heat of the liquid metal. After the temperature rises, it enters the auxiliary turbine (18) through branch V to work and drive the generator (10) to generate electricity. After the work is completed, it enters the low-temperature regenerator (12) through branch W to release the residual heat. It enters the pre-cooler (13) through branch I for pre-cooling. After pre-cooling, it enters the pre-compressor (14) through branch J for pre-compression. It enters the cooler (15) through branch R, three-way valve 11 (k11) and branch L for cooling. It enters the main compressor (16) through branch M for compression. After compression, it enters the low-temperature regenerator (12) from branch N to absorb heat recovery. Then, supercritical CO 2 The product flows back to the heat exchanger (3) through branch O, three-way valve 13 (k13), branch R, three-way valve 12 (k12), and branch S in turn, completing the supercritical CO2 generation mode of the traditional nuclear power system. 2 Brayton cycle. The above steps are performed simultaneously when the system is running.

[0025] Beneficial effects:

[0026] 1. The present invention ingeniously combines liquid metal magnetic fluid power generation, supercritical fluid liquid metal transportation and supercritical CO 2 The organic combination of the three Brayton cycle power generation not only effectively improves the efficiency of liquid metal magnetohydrodynamic power generation, but also reduces the heat absorbed by phase change due to the use of low-boiling point working fluids. It can fully utilize the energy generated by the system's nuclear energy and improve the overall energy utilization efficiency of the system.

[0027] 2. Compared with the traditional nuclear power system, the present invention adds liquid metal magnetic fluid power generation, which does not require mechanical conversion links and can directly convert the thermal energy of liquid metal into electrical energy output with high conversion efficiency. At the same time, it adopts multi-stage power generation and multi-mode parallel supercritical transport magnetic fluid power generation. When the magnetic fluid speed is high, supercritical carbon dioxide is used for multi-stage single-phase magnetic fluid power generation. After the speed is reduced, it enters supercritical CO 2 A two-phase mixing transporter is used to generate two-phase magnetohydrodynamic power. When the magnetohydrodynamic speed is low, supercritical carbon dioxide two-phase flow mixing transport is directly used to generate power.

[0028] 3. In the use of supercritical CO 2 During the consignment and transportation of liquid metal, due to supercritical CO 2 Direct contact with high-temperature liquid metal for sufficient heat exchange, supercritical CO 2 The temperature rises and has higher thermodynamic energy, so supercritical CO can be used 2 The Brayton cycle further generates electricity, where supercritical CO 2 The Brayton cycle adopts the partially cooled Brayton cycle (PC) method, which can obtain the highest power generation energy and better applicability of the heat storage system.

[0029] 4. The present invention can realize power generation in two different working modes through reasonable system layout and related valve layout, namely 1) traditional nuclear power system power generation system; 2) supercritical CO 2 The liquid metal magnetic fluid transported is combined with the Brayton cycle power generation system. Therefore, when the combined power generation system fails, the present invention can quickly change the working mode by adjusting the valve, start the traditional nuclear power generation mode for emergency power generation, and improve the risk resistance of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention provides a method based on supercritical CO 2 Schematic diagram of the structure of the combined power generation system of liquid metal magnetic fluid and Brayton cycle;

[0031] Among them, the main devices include: 1-nuclear reaction device; 2-pressure buffer device; 3-heat exchanger; 4-electromagnetic pump; 5-supercritical fluid consignment multi-stage magnetohydrodynamic power generation device; 6-supercritical fluid-liquid metal two-phase mixer; 7-two-phase flow magnetohydrodynamic power generation device; 8-gas-liquid separator; 9-main turbine; 10-generator; 11-high temperature regenerator; 12-low temperature regenerator; 13-precooler; 14-precompressor; 15-cooler; 16-main compressor; 17-recompressor; 18-auxiliary turbine. The main valves include: k1-isolation valve 1; k2-isolation valve 2; k3-isolation valve 3; k4-isolation valve 4; k5-isolation valve 5; k6-isolation valve 6; k7-isolation valve 7; k8-isolation valve 8; k9-isolation valve 9; k10-isolation valve 10; k11-three-way valve 11; k12-three-way valve 12; k13-three-way valve 13.

[0032] Figure 2 This is a cross-sectional view of the supercritical fluid consignment section and the magnetofluid power generation section of the supercritical fluid consignment multi-stage magnetofluid power generation device of the present invention:

[0033] The supercritical fluid transport section corresponds to the section α-α, and the magnetohydrodynamic power generation section corresponds to the section β-β. 5(1) is the flow channel housing, 5(2) is the built-in magnetohydrodynamic power generation device, 5(3) is the permanent magnet, and 5(4) is the support of the built-in magnetohydrodynamic power generation device, which is used to connect the flow channel housing 5(1) and the built-in magnetohydrodynamic power generation device 5(2).

[0034] Figure 3 In the present invention, in supercritical CO 2 Supercritical CO transported by liquid metal magnetic fluid and Brayton cycle combined power generation mode 2 TS (temperature-entropy change) diagram:

[0035] The letters in the figure are Figure 1 The letters in the correspondence represent the supercritical CO in this branch. 2 The temperature and entropy of the

[0036] Figure 4 It is a simulation data diagram of the supercritical fluid consignment section of the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device 5 under space conditions (no gravity), wherein (a) is the supercritical fluid consignment section model, and (b) is the simulation data. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings.

[0038] A supercritical CO 2 Liquid metal magnetic fluid transport and Brayton cycle combined power generation system (such as Figure 1 ), including liquid metal magnetohydrodynamic power generation cycle and supercritical CO 2 Brayton cycle power generation circulation loop. The main devices in the liquid metal magnetofluid power generation circulation loop include a nuclear reactor 1, a pressure buffer device 2, a heat exchanger 3, an electromagnetic pump 4, a supercritical fluid consignment multi-stage magnetofluid power generation device 5, a supercritical fluid-liquid metal two-phase mixer 6, a two-phase flow magnetofluid power generation device 7, and a gas-liquid separator 8; the main valves in the liquid metal magnetofluid power generation circulation loop include isolation valves k1, k2, k3, k4, k5, and k10, and each device and valve is connected by a pipe with radiation shielding function. Supercritical CO 2 The main devices in the Brayton cycle power generation cycle loop include a heat exchanger 3, a supercritical fluid transport multi-stage magnetohydrodynamic power generation device 5, a supercritical fluid-liquid metal two-phase mixer 6, a two-phase flow magnetohydrodynamic power generation device 7, a gas-liquid separator 8, a main turbine 9, a generator 10, a high-temperature regenerator 11, a low-temperature regenerator 12, a precooler 13, a precompressor 14, a cooler 15, a main compressor 16, a recompressor 17, and an auxiliary turbine 18; the supercritical CO 2The main valves in the Brayton cycle power generation cycle include isolation valve k6, isolation valve k7, isolation valve k8, isolation valve k9, three-way valve k11, three-way valve k12, and three-way valve k13. Pipes with radiation shielding function are used to connect each device and valve.

[0039] A supercritical CO 2 The combined power generation mode of liquid metal magnetic fluid and Brayton cycle (such as Figure 1 ) includes the following steps:

[0040] Step 1: Close isolation valve k1, isolation valve k2, isolation valve k4, and isolation valve k8; open isolation valve k3, isolation valve k5, isolation valve k6, isolation valve k7, isolation valve k9, isolation valve k10, three-way valve k11, three-way valve k12, and three-way valve k13.

[0041] Step 2: The liquid metal absorbs the heat generated by the nuclear reaction in the nuclear reactor 1 and its temperature rises. The high-temperature liquid metal enters the pressure buffer device 2 through branch a to maintain stable flow, and then flows through branch b, isolation valve k3, branch g, isolation valve k5, branch h in turn to enter the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device 5. The high-temperature liquid metal is heated in the high-speed supercritical CO 2 The multi-stage magnetohydrodynamic power generation and heat exchange are carried out under the drag of the multi-stage magnetohydrodynamic power generation device 5. After the speed and temperature of the liquid metal are reduced, it enters the supercritical fluid-liquid metal two-phase mixer 6 through the branch i and branch j and the high-speed supercritical CO 2 The two-phase mixed fluid after power generation in the two-phase flow magnetohydrodynamic power generation device 7 enters the gas-liquid separator 8 through the branch l to separate the liquid metal from the supercritical CO 2 The liquid metal flows through branch m and isolation valve k10 into heat exchanger 3 and supercritical CO 2 After heat exchange to release excess heat, it is pumped through branch e and electromagnetic pump 4 and flows back to nuclear reactor 1 from branch f to complete supercritical CO 2 The liquid metal loop circulation of the liquid metal magnetic fluid transport and Brayton cycle combined power generation mode.

[0042] Step 3: High-speed supercritical CO 2From branch A, through isolation valve k6, branch B and isolation valve k7, branch C, it enters the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device 5 to consign liquid metal for power generation and absorbs part of the heat, and then enters the supercritical fluid-liquid metal two-phase mixer 6 through branch D and isolation valve k9 to mix with the low-speed liquid metal, pushing the liquid metal from branch k to enter the two-phase flow magnetohydrodynamic power generation device 7 to generate electricity. During the mixing and power generation process, the supercritical CO2 continues to absorb heat and the temperature rises. It has higher thermodynamic energy. After separation, it enters the gas-liquid separator 8 through branch l. The supercritical CO2 with higher thermodynamic energy 2 The supercritical CO2 flows from branch F into the main turbine 9 to perform work, driving the generator 10 to generate electricity. 2 The exhaust gas enters the high-temperature regenerator 11 through branch G and the low-temperature regenerator 12 through branch H to release the residual heat, and then enters the precooler 13 through branch I to reduce the temperature, and then enters the precompressor 14 through branch J for precompression. After the precompression is completed, most of the CO 2 It enters the main cooler 15 from branch L to cool down, enters the main compressor 16 through branch M to increase the pressure after compression, and enters the low-temperature regenerator 12 through branch N to absorb low-temperature waste heat. At the same time, another part of the supercritical CO2 passes through the three-way valve k11 from branch R. 2 The liquid metal is directly recompressed in the recompressor 17 through the branch P, and a part of it enters the heat exchanger 3 from the branch S through the three-way valve k12 through the branch Q to provide cooling for the liquid metal, and the other part passes through the branch R and the three-way valve k13 to the supercritical CO2 that absorbs the low-temperature waste heat in the low-temperature regenerator 12. 2 The supercritical fluid is transported by the multi-stage magnetohydrodynamic power generation device 5, and the supercritical fluid-liquid metal two-phase mixer 6 provides transport and transportation for the liquid metal, completing the supercritical CO 2 Supercritical CO transported by liquid metal magnetic fluid and Brayton cycle combined power generation mode 2 Partially cooled Brayton circuit cycle.

[0043] Step 4: A portion of the supercritical CO flows from branch Q through three-way valve k12 2 , enters heat exchanger 3 from branch S, cools the liquid metal that is about to enter nuclear reactor 1 and absorbs the residual heat in the liquid metal after magnetic fluid power generation. 2 After the temperature is raised, it enters the auxiliary turbine 18 through the branch V to drive the generator 10 to generate electricity. After the work is completed, it passes through the branch G and the supercritical CO2 that releases the waste heat from the high-temperature regenerator 11. 2 The air flows converge and enter the low-temperature regenerator 12 together to release low-temperature waste heat, thereby completing heat recovery of the liquid metal.

[0044] Step 5: If the liquid metal flow rate out of the nuclear reactor 1 is too low to enter the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device 5 to achieve consignment power generation, adjust the supercritical CO 2 The first step of the working method of the combined power generation mode of the transported liquid metal magnetic fluid and the Brayton cycle is: close the isolation valve k1, isolation valve k2, isolation valve k4, close the isolation valve k5, isolation valve k6, isolation valve k7, isolation valve k8, isolation valve k9; open the isolation valve k3, isolation valve k10, three-way valve k11), three-way valve k12, and three-way valve k13. The liquid metal from branch g passes through the isolation valve k4 and the supercritical CO from branch A. 2 It directly enters the supercritical fluid-liquid metal two-phase mixer 6 through the isolation valve k8. The above steps are carried out simultaneously when the system is running. 2 The temperature and entropy when flowing through each branch are as follows Figure 3 shown.

[0045] An emergency conventional nuclear power system power generation mode (such as Figure 1 ) includes the following steps:

[0046] Step 1: Close isolation valve k3 and isolation valve k10, three-way valve 11 closes P branch, three-way valve k12 closes Q branch, and three-way valve closes U branch; open isolation valve 1 and isolation valve 2.

[0047] Step 2: The liquid metal absorbs the heat released by the nuclear reaction from the nuclear reactor 1, passes through branch a, is buffered in the pressure buffer device 2, and then passes through branch b, isolation valve k1, branch c, isolation valve k2, and branch d to enter the heat exchanger 3, transferring the heat to the low-temperature supercritical CO 2 After the temperature of the liquid metal drops, it enters the electromagnetic pump 4 through the branch e and pumps the liquid metal back to the nuclear reactor 1 from the branch f, completing the liquid metal loop circulation of the traditional nuclear power system power generation mode.

[0048] Step 3: Supercritical CO 2 It enters the heat exchanger 3 from branch S to absorb the heat of the liquid metal. After the temperature rises, it enters the auxiliary turbine 18 through branch V to drive the generator 10 to generate electricity. After the work is completed, it enters the low-temperature regenerator 12 through branch W to release the waste heat, and then enters the pre-cooler 13 through branch I for pre-cooling. After pre-cooling, it enters the pre-compressor 14 through branch J for pre-compression, enters the cooler 15 through branch R, three-way valve k11, and branch L for cooling, and enters the main compressor 16 through branch M for compression. After compression, it enters the low-temperature regenerator 12 from branch N to absorb heat recovery, and then the supercritical CO 2 The gas then flows back to the heat exchanger 3 through branch O, three-way valve k13, branch R, three-way valve k12, and branch S, completing the supercritical CO2 generation mode of the traditional nuclear power system. 2 Brayton cycle.

[0049] The above steps are performed simultaneously when the system is running.

[0050] Supercritical fluid consignment multi-stage magnetohydrodynamic power generation device 5 (such as Figure 1 and Figure 2 The working method of the cross-section diagram is as follows:

[0051] The supercritical fluid wraps the liquid metal and flows into the device in a concentric and parallel manner. The device is equipped with several magnetic fluid power generation sections parallel to the flow direction (such as Figure 2 Section β-β). When the entire system is in space conditions and moves at a uniform speed, in the supercritical fluid consignment section (such as Figure 2 Cross-section α-α), the high-speed supercritical fluid will drag the liquid metal to flow in parallel, reduce the friction between the pure liquid metal flow and the pipeline and increase the liquid metal flow rate on the contact surface. In the magnetofluid power generation section, since the liquid metal flow cross-section is equal to and parallel to the magnetofluid power generation section cross-section, the liquid metal enters the magnetofluid power generation section to generate electricity, and the supercritical fluid flows around the magnetofluid power generation section. The above process is repeated in the device until the liquid metal flow rate drops to a specific value and then flows out. The specific value is the flow rate at which the liquid metal can only maintain flow but cannot further generate electricity. This value varies depending on the pipe diameter and flow rate, depending on the specific working conditions. The liquid metal then enters the supercritical fluid-liquid metal two-phase mixer 6, so that the supercritical fluid and liquid metal are mixed (completely blended), thereby increasing the flow rate of the liquid metal magnetofluid again.

[0052] The simulation data of the supercritical fluid consignment section of the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device 5 under space conditions (no gravity) are as follows Figure 4 .

[0053] From the simulation data, we can see that under space conditions, when liquid metal and supercritical carbon dioxide (S-CO 2 ) In the supercritical fluid consignment section Figure 4 When the two flow in parallel as shown in (a), they will not mix during the flow, and S-CO 2 Can effectively transport liquid metal.

[0054] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A liquid metal magnetic fluid power generation system, comprising a liquid metal magnetic fluid circulation loop and a supercritical fluid circulation loop, It is characterized in that It also includes a supercritical fluid-carrying multi-stage magnetohydrodynamic power generation device (5), the supercritical fluid-carrying multi-stage magnetohydrodynamic power generation device (5) comprising a shell, in which concentric and parallel supercritical fluid channels and liquid metal channels are arranged, the supercritical fluid channel wraps the liquid metal channel; the liquid metal channel is provided with a plurality of magnetohydrodynamic power generation sections parallel to the flow direction, the liquid metal flow cross section is equal to and parallel to the magnetohydrodynamic power generation section cross section, the liquid metal channel is arranged in the liquid metal magnetohydrodynamic circulation loop, and the supercritical fluid channel is arranged in the supercritical fluid circulation loop; The liquid metal magnetohydrodynamic power generation system further comprises a supercritical fluid-liquid metal two-phase mixer (6), a two-phase flow magnetohydrodynamic power generation device (7), and a gas-liquid separator (8); the supercritical fluid channel outlet and the liquid metal channel outlet of the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) are respectively connected to the supercritical fluid inlet and the liquid metal inlet of the supercritical fluid-liquid metal two-phase mixer (6); the outlet of the supercritical fluid-liquid metal two-phase mixer (6) is connected to the inlet of the two-phase flow magnetohydrodynamic power generation device (7); the outlet of the two-phase flow magnetohydrodynamic power generation device (7) is connected to the inlet of the gas-liquid separator (8); the liquid metal outlet of the gas-liquid separator (8) is connected to the liquid metal magnetohydrodynamic circulation loop, and the supercritical fluid outlet of the gas-liquid separator (8) is connected to the supercritical fluid circulation loop.

2. A liquid metal magnetohydrodynamic power generation system according to claim 1, It is characterized in that Including liquid metal magnetohydrodynamic circulation and supercritical CO 2 Brayton power generation has two circulation loops; the liquid metal working fluid in the liquid metal magnetohydrodynamic power generation circulation loop relies on supercritical CO 2 Supercritical CO in a Brayton cycle 2 The transport and consignment of working fluid realizes flow; supercritical CO 2 Supercritical CO in a Brayton cycle 2 The working fluid is in direct contact with the liquid metal working fluid in the liquid metal magnetohydrodynamic power generation circulation loop, and after absorbing the heat of the liquid metal, it is further partially cooled to generate electricity through the Brayton cycle.

3. A liquid metal magnetohydrodynamic power generation system according to claim 2, It is characterized in that The devices in the liquid metal magnetofluid power generation circulation loop include a nuclear reaction device (1), a pressure buffer device (2), a heat exchanger (3), an electromagnetic pump (4), a supercritical fluid consignment multi-stage magnetofluid power generation device (5), a supercritical fluid-liquid metal two-phase mixer (6), a two-phase flow magnetofluid power generation device (7), and a gas-liquid separator (8); the valves in the liquid metal magnetofluid power generation circulation loop include an isolation valve 1 (k1), an isolation valve 2 (k2), an isolation valve 3 (k3), an isolation valve 4 (k4), an isolation valve 5 (k5), and an isolation valve 10 (k10), and the devices and valves are connected by pipelines with radiation shielding function; The connection relationship between the components is: The outlet of the nuclear reaction device (1) is connected to the inlet of the pressure buffer device (2) via a branch a; The outlet of the pressure buffer device (2) is divided into two branches through the branch b, one branch is connected to the inlet of the isolation valve 2 (k2) through the isolation valve 1 (k1) and the branch c, and the other branch is connected to the inlet of the isolation valve 4 (k4) through the isolation valve 3 (k3) and the branch g; The outlet of the isolation valve 2 (k2) is connected to the liquid metal inlet of the heat exchanger (3) through the branch d; The outlet of the isolation valve 4 (k4) is connected to the inlet of the liquid metal channel of the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) through a branch line h; The liquid metal channel outlet of the supercritical fluid-carrying multi-stage magnetohydrodynamic power generation device (5) is connected to the liquid metal inlet of the supercritical fluid-liquid metal two-phase mixer (6) through a branch i and a branch j; The outlet of the supercritical fluid-liquid metal two-phase mixer (6) is connected to the inlet of the two-phase flow magnetohydrodynamic power generation device (7) via a branch k; The outlet of the two-phase flow magnetohydrodynamic power generation device (7) is connected to the inlet of the gas-liquid separator (8) via a branch line 1; The liquid metal outlet of the gas-liquid separator (8) is connected to the liquid metal inlet of the heat exchanger (3) through a branch line m and an isolation valve 10 (k10); The liquid metal outlet of the heat exchanger (3) is connected to the inlet of the electromagnetic pump (4) via a branch e; The outlet of the electromagnetic pump (4) is connected to the inlet of the nuclear reaction device (1) via a branch line f; Each device and valve is connected by a pipe with radiation shielding function.

4. A liquid metal magnetohydrodynamic power generation system according to claim 3, It is characterized in that Supercritical CO 2 The devices in the Brayton cycle power generation cycle include a heat exchanger (3), a supercritical fluid transport multi-stage magnetohydrodynamic power generation device (5), a supercritical fluid-liquid metal two-phase mixer (6), a two-phase flow magnetohydrodynamic power generation device (7), a gas-liquid separator (8), a main turbine (9), a generator (10), a high-temperature regenerator (11), a low-temperature regenerator (12), a precooler (13), a precompressor (14), a cooler (15), a main compressor (16), a recompressor (17), and an auxiliary turbine (18); the supercritical CO 2 The valves in the Brayton cycle power generation cycle include isolation valve 6 (k6), isolation valve 7 (k7), isolation valve 8 (k8), isolation valve 9 (k9), three-way valve 11 (k11), three-way valve 12 (k12), and three-way valve 13 (k13), and each device and valve are connected by a pipe with radiation shielding function; The connection relationship between the components is: The inlet of the supercritical fluid channel of the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) is connected to the outlet of the isolation valve 7 (k7) through a branch C, the inlet of the isolation valve 7 (k7) is connected to the outlet of the isolation valve 6 (k6) through a branch B, and the inlet of the isolation valve 6 (k6) is connected to the outlet of the high-temperature regenerator (11) through a branch A; The outlet of the supercritical fluid channel of the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) is connected to the inlet of the isolation valve 9 (k9) through a branch D, and the outlet of the isolation valve 9 (k9) is connected to the supercritical fluid inlet of the supercritical fluid-liquid metal two-phase mixer (6) through a branch E; The supercritical fluid outlet of the gas-liquid separator (8) is connected to the inlet of the main turbine (9) through a branch line F; The outlet of the main turbine (9) is connected to the inlet of the high-temperature regenerator (11) via a branch G; The outlet of the high-temperature regenerator (11) is connected to the inlet of the low-temperature regenerator (12) via a branch H; The outlet of the low-temperature regenerator (12) is connected to the inlet of the precooler (13) via a branch I; The outlet of the precooler (13) is connected to the inlet of the precompressor (14) via a branch J; The outlet of the pre-compressor (14) is divided into two branches through the branch R, one of which is connected to the inlet of the cooler (15) through the three-way valve 11 (k11) and the branch L, and the other is connected to the inlet of the re-compressor (17) through the three-way valve 11 (k11) and the branch P; The outlet of the cooler (15) is connected to the inlet of the main compressor (16) via a branch M; The outlet of the main compressor (16) is connected to the inlet of the low-temperature regenerator (12) via a branch line N; The outlet of the re-compressor (17) is divided into two branches through the branch Q, one branch is connected to the supercritical fluid inlet of the heat exchanger (3) through the three-way valve 12 (k12) and the branch S, and the other branch is connected to the inlet of the three-way valve 13 (k13) through the three-way valve 12 (k12) and the branch R; The supercritical fluid outlet of the heat exchanger (3) is connected to the inlet of the auxiliary turbine (18) via a branch line V; The outlet of the auxiliary turbine (18) is connected to the inlet of the low-temperature regenerator (12) via a branch line W; The outlet of the three-way valve 13 (k13) is connected to the inlet of the high-temperature regenerator (11) through a branch U; Each device and valve is connected by a pipe with radiation shielding function.

5. A method for generating electricity based on the power generation system according to claim 4, It is characterized in that The method includes the following steps which are performed simultaneously: Step 1: Close isolation valve 1 (k1), isolation valve 2 (k2), isolation valve 4 (k4), isolation valve 8 (k8); open isolation valve 3 (k3), isolation valve 5 (k5), isolation valve 6 (k6), isolation valve 7 (k7), isolation valve 9 (k9), isolation valve 10 (k10), three-way valve 11 (k11), three-way valve 12 (k12), three-way valve 13 (k13); Step 2: Liquid metal absorption The high-temperature liquid metal generated by the nuclear reaction in the nuclear reaction device (1) enters the pressure buffer device (2) through branch a and maintains a stable flow, then flows through branch b, isolation valve 3 (k3), branch g, isolation valve 5 (k5), and branch h in sequence to enter the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) for multi-stage magnetohydrodynamic power generation and heat exchange. After the speed and temperature of the liquid metal are reduced, it enters the supercritical fluid-liquid metal two-phase mixer (6) through branches i and j and mixes with the high-speed supercritical CO2 discharged from the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5). 2 The two-phase mixed fluid after power generation in the two-phase flow magnetohydrodynamic power generation device (7) enters the gas-liquid separator (8) through the branch l to separate the liquid metal from the supercritical CO 2 The liquid metal flows through branch m and isolation valve 10 (k10) into heat exchanger (3) and supercritical CO 2 After the excess heat is released through heat exchange, it is pumped through branch e and electromagnetic pump (4) and flows back to the nuclear reactor (1) from branch f to complete the supercritical CO 2 The liquid metal loop circulation of the liquid metal magnetic fluid transport and Brayton cycle combined power generation mode.

6. The method for generating electricity according to claim 5, It is characterized in that It also includes the following steps that are performed simultaneously: Step 3: High-speed supercritical CO 2 From branch A, through isolation valve 6 (k6), branch B and isolation valve 7 (k7), branch C, it enters the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) to consign liquid metal for power generation and absorb part of the heat, and then enters the supercritical fluid-liquid metal two-phase mixer (6) through branch D and isolation valve 9 (k9) to mix with the low-speed liquid metal, pushing the liquid metal from branch k into the two-phase flow magnetohydrodynamic power generation device (7) to generate electricity. During the mixing and power generation process, supercritical CO 2 It continues to absorb heat and its temperature rises. After separation, it enters the gas-liquid separator (8) through branch l, and the supercritical CO 2 The supercritical CO2 flows from branch F into the main turbine (9) to perform work, driving the generator (10) to generate electricity. The temperature and pressure of the supercritical CO2 are reduced after the work is completed. 2 The exhaust gas enters the high-temperature regenerator (11) through branch G and the low-temperature regenerator (12) through branch H to release the residual heat. It then enters the precooler (13) through branch I to reduce the temperature and enters the pre-compressor (14) through branch J for pre-compression. After the pre-compression is completed, most of the CO is discharged through the three-way valve 11 (k11) of branch R. 2 It enters the main cooler (15) from branch L to cool down, enters the main compressor through branch M to increase the pressure after compression, and enters the low-temperature regenerator (12) through branch N to absorb low-temperature waste heat. At the same time, another part of the supercritical CO2 passes through the three-way valve 11 (k11) from branch R. 2 The liquid metal is directly recompressed in the recompressor (17) through the branch line P, and a part of it passes through the three-way valve 12 (k12) through the branch line Q and enters the heat exchanger (3) from the branch line S to provide cooling for the liquid metal. The other part passes through the branch line R and the three-way valve 13 (k13) and is combined with the supercritical CO2 that absorbs the low-temperature waste heat in the low-temperature regenerator (12). 2 The supercritical fluid is transported by the multi-stage magnetohydrodynamic power generation device (5) and the supercritical fluid-liquid metal two-phase mixer (6) to provide transport and transportation for the liquid metal, thus completing the supercritical CO 2 Supercritical CO transported by liquid metal magnetic fluid and Brayton cycle combined power generation mode 2 Partially cooled Brayton loop cycle; Step 4: A portion of the supercritical CO flows from branch Q through three-way valve 12 (k12) 2 , enters the heat exchanger (3) from branch S, cools the liquid metal that is about to enter the nuclear reactor (1) and absorbs the residual heat in the liquid metal after the magnetohydrodynamic power generation. The supercritical CO 2 After the temperature is increased, it enters the auxiliary turbine (18) through the branch V to drive the generator (10) to generate electricity. After the work is completed, it passes through the branch G and releases the supercritical CO2 from the high-temperature regenerator (11). 2 The air flows converge and enter the low-temperature regenerator (12) together to release low-temperature waste heat, thereby completing heat recovery of the liquid metal.

7. A method for generating electricity based on the power generation system according to claim 5, It is characterized in that If the flow rate of the liquid metal flowing out of the nuclear reactor (1) is too low to enter the supercritical fluid consignment multi-stage magnetohydrodynamic power generation device (5) to realize consignment power generation, close the isolation valve 1 (k1), isolation valve 2 (k2), isolation valve 4 (k4), close the isolation valve 5 (k5), isolation valve 6 (k6), isolation valve 7 (k7), isolation valve 8 (k8), isolation valve 9 (k9); open the isolation valve 3 (k3), isolation valve 10 (k10), three-way valve 11 (k11), three-way valve 12 (k12), three-way valve 13 (k13); so that the liquid metal from branch g passes through the isolation valve 4 (k4) and the supercritical CO from branch A. 2 It directly enters the supercritical fluid-liquid metal two-phase mixer (6) through the isolation valve 8 (k8).

8. A method for generating electricity based on the power generation system according to claim 5, It is characterized in that The method includes the following steps which are performed simultaneously: Step 1: Close isolation valve 3 (k3) and isolation valve 10 (k10), three-way valve 11 closes P branch, three-way valve 12 (k12) closes Q branch, and three-way valve closes U branch; open isolation valve 1 and isolation valve 2; Step 2: The liquid metal absorbs the heat released by the nuclear reaction from the nuclear reactor (1), passes through branch a, is buffered in the pressure buffer device (2), and then flows through branch b, isolation valve 1 (k1), branch c, isolation valve 2 (k2), and branch d into the heat exchanger (3), where it transfers the heat to the low-temperature supercritical CO 2 After the temperature of the liquid metal drops, it enters the electromagnetic pump (4) through the branch e to pump the liquid metal back to the nuclear reactor (1) from the branch f, thus completing the liquid metal loop circulation of the traditional nuclear power system power generation mode; Step 3: Supercritical CO 2 It enters the heat exchanger (3) from branch S to absorb the heat of the liquid metal. After the temperature rises, it enters the auxiliary turbine (18) through branch V to perform work and drive the generator (10) to generate electricity. After the work is completed, it enters the low-temperature regenerator (12) through branch W to release the residual heat. It enters the pre-cooler (13) through branch I for pre-cooling. After pre-cooling, it enters the pre-compressor (14) through branch J for pre-compression. It enters the cooler (15) through branch R, three-way valve 11 (k11), and branch L for cooling. It enters the main compressor (16) through branch M for compression. After compression, it enters the low-temperature regenerator (12) from branch N to absorb heat recovery. Then, supercritical CO 2 The gas then flows back to the heat exchanger (3) through branch O, three-way valve 13 (k13), branch R, three-way valve 12 (k12), and branch S, completing the supercritical CO2 generation mode of the traditional nuclear power system. 2 Brayton cycle.

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