Thermal simulation method and device for two-phase liquid helium forced flow cooling superconducting magnet and electronic equipment

Abstract

The invention provides a two-phase liquid helium forced flow cooling superconducting magnet thermal simulation method and device and electronic equipment, and relates to the technical field of thermal simulation. The superconducting magnet comprises superconducting cables and a cooling structure, the cooling structure is arranged between the two superconducting cables in parallel, two-phase liquid helium flows in a solid pipeline of the cooling structure, and the method comprises the steps that a one-dimensional fluid model of the two-phase liquid helium is established, the wall surface temperature of the solid pipeline is obtained based on the one-dimensional fluid model, and the wall surface temperature is distributed in a one-dimensional mode in the axial direction of the pipeline; establishing a three-dimensional solid model of the superconducting magnet, and obtaining the summation heat flux density of the solid pipeline based on the three-dimensional solid model; the wall surface temperature of the solid pipeline is correspondingly transmitted to the three-dimensional solid model, and the summation heat flux density of the solid pipeline is correspondingly transmitted to the one-dimensional fluid model; and in one time step, the one-dimensional fluid model and the three-dimensional solid model are mutually coupled and iterated until a convergence condition is met, and the step of mutually coupling and iterating the one-dimensional fluid model and the three-dimensional solid model is repeated in the next time step.

Description

Technical Field

[0001] The present invention relates to the field of thermal simulation technology, and in particular to a thermal simulation method, device and electronic equipment for two-phase liquid helium forced-flow cooling of a superconducting magnet. Background Art

[0002] When accelerating particles to a high energy state, a particle accelerator can use a superconducting magnet to provide a rapidly changing strong magnetic field. The superconducting magnet may include a metal structure and a superconducting coil made of a superconducting cable wound around the metal structure. Passing current through the superconducting coil can cause the superconducting magnet to generate a strong magnetic field, thereby providing a rapidly changing strong magnetic field.

[0003] Superconducting magnets generally use the special properties of superconducting cables at low temperatures to generate strong magnetic fields. The magnetic field provided by superconducting magnets will generate AC losses on coils and metal structures during rapid changes, thereby generating heat. In order to prevent the heat generated by AC losses from changing the temperature environment of the superconducting cables, a cooling pipe is generally arranged between the two superconducting cables. The superconducting cables are cooled by boiling two-phase liquid helium flowing in the cooling pipe, and the heat generated by AC losses is removed by boiling latent heat.

[0004] At present, in the design process of fluid heat dissipation, a three-dimensional CFD simulation is generally performed on the cooled structure through a three-dimensional CFD boiling model of the fluid to perform thermal simulation analysis, and the temperature distribution of the cooled structure and the state parameters of the fluid in the cooling pipe are obtained for temperature control. However, compared with normal temperature fluids, the state parameters of two-phase liquid helium involve the boiling phase change of the two-phase liquid helium in the cooling pipe, and the working temperature of boiling two-phase liquid helium is extremely low (4.2K). It is impossible to refer to the thermal simulation analysis method of normal temperature fluids through the three-dimensional CFD boiling model of the fluid to perform thermal simulation analysis on the two-phase liquid helium forced flow cooling superconducting magnet. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a thermal simulation method, device and electronic equipment for two-phase liquid helium forced flow cooling of a superconducting magnet.

[0006] The present invention provides a thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet, the superconducting magnet comprises a superconducting cable and a cooling structure, the cooling structure is arranged in parallel between two superconducting cables, the two-phase liquid helium flows in a solid pipe of the cooling structure, and the superconducting magnet is subjected to two-phase liquid helium forced flow cooling, the method comprising: A one-dimensional fluid model of the two-phase liquid helium is established, and the wall temperature of the solid pipeline is obtained based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the pipeline axis; a three-dimensional solid model of the superconducting magnet is established, and the summed heat flux density of the solid pipeline is obtained based on the three-dimensional solid model; The wall temperature of the solid pipeline is correspondingly transferred to the three-dimensional solid model, and the summed heat flux density of the solid pipeline is correspondingly transferred to the one-dimensional fluid model; In one time step, the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other until a convergence condition is reached, and the step of coupling the one-dimensional fluid model and the three-dimensional solid model with each other is repeated in the next time step.

[0007] According to a thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet provided by the present invention, the wall temperature of the solid pipeline is obtained based on the one-dimensional fluid model, specifically comprising: dividing a one-dimensional fluid grid along the pipeline axis, and obtaining the wall temperature of the corresponding solid pipeline based on the one-dimensional fluid grid; Acquiring the summed heat flux density of the solid pipeline based on the three-dimensional solid model specifically includes: dividing the three-dimensional solid pipeline in the three-dimensional solid model into corresponding pipeline areas according to the one-dimensional fluid grid, and acquiring the summed heat flux density of each pipeline area; The method of transferring the wall temperature of the solid pipe to the three-dimensional solid model and transferring the summed heat flux density of the solid pipe to the one-dimensional fluid model specifically includes: transferring the wall temperature of the solid pipe corresponding to each one-dimensional fluid grid to the pipe area and transferring the summed heat flux density of each pipe area to the one-dimensional fluid grid.

[0008] According to a thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet provided by the present invention, obtaining the summed heat flux density of each pipeline area specifically includes: A three-dimensional finite element mesh is divided in each of the pipeline regions, and the summed heat flux density of each of the pipeline regions is obtained based on the three-dimensional finite element mesh.

[0009] According to a thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet provided by the present invention, a one-dimensional fluid model of the two-phase liquid helium is established, and the wall temperature of the solid pipeline is obtained based on the one-dimensional fluid model, which specifically includes: Establish the mass conservation equation, momentum conservation equation and energy conservation equation for one-dimensional two-phase liquid helium flow heat transfer; Selecting a supplementary equation based on two-phase liquid helium, and performing discretization processing on the supplementary equation together with the mass conservation equation, momentum conservation equation, and energy conservation equation to obtain the central fluid temperature of the one-dimensional fluid model, wherein the central fluid temperature is distributed one-dimensionally along the axial direction of the pipeline; The wall temperature of the solid pipe is obtained based on the core fluid temperature and the summed heat flux density of the solid pipe.

[0010] According to a thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet provided by the present invention, a supplementary equation is selected based on the two-phase liquid helium, and the supplementary equation is combined with the mass conservation equation, the momentum conservation equation, and the energy conservation equation for discretization, specifically including: A homogeneous flow model, a cavitation fraction model and a boiling heat transfer model are selected based on two-phase liquid helium, and the homogeneous flow model, the cavitation fraction model and the boiling heat transfer model are combined with the mass conservation equation, the momentum conservation equation and the energy conservation equation for discretization.

[0011] According to a thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet provided by the present invention, the summed heat flux density of the solid pipeline is obtained based on the three-dimensional solid model, specifically comprising: The AC loss heat power distribution of the three-dimensional solid model is obtained based on the three-dimensional magnetic field distribution during the excitation of the superconducting magnet, and the summed heat flux density of the solid pipeline is obtained according to the AC loss heat power distribution and the wall temperature of the solid pipeline.

[0012] According to a thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet provided by the present invention, the AC loss heat power distribution of the three-dimensional solid model is obtained based on the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet, specifically comprising: Based on the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet, an AC loss parameter is obtained, and based on the AC loss parameter, a three-dimensional AC loss thermal power distribution of the superconducting magnet is obtained.

[0013] According to a thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet provided by the present invention, the summed heat flux density of the solid pipeline is obtained according to the AC loss heat power distribution and the wall temperature of the solid pipeline, specifically comprising: Obtaining heat load according to the AC loss heat power distribution; Performing meshing processing on the three-dimensional solid model to obtain a three-dimensional finite element mesh and a wall temperature of the three-dimensional finite element mesh; A thermal simulation analysis is performed on the three-dimensional solid model based on the thermal load and the wall temperature of the three-dimensional finite element mesh to obtain the summed heat flux density of the solid pipeline.

[0014] The present invention also provides a thermal simulation device for two-phase liquid helium forced flow cooling superconducting magnets, wherein the superconducting magnets include superconducting cables and a cooling structure, wherein the cooling structure is arranged in parallel between two superconducting cables, and the two-phase liquid helium flows in a solid pipe of the cooling structure, and the superconducting magnets are cooled by two-phase liquid helium forced flow. The device includes: A parameter acquisition module is used to establish a one-dimensional fluid model of the two-phase liquid helium, and acquire the wall temperature of the solid pipeline based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the axial direction of the pipeline; establish a three-dimensional solid model of the superconducting magnet, and acquire the summed heat flux density of the solid pipeline based on the three-dimensional solid model; A parameter transfer module, used to transfer the wall temperature of the solid pipeline to the three-dimensional solid model, and to transfer the summed heat flux density of the solid pipeline to the one-dimensional fluid model; The coupling iteration module is used for coupling and iterating the one-dimensional fluid model and the three-dimensional solid model with each other within a time step until a convergence condition is reached, and then repeating the coupling and iterating steps of the one-dimensional fluid model and the three-dimensional solid model with each other in the next time step.

[0015] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, a thermal simulation method for two-phase liquid helium forced flow cooling a superconducting magnet as described in any one of the above methods is implemented.

[0016] The present invention provides a two-phase liquid helium forced flow cooling superconducting magnet thermal simulation method, device and electronic equipment, which obtain the wall temperature of the solid pipeline through a one-dimensional fluid model of the two-phase liquid helium and transmit it to the three-dimensional solid model of the superconducting magnet, obtain the summed heat flux density of the solid pipeline through the three-dimensional solid model of the superconducting magnet, and transmit it to the one-dimensional fluid model of the two-phase liquid helium, and perform thermal simulation analysis on the cooling structure of the two-phase liquid helium forced flow cooling superconducting magnet through mutual coupling and iteration of the one-dimensional fluid model and the three-dimensional solid model. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of the superconducting magnet provided by the present invention.

[0019] Figure 2 It is a structural schematic diagram of the cooling structure of the superconducting magnet provided by the present invention.

[0020] Figure 3 It is a structural schematic diagram of a solid pipeline of a cooling structure of a superconducting magnet provided by the present invention.

[0021] Figure 4This is one of the flow diagrams of the thermal simulation method for two-phase liquid helium forced flow cooling of superconducting magnets provided by the present invention.

[0022] Figure 5 It is a schematic diagram of the coupling of a one-dimensional fluid model and a three-dimensional solid model in the thermal simulation method of two-phase liquid helium forced flow cooling superconducting magnet provided by the present invention.

[0023] Figure 6 This is the second flow diagram of the thermal simulation method of two-phase liquid helium forced flow cooling superconducting magnet provided by the present invention.

[0024] Figure 7 It is a structural schematic diagram of a thermal simulation device for cooling a superconducting magnet using two-phase liquid helium forced flow provided by the present invention.

[0025] Figure 8 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] As mentioned above, compared with room-temperature fluids, the state parameters of two-phase liquid helium involve the boiling phase change of the two-phase liquid helium in the cooling pipe, and the working temperature of the boiling two-phase liquid helium is extremely low. It is impossible to refer to the thermal simulation analysis method of room-temperature fluids to perform thermal simulation analysis on the superconducting magnet cooling structure with two-phase liquid helium forced flow cooling through the three-dimensional CFD boiling model of the fluid.

[0028] In order to obtain the simulation of two-phase liquid helium forced flow cooling superconducting magnets, the flow of two-phase liquid helium along the pipeline can be equivalent to one-dimensional flow, and a one-dimensional fluid model of two-phase liquid helium is established to perform one-dimensional simulation on the two-phase liquid helium forced flow cooling superconducting magnets. However, the temperature distribution of superconducting magnets is three-dimensional, so the one-dimensional simulation of two-phase liquid helium cannot obtain the temperature distribution of superconducting magnets. When the structure of the superconducting magnet body is simple, it can meet the simulation analysis requirements of superconducting magnets, but when the structure of the superconducting magnet body is complex, it cannot meet the simulation analysis requirements of superconducting magnets.

[0029] In order to solve the simulation analysis problem of two-phase liquid helium forced flow cooling superconducting magnets and provide support for the design of cooling structure of superconducting magnets with two-phase liquid helium forced flow cooling, the present invention provides a thermal simulation method, device and electronic equipment for two-phase liquid helium forced flow cooling superconducting magnets. Figure 1-Figure 8 Give a description.

[0030] Superconducting magnets can also be called superconducting magnets, superconducting conductors, etc. Superconducting magnets use the resistance-free characteristics of superconducting materials at low temperatures to generate strong magnetic fields. Therefore, during the operation of superconducting magnets, it is necessary to maintain the required low-temperature environment to maintain the superconducting state of superconducting materials. Generally, the low-temperature environment required by superconducting materials is much lower than room temperature, so an effective cooling system needs to be designed to cool the superconducting magnets and maintain the low-temperature environment.

[0031] like Figure 1 As shown, in this embodiment, the superconducting magnet includes a superconducting cable 10 and a cooling structure 20, wherein the cooling structure 20 is arranged in parallel between two superconducting cables 10, and the two-phase liquid helium flows in a solid pipe 21 of the cooling structure 20, so as to perform two-phase liquid helium forced flow cooling on the superconducting magnet.

[0032] Combination Figure 2 and Figure 3 Exemplarily, the cooling structure 20 may include a solid pipe 21 and a cooling iron sheet 22 , the solid pipe 21 is sandwiched in parallel between the superconducting cables 10 , and the cooling iron sheet 22 is placed between the solid pipe 21 and the superconducting cable 10 located on one side of the solid pipe 21 .

[0033] The heat transfer efficiency of the cooling iron sheet 22 is higher than that of the air. Thus, by providing the cooling iron sheet 22, the heat in the superconducting cable 10 can be transferred to the solid pipe 21 more quickly. The solid pipe 21 is cooled by the two-phase liquid helium flowing therein, thereby cooling the superconducting cable 10 and increasing the cooling effect of the cooling structure 20 on the superconducting magnet.

[0034] Two-phase liquid helium refers to helium in two different phases. Two-phase liquid helium can be a state where the liquid phase and gas phase of helium coexist. Two-phase liquid helium can also be called two-phase helium.

[0035] As liquid helium flows in the solid pipe, it absorbs the heat generated by the superconducting magnet, causing part of the liquid helium to boil and turn into gas. The boiling point of liquid helium is around 4.2K, so liquid helium absorbs heat when boiling and maintains a relatively constant temperature. The temperature of the helium will not increase significantly due to the absorption of heat, thereby effectively conducting heat away from the superconducting magnet.

[0036] Exemplarily, liquid helium can be stored in a liquid helium storage tank, and a liquid helium pump can be provided between the liquid helium storage tank and the solid pipeline. The liquid helium pump is used to extract liquid helium from the liquid helium storage tank and push it into the solid pipeline to perform two-phase liquid helium forced flow cooling on the superconducting magnet.

[0037] Figure 4 FIG. 1 is one of the flow diagrams of the thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet provided by the present invention. Figure 4 As shown, the method includes: Step 110: Establish a one-dimensional fluid model of the two-phase liquid helium, and obtain the wall temperature of the solid pipeline based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the axial direction of the pipeline; establish a three-dimensional solid model of the superconducting magnet, and obtain the summed heat flux density of the solid pipeline based on the three-dimensional solid model.

[0038] The one-dimensional fluid model is used to describe the flow and heat transfer behavior of two-phase liquid helium in a solid pipe, but only the axial direction of the pipe is considered. The wall temperature is the temperature of the wall in contact with the two-phase liquid helium in the solid pipe.

[0039] The 3D solid model is used to describe the solid structure of the superconducting magnet and perform thermal simulation analysis of the superconducting magnet. The heat flux density is used to describe the direction of heat flow between the superconducting magnet and the solid pipe, as well as the speed at which heat passes through the surface of the solid pipe.

[0040] Step 120: The wall temperature of the solid pipeline is correspondingly transferred to the three-dimensional solid model, and the summed heat flux density of the solid pipeline is correspondingly transferred to the one-dimensional fluid model.

[0041] For example, after obtaining the wall temperature of the solid pipeline based on the one-dimensional fluid model, the data transmission interface of the three-dimensional solid model can be called, and the wall temperature of the solid pipeline can be correspondingly transferred to the three-dimensional solid model through the data transmission interface. After obtaining the summed heat flux density of the solid pipeline based on the three-dimensional solid model, the data transmission interface of the one-dimensional fluid model can be called, and the heat flux density of the solid pipeline can be correspondingly transferred to the three-dimensional solid model through the data transmission interface.

[0042] Step 130: Within a time step, the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other until a convergence condition is reached, and then the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other in the next time step.

[0043] When simulating the continuous dynamic process of heat generation, transfer and distribution in the system, the time axis can be discretized to divide the time into a series of small, finite time intervals, where each time interval is a time step.

[0044] Exemplarily, within a time step, the one-dimensional fluid model receives the summed heat flux density of the solid pipeline sent by the three-dimensional solid model, uses the summed heat flux density of the solid pipeline as a boundary condition to obtain the wall temperature of the solid pipeline, and feeds back the wall temperature of the solid pipeline to the three-dimensional solid model. The three-dimensional solid model receives the wall temperature of the solid pipeline sent by the one-dimensional fluid model, uses the wall temperature of the solid pipeline as a boundary condition to obtain the summed heat flux density of the solid pipeline, and feeds back the summed heat flux density of the solid pipeline to the one-dimensional fluid model. Until the results of the one-dimensional fluid model and the three-dimensional solid model meet their respective predetermined convergence criteria, such as temperature change, summed heat flux change or residual value, etc. are lower than a preset threshold. The specific threshold setting can be set according to actual needs, and the present invention is not further limited here.

[0045] After the two models reach convergence conditions in the current time step, the two models can use the solutions of the current time step as the initial conditions of the next time step and start a new round of iteration to reflect the changes of two-phase liquid helium forced flow cooling of superconducting magnets at different times.

[0046] The thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet provided by the present invention obtains the wall temperature of the solid pipeline through a one-dimensional fluid model of the two-phase liquid helium and transmits it to the three-dimensional solid model of the superconducting magnet; obtains the summed heat flux density of the solid pipeline through the three-dimensional solid model of the superconducting magnet and transmits it to the one-dimensional fluid model of the two-phase liquid helium; and performs thermal simulation analysis on the cooling structure of the two-phase liquid helium forced flow cooling superconducting magnet through mutual coupling and iteration of the one-dimensional fluid model and the three-dimensional solid model.

[0047] Based on the above embodiment, the wall temperature of the solid pipe is obtained based on the one-dimensional fluid model, which specifically includes: dividing a one-dimensional fluid grid along the axial direction of the pipe, and obtaining the wall temperature of the corresponding solid pipe based on the one-dimensional fluid grid.

[0048] The one-dimensional fluid grid is a segment or a node in a series of discrete segments or nodes into which the flow path of the two-phase liquid helium is divided along the axial direction of the solid pipe.

[0049] Exemplarily, after obtaining the one-dimensional fluid grid, the wall temperature of the solid pipe at each one-dimensional fluid grid can be obtained, and the wall temperature of the entire solid pipe can be obtained based on the wall temperature of the solid pipe at each one-dimensional fluid grid.

[0050] Figure 5 Schematic diagram of the coupling between a one-dimensional fluid model and a three-dimensional solid model in the thermal simulation method of two-phase liquid helium forced flow cooling superconducting magnet provided by the present invention, such as Figure 5As shown, in one embodiment, obtaining the summed heat flux density of the solid pipeline based on the three-dimensional solid model specifically includes: dividing the three-dimensional solid pipeline in the three-dimensional solid model into corresponding pipeline areas according to the one-dimensional fluid grid, and obtaining the summed heat flux density of each pipeline area; The method of transferring the wall temperature of the solid pipe to the three-dimensional solid model and transferring the summed heat flux density of the solid pipe to the one-dimensional fluid model specifically includes: transferring the wall temperature of the solid pipe corresponding to each one-dimensional fluid grid to the pipe area and transferring the summed heat flux density of each pipe area to the one-dimensional fluid grid.

[0051] The pipeline region is the solid pipeline part corresponding to the one-dimensional fluid grid in the three-dimensional space. Corresponding to the one-dimensional fluid grid, the pipeline region can also be a section of pipeline or a grid point. The pipeline region corresponds to the one-dimensional fluid grid one-to-one.

[0052] The summed heat flux refers to the total amount of heat in the target area. For example, the summed heat flux of a pipeline area refers to the total amount of heat passing through the area per unit time. The summed heat flux can also be called heat flow, heat flow, heat flux, etc.

[0053] Exemplarily, after obtaining the pipeline area, the heat flux density and pipeline area area of ​​each pipeline area can be obtained, and the summed heat flux density of the pipeline area is obtained according to the product of the heat flux density and the pipeline area area, and the summed heat flux density of the pipeline area is transferred to the corresponding one-dimensional fluid grid.

[0054] In this embodiment, the one-dimensional fluid model is divided into one-dimensional fluid grids along the pipeline axis, the wall temperature of the solid pipeline corresponding to each one-dimensional fluid grid is obtained, the three-dimensional solid pipeline is divided into corresponding pipeline areas, the summed heat flux density of each pipeline area is obtained, the wall temperature of the solid pipeline corresponding to each one-dimensional fluid grid is transferred to the pipeline area, and the summed heat flux density of each pipeline area is transferred to the one-dimensional fluid grid. In this way, the mutual coupling iteration of the one-dimensional fluid model and the three-dimensional solid model is achieved through the mutual coupling iteration of multiple local one-dimensional fluid models and local three-dimensional solid models, which can provide higher simulation accuracy and more accurately predict and optimize the thermal behavior and cooling efficiency of superconducting magnets.

[0055] Moreover, compared with using three-dimensional grids, in this embodiment, the wall temperature of the solid pipe corresponding to each one-dimensional fluid grid is obtained through one-dimensional fluid grids, which reduces the number of grids required to be processed, reduces the required computing resources and computing time, and can further improve the simulation efficiency.

[0056] In order to further improve the simulation accuracy, based on any of the above embodiments, the summed heat flux density of each pipeline area is obtained, specifically including: dividing a three-dimensional finite element grid in each pipeline area, and obtaining the summed heat flux density of each pipeline area based on the three-dimensional finite element grid.

[0057] The three-dimensional finite element mesh can represent the geometry and structure of the pipeline area in more detail in three-dimensional space. Thus, by obtaining the three-dimensional finite element mesh of each pipeline area, the geometry and structure of the solid pipeline can be represented in more detail. It can be understood that the summed heat flux density of each three-dimensional finite element mesh is different.

[0058] In this embodiment, by performing further division processing on each pipeline area, multiple three-dimensional finite element meshes in each pipeline area are obtained, and the summed heat flux density of each three-dimensional finite element mesh in the pipeline area is obtained. The summed heat flux density of each pipeline area is obtained based on each three-dimensional finite element mesh in each pipeline area, so that a more accurate distribution of the summed heat flux density in each pipeline area can be obtained, providing a higher simulation accuracy for the summed heat flux density of each pipeline area.

[0059] Based on any of the above embodiments, a one-dimensional fluid model of the two-phase liquid helium is established, and the wall temperature of the solid pipeline is obtained based on the one-dimensional fluid model, specifically including: The mass conservation equation, momentum conservation equation and energy conservation equation for one-dimensional two-phase liquid helium flow heat transfer are established.

[0060] Among them, the mass conservation equation can describe the mass change of the two-phase liquid helium; the momentum conservation equation can describe the flow characteristics of the two-phase liquid helium, such as the flow velocity change of the two-phase liquid helium; the energy conservation equation can describe the energy change of the two-phase liquid helium, such as the heat absorbed and transferred by the two-phase liquid helium.

[0061] The following is a set of examples of the mass conservation equation, momentum conservation equation, and energy conservation equation.

[0062] The mass conservation equation:

[0063] in, is the velocity of the gas-liquid mixture (m / s), is the density of the gas-liquid mixture (kg / m³), is the length variable (m), t is the time variable (s).

[0064] Momentum conservation equation:

[0065] in, is the velocity of the gas-liquid mixture (m / s), is the density of the gas-liquid mixture (kg / m³), is the two-phase friction pressure drop (Pa / m), is the gravity pressure drop (Pa / m), is the accelerating pressure drop (Pa / m), is the length variable (m), t is the time variable (s), P is the pressure (Pa).

[0066] Energy conservation equation:

[0067] in, is the velocity of the gas-liquid mixture (m / s), is the density of the gas-liquid mixture (kg / m³), is the enthalpy of the gas-liquid mixture (kJ / kg), Q is the summed heat flux density of the solid pipe (W / m 2 ), A is the flow cross-sectional area (m 2 ), t is the time variable (s), is the length variable (m).

[0068] A supplementary equation is selected based on two-phase liquid helium, and the supplementary equation is combined with the mass conservation equation, momentum conservation equation and energy conservation equation for discretization to obtain the central fluid temperature of the one-dimensional fluid model, wherein the central fluid temperature is distributed one-dimensionally along the axial direction of the pipeline.

[0069] Supplementary equations can also be called additional equations, which are equations that assist in solving the mass conservation equation, momentum conservation equation, and energy conservation equation under given physical conditions.

[0070] Exemplarily, after selecting the supplementary equation, the supplementary equation can be combined with the mass conservation equation, the momentum conservation equation, and the energy conservation equation for discretization on each one-dimensional fluid grid, and the pressure gradient algorithm is used for numerical solution. The obtained solution is combined with the initial boundary conditions of the one-dimensional fluid model to obtain the central fluid temperature of the one-dimensional fluid model.

[0071] Specifically, in one embodiment, a homogeneous flow model, a cavitation fraction model and a boiling heat transfer model can be selected based on two-phase liquid helium, and the homogeneous flow model, the cavitation fraction model and the boiling heat transfer model are combined with the mass conservation equation, the momentum conservation equation and the energy conservation equation for discretization.

[0072] The homogeneous flow model can regard the two-phase fluid as a uniformly mixed medium, and the pressure drop of the two-phase liquid helium can be calculated based on the parameters of the two-phase liquid helium. The physical properties of the two-phase liquid helium are the corresponding two-phase flow parameters, and the pressure drop of the two-phase liquid helium is the sum of the friction pressure drop, acceleration pressure drop and gravity pressure drop of the two-phase.

[0073] A set of specific examples of two-phase friction pressure drop, acceleration pressure drop and gravity pressure drop are given below.

[0074] Two-phase friction pressure drop:

[0075] in, is the two-phase friction pressure drop (Pa / m), G is the mass flow density (kg / (m 2 s))、 is the length of the control body (m), is the mass gas content, v g is the vapor volume (m 3 •kg -1 ), is the liquid phase volume (m 3 •kg -1 ), μ g is the saturated vapor phase viscosity coefficient (Pa•s), is the saturated liquid phase viscosity coefficient (Pa•s), is the wall roughness ( μm ), d i is the inner diameter of the pipe (m), is the two-phase friction factor, is the friction coefficient, is the liquid density (kg•m -3 ), is the total liquid phase Reynolds number.

[0076] Accelerated pressure drop:

[0077] in, is the acceleration pressure drop (Pa / m), G is the mass flow density (kg / (m 2 s))、 is the mass gas content, is the vacuolar fraction, is the liquid density (kg•m -3 ), is the control volume export variable, is the control body input variable.

[0078] Slip speed ratio in homogeneous flow model =1, the cavitation share can be obtained through the cavitation share model, which is:

[0079] in, is the vacuolar fraction, is the mass gas content, is the slip speed ratio, is the vapor phase density (kg•m -3 ), is the liquid density (kg•m -3 ).

[0080] Gravity pressure drop:

[0081] in, is the gravity pressure drop (Pa / m), is the density of the gas-liquid mixture ( kg / m 3 ), g is the acceleration due to gravity ( m / s 2 ), is the tilt angle (°).

[0082] The wall temperature of the solid pipe is obtained based on the core fluid temperature and the summed heat flux density of the solid pipe.

[0083] Exemplarily, the wall temperature of the solid pipe may be obtained based on the following formula.

[0084]

[0085] in, is the summed heat flux density of the solid pipe (W / m 2 ), is the heat transfer coefficient (W / (m 2 K)), is the core fluid temperature (K), is the wall temperature of the solid pipe (K).

[0086] Furthermore, h can be selected based on the single-phase heat transfer coefficient of liquid helium flowing in the solid pipeline. h s , h can also be selected according to the two-phase liquid helium flowing in the solid pipeline. ht .

[0087] When single-phase liquid helium flows in a solid pipe, the single-phase heat transfer coefficient can be obtained according to the following formula: h s .

[0088]

[0089] in, is the thermal conductivity of liquid helium (W / (m·K)), Re is the Reynolds number, Pr is the Prandtl number, is the hydraulic diameter of the pipe (m).

[0090] When two-phase liquid helium flows in a solid pipe, the two-phase heat transfer coefficient can be obtained according to the following formula: ht .

[0091]

[0092] in, h t is the two-phase heat transfer coefficient ( W / (m 2 •K) ), h NB is the boiling heat transfer coefficient ( W / (m 2 •K) ), h CB is the convective heat transfer coefficient ( W / (m 2 •K) ).

[0093] The boiling heat transfer coefficient can be obtained according to the following formula: h NB .

[0094]

[0095] in, is the boiling heat transfer coefficient under reference conditions, is the heat flux (W / m 2 ), is the pipe diameter (m), is the wall roughness ( μm ), other parameters are reference status values.

[0096] =1000W / m 2 , =0.86, =1 μm , =0.01m, n=0.8-0.1exp(1.75P R );

[0097] in, ≤0.95, is the corresponding coefficient, is the coefficient.

[0098] The convective heat transfer coefficient can be obtained according to the following formula: h CB .

[0099]

[0100] in, is the mass gas content, is the liquid density (kg•m -3 ), is the vapor phase density (kg•m -3 ), is the liquid phase thermal conductivity ( W / (m·K) ) is the total liquid convection heat transfer coefficient ( W / (m 2 ·K） ), is the total liquid phase Reynolds number, is the liquid phase Prandtl number, D is the pipe diameter (m), is the Prandtl number, is the liquid phase friction coefficient, is the single liquid relative flow heat transfer coefficient ( W / (m 2 •K) ).

[0101] Based on any of the above embodiments, obtaining the summed heat flux density of the solid pipeline based on the three-dimensional solid model specifically includes: The AC loss heat power distribution of the three-dimensional solid model is obtained based on the three-dimensional magnetic field distribution during the excitation of the superconducting magnet, and the summed heat flux density of the solid pipeline is obtained according to the AC loss heat power distribution and the wall temperature of the solid pipeline.

[0102] Superconducting magnet excitation means gradually increasing the current passing through the superconducting cable to generate a strong magnetic field. The three-dimensional magnetic field distribution can describe the relationship between the magnetic field strength and position changes in the space inside and around the superconducting magnet.

[0103] AC loss is the heat generated by the rapid change of magnetic field during the excitation process. Therefore, the AC loss heat power distribution of the three-dimensional solid model can be obtained based on the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet.

[0104] In this embodiment, the heat generated by the superconducting magnet during operation can be more accurately predicted through the AC loss heat power distribution, and the summed heat flux density of the solid pipeline can be obtained more accurately. As mentioned above, the wall temperature of the solid pipeline can be obtained by combining the summed heat flux density of the solid pipeline and the one-dimensional fluid model. Therefore, the wall temperature of the solid pipeline can be obtained more accurately, thereby better optimizing the design of the cooling system.

[0105] Based on any of the above embodiments, obtaining the AC loss heat power distribution of the three-dimensional solid model based on the three-dimensional magnetic field distribution during the excitation of the superconducting magnet specifically includes: Based on the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet, an AC loss parameter is obtained, and based on the AC loss parameter, a three-dimensional AC loss thermal power distribution of the superconducting magnet is obtained.

[0106] AC loss parameters may include superconductor critical current density, superconducting filament diameter, magnetic field change rate, operating current density, time constant and vacuum permeability.

[0107] Exemplarily, after obtaining the AC loss parameters, the three-dimensional AC loss thermal power distribution of the superconducting magnet can be obtained by the following formula.

[0108] The hysteresis loss of a superconducting magnet can be obtained according to the following formula.

[0109]

[0110] in, is the critical current density of the superconductor (A / m 2 ), is the superconducting wire diameter (m), is the rate of change of magnetic field (T / s), is the operating current density (A / m 2 ), The coupling loss of the superconducting magnet can be obtained according to the following formula.

[0111]

[0112] in, is the time constant (s), is the vacuum permeability (H / m), is the rate of change of magnetic field (T / s).

[0113] Based on any of the above embodiments, obtaining the summed heat flux density of the solid pipeline according to the AC loss heat power distribution and the wall temperature of the solid pipeline specifically includes: Obtaining heat load according to the AC loss heat power distribution; Performing meshing processing on the three-dimensional solid model to obtain a three-dimensional finite element mesh and a wall temperature of the three-dimensional finite element mesh; A thermal simulation analysis is performed on the three-dimensional solid model based on the thermal load and the wall temperature of the three-dimensional finite element mesh to obtain the summed heat flux density of the solid pipeline.

[0114] The thermal load is the internal heat source that causes the temperature of the superconducting magnet to rise. The AC loss heat power distribution can describe the intensity of the heat source at each position inside the superconducting magnet. Therefore, the thermal load of the three-dimensional solid model can be obtained based on the AC loss heat power distribution.

[0115] For example, after obtaining the heat load, the three-dimensional solid pipe in the three-dimensional solid model can be meshed, the three-dimensional finite element mesh of the three-dimensional solid pipe part and the wall temperature of the three-dimensional finite element mesh can be obtained, and the boundary condition of the three-dimensional finite element mesh can be obtained according to the wall temperature of the three-dimensional finite element mesh. Optionally, the wall temperature of the three-dimensional finite element mesh can be directly used as the boundary condition of the three-dimensional finite element mesh.

[0116] In this embodiment, by meshing the three-dimensional solid model, the wall temperature of each three-dimensional finite element mesh can be obtained, and the summed heat flux density of the solid pipeline is obtained by combining the AC loss heat power distribution to further improve the accuracy of obtaining the summed heat flux density of the solid pipeline, so as to better optimize the design of the cooling system.

[0117] In order to specifically illustrate the function of the thermal simulation method for cooling a superconducting magnet with two-phase liquid helium forced flow provided in this embodiment, Figure 6 This is a second flow chart of the thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet provided by the present invention. Figure 6 Provide a specific example.

[0118] A one-dimensional fluid model of two-phase liquid helium and a three-dimensional solid model of superconducting magnet are established, initial values ​​of the one-dimensional fluid model and the three-dimensional solid model are set, and the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated within the current time step.

[0119] The three-dimensional solid model is meshed by three-dimensional finite element software to obtain the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet; According to the three-dimensional magnetic field distribution and the superconducting magnet AC loss model, the three-dimensional AC loss heat power distribution of the superconducting magnet is obtained; Import the three-dimensional AC loss heat power distribution into the ANSYS thermal analysis module as a thermal load through APDL (ANSYS Parametric Design Language); The heat diffusion equation of the three-dimensional solid model is established, and the finite element method is used to discretize and solve the heat diffusion equation of the three-dimensional solid model to obtain the three-dimensional temperature distribution and the heat flux density of the solid pipeline, so as to obtain the heat flux of the pipeline area of ​​each solid pipeline and transfer it to the one-dimensional fluid model accordingly.

[0120] According to the one-dimensional fluid model, the flow heat transfer of two-phase liquid helium is obtained: Establish the mass conservation equation, momentum conservation equation and energy conservation equation for one-dimensional two-phase liquid helium flow heat transfer; A homogeneous flow model is selected based on two-phase liquid helium, and the homogeneous flow model includes two-phase friction pressure drop, acceleration pressure drop and gravity pressure drop; Select boiling heat transfer model based on two-phase liquid helium; Based on the heat flux transferred to the one-dimensional fluid model corresponding to the pipeline area of ​​each solid pipeline, the mass conservation equation, momentum conservation equation and energy conservation equation of the one-dimensional two-phase liquid helium flow heat transfer are discretely solved to obtain the wall temperature of the pipeline area of ​​each solid pipeline and transfer it to the three-dimensional solid model accordingly.

[0121] The one-dimensional fluid model and the three-dimensional solid model are coupled and iterated mutually until a convergence condition is reached, and the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated mutually in the next time step.

[0122] The thermal simulation device for cooling a superconducting magnet with two-phase liquid helium forced flow provided by the present invention is described below. The thermal simulation device for cooling a superconducting magnet with two-phase liquid helium forced flow described below and the thermal simulation method for cooling a superconducting magnet with two-phase liquid helium forced flow described above can be referred to each other.

[0123] Figure 7 1 is a schematic diagram of a thermal simulation device for cooling a superconducting magnet with two-phase liquid helium forced flow provided by the present invention, wherein the superconducting magnet comprises a superconducting cable and a cooling structure, wherein the cooling structure is arranged in parallel between two superconducting cables, and the two-phase liquid helium flows in a solid pipe of the cooling structure, and the superconducting magnet is cooled with two-phase liquid helium forced flow. Figure 7 As shown, the device comprises: A parameter acquisition module is used to establish a one-dimensional fluid model of the two-phase liquid helium, and acquire the wall temperature of the solid pipeline based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the axial direction of the pipeline; establish a three-dimensional solid model of the superconducting magnet, and acquire the summed heat flux density of the solid pipeline based on the three-dimensional solid model; A parameter transfer module, used to transfer the wall temperature of the solid pipeline to the three-dimensional solid model, and to transfer the summed heat flux density of the solid pipeline to the one-dimensional fluid model; The coupling iteration module is used for coupling and iterating the one-dimensional fluid model and the three-dimensional solid model with each other within a time step until a convergence condition is reached, and then repeating the coupling and iterating steps of the one-dimensional fluid model and the three-dimensional solid model with each other in the next time step.

[0124] Based on any of the above embodiments, the parameter acquisition module is specifically used to: Dividing a one-dimensional fluid grid along the axial direction of the pipeline, and acquiring the wall temperature of the corresponding solid pipeline based on the one-dimensional fluid grid; Dividing the three-dimensional solid pipeline in the three-dimensional solid model into corresponding pipeline areas according to the one-dimensional fluid grid, and obtaining the summed heat flux density of each pipeline area; Parameter passing module, specifically used for: The wall temperature of the solid pipeline corresponding to each one-dimensional fluid grid is transferred to the pipeline area, and the summed heat flux density of each pipeline area is transferred to the one-dimensional fluid grid.

[0125] Based on any of the above embodiments, the parameter acquisition module is specifically used to: divide a three-dimensional finite element grid in each of the pipeline regions, and acquire the summed heat flux density of each of the pipeline regions based on the three-dimensional finite element grid.

[0126] Based on any of the above embodiments, the parameter acquisition module includes an equation building unit, a discrete processing unit and a temperature acquisition unit; An equation building unit is used to build the mass conservation equation, momentum conservation equation and energy conservation equation for one-dimensional two-phase liquid helium flow heat transfer; A discrete processing unit is used to select a supplementary equation based on the two-phase liquid helium, and perform discrete processing on the supplementary equation together with the mass conservation equation, the momentum conservation equation, and the energy conservation equation to obtain the central fluid temperature of the one-dimensional fluid model, wherein the central fluid temperature is distributed one-dimensionally along the axial direction of the pipeline; A temperature acquisition unit is used to acquire the wall temperature of the solid pipeline based on the central fluid temperature and the summed heat flux density of the solid pipeline.

[0127] Based on any of the above embodiments, the discrete processing unit is specifically used to: select a homogeneous flow model, a cavitation fraction model and a boiling heat transfer model based on two-phase liquid helium, and discretely process the homogeneous flow model, the cavitation fraction model and the boiling heat transfer model together with the mass conservation equation, the momentum conservation equation and the energy conservation equation.

[0128] Based on any of the above embodiments, the parameter acquisition module is specifically used to: obtain the AC loss heat power distribution of the three-dimensional solid model based on the three-dimensional magnetic field distribution during the excitation of the superconducting magnet, and obtain the summed heat flux density of the solid pipeline according to the AC loss heat power distribution and the wall temperature of the solid pipeline.

[0129] Based on any of the above embodiments, the parameter acquisition module also includes a thermal power distribution acquisition unit, which is used to obtain AC loss parameters based on the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet, and obtain the three-dimensional AC loss thermal power distribution of the superconducting magnet based on the AC loss parameters.

[0130] Based on any of the above embodiments, the parameter acquisition module further includes a summation heat flux density acquisition unit, which is specifically used to: Obtaining heat load according to the AC loss heat power distribution; Performing meshing processing on the three-dimensional solid model to obtain a three-dimensional finite element mesh and a wall temperature of the three-dimensional finite element mesh; A thermal simulation analysis is performed on the three-dimensional solid model based on the thermal load and the wall temperature of the three-dimensional finite element mesh to obtain the summed heat flux density of the solid pipeline.

[0131] Figure 8 An example of a structural diagram of an electronic device is shown in FIG. Figure 8 As shown, the electronic device may include: a processor (processor) 810, a communication interface (Communications Interface) 820, a memory (memory) 830 and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call the logic instructions in the memory 830 to execute the thermal simulation method of two-phase liquid helium forced flow cooling superconducting magnet, which method includes: establishing a one-dimensional fluid model of the two-phase liquid helium, and obtaining the wall temperature of the solid pipeline based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the pipeline axis; establishing a three-dimensional solid model of the superconducting magnet, and obtaining the summed heat flux density of the solid pipeline based on the three-dimensional solid model; transferring the wall temperature of the solid pipeline to the three-dimensional solid model, and transferring the summed heat flux density of the solid pipeline to the one-dimensional fluid model; within a time step, the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other until a convergence condition is reached, and entering the next time step to repeat the step of coupling the one-dimensional fluid model and the three-dimensional solid model with each other.

[0132] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0133] On the other hand, the present invention also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the thermal simulation method of two-phase liquid helium forced flow cooling superconducting magnet provided by the above methods, the method comprising: establishing a one-dimensional fluid model of the two-phase liquid helium, and obtaining the wall temperature of the solid pipe based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the axial direction of the pipe; establishing a three-dimensional solid model of the superconducting magnet, and obtaining the summed heat flux density of the solid pipe based on the three-dimensional solid model; transferring the wall temperature of the solid pipe to the three-dimensional solid model, and transferring the summed heat flux density of the solid pipe to the one-dimensional fluid model; within a time step, the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other until a convergence condition is reached, and entering the next time step to repeat the step of coupling the one-dimensional fluid model and the three-dimensional solid model with each other.

[0134] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the processor executes the thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet provided by the above methods, the method comprising: establishing a one-dimensional fluid model of the two-phase liquid helium, and obtaining the wall temperature of the solid pipe based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the axial direction of the pipe; establishing a three-dimensional solid model of the superconducting magnet, and obtaining the summed heat flux density of the solid pipe based on the three-dimensional solid model; transferring the wall temperature of the solid pipe to the three-dimensional solid model, and transferring the summed heat flux density of the solid pipe to the one-dimensional fluid model; within a time step, the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other until a convergence condition is reached, and the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other in the next time step.

[0135] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0136] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermal simulation method for cooling a superconducting magnet using two-phase liquid helium forced flow, characterized in that: The superconducting magnet comprises a superconducting cable and a cooling structure, wherein the cooling structure is arranged in parallel between two superconducting cables, the two-phase liquid helium flows in a solid pipe of the cooling structure, and the superconducting magnet is subjected to two-phase liquid helium forced flow cooling, and the method comprises: A one-dimensional fluid model of the two-phase liquid helium is established, and the wall temperature of the solid pipeline is obtained based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the pipeline axis; a three-dimensional solid model of the superconducting magnet is established, and the summed heat flux density of the solid pipeline is obtained based on the three-dimensional solid model; The wall temperature of the solid pipeline is correspondingly transferred to the three-dimensional solid model, and the summed heat flux density of the solid pipeline is correspondingly transferred to the one-dimensional fluid model; In one time step, the one-dimensional fluid model and the three-dimensional solid model are coupled and iterated with each other until a convergence condition is reached, and the step of coupling the one-dimensional fluid model and the three-dimensional solid model with each other is repeated in the next time step.

2. The thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet according to claim 1, characterized in that: Acquiring the wall temperature of the solid pipeline based on the one-dimensional fluid model specifically includes: dividing a one-dimensional fluid grid along the pipeline axis, and acquiring the wall temperature of the corresponding solid pipeline based on the one-dimensional fluid grid; Acquiring the summed heat flux density of the solid pipeline based on the three-dimensional solid model specifically includes: dividing the three-dimensional solid pipeline in the three-dimensional solid model into corresponding pipeline areas according to the one-dimensional fluid grid, and acquiring the summed heat flux density of each pipeline area; The method of transferring the wall temperature of the solid pipe to the three-dimensional solid model and transferring the summed heat flux density of the solid pipe to the one-dimensional fluid model specifically includes: transferring the wall temperature of the solid pipe corresponding to each one-dimensional fluid grid to the pipe area and transferring the summed heat flux density of each pipe area to the one-dimensional fluid grid.

3. The thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet according to claim 2, characterized in that: Obtaining the summed heat flux density of each pipeline area specifically includes: A three-dimensional finite element mesh is divided in each of the pipeline regions, and the summed heat flux density of each of the pipeline regions is obtained based on the three-dimensional finite element mesh.

4. The thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet according to claim 1, characterized in that: Establishing a one-dimensional fluid model of the two-phase liquid helium, and acquiring the wall temperature of the solid pipeline based on the one-dimensional fluid model, specifically includes: Establish the mass conservation equation, momentum conservation equation and energy conservation equation for one-dimensional two-phase liquid helium flow heat transfer; Selecting a supplementary equation based on two-phase liquid helium, and performing discretization processing on the supplementary equation together with the mass conservation equation, momentum conservation equation, and energy conservation equation to obtain the central fluid temperature of the one-dimensional fluid model, wherein the central fluid temperature is distributed one-dimensionally along the axial direction of the pipeline; The wall temperature of the solid pipe is obtained based on the core fluid temperature and the summed heat flux density of the solid pipe.

5. The thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet according to claim 4, characterized in that: Based on the two-phase liquid helium, a supplementary equation is selected to combine the supplementary equation with the mass conservation equation, momentum conservation equation and energy conservation equation for discretization, specifically including: A homogeneous flow model, a cavitation fraction model and a boiling heat transfer model are selected based on two-phase liquid helium, and the homogeneous flow model, the cavitation fraction model and the boiling heat transfer model are combined with the mass conservation equation, the momentum conservation equation and the energy conservation equation for discretization.

6. The thermal simulation method for two-phase liquid helium forced flow cooling superconducting magnet according to claim 1, characterized in that: Acquiring the summed heat flux density of the solid pipeline based on the three-dimensional solid model specifically includes: The AC loss heat power distribution of the three-dimensional solid model is obtained based on the three-dimensional magnetic field distribution during the excitation of the superconducting magnet, and the summed heat flux density of the solid pipeline is obtained according to the AC loss heat power distribution and the wall temperature of the solid pipeline.

7. The thermal simulation method for two-phase liquid helium forced flow cooling of superconducting magnets according to claim 6, characterized in that: The AC loss heat power distribution of the three-dimensional solid model is obtained based on the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet, specifically including: Based on the three-dimensional magnetic field distribution during the excitation process of the superconducting magnet, an AC loss parameter is obtained, and based on the AC loss parameter, a three-dimensional AC loss thermal power distribution of the superconducting magnet is obtained.

8. The thermal simulation method for two-phase liquid helium forced flow cooling of superconducting magnets according to claim 6, characterized in that: The summed heat flux density of the solid pipeline is obtained according to the AC loss heat power distribution and the wall temperature of the solid pipeline, specifically including: Obtaining heat load according to the AC loss heat power distribution; Performing meshing processing on the three-dimensional solid model to obtain a three-dimensional finite element mesh and a wall temperature of the three-dimensional finite element mesh; A thermal simulation analysis is performed on the three-dimensional solid model based on the thermal load and the wall temperature of the three-dimensional finite element mesh to obtain the summed heat flux density of the solid pipeline.

9. A thermal simulation device for cooling a superconducting magnet using two-phase liquid helium forced flow, characterized in that: The superconducting magnet comprises a superconducting cable and a cooling structure, wherein the cooling structure is arranged in parallel between two superconducting cables, and the two-phase liquid helium flows in a solid pipe of the cooling structure to perform two-phase liquid helium forced flow cooling on the superconducting magnet. The device comprises: A parameter acquisition module is used to establish a one-dimensional fluid model of the two-phase liquid helium, and acquire the wall temperature of the solid pipeline based on the one-dimensional fluid model, wherein the wall temperature is distributed one-dimensionally along the axial direction of the pipeline; establish a three-dimensional solid model of the superconducting magnet, and acquire the summed heat flux density of the solid pipeline based on the three-dimensional solid model; A parameter transfer module, used to transfer the wall temperature of the solid pipeline to the three-dimensional solid model, and to transfer the summed heat flux density of the solid pipeline to the one-dimensional fluid model; The coupling iteration module is used for coupling and iterating the one-dimensional fluid model and the three-dimensional solid model with each other within a time step until a convergence condition is reached, and then repeating the coupling and iterating steps of the one-dimensional fluid model and the three-dimensional solid model with each other in the next time step.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the thermal simulation method for two-phase liquid helium forced flow cooling of a superconducting magnet as claimed in any one of claims 1 to 8 is implemented.

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