A method for obtaining surface heat flux of a divertor target plate by using surface feature temperature of a tungsten-copper module

Abstract

The application discloses a method for obtaining surface heat flux of a divertor target plate by using surface characteristic temperature of a tungsten-copper module, and relates to the field of magnetic confinement fusion. The method comprises the following steps: when a magnetic confinement fusion experimental device is running, the surface temperature distribution of the tungsten-copper module of the divertor target plate is measured by using a high-resolution infrared thermal imager; a characteristic temperature distribution database of each tungsten-copper module under different circumferential parallel heat flux values is obtained based on three-dimensional profile measurement and thermal analysis simulation in advance; the circumferential parallel heat flux value consistent with the temperature distribution measurement is obtained by comparison; and the results of the modules at different circumferential positions are self-consistently calibrated to accurately obtain the surface heat flux distribution data of the entire divertor target plate. The surface characteristic temperature distribution of the tungsten-copper module can accurately obtain the surface heat flux value of the divertor target plate, which provides reliable heat flux data for evaluating the service performance and life of the tungsten-copper component of the divertor target plate, and for controlling the physical operation of the device and optimizing the engineering structure.

Description

Technical Field

[0001] This invention belongs to the field of magnetic confinement nuclear fusion, specifically relating to a method for obtaining the surface heat flux of a divertor target plate by utilizing the surface characteristic temperature of a tungsten-copper module. The method is a method for obtaining the surface heat flux distribution of a divertor target plate by utilizing the surface characteristic temperature distribution of an actively water-cooled tungsten-copper divertor tube module. Background Technology

[0002] The divertor is one of the key components of a magnetic confinement fusion device. Its main functions include: shielding various impurities from the device walls to reduce contamination of the central plasma; removing helium ash generated during the fusion reaction; and withstanding and removing the extremely high heat flux from the central plasma. Currently, long-pulse fusion experimental devices such as EAST and ITER employ actively water-cooled tungsten-copper divertors. To alleviate the thermal stress and electromagnetic forces on the divertor components, tungsten-copper tube-mounted modular components with a slotted structure are used. This tube-mounted structure has broad application prospects in future fusion reactors and is the preferred choice for the divertor engineering design of future BEST and CFETR fusion devices. However, under the bombardment and fatigue effects of the extremely high heat load of fusion, the tube-mounted components of actively water-cooled tungsten-copper divertors can suffer damage, including deformation, cracking, and melting. Therefore, accurate heat flux distribution data is crucial for evaluating the service performance and lifespan of divertor materials and components, and also has significant scientific value for the physical operation control and engineering structure optimization of the device.

[0003] For tungsten-copper divertor modules, surface misalignment is unavoidable during manufacturing and installation, resulting in unique gap and edge misalignment dimensions for each module, leading to characteristic heat flux and temperature distributions. This characteristic can be utilized by measuring the surface temperature distribution of the active water-cooled tungsten-copper divertor module, combining this with temperature distribution simulations under different circumferential parallel heat flux values, and comparing the obtained parallel heat flux values ​​on the target plate surface with the actual measured temperature distribution. Furthermore, self-consistent calibration is performed with the results from modules at different circumferential positions to obtain the target plate surface heat flux distribution data. Summary of the Invention

[0004] The purpose of this invention is to address the uneven surface temperature distribution of active water-cooled tungsten copper divertor tube module components, which presents difficulties in measuring and retrieving absolute heat flux data. This invention utilizes the characteristic temperature distribution generated by tooling misalignment in the active water-cooled tungsten copper module. By measuring the surface characteristic temperature distribution with high-resolution infrared measurements, and comparing the temperature distribution simulation results under different circumferential parallel heat flux values, the absolute heat flux data of the divertor target plate, consistent with the temperature distribution measurement, can be obtained.

[0005] To obtain more accurate heat flux information on the surface of a divertor target plate, this invention proposes a method for obtaining the heat flux on the surface of a divertor target plate using the characteristic temperature of a tungsten-copper module, specifically including the following steps:

[0006] Step 1: Before the experiment of the magnetic confinement nuclear fusion device, the three-dimensional structural profile of the tungsten copper module component of the divertor target plate is accurately measured using a three-dimensional profilometer to obtain key information such as the gap structure size (width g and misalignment Δ) between each tungsten copper module.

[0007] Step 2: When the magnetic confinement fusion device is operating stably with long pulses (usually >20s) (without changes in magnetic field configuration and plasma parameters), a high-resolution (spatial resolution is usually required to be less than 0.5mm) infrared thermal imager is used to measure and record the temperature distribution information on the surface of each tungsten-copper module of the divertor target plate (radial, polar and circumferential). Due to the different misalignments and gap sizes between the tungsten-copper tube modules, the temperature distribution on the surface of each tungsten-copper module is different, and there is a temperature distribution curve under the characteristic structure.

[0008] Step 3: Based on the configuration parameters of the long-pulse discharge magnetic field, the heat flow distribution pattern of each tungsten-copper module surface and gap region is obtained by using the magnetic field line tracking program PFC-flux (to obtain the incident angle of the magnetic field lines on the target plate surface, and thus obtain the heat flow distribution trend) and the particle simulation program PIC (to obtain the heat flow distribution trend of the module edge region more accurately). By utilizing the consistency of the circumferential parallel heat flow distribution of the divertor target plate, the functional distribution relationship between the actual absorbed heat flow and the circumferential parallel heat flow of each tungsten-copper module is constructed.

[0009] Step 4: Combining Step 1 and Step 3, establish a thermal simulation model that reflects the actual working conditions, calculate the temperature distribution of multiple modules in the same radial and polar positions in the divertor target plate area under different circumferential parallel heat flux values, and establish a database;

[0010] Step 5: Compare the measured temperature distribution of each tungsten-copper module in Step 2 with the simulated temperature distribution in Step 4, and obtain the simulated temperature distribution curve that is consistent with the actual measured distribution in Step 2, as well as the circumferential parallel heat flow value.

[0011] Step 6: Perform self-consistent analysis on the circumferential parallel heat flux values ​​obtained from the characteristic temperatures of multiple modules at specific radial and polar positions, remove outliers with large deviations (deviation > 10%), as well as the maximum and minimum values, and perform a weighted average on the other values ​​to obtain the circumferential parallel heat flux values ​​at specific radial and polar positions of the divertor target plate more accurately.

[0012] Step 7: Repeat steps 4, 5 and 6 above to obtain the circumferential heat flux values ​​at different (radial and polar) positions on the divertor target plate surface, and then fit the heat flux distribution function on the divertor target plate surface.

[0013] This invention provides a self-consistent and reliable method for obtaining the heat flux of a divertor target plate, which can accurately obtain the heat flux value of the target plate during long pulse discharge, providing more accurate heat flux data for the service performance and life assessment of divertor components, as well as for the physical operation and engineering design of the device. Attached Figure Description

[0014] Figure 1 A schematic diagram of the method for obtaining heat flow on the surface of a divertor target plate using the characteristic distribution of a tungsten-copper module in this invention;

[0015] Figure 2 This is a typical divertor target plate structure diagram (the schematic diagram contains 2 components, each component consists of 4 tungsten copper strings, each tungsten copper string contains 5 tungsten copper modules, and the water pipe in the middle is a straight pipe);

[0016] Figure 3 for Figure 2 Single tungsten copper module (number N) 3,3 A schematic diagram comparing the surface temperature measured and the temperature distribution calculated by numerical simulation;

[0017] Figure 4 To obtain the characteristic temperature of the tungsten copper module Figure 2 Polar distribution of heat flux (circumferential heat flux value) on the surface of the divertor target plate component. Detailed Implementation

[0018] To better illustrate how to obtain heat flow information on the surface of a divertor target plate using the surface characteristic temperature of a tungsten-copper module, the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0019] Reference Figure 1-2 An active water-cooled tungsten-copper divertor tube module is assembled in a string from multiple (usually 5-30) tungsten-copper modules with coaxial, same-diameter cooling pipes. The central cooling pipe of each string can be a straight or curved pipe. Multiple strings (usually 4-10 strings) are assembled into one component, and multiple components (usually around 80) are arranged in a ring to form a divertor. The tungsten-copper module is an active water-cooled tungsten-copper tube-mounted component. A method for obtaining the surface heat flux of a divertor target plate using the surface characteristic temperature distribution of an active water-cooled tungsten-copper module specifically includes the following steps:

[0020] Step 1: Before the magnetic confinement fusion device experiment begins, the three-dimensional structural profile of the tungsten copper component of the divertor is accurately measured using a three-dimensional profilometer to obtain key information such as the gap structure dimensions (width g and misalignment Δ) between each tungsten copper module and adjacent modules.

[0021] Step 2: When the long pulse (usually >20s) of the magnetic confinement fusion device is running stably (without changes in magnetic field configuration and plasma parameters), a high-resolution infrared thermal imager (TELPS FM100K, spatial resolution less than 0.5mm, but not limited to any particular infrared thermal imager model) is used to measure and record the temperature distribution information on the surface of each tungsten-copper module. Due to the different misalignments between the modules, the temperature distribution on the surface of each tungsten-copper module is different, and it has a characteristic temperature distribution curve corresponding to the misalignment value and heat flux value.

[0022] Step 3: Based on the configuration parameters of the long-pulse (typically >20s) discharge magnetic field (circumferential magnetic field Bt and poloidal magnetic field Bp), the magnetic field line tracing program PFC-flux (to obtain the incident angle of the magnetic field lines on the target plate surface, and thus obtain the heat flow distribution law) and the particle tracing program PIC (to obtain the heat flow distribution trend of the module edge region more accurately) are used to obtain the heat flow distribution law of the surface and gap region of the single module (i.e., the relationship between the actual heat flow absorbed at each point on the surface and the circumferential parallel heat flow). The consistency of the circumferential parallel heat flow distribution of the divertor target plate (i.e., the q at each poloidal position on the target plate surface) is used to obtain the heat flow distribution law of the single module surface and gap region (i.e., the relationship between the actual heat flow absorbed at each point on the surface and the circumferential parallel heat flow). ∥ It is fixed, relative to the circumferential coordinates. (Irrelevant), construct the functional relationship between the actual absorbed heat flux distribution of each individual module and the circumferential parallel heat flux;

[0023]

[0024] Where, q / / (ρ,θ) represents the circumferential parallel heat flow incident along the magnetic field lines at specific spatial radial and polar positions; Let ρ be the grazing angle of the magnetic field lines on the surface of the module at a specific spatial location, and θ be the radial coordinate and θ be the polar coordinate. For circumferential coordinates.

[0025] Step 4: Combining the module geometry from Step 1, the measured gap width and misalignment, and the heat flow distribution from Step 3, establish an ANSYS thermal simulation analysis finite element model that reflects the actual thermal loading and cooling conditions of a single tungsten-copper module. Simulate and obtain the temperature distribution curves of multiple circumferential modules at specific (radial and polar) locations under different circumferential heat flow values.

[0026]

[0027] Note: For a single module, the temperature distribution is related to ① module geometry г, ② water cooling conditions h, ③ gap width g, ④ misalignment with adjacent modules Δ, and ⑤ heat flux distribution. Related, where ① and ② are known design results; ③ and ④ are measurement results from step 1, and As determined in step 3, the only variable is q. / / (ρ,θ). Therefore, temperature and q / / (ρ,θ) have a corresponding relationship.

[0028] Step 5: Compare the measured temperature distribution of each circumferential tungsten-copper module in Step 2 with the simulated temperature distribution in Step 4, and obtain the simulated temperature distribution curve and circumferential parallel heat flow value that almost completely overlap with the actual measured distribution in Step 2 (data point deviation <5%).

[0029] Step 6: Analyze and compare the circumferential parallel heat flow values ​​obtained from the characteristic temperatures of multiple (N, where N is a positive integer) tungsten-copper modules at specific radial and polar positions. Remove outliers with large deviations (generally >10%, which can be adjusted reasonably according to actual conditions), as well as the maximum and minimum values. Perform a weighted average on the other values ​​to obtain the circumferential parallel heat flow values ​​at specific radial and polar positions on the surface of the long-pulse discharge divertor target plate. The larger N is, the more reliable the result.

[0030]

[0031] Note: Due to calculation and measurement errors, the results may have some deviation. Therefore, a weighted average is taken at multiple locations around the circumference to obtain a more accurate parallel heat flux value.

[0032] Step 7: Repeat steps 4, 5 and 6 above to obtain the circumferential parallel heat flow values ​​at each (radial and polar) position on the divertor target plate surface, and then fit to obtain the polar distribution data of the parallel heat flow on the divertor target plate surface.

[0033] q / / (ρ,θ)=f(ρ,θ)

[0034] Note: By fitting the data, heat flow data at different polar positions can be obtained, thus fitting a function of radial ρ and polar θ, and comparing it with the circumferential direction. Irrelevant.

[0035] Example:

[0036] A typical divertor component of a fusion device (composed of multiple tungsten-copper modules, where the radial coordinates of each module remain constant, and only two coordinate variables, polar and circumferential), is illustrated in the diagram below. Figure 2 As shown. The heat flux value was obtained by performing the above real-time steps for this structure, as detailed below:

[0037] S1: Use a 3D profilometer to accurately measure the 3D structural profile of the component, and read the structural dimensions of the gaps (width g and misalignment Δ) between each tungsten-copper module, such as... Figure 2 N 3,3 Module and adjacent N 4,3 The width of the gap between the blocks is 0.8 mm and the misalignment is 0.2 mm;

[0038] S2: Measure and record the temperature distribution of each tungsten-copper module using a high-resolution infrared thermal imager (TELPS FM100K);

[0039] S3: Use the magnetic field line tracing program PFC-flux to obtain the heat flow distribution on the surface and in the gap area of ​​each tungsten copper module;

[0040] S4: Combining the tungsten-copper module geometry from step S1, and measuring the gap width g and misalignment Δ with the heat flow distribution from step 3, establish a model reflecting the tungsten-copper module (N i,j The ANSYS thermal simulation analysis of the finite element model under actual heat loading and cooling conditions (7m / s, 20℃, 1.5MPa) simulates and obtains the temperature distribution under different circumferential parallel heat flow values.

[0041] S5: The tungsten-copper module (N) measured in step S2 i,j A comparative analysis of the temperature distribution curves under multiple heat flux values ​​in step S4 is performed, such as... Figure 3 As shown, (N) 3,3 The experimentally measured and simulated parallel heat flux values ​​are in agreement, q≈q⁴=120MW / m 2 ;

[0042] S6: Repeat steps S1-S5 above to obtain the heat flux values ​​q of the tungsten-copper modules at multiple locations. i,j (i = 1, 2, ..., 8, j = 1, 2, ..., 5), and remove the deviation values ​​(>10%) of each polar position and different circumferential positions, perform weighted averaging and fitting, and obtain as shown below. Figure 4 The target plate heat flux distribution data are shown.

[0043] The parts of this invention not described in detail are well-known to those skilled in the art. The embodiments described above are merely preferred embodiments of the invention, and do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Various modifications and improvements to the technical solutions of this invention made by those skilled in the art without departing from the spirit of the invention should fall within the protection scope defined by the claims of this invention.

Claims

1. A method for obtaining the surface heat flux of a divertor target plate using the surface characteristic temperature of a tungsten-copper module, characterized in that, Includes the following steps: Step 1: Before the magnetic confinement nuclear fusion device experiment, the three-dimensional structural profile of the tungsten-copper module component of the divertor target plate is measured using a three-dimensional profilometer to obtain the gap structure size information between each tungsten-copper module; wherein, the gap structure size information is the width g and the misalignment Δ; Step 2: During the long pulse stable operation of the magnetic confinement nuclear fusion device, the temperature information of each tungsten copper module surface at the radial, polar and circumferential positions of the divertor target plate is measured and recorded using an infrared thermal imager. Due to the different misalignments and gap sizes between the tungsten copper modules, the surface temperature distribution of each tungsten copper module is different, that is, it has a characteristic temperature distribution. Step 3: Based on the configuration parameters of the long-pulse discharge magnetic field, the heat flow distribution trend on the surface and near the gap area of ​​each tungsten-copper module is obtained using the magnetic field line tracking program and particle simulation program. By utilizing the consistency of the circumferential parallel heat flow distribution along the magnetic field lines incident on the surface of the divertor target plate, the functional distribution relationship between the actual absorbed heat flow and the circumferential parallel heat flow of each tungsten-copper module is constructed. Step 4: Combining Step 1 and Step 3, establish a thermal simulation model that reflects the actual working conditions, calculate the temperature distribution of multiple modules in the circumferential direction at specific radial and polar positions in the divertor target plate area under different circumferential parallel heat flux values, and establish a database. Step 5: Compare the measured characteristic temperature distribution of each tungsten-copper module in Step 2 with the simulated temperature distribution in Step 4, and obtain the simulated temperature distribution curve that is consistent with the actual measured distribution in Step 2, as well as the circumferential parallel heat flow value. Step 6: Perform self-consistent analysis on the circumferential parallel heat flux values ​​obtained from the characteristic temperatures of multiple modules at specific radial and pole positions, remove outliers with large deviations, as well as the maximum and minimum values, and perform weighted averaging on the other values ​​to obtain the circumferential parallel heat flux values ​​at specific radial and pole positions of the divertor target plate more accurately. Step 7: Repeat steps 4, 5 and 6 above to obtain the circumferential parallel heat flux values ​​at each radial and polar position on the divertor target plate surface, and then fit the heat flux distribution function on the divertor target plate surface.

2. The method according to claim 1, characterized in that, In step 2, the long pulse of the magnetic confinement nuclear fusion device refers to >20s, and the stable operation refers to the absence of changes in the magnetic field configuration and plasma parameters.

3. The method according to claim 1, characterized in that, In step 3, the glancing angle of the magnetic field lines on the surface of the target plate component is obtained using the magnetic field line tracing program PFC-flux, thereby obtaining the heat flow distribution trend on the surface of each tungsten-copper module; the heat flow distribution trend of the edge region of each tungsten-copper module is obtained using the particle simulation program PIC.

4. The method according to claim 1, characterized in that, In step 3, the functional distribution relationship between the actual absorbed heat flux and the circumferential parallel heat flux of each tungsten-copper module is as follows: in, A circumferential parallel heat flow incident along magnetic field lines at a specific radial and polar position; ρ represents the glancing angle of the magnetic field lines on the surface of the module at a specific spatial location, θ represents the polar coordinate, and φ represents the circumferential coordinate.

5. The method according to claim 1, characterized in that, In step 4, the temperature distribution curve is as follows: Where Δ represents the misalignment between modules; g represents the gap width; For a specific radial ρ and pole θ position, the circumferential parallel heat flux value; ρ represents the glancing angle of the magnetic field lines on the module surface at a specific spatial location, θ represents the radial coordinate, φ represents the polar coordinate, φ represents the circumferential coordinate, г represents the module geometry, and h represents the water cooling condition.

6. The method according to claim 1, characterized in that, In step 6, a relatively large deviation means a deviation > 10%.

7. The method according to claim 1, characterized in that, In step 6, the self-consistent circumferential parallel heat flux values ​​at the specific radial ρ0 and pole θ0 positions are: Where N is the number, and its value is a positive integer.

8. The method according to claim 1, characterized in that, In step 7, the heat flux distribution function on the surface of the divertor target plate can be expressed as: The function is obtained by fitting the following: by obtaining circumferential heat flow data at multiple pole and radial positions through a fitting method, it can be fitted into a function of radial coordinate ρ and pole θ, which is independent of circumferential φ.

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