Optimization design method and device for tail structure of cable terminal and storage medium

Abstract

The invention relates to the technical field of cable terminal design, and particularly provides an optimization design method of a cable terminal tail structure. The method comprises the steps that COMSOL simulation software is used for establishing an electricity-heat-flow multi-physics field coupling model of the direct-current cable terminal, optimization design is conducted on the tail structure of the cable terminal based on the model, and the optimization design comprises metal sheath recovery and optimization design of forming a heat dissipation window in a cone support. Then, carrying out simulation analysis on the natural convection flow velocity of the tail pipe air, the air temperature distribution of the tail pipe and the mechanical stress distribution before and after the tail structure of the cable terminal is optimized, and verifying the heat dissipation effect and the mechanical stress distribution of the tail structure of the cable terminal after the optimization design through the simulation analysis; therefore, the cable terminal can achieve the optimal heat dissipation effect in various application scenes. According to the method, a theoretical basis is provided for tail structure design, the cable terminal with good heat dissipation efficiency can be designed through the method, and meanwhile installation convenience and mechanical safety in actual operation are both considered.

Description

Technical Field

[0001] This application belongs to the field of cable terminal design technology, specifically relating to an optimization design method, equipment and storage medium for cable terminal tail structure. Background Technology

[0002] In high-voltage / ultra-high-voltage DC cable systems, cable terminals, as key components connecting the cable body to external equipment, directly impact the system's operational reliability and transmission efficiency through their overall heat dissipation performance. Since the conductors generate significant heat during operation, poor heat dissipation can lead to localized overheating, causing serious problems such as insulation aging and even breakdown. Currently, the bottleneck in terminal heat dissipation performance is primarily concentrated in the enclosed air cavity of the tail section. Due to the extremely low thermal conductivity of still air and the structural limitations on natural air convection in this area, heat easily accumulates, resulting in particularly pronounced localized overheating.

[0003] Currently, research on the impact of fluid flow within cable terminals on heat transfer is insufficient, lacking a scientific basis for optimizing heat dissipation design. Existing technologies for optimizing heat dissipation in the tail structure mostly rely on experience or single-physics simulations, generally suffering from problems such as neglecting natural air convection and insufficient simulation accuracy, making it difficult to effectively solve the problems of localized overheating and low heat dissipation efficiency. Therefore, optimizing the tail structure design to improve the heat dissipation conditions of the enclosed air cavity and enhance the heat transfer efficiency in this area has become a key technical challenge for improving the performance of high-voltage / ultra-high-voltage DC cable systems. Summary of the Invention

[0004] To address the shortcomings in existing technologies, such as insufficient research on the impact of fluid flow within cable terminals on heat transfer and the neglect of natural air convection and insufficient simulation accuracy in the heat dissipation optimization design methods for tail structures, this application proposes an optimization design method for cable terminal tail structures. By combining COMSOL software to establish an electro-thermal-fluid multiphysics coupled simulation model, the influence of enclosed natural air convection on the overall temperature distribution is systematically analyzed, providing a basis for tail structure design.

[0005] First, this application provides an optimized design method for the tail structure of a cable terminal, including the following steps: Step 1: Obtain the material parameters of each component of the cable terminal, including density, thermal conductivity, constant pressure heat capacity, and elastic modulus and yield strength of the cone support material; Step 2: Use COMSOL finite element simulation software to establish an electro-thermal-fluid multiphysics coupled simulation model of the cable structure, and record the initial maximum air temperature TI in the tailpipe. When establishing a multiphysics-physics coupled simulation model of the cable structure, the process includes constructing the governing equations and setting the fluid flow model. The governing equations include the electric field governing equation, the heat transfer governing equation, the closed boundary flow field governing equation, and the statics governing equation. Step 3: Optimize the design of the tail structure of the cable terminal, including the optimization of the metal sheath restoration and the optimization of the cone support window design. Step 4: Import the optimized cable terminal structure from Step 3 into the simulation model from Step 2, and record the maximum optimized tailpipe air temperature TR; compare the difference TC between the initial maximum tailpipe air temperature TI and the maximum optimized tailpipe air temperature TR to see if it meets the temperature requirements. When the temperature difference TC does not meet the temperature requirement, repeat steps three and four. When the difference TC meets the temperature requirements, the final optimized design result is obtained, and the optimization design step ends.

[0006] In some embodiments, when establishing the electro-thermal-fluid multiphysics coupling simulation model of the cable structure in step two, the electric field control equation used is: ; Where: ▽ is the vector differential operator; J The current surface density vector, in units of ; For current source, unit is ; σ Electrical conductivity, measured in S / m; E This is the electric field intensity vector, with units of V / m; φ Electric potential, measured in V; This refers to the externally injected current density, in units of .

[0007] In some embodiments, when establishing the electro-thermal-fluid multiphysics coupling simulation model of the cable structure in step two, the heat transfer control equations used include fluid heat transfer control equations and solid heat transfer control equations. The governing equation for fluid heat transfer is: ; in: This is the constant-pressure heat capacity of the fluid material, expressed in J / (kg·K). T The thermodynamic temperature scale is expressed in Kelvin (K). q Heat flux density, in units of ; τ This is the viscous stress tensor, with units of Pa. S = 0.5[▽v + (▽v)T] This is the strain rate tensor, with units of 1 / s; The density of the heat source in the fluid, in units of ; The governing equation for heat transfer in solids is: ; in: The density of a solid material; The constant-pressure heat capacity of a solid material; λ is the thermal conductivity of a solid material, expressed in W / (m·K); Density of the heat source in a solid, in units of .

[0008] In some embodiments, when establishing the electro-thermal-fluid multiphysics coupled simulation model of the cable structure in step two, the closed boundary flow field control equations used are: ; in: The density of the fluid material, in units of ; v This is the velocity vector of the fluid, in m / s. p Pressure, measured in Pa; μ This is the dynamic viscosity, measured in Pa·s. I It is the identity matrix; The static control equations used are: ; in: σ This is the stress tensor, with units of Pa. f This is a volume force, with units of . .

[0009] In some embodiments, the fluid at the cable terminal includes the closed air inside the top equalizing ring and end cap, the tailpipe air, and the silicone oil in the oil chamber, depending on the fluid flow model settings. The flow model of the equalizing ring at the top of the cable terminal and the closed air inside the end cap is set as an isothermal region. Set the airflow model in the tailpipe to a laminar flow model; The silicone oil flow model in the oil cavity was set up using the Bousineske approximation simplified control equations.

[0010] In some embodiments, in step three, the metal sheath is first restored and optimized, that is, the length of the metal sheath is restored and optimized step by step according to a certain gradient. The length of the metal sheath restored is in the range from one-third of the height of the air cavity to the bottom of the stress cone. The gradient value of each restoration is any value between 100mm and 500mm. Record the maximum value of the first optimized temperature T1max of the tailpipe air after each metal sheath restoration and optimization, and compare whether the maximum value of the first optimized temperature T1max1 of the next time is less than the maximum value of the first optimized temperature T1max0 of the previous time, until the minimum value of the maximum value of the first optimized temperature T1max is obtained, and the metal sheath restoration and optimization is completed.

[0011] In some embodiments, in step three, the design optimization of the cone support window includes sequentially optimizing the position height of the heat dissipation window, the size of the heat dissipation window, and the number of heat dissipation windows using a single variable method. After each design optimization, a static simulation model of the cone support is established using COMSOL simulation software to analyze its mechanical stress distribution and further calculate the von Miese equivalent stress to ensure that the maximum value of the equivalent stress does not exceed the design allowable value. Under the condition that the equivalent stress is satisfied, record the maximum value of the second optimized temperature T2max of the tailpipe air after each cone support window design optimization, and compare whether the maximum value of the second optimized temperature T2max1 of the next time is less than the maximum value of the second optimized temperature T2max0 of the previous time, until the minimum value of the maximum value of the second optimized temperature T2max is obtained, and the cone support window design optimization is completed.

[0012] In some embodiments, the formula for calculating von Mies equivalent stress is as follows: ; in: This is the equivalent stress, in MPa. The first principal stress is expressed in MPa. This is the second principal stress, expressed in MPa. This is the third principal stress, measured in MPa.

[0013] Secondly, an apparatus is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the above-described method.

[0014] Finally, a storage medium is provided on which a computer program is stored, which, when executed by a processor, implements the steps of the above method.

[0015] Compared with the prior art, the beneficial effects that this application can achieve are: 1. By employing multiphysics coupling simulation technology, the impact of natural air convection on heat dissipation is analyzed in depth, providing a scientific basis for tail structure design and avoiding empirical errors in traditional design.

[0016] 2. By creating heat dissipation windows in the tapered support of the cable terminal tail structure and restoring the metal sheath, air convection and heat conduction efficiency are significantly improved. Simultaneously, the increased heat dissipation area effectively reduces heat accumulation inside the tail structure, thereby enhancing heat dissipation efficiency. 3. Through simulation optimization, the design scheme can adapt to different working conditions and environmental conditions, ensuring that the best heat dissipation effect can be achieved in various application scenarios.

[0017] 4. By reducing the internal temperature of the tail structure, the performance degradation and aging problems caused by overheating of the equipment are reduced, thus extending the service life of the cable terminal.

[0018] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of the cable terminal structure in this application is shown; Figure 2 A flowchart illustrating the optimized design method for the cable terminal tail structure in this application is shown. Figure 3 This application shows a comparison of the temperature distribution of the tailpipe air before and after the metal sheath is restored. Figure 4 This paper shows the relationship between the recovery length of the metal sheath and the maximum air temperature in the tailpipe in this application. Figure 5 A schematic diagram of the cone support structure in this application is shown; Figure 6 The von Mises stress distribution diagram of the cone-shaped support in this application is shown; Figure 7 This application shows a comparison of the airflow velocity in the tailpipe before and after the heat dissipation window is opened in the cone support; Figure 8 This paper shows the relationship between the location of the heat dissipation window and the maximum air temperature in the tailpipe in this application; Figure 9 This paper presents a comparison diagram of the air temperature distribution in the tailpipe when the heat dissipation window is located at different positions. Figure 10 This application shows a graph illustrating the relationship between the height of the heat dissipation window and the maximum air temperature in the tailpipe. Figure 11 A schematic diagram of the optimized cable terminal tail structure in this application is shown.

[0021] In the diagram: 1-Copper conductor, 2-XLPE insulation layer, 3-Silicone oil, 4-Porcelain bushing, 5-Epoxy resin sleeve, 6-Tail tube, 7-Cable body, 8-Stress cone, 9-Cone support, 91-Heat dissipation window, 92-Top, 93-Body, 94-Base, 10-Metal sheath, 11-Equalizing ring, 12-End cap, 13-Copper guide post, A-First reference line. Detailed Implementation

[0022] The term "comprising" in this application specification is synonymous with "including," "containing," or "characterized in," and is inclusive or open-ended, and does not exclude additional undescribed elements or method steps.

[0023] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0026] Example 1 This embodiment provides an optimized design method for the cable termination tail structure. The cable termination structure is as follows: Figure 1As shown, the cable includes a cable body 7, a tail structure, a porcelain bushing 4, an end cap 12, and an equalizing ring 11. The cable body 7 includes a copper conductor 1 and an XLPE insulation layer 2 disposed outside the copper conductor 1, which passes through the tail structure. A copper guide post 13 is disposed on the end cap 12, and the end of the copper conductor 1 is connected to the copper guide post 13, which is connected to the equalizing ring 11. The tail structure is partially disposed within the porcelain bushing 4, and silicone oil 3 is filled between the tail structure and the porcelain bushing 4.

[0027] The tail structure of the cable terminal includes a stress cone 8, a tail tube 6 connected to the lower side of the stress cone 8, the stress cone 8 being at least partially located inside the tail tube 6, the tail tube being filled with tail tube air, an epoxy resin sleeve 5 covering part of the stress cone 8 and the outside of the tail tube 6, and also includes a cone support 9 as described in the above embodiment, the cone support 9 being located inside the tail tube 6 for supporting the stress cone 8.

[0028] like Figure 2 As shown, the optimized design method for the cable terminal tail structure includes the following steps: Step 1: Obtain the material parameters of each component of the cable terminal, including density, thermal conductivity, constant pressure heat capacity, and elastic modulus and yield strength of the cone support material; the material parameters are obtained from the factory-known parameters or measured using laboratory equipment.

[0029] Step 2: Use COMSOL finite element simulation software to establish an electro-thermal-fluid multiphysics coupling simulation model of the cable structure, and record the maximum initial tailpipe air temperature TI.

[0030] When establishing a multiphysics-physics coupled simulation model of the cable structure, the process includes constructing the governing equations and setting the fluid flow model. The governing equations include the electric field governing equation, the heat transfer governing equation, the closed boundary flow field governing equation, and the statics governing equation.

[0031] The governing equations are constructed as follows: The governing equations for the electric field are: (1); In formula (1): ▽ is the vector differential operator; J The current surface density vector, in units of ; For current source, unit is σ is the electrical conductivity, in units of S / m; E is the electric field intensity vector, in units of V / m; φ is the electric potential, in units of V. This refers to the externally injected current density, in units of The main heat source for DC cable terminals is Joule heating of the conductor. In addition, the conductivity loss of each insulation material under the action of an electric field should also be considered.

[0032] The governing equations for a closed boundary flow field are: (2); In formula (2): The density of the fluid material, in units of ; v This is the velocity vector of the fluid, in m / s. p Pressure, measured in Pa; μ This is the dynamic viscosity, measured in Pa·s. I It is an identity matrix.

[0033] The heat transfer control equations include fluid heat transfer control equations and solid heat transfer control equations. The governing equation for fluid heat transfer is: (3); In formula (3): This is the constant-pressure heat capacity of the fluid material, expressed in J / (kg·K). T The thermodynamic temperature scale is expressed in Kelvin (K). q Heat flux density, in units of ; τ This is the viscous stress tensor, with units of Pa. S = 0.5[▽v + (▽v)T] This is the strain rate tensor, with units of 1 / s; The density of the heat source in the fluid, in units of ; The governing equation for heat transfer in solids is: (4); In formula (4): The density of a solid material; λ is the constant-pressure heat capacity of the solid material; λ is the thermal conductivity of the solid material, in W / (m·K); Density of the heat source in a solid, in units of Solid components include all solid-material parts on the cable terminal.

[0034] Static governing equations: (5); In formula (5): σ This is the stress tensor, with units of Pa. f This is a volume force, with units of . The equation indicates that the internal stress of the solid is in equilibrium with the external force, and the solid is in a static state.

[0035] The process of setting up the flow model is as follows: The fluids in the cable terminal include the top 92 equalizing ring and the closed air inside the end cap, the tailpipe air, and the silicone oil in the oil chamber.

[0036] 1) For the 92 equalizing ring at the top of the terminal and the closed air inside the end cover, since its flow space is small and far away from the terminal hot spot, the overall temperature difference is small (less than 0.5℃), so it is regarded as an isothermal region.

[0037] 2) For the air inside the tail structure, due to the large cavity volume and the high temperature of the tail structure as the hot spot area of ​​the entire terminal, the influence of airflow on heat transfer should be considered. In natural convection, the choice between laminar or turbulent flow models depends on the Rayleigh number (Ra), as shown in equation (6): (6); In formula (6): g is Local gravitational acceleration, in units of ; β The coefficient of thermal expansion is ; ΔT This represents the fluid temperature difference, expressed in Kelvin (K). L The characteristic length of the fluid domain, in meters; Kinematic viscosity, unit: ; α Thermal diffusivity, in units of Regarding air, β=1 / T For 525 kV DC cable terminals, the Rayleigh number of the tailpipe air is much lower than the critical value. Therefore, the flow is laminar.

[0038] 3) For the silicone oil in the oil cavity, its density changes little with temperature, and the governing equations can be simplified using the Bousineske approximation, as shown in equations (7)-(8): Buoyancy term: (7); Other items: (8); In the above formula: Reference temperature The corresponding reference density means that density changes only affect the buoyancy term of the momentum equation, while density changes are negligible in other terms of the continuity and momentum equations, thus significantly reducing the simulation time required.

[0039] Based on the above control equations and fluid model settings, an electro-thermal-fluid multiphysics coupling model of the original structure of the DC cable terminal was established using COMSOL simulation software. The air temperature distribution in the tailpipe was calculated, and the initial maximum temperature TI of the tailpipe air was recorded.

[0040] Step 3: Optimize the tail structure of the cable terminal, including the restoration and optimization of the metal sheath 10, and the optimization of the cone support window design.

[0041] Optimization for Metal Sheath 10 Restoration: First, the length of the metal sheath 10 is restored and optimized successively according to a certain gradient. In some embodiments, the metal sheath is an aluminum sheath, and the value range of the restored length of the metal sheath 10 is from one-third of the air cavity height to the bottom end of the stress cone. The gradient value for each restoration is any value between 100 mm and 500 mm. Import the terminal geometric model of the restored metal sheath 10 into COMSOL, recalculate the temperature distribution of the air in the tail pipe in the terminal tail structure, and record the maximum value T1max of the first optimized temperature of the air in the tail pipe after each restoration and optimization of the metal sheath 10. Compare whether the maximum value T1max1 of the first optimized temperature in the next time is less than the maximum value T1max0 of the first optimized temperature in the previous time until the minimum value of the maximum value T1max of the first optimized temperature is obtained, and complete the restoration and optimization of the metal sheath 10.

[0042] Specifically, when initially restoring and optimizing the metal sheath 10, the extended length of the restored metal sheath 10 is 500 mm or one-third of the air cavity height, and the smaller value of the two is taken. Import the terminal geometric model of the restored metal sheath 10 into COMSOL, recalculate the temperature distribution of the air in the tail pipe in the terminal tail structure, and record the maximum value T1max0 of the first optimized temperature of the air in the tail pipe.

[0043] Compare the temperature distribution of the air in the tail pipe without the restored metal sheath 10 with the temperature distribution of the air in the tail pipe after the metal sheath 10 is restored. As Figure 3 shown, when the metal sheath 10 is not restored, the initial maximum temperature TI of the air in the tail pipe is 65.7 °C. When the extended length of the metal sheath 10 is 500 mm, the maximum value T1max0 of the first optimized temperature of the air in the tail pipe is 64.22 °C. It can be seen that after the metal sheath 10 is restored, the maximum temperature of the tail structure has decreased significantly.

[0044] Continue to restore and optimize the length of the metal sheath 10 successively according to a certain gradient. In this embodiment, the restored length is extended by a gradient of 500 mm specifically, that is, the metal sheath 10 is restored to a length of 1000 mm for the second time. Record the maximum value T1max1 of the first optimized temperature of the air in the tail pipe as 60.57 °C. By comparison, it is found that T1max1 < T1max0. After reassigning the maximum value of the first optimized temperature, that is, T1max0 = T1max1, continue to extend and restore the metal sheath 10, and form a temperature change curve with the maximum value T1max of the first optimized temperature of the air in the tail pipe recorded each time. As Figure 4 shown, when the length of the metal sheath 10 is extended to 1500 mm, the maximum value T1max of the first optimized temperature of the air in the tail pipe drops to 59.42 °C. It is found that the greater the restored length of the metal sheath 10, the better the heat dissipation effect. Therefore, further, the restoration height of the metal sheath 10 can be restored up to the bottom end of the stress cone 8 at most.

[0045] Optimization of the cone-shaped window design: This includes optimizing the position height, size, and number of heat dissipation windows 91 using a single variable method.

[0046] After each design optimization, a static simulation model of the cone support is established using COMSOL simulation software to analyze its mechanical stress distribution and further calculate the von Mises equivalent stress to ensure that the maximum value of the equivalent stress does not exceed the design allowable value.

[0047] Under the condition that the equivalent stress is satisfied, record the maximum value of the second optimized temperature T2max of the tailpipe air after each cone support window design optimization, and compare whether the maximum value of the second optimized temperature T2max1 of the next time is less than the maximum value of the second optimized temperature T2max0 of the previous time, until the minimum value of the maximum value of the second optimized temperature T2max is obtained, and the cone support window design optimization is completed.

[0048] Specifically, the cone support 9 includes a top 92, a main body 93, and a base 94, with the main body 93 connecting the base 94 and the top 92. The top 92 is a funnel-shaped structure used to support and fix the stress cone 8; the main body 93 is a cylindrical structure, and the base 94 has a cross-sectional diameter larger than that of the main body 93, extending outwards with a protrusion. The connection point between the top 92 and the main body 93 is set as a first reference line A. Heat dissipation windows 91 are provided on the main body 93 near the first reference line A, and the heat dissipation windows 91 are spaced apart circumferentially along the main body 93. In this embodiment, there are 8 windows, each with a height of 50mm and a width corresponding to a central angle of 20° in the circumferential direction. Figure 5 As shown, Figure 5 (a) is a front view of the cone holder. Figure 5 (b) is a cross-sectional view at the location of the heat dissipation window 91 of the cone support.

[0049] Furthermore, the mechanical stress distribution of the cone support was simulated, and the corresponding von Mises stress distribution is as follows: Figure 6 As shown, the maximum stress is 20.00 MPa, which is far lower than the yield strength of the alloy used in the cone support. That is, the structure of the cone support in this embodiment meets the mechanical stress requirements.

[0050] Furthermore, simulation analysis was conducted on the airflow velocity in the tailpipe of the high-voltage cable terminal, such as... Figure 7 As shown. Without a heat dissipation window 91 provided for the stress cone support 9, as... Figure 7 As shown in (a), the air velocity in the tailpipe inside the cone support 9 is basically the same, while the air velocity in the tailpipe outside the cone support 9 is 0.15 m / s; and when a heat dissipation window 91 is opened on the cone support 9, as Figure 7As shown in (b), the air in the tailpipe inside the cone support 9 flows rapidly outward at the heat dissipation window 91, with a maximum flow velocity of 0.35 m / s. Clearly, by setting the heat dissipation window 91 on the cone support 9, the air convection path in the tailpipe is increased, significantly enhancing the convection between the air inside and outside the cone support 9, thereby greatly improving the heat dissipation effect of the tailpipe air inside the stress cone support 9. Natural convection causes the hot airflow to rise to the top region 92; therefore, opening a window above the cone support has a more significant impact on the air convection effect in the tailpipe.

[0051] Furthermore, the position of the heat dissipation window 91 is optimized, moving it further away from the first reference line A. Specifically, the distance between the upper edge of the heat dissipation window 91 and the first reference line A is gradually varied in gradients of 10mm-50mm, and the second optimized maximum temperature T2max of the tailpipe air is recorded. Specifically, during the optimization design process, a trend line is formed based on the maximum temperature distribution at different positions of the heat dissipation window, such as... Figure 8 As shown, when the upper edge of the heat dissipation window 91 is 10mm away from the first reference line A, the second optimal maximum temperature T2max of the tailpipe air is 57.47℃; when the upper edge of the heat dissipation window 91 is 50mm away from the first reference line A, the second optimal maximum temperature T2max of the tailpipe air is 58.13℃, showing a significant increase. When the upper edge of the heat dissipation window 91 is between 50mm and 150mm away from the first reference line A, the change in the second optimal maximum temperature T2max is not very significant; when the upper edge of the heat dissipation window 91 is 300mm away from the first reference line A, the second optimal maximum temperature T2max of the tailpipe air exceeds 60℃, which no longer meets the optimization design target.

[0052] As the above analysis shows, the smaller the distance between the upper edge of the heat dissipation window 91 and the first reference line A, the more obvious the heat dissipation effect. When the distance between the upper edge of the heat dissipation window 91 and the first reference line A reaches 300mm, the maximum temperature no longer meets the optimization design target. A comparative analysis of the temperature distribution of the cable terminal tail structure when the distance between the upper edge of the heat dissipation window 91 and the first reference line A is 10mm and 300mm is performed. Figure 9 As shown, the distance between the upper edge of the heat dissipation window 91 and the first reference line A is the hot air accumulation section. The larger this distance is, the easier it is for the hot air to be diverted at the heat dissipation window 91, which prevents the hot air from flowing out of the heat dissipation window completely, causing the hot air to accumulate at this section, resulting in heat accumulation and reduced heat dissipation effect.

[0053] Furthermore, the dimensions of the heat dissipation window 91 are optimized. Specifically, when the distance between the upper edge of the heat dissipation window 91 and the first reference line A is 10mm, the height of the heat dissipation window 91 is gradually increased from 50mm in increments of 50mm, and the maximum second optimized temperature T2max is recorded during the process to form a trend curve, such as... Figure 10 As shown, when the height of the heat dissipation window 91 varies from 50mm to 300mm, the maximum second optimal temperature T2max of the tailpipe air decreases from 57.47℃ to 56.66℃. With the increase in the height of the heat dissipation window 91, the maximum second optimal temperature of the tailpipe air exhibits slight fluctuations and decreases. It can be seen that at the same height, the height of the heat dissipation window 91 has little effect on temperature, but the design of the heat dissipation window 91's height has a certain impact on mechanical stress. The height of the heat dissipation window 91 should not be too large; when the height of the heat dissipation window 91 exceeds 300mm, it will be difficult to meet the mechanical stress requirements.

[0054] Step 4: Import the optimized cable terminal structure from Step 3 into the simulation model from Step 2, record the maximum optimized tailpipe air temperature TR, and compare the difference TC between the maximum optimized tailpipe air temperature TR and the initial maximum tailpipe air temperature TI to see if it meets the temperature requirements. When the temperature difference TC does not meet the temperature requirement, repeat steps three and four. When the difference TC meets the temperature requirements, the final optimized design result is obtained, and the optimization design step ends.

[0055] Specifically, the difference TC is at least 5℃, meaning that the maximum air temperature of the tailpipe is reduced by at least 5℃ after the optimized design compared to before the cable terminal optimization design.

[0056] Furthermore, steps three and four can be repeated to record all tail structure optimization design schemes that meet the temperature requirements for all differences in TC, and selection can be made based on actual working conditions and installation conditions.

[0057] The optimized cable termination tail structure is as follows: Figure 11 As shown, the restored height of the metal sheath 10 reaches at least the lower edge of the heat dissipation window, and the height of the heat dissipation window is preferably 10-100mm away from the first reference line A. By opening the heat dissipation window 91 in the cone support of the cable terminal tail structure and restoring the metal sheath 10, the convection and heat conduction efficiency of the tail pipe air is significantly improved.

[0058] This application also provides an apparatus, which includes a processor and a memory. The memory stores computer-executable instructions, which, when executed by the processor, implement the optimized design method for the cable terminal tail structure described above.

[0059] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the cable termination component construction method.

[0060] As can be seen from the above analysis, the optimized design method for the cable terminal tail structure provided in this application employs multi-physics coupled simulation technology to deeply analyze the impact of natural air convection on heat dissipation in the tail pipe, providing a scientific basis for tail structure design and avoiding empirical errors in traditional designs. By opening a heat dissipation window 91 in the cone support of the cable terminal tail structure and restoring the metal sheath 10, the convection and heat conduction efficiency of the tail pipe are significantly improved. At the same time, the heat dissipation area is increased, effectively reducing heat accumulation inside the tail structure and improving heat dissipation efficiency.

[0061] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An optimized design method for the tail structure of a cable termination, characterized in that, The optimized design method for the cable terminal tail structure includes the following steps: Step 1: Obtain the material parameters of each component of the cable terminal, including density, thermal conductivity, constant pressure heat capacity, and elastic modulus and yield strength of the cone support material; Step 2: Use COMSOL finite element simulation software to establish an electro-thermal-fluid multiphysics coupled simulation model of the cable structure, and record the initial maximum air temperature TI in the tailpipe. When establishing a multiphysics-physics coupled simulation model of the cable structure, the process includes constructing the governing equations and setting the fluid flow model. The governing equations include the electric field governing equation, the heat transfer governing equation, the closed boundary flow field governing equation, and the statics governing equation. Step 3: Optimize the design of the tail structure of the cable terminal, including the optimization of the metal sheath restoration and the optimization of the cone support window design. Step 4: Import the optimized cable terminal structure from Step 3 into the simulation model from Step 2, and record the maximum optimized tailpipe air temperature TR; compare the difference TC between the initial maximum tailpipe air temperature TI and the maximum optimized tailpipe air temperature TR to see if it meets the temperature requirements. When the temperature difference TC does not meet the temperature requirement, repeat steps three and four. When the difference TC meets the temperature requirements, the final optimized design result is obtained, and the optimization design step ends.

2. The optimized design method for the cable terminal tail structure according to claim 1, characterized in that, In step two, when establishing the electro-thermal-fluid multiphysics coupled simulation model of the cable structure, the electric field control equation used is: ; Where: ▽ is the vector differential operator; J The current surface density vector, in units of ; For current source, unit is ; σ Electrical conductivity, measured in S / m; E This is the electric field intensity vector, with units of V / m; φ Electric potential, measured in V; This refers to the externally injected current density, in units of .

3. The optimized design method for the cable terminal tail structure according to claim 1, characterized in that, When establishing the electro-thermal-fluid multiphysics coupling simulation model of the cable structure in step two, the heat transfer control equations used include fluid heat transfer control equations and solid heat transfer control equations. The governing equation for fluid heat transfer is: ； in: is the isobaric heat capacity of the fluid material, in J / (kg·K); T is the thermodynamic temperature scale, in K; q Heat flux density, in units of ; τ S is the viscous stress tensor, in Pa; S = 0.5[▽v + (▽v)T] is the strain rate tensor, in 1 / s; The density of the heat source in the fluid, in units of ; The governing equation for heat transfer in solids is: ; in: The density of a solid material; λ is the constant-pressure heat capacity of the solid material; λ is the thermal conductivity of the solid material, in W / (m·K); Density of the heat source in a solid, in units of .

4. The optimized design method for the cable terminal tail structure according to claim 1, characterized in that, In step two, when establishing the electro-thermal-fluid multiphysics coupled simulation model of the cable structure, the closed boundary flow field governing equations used are: ； in: The density of the fluid material, in units of ; v This is the velocity vector of the fluid, in m / s. p Pressure, measured in Pa; μ This is the dynamic viscosity, measured in Pa·s. I It is the identity matrix; The static control equations used are: ； in: σ This is the stress tensor, with units of Pa. f This is a volume force, with units of . .

5. The optimized design method for the cable terminal tail structure according to claim 1, characterized in that, The fluids in the cable terminal include the top equalizing ring and the closed air inside the end cap, the tailpipe air, and the silicone oil in the oil chamber. When setting the fluid flow model, The flow model of the equalizing ring at the top of the cable terminal and the closed air inside the end cap is set as an isothermal region. Set the airflow model in the tailpipe to a laminar flow model; The silicone oil flow model in the oil cavity was set up using the Bousineske approximation simplified control equations.

6. The optimized design method for the cable terminal tail structure according to claim 1, characterized in that, In step three, the metal sheath is first restored and optimized, that is, the length of the metal sheath is restored and optimized step by step according to a certain gradient. The length of the metal sheath is restored in the range of one-third of the height of the air cavity to the bottom of the stress cone. The gradient value of each restoration is any value between 100mm and 500mm. Record the maximum value of the first optimized temperature T1max of the tailpipe air after each metal sheath restoration and optimization, and compare whether the maximum value of the first optimized temperature T1max1 of the next time is less than the maximum value of the first optimized temperature T1max0 of the previous time, until the minimum value of the maximum value of the first optimized temperature T1max is obtained, and the metal sheath restoration and optimization is completed.

7. The optimized design method for the cable terminal tail structure according to claim 1, characterized in that, In step three, the design of the cone support window is optimized, including optimizing the position height, size and number of heat dissipation windows using a single variable method. After each design optimization, a static simulation model of the cone support is established using COMSOL simulation software to analyze its mechanical stress distribution and further calculate the von Miese equivalent stress to ensure that the maximum value of the equivalent stress does not exceed the design allowable value. Under the condition that the equivalent stress is satisfied, record the maximum value of the second optimized temperature T2max of the tailpipe air after each cone support window design optimization, and compare whether the maximum value of the second optimized temperature T2max1 of the next time is less than the maximum value of the second optimized temperature T2max0 of the previous time, until the minimum value of the maximum value of the second optimized temperature T2max is obtained, and the cone support window design optimization is completed.

8. The optimized design method for the cable terminal tail structure according to claim 7, characterized in that, The formula for calculating von Mises equivalent stress is shown below: ； in: This is the equivalent stress, in MPa. The first principal stress is expressed in MPa. This is the second principal stress, expressed in MPa. This is the third principal stress, measured in MPa.

9. A device, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1-8.

10. A storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method according to any one of claims 1-8.

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