Anti-dirt-accumulation train roof insulator structure

Abstract

The invention provides an anti-dirt-accumulation train roof insulator structure, and relates to the technical field of high-speed trains, the anti-dirt-accumulation train roof insulator structure comprises a plurality of core rods and a plurality of umbrella skirts, the umbrella skirts are fixed at two ends of the core rods, and upper inclination angles and lower inclination angles of the plurality of umbrella skirts are adjustable. The wind blowing effect is considered, the pressure condition of the leeward side of the insulator is improved by changing the up-down dip angle of the umbrella skirts and the height of the core rod, the change of the airflow condition on the surface of the insulator is realized, the purpose of optimizing the surface pollution of the insulator surface is achieved, and the probability of pollution flashover accidents of the roof insulator is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of high-speed trains, and in particular to a pollution-proof train roof insulator structure. Background Art

[0002] At present, there are three mainstream methods to improve the anti-pollution flashover capability of roof insulators: one is to increase the creepage distance of the roof insulators. By increasing the creepage distance of the roof insulators, the flashover voltage of the insulators can be increased to a certain extent, but due to the limitations of the insulator structure size and production process, the creepage distance of the roof insulators is limited to a certain size; the second is to manually clean the dirt on the surface of the roof insulator regularly. This method is currently the most widely used, but for the composite materials commonly used in roof insulators, the surface of the composite materials will be damaged due to the friction of the wiping equipment, resulting in a decrease in the self-cleaning performance of the composite materials on the surface of the roof insulators; the third is to spray the surface of the roof insulator with an anti-fouling coating. The roof insulators sprayed with anti-fouling coating have a good anti-fouling effect, but the anti-fouling coating is expensive and has a short validity period. Therefore, it is very necessary to find an insulator structure that can effectively improve the anti-fouling performance of the roof insulator. Summary of the invention

[0003] The purpose of the present invention is to provide a structure of anti-pollution train roof insulator to improve the above problems. In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0004] In a first aspect, the present application provides an anti-pollution train roof insulator structure, comprising a plurality of core rods and a plurality of sheds, wherein the sheds are fixed at both ends of the core rods, and the upward and downward inclination angles of the plurality of sheds are adjustable.

[0005] Furthermore, the umbrella skirt includes a large umbrella skirt and a small umbrella skirt, the diameter of the large umbrella skirt is larger than the diameter of the small umbrella skirt, the large umbrella skirt and the small umbrella skirt are respectively fixed at both ends of each core rod, the large umbrella skirts are parallel to each other and arranged at equal intervals, and the small umbrella skirts are parallel to each other and arranged at equal intervals.

[0006] Furthermore, the upward inclination angles of the large umbrella skirt and the small umbrella skirt range from 0° to 10°.

[0007] Furthermore, the downward inclination angles of the large umbrella skirt and the small umbrella skirt range from 0° to 5°.

[0008] Furthermore, the height of the core rod ranges from 20 mm to 60 mm.

[0009] Furthermore, the diameter of the large umbrella skirt is 182 mm, and the diameter of the small umbrella skirt is 152 mm.

[0010] Furthermore, the diameter of the core rod is 70 mm. In a second aspect, the present application also provides a method for determining the structure of a pollution-proof train roof insulator, comprising:

[0011] Constructing a three-dimensional model of an insulator structure, wherein the insulator structure includes a plurality of core rods and a plurality of sheds, wherein the plurality of sheds include a large shed and a small shed, and the diameter of the large shed is greater than the diameter of the small shed;

[0012] Importing the three-dimensional model into fluid dynamics software for meshing to obtain a plurality of target mesh units;

[0013] Inputting boundary conditions into the fluid dynamics software, and performing pollution simulation of the insulator based on the discrete phase model preset in the fluid dynamics software, to obtain a plurality of insulator simulation results, wherein the insulator simulation results are obtained by weighted summation of the simulation results corresponding to each target unit grid;

[0014] Determine an optimal simulation result and a corresponding boundary parameter from multiple insulator simulation results, wherein the optimal simulation result is used to characterize a simulation result with a minimum contamination volume fraction corresponding to a three-dimensional model in a contamination simulation, and the boundary parameters include a core rod height, an upward inclination angle of a shed, and a downward inclination angle of a shed;

[0015] The insulator structure is correspondingly arranged based on the boundary parameters, and the insulator structure is fixed on the roof of the train.

[0016] The beneficial effects of the present invention are:

[0017] The present invention takes the wind blowing effect into consideration and changes the up and down inclination angles of the shed skirt and the core rod height, thereby improving the pressure condition on the leeward side of the insulator, realizing the change of the airflow condition on the surface of the insulator, and achieving the purpose of optimizing the pollution accumulation on the surface of the insulator, thereby effectively reducing the probability of pollution flashover accidents of the roof insulator.

[0018] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0020] Figure 1 It is a schematic diagram of the structure of the anti-pollution train roof insulator described in an embodiment of the present invention;

[0021] Figure 2 It is a schematic flow chart of a method for determining the structure of a roof insulator for an anti-pollution train according to an embodiment of the present invention;

[0022] Figure 3 The pollution accumulation and flow field conditions corresponding to the initial insulator described in the embodiment of the present invention in the fluid dynamics software simulation;

[0023] Figure 4 The optimal simulation result described in the embodiment of the present invention corresponds to the pollution accumulation and flow field conditions in the fluid dynamics software simulation;

[0024] Figure 5 A comparison diagram of pressure values ​​on the leeward side of the insulator described in an embodiment of the present invention;

[0025] Figure 6 A schematic diagram of a flow field of a roof insulator group described in an embodiment of the present invention;

[0026] Figure 7 It is a schematic diagram of the flow field of another roof insulator group described in an embodiment of the present invention.

[0027] Markings in the figure: 1, core rod; 2, large umbrella skirt; 3, small umbrella skirt. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0030] Embodiment 1:

[0031] See also Figure 1 This embodiment provides a structure of a roof insulator for a train that prevents contamination accumulation, comprising:

[0032] A plurality of core rods 1 and a plurality of sheds, wherein the sheds are fixed at both ends of the core rod 1, and the upward and downward inclination angles of the plurality of sheds are adjustable;

[0033] Specifically, there are two main reasons for the occurrence of contamination on the surface of insulators: first, when the dirt flows through the roof insulator, it is affected by the negative pressure area formed by the reduced flow velocity on the leeward side, and the airflow forms turbulence on the leeward side. When the dirt follows the turbulent movement on the leeward side of the insulator, when the resultant force acting on the dirt is zero, the dirt will be deposited on the insulation surface; second, the dirt that has accumulated on the windward and lateral sides of the insulator will slide along the surface of the insulator under the action of the wind blowing effect, and part of the dirt will slide to the leeward side of the insulator, resulting in increased dirt accumulation.

[0034] Therefore, the present application considers adjusting the up and down inclination angles of the insulator shed and the height of the core rod 1 to affect the airflow passing through the insulator, and selecting appropriate shed inclination angles and core rod 1 heights to optimize the flow field of the insulator, thereby reducing the surface contamination of the insulator.

[0035] The umbrella skirt comprises a large umbrella skirt 2 and a small umbrella skirt 3. The diameter of the large umbrella skirt 2 is larger than that of the small umbrella skirt 3. The large umbrella skirt 2 and the small umbrella skirt 3 are respectively fixed at both ends of each core rod 1. The large umbrella skirts 2 are parallel to each other and arranged at equal intervals, and the small umbrella skirts 3 are parallel to each other and arranged at equal intervals. The large umbrella skirt 2 and the small umbrella skirt 3 are arranged at intervals. The large umbrella skirt 2 can provide a larger coverage area, effectively change the airflow path, reduce the negative pressure area and turbulence on the leeward side, thereby reducing the possibility of dirt deposition; the small umbrella skirt 3 provides additional protection and further optimizes the uniformity of the airflow.

[0036] The upward inclination angle of the large shed 2 and the small shed 3 is in the range of 0° to 10°; the downward inclination angle of the large shed 2 and the small shed 3 is in the range of 0° to 5°; the height of the core rod 1 is in the range of 20mm to 60mm; the diameter of the large shed 2 is 182mm, the diameter of the small shed 3 is 152mm; the diameter of the core rod 1 is 70mm; in the present application, when the diameters of the large shed 2, the small shed 3 and the core rod 1 are fixed, only the upward and downward inclination angles of the large shed 2 and the small shed 1 and the height of the core rod 1 are adjusted, so as to achieve the purpose of optimizing airflow distribution, improving airflow dynamics on the surface of the insulator, and reducing contamination on the surface of the insulator.

[0037] Embodiment 2:

[0038] The insulator model was constructed using SolidWorks software, and multiple insulator models were simulated after changing the up and down inclination angles of the insulator shed and the height of the core rod 1. The flow field and contamination of the insulator under different insulator structural parameters were obtained. The optimal insulator structural parameters were obtained by comparing the insulator contamination conditions. According to the flow field distribution corresponding to the optimal insulator structural parameters, the improvement mechanism of the roof insulator contamination condition was determined.

[0039] The specific implementation steps are as follows Figure 2 As shown, this embodiment provides a method for determining the structure of a roof insulator of an anti-pollution train. The figure shows that the method includes step S10, step S20, step S30, step S40 and step S50:

[0040] Step S10. construct a three-dimensional model of an insulator structure, wherein the insulator structure includes a plurality of core rods 1 and a plurality of sheds, wherein the plurality of sheds include a large shed 2 and a small shed 3, and the diameter of the large shed 2 is greater than the diameter of the small shed 3;

[0041] Step S20. Importing the three-dimensional model into fluid dynamics software for meshing to obtain a plurality of target mesh units;

[0042] Specifically, step S20 specifically includes step S21 and step S22:

[0043] Step S21. Meshing the three-dimensional model based on fluid dynamics software to obtain a plurality of initial mesh units, wherein a refined mesh is used for the insulator surface area, and a conventional mesh is used for areas other than the insulator surface area;

[0044] Step S22. Setting a boundary layer on the surface area of ​​the insulator, and correspondingly setting the number of boundary layer layers, stretching factor and thickness adjustment factor to obtain a plurality of target grid cells, wherein the number of boundary layer layers is used to characterize the number of grid cell layers in the boundary layer, the stretching factor is used to characterize the size ratio change of adjacent grid cells in the boundary layer, and the thickness adjustment factor is used to control the overall thickness of the boundary layer;

[0045] Specifically, in the fluid dynamics software simulation, the surface of the roof insulator is meshed and refined, and the rest is meshed in a conventional manner. The boundary layer of the roof insulator is set. Usually, the number of boundary layers is set to 1, the stretching factor is set to 1.1, and the thickness adjustment factor is set to 1.1. Therefore, the complete mesh of the roof insulator includes 831072 units.

[0046] Step S30. Input the boundary conditions into the fluid dynamics software, and perform a pollution simulation of the insulator based on the discrete phase model preset in the fluid dynamics software to obtain a plurality of insulator simulation results, wherein the insulator simulation results are obtained by weighted summation of the simulation results corresponding to each target unit grid;

[0047] Specifically, in order to obtain the pollution accumulation and flow field of the roof insulator, COMSOL software is used for simulation calculation. The boundary conditions required for the simulation calculation are shown in Table 1:

[0048] Table 1

[0049]

[0050] In the fluid dynamics software simulation, the physical field is set to "mixture model", "RANS-based k-ε turbulence model" and "global ordinary differential equation" to simulate the interaction between airflow and contamination particles. The continuous phase is air, and the discrete phase, i.e., contamination, is calcium carbonate particles with a diameter of 10μm. The distribution of contamination in the air accounts for 15%; the calculation domain is set to a cylinder with a radius of 0.5m and a length of 2m. The turbulence model and mixture model can accurately simulate the process of airflow pushing, sliding and depositing contamination particles, so as to more accurately predict the deposition of contamination particles on the surface of the insulator, determine which areas are more prone to contamination, and provide direction for the optimization of the insulator structure.

[0051] Step S40. Determine the optimal simulation result and the corresponding boundary parameters from the multiple insulator simulation results, the optimal simulation result is used to characterize the simulation result with the minimum contamination volume fraction corresponding to the three-dimensional model in the contamination simulation, and the boundary parameters include the height of the core rod 1, the upward inclination angle of the shed skirt, and the downward inclination angle of the shed skirt;

[0052] Specifically, in fluid dynamics software simulation, in order to more intuitively represent the contamination condition of the insulator surface in high-speed airflow, the contamination amount is usually expressed by the contamination volume fraction. The calculation formula for the contamination volume fraction is:

[0053]

[0054] Where ρ is the contamination volume fraction dimensionless; V p V is the volume of contamination; g is the volume of air.

[0055] The above-mentioned pollution volume and air volume need to be calculated at the same temperature and pressure.

[0056] In the fluid dynamics software simulation, the analysis of the flow field and contamination of the roof insulator will also be displayed through images. First, the cross-sectional pressure of the roof insulator and the pressure value on the leeward side are extracted. By performing cross-sectional simulation on the insulator, the cross-sectional pressure diagram of the insulator is obtained. At the same time, the pressure value is extracted on the leeward side of the insulator, and the extracted pressure value is imported into the origin drawing software to construct the leeward surface pressure value curve. The cross-sectional pressure diagram of the roof insulator and the leeward surface pressure curve corresponding to the initial simulation results and the optimal simulation results are compared, thereby providing an optimization direction for improving the contamination of the roof insulator.

[0057] like Figure 3 As shown in the figure, the pollution accumulation and flow field of the initial insulator in the fluid dynamics software simulation are very serious. Figure 4 As shown in the figure, the fluid dynamics software simulation results of the insulator structural parameters corresponding to the optimal simulation results are shown. It can be seen that the pollution accumulation on the windward side of the insulator is similar to Figure 3 There is no significant change compared with the traditional method, but the pressure in the leeward area of ​​the insulator is significantly increased, and the negative pressure area is greatly reduced. The turbulence formed by the existence of the negative pressure area can be effectively reduced, thereby effectively preventing the accumulation of dirty particles on the leeward side of the insulator and improving the anti-pollution flashover level of the roof insulator.

[0058] like Figure 5 As shown in the figure, the pressure values ​​on the leeward side of the roof insulator are collected. It can be seen from the figure that the leeward side surface pressure corresponding to the optimal simulation result is significantly greater than the leeward side surface pressure of the initial insulator, which numerically shows the comparison of the leeward side pressure of the insulator.

[0059] Step S50: setting an insulator structure based on the boundary parameters, and fixing the insulator structure on the roof of the train;

[0060] Specifically, the present application further explores the flow field conditions corresponding to different installation methods of the roof insulator group, simplifies the structure of the roof insulator group of the high-speed train, retains only the insulator group, and removes other auxiliary structures.

[0061] The initial installation method of the insulator group is that the distance between the front and rear roof insulators is 2.5m, the distance between the left and right roof insulators is 2m, and the distance between the left and right roof insulators is 1m behind the rear roof insulator. Under the premise of ensuring the insulation spacing, the variable distance between the left and right roof insulators is 1m to 2.5m, and the variable distance between the front and rear roof insulators is 2m to 3m. Through simulation analysis of roof insulators with different installation methods, the current receiving conditions of each insulator under different installation methods are explored.

[0062] like Figure 6 and Figure 7As shown in the two figures, the flow field conditions of the roof insulator group at different installation positions are demonstrated. It can be seen from the figure that shortening the roof insulators at the left and right ends can effectively reduce the negative pressure area of ​​the rearmost roof insulator. At the same time, the negative pressure areas of the remaining roof insulators will not change much. The reduction of the negative pressure area effectively reduces the turbulence, thereby greatly reducing the pollution.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0064] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A pollution-proof train roof insulator structure, characterized in that: It comprises a plurality of core rods (1) and a plurality of sheds, wherein the sheds are fixed at two ends of the core rods (1), and the upward and downward inclination angles of the plurality of sheds are adjustable.

2. The anti-pollution train roof insulator structure according to claim 1 is characterized in that The umbrella skirt comprises a large umbrella skirt (2) and a small umbrella skirt (3), the diameter of the large umbrella skirt (2) is larger than the diameter of the small umbrella skirt (3), the large umbrella skirt (2) and the small umbrella skirt (3) are respectively fixed at both ends of each core rod (1), the large umbrella skirts (2) are parallel to each other and are arranged at equal intervals, and the small umbrella skirts (3) are parallel to each other and are arranged at equal intervals.

3. The anti-pollution train roof insulator structure according to claim 2 is characterized in that The upward inclination angles of the large umbrella skirt (2) and the small umbrella skirt (3) range from 0° to 10°.

4. The anti-pollution train roof insulator structure according to claim 2 is characterized in that The downward inclination angles of the large umbrella skirt (2) and the small umbrella skirt (3) range from 0° to 5°.

5. The anti-pollution train roof insulator structure according to claim 1 is characterized in that , the height of the core rod (1) ranges from 20 mm to 60 mm.

6. The anti-pollution train roof insulator structure according to claim 2 is characterized in that The diameter of the large umbrella skirt (2) is 182 mm, and the diameter of the small umbrella skirt (3) is 152 mm.

7. The anti-pollution train roof insulator structure according to claim 5 is characterized in that , the diameter of the core rod (1) is 70 mm.

8. A method for determining the structure of an anti-pollution train roof insulator, applicable to the anti-pollution train roof insulator structure according to claims 1 to 7, characterized in that: include: Constructing a three-dimensional model of an insulator structure, the insulator structure comprising a plurality of core rods (1) and a plurality of sheds, the plurality of sheds comprising a large shed (2) and a small shed (3), the diameter of the large shed (2) being greater than the diameter of the small shed (3); Importing the three-dimensional model into fluid dynamics software for meshing to obtain a plurality of target mesh units; Inputting boundary conditions into the fluid dynamics software, and performing pollution simulation of the insulator based on the discrete phase model preset in the fluid dynamics software, to obtain a plurality of insulator simulation results, wherein the insulator simulation results are obtained by weighted summation of the simulation results corresponding to each target unit grid; Determining an optimal simulation result and a corresponding boundary parameter from a plurality of insulator simulation results, wherein the optimal simulation result is used to characterize a simulation result with a minimum contamination volume fraction corresponding to a three-dimensional model in a contamination accumulation simulation, wherein the boundary parameters include a core rod (1) height, an upward inclination angle of the shed, and a downward inclination angle of the shed; The insulator structure is correspondingly arranged based on the boundary parameters, and the insulator structure is fixed on the roof of the train.

9. The method for determining the structure of the anti-pollution train roof insulator according to claim 8, characterized in that ,The three-dimensional model is imported into the fluid dynamics software for meshing, and a plurality of target mesh units are obtained, including: Meshing the three-dimensional model based on the fluid dynamics software to obtain a plurality of initial mesh units, wherein a refined mesh is used for the insulator surface area, and a conventional mesh is used for areas other than the insulator surface area; A boundary layer is set on the surface area of ​​the insulator, and the number of boundary layer layers, a stretching factor and a thickness adjustment factor are set accordingly to obtain a plurality of target grid units, wherein the number of boundary layer layers is used to characterize the number of grid unit layers in the boundary layer, the stretching factor is used to characterize the size ratio change of adjacent grid units in the boundary layer, and the thickness adjustment factor is used to control the overall thickness of the boundary layer.

10. The method for determining the structure of the anti-pollution train roof insulator according to claim 8, characterized in that , the calculation formula of the pollution volume fraction is: Where ρ is the contamination volume fraction; V p V is the volume of contamination; g is the volume of air.

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