A method for reducing fretting wear of a steam generator

Abstract

The present invention relates to a method for reducing fretting wear of a steam generator, which includes establishing a local model for the location where fretting wear occurs in the steam generator; loading a superhydrophobic surface onto the local model; conducting a numerical simulation of the fluid flow in the steam generator; analyzing the change in the load generated by the fluid flow on the steam generator; analyzing the structural response and fretting wear change of the steam generator under the excitation of the load. The superhydrophobic surface has good drag reduction performance. After conducting the numerical simulation of the fluid flow in the steam generator and analyzing the change in the load generated by the fluid flow on the steam generator, it is possible to clarify the influence of the superhydrophobic surface on the fluid under the excitation of the load, thereby clarifying the structural response and fretting wear change of the steam generator. In practical applications, the fretting wear of the steam generator can be reduced by adjusting the characterization of the superhydrophobic surface according to the analysis, which has good practicability.

Description

Technical Field

[0001] The present invention belongs to the technical fields of fluid mechanics and vibration mechanics, and particularly relates to a method for reducing fretting wear of a steam generator. Background Art

[0002] When the secondary side fluid flows in the evaporator in a nuclear power plant, it may cause fretting wear between the tube and the support plate (or anti-vibration strip). From existing research, when the fluid velocity exceeds a certain critical value, the fluid will undergo elastic vibration, and fluidelastic excitation is the main cause of large-amplitude vibration and rapid wear of the heat exchange tubes.

[0003] In a steam generator, lateral flow or axial flow will cause vibration of the tubes, anti-vibration strips or support plates. The vibration of the tubes will cause collision or sliding of the anti-vibration strips or support plates. This amplitude is small, which will cause local wear of the heat exchange tubes. This process of surface friction reduction is called fretting wear.

[0004] Currently, the methods for reducing fretting wear studied at home and abroad mainly include the following: improving the material of the anti-vibration strip and enhancing the wear resistance of the anti-vibration strip material; increasing the number of contact points between the anti-vibration strip and the tube; strictly controlling the gap between the anti-vibration strip and the tube, and accurately installing the anti-vibration strip, etc. However, the above methods all have defects such as low economy and complex design.

[0005] Currently, there is no accurate and reliable analysis method for reducing fretting wear of a steam generator. Therefore, it is necessary to provide a method for reducing fretting wear of a steam generator, which has good usability and economy while effectively reducing fretting wear of the steam generator. Summary of the Invention

[0006] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide a method for improving and optimizing the manufacturing process of a sample to reduce fretting wear of a steam generator, realizing good usability and economy while effectively reducing fretting wear of the steam generator.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for reducing fretting wear of a steam generator, comprising the following steps:

[0008] Step (1), establishing a local model for the location where fretting wear occurs in the steam generator;

[0009] Step (2), loading a superhydrophobic surface onto the local model;

[0010] Step (3), performing a numerical simulation on the fluid flow of the steam generator;

[0011] Step (4), analyzing the change in the load generated by the fluid flow on the steam generator;

[0012] Step (5), analyze the structural response and fretting wear change of the steam generator under the excitation of the load.

[0013] Optionally, in step (1), the local model is a heat transfer tube model.

[0014] Optionally, in step (2), loading the superhydrophobic surface onto the local model specifically includes:

[0015] Loading the superhydrophobic surface onto the pipes of the local model;

[0016] Loading the superhydrophobic surface onto the anti-vibration strips of the local model;

[0017] Loading the superhydrophobic surface onto the support plates of the local model.

[0018] Optionally, in step (4), analyzing the change in the load generated by the fluid flow on the steam generator specifically includes:

[0019] Determine the gas-liquid ratio of the superhydrophobic surface;

[0020] Determine the turbulent vortex intensity generated by the fluid flow;

[0021] Determine the structural response generated by the steam generator of the fluid.

[0022] Optionally, in step (5), analyzing the structural response and fretting wear change of the steam generator under the excitation of the load specifically includes:

[0023] Analyze the variation relationship of the turbulent vortex intensity with the gas-liquid ratio;

[0024] Analyze the variation relationship of the vibration amplitude of the local model with the turbulent vortex intensity;

[0025] Analyze the variation relationship of the fretting wear of the local model with the vibration amplitude of the local model.

[0026] Optionally, the gas-liquid ratio GF of the superhydrophobic surface = (P - W) / P, where P is the length of the topography period in the microstructure of the superhydrophobic surface, and W is the contact length between the liquid and the solid within the topography period.

[0027] The effect of the present invention is as follows: Since the superhydrophobic surface is loaded onto the local model in the method of the present invention; the superhydrophobic surface has good drag reduction performance; after numerically simulating the fluid flow of the steam generator and analyzing the change in the load generated by the fluid flow on the steam generator, the influence of the superhydrophobic surface on the fluid under the excitation of the load can be clarified, thereby clarifying the structural response and fretting wear change of the steam generator. In practical applications, the micro-motion wear of the steam generator can be reduced by adjusting the characterization of the superhydrophobic surface according to the analysis. Description of the Drawings

[0028] Figure 1 is a local model diagram of the location where fretting wear occurs in the steam generator of the present invention;

[0029] Figure 2 is a flow chart of the method for reducing fretting wear of the steam generator of the present invention;

[0030] Figure 3 is a schematic diagram of the microstructure of the superhydrophobic surface of the present invention;

[0031] Figure 4 is a curve graph showing the change of the turbulent vortex intensity of the present invention with the gas-liquid ratio of the superhydrophobic surface. Detailed implementation manners

[0032] The present invention will be further described below in conjunction with the accompanying drawings and detailed implementation manners.

[0033] As Figure 2 shown, this embodiment provides a method for reducing fretting wear of a steam generator, including the following steps:

[0034] Step (1), establish a local model for the location where fretting wear occurs in the steam generator; as Figure 1 shown, the local model in this embodiment is a heat transfer tube model. The heat transfer tube model includes a pipeline, anti-vibration strips and support plates, where the anti-vibration strips are in contact with the heat transfer tubes.

[0035] Step (2), load a superhydrophobic surface onto the local model; specifically loading a superhydrophobic surface onto the local model includes: loading a superhydrophobic surface onto the pipeline of the local model; loading a superhydrophobic surface onto the anti-vibration strips of the local model; and loading a superhydrophobic surface onto the support plates of the local model. The superhydrophobic surface has good drag reduction performance. As Figure 3 shown, in this embodiment, the gas-liquid ratio GF of the superhydrophobic surface = (P - W) / P, where P is the length of the topography period in the microstructure of the superhydrophobic surface, and W is the contact length between the liquid and the solid within the topography period.

[0036] Step (3), perform a numerical simulation on the fluid flow of the steam generator; by simulating the flow velocity of the fluid, the actual flow velocity of the steam generator during actual use can be simulated, and the turbulent flow and the excitation caused by the fluid flow instability are the main reasons for the large-amplitude vibration and rapid wear of the heat exchange tubes.

[0037] Step (4), analyze the change of the load generated by the fluid flow on the steam generator; in step (4), specifically analyzing the change of the load generated by the fluid flow on the steam generator includes: determining the gas-liquid ratio of the superhydrophobic surface; determining the turbulent vortex intensity generated by the fluid flow, and determining the structural response generated by the steam generator.

[0038] Step (5), analyze the structural response and fretting wear change of the steam generator under the excitation of the load. In step (5), analyzing the structural response and fretting wear change of the steam generator under the excitation of the load specifically includes: analyzing the variation relationship between the turbulent vortex intensity and the gas-liquid ratio. The turbulent vortex intensity generated by fluid flow is affected by the gas-liquid ratio of the superhydrophobic surface. As Figure 4 shown, the larger the gas-liquid ratio of the superhydrophobic surface, the smaller the turbulent vortex intensity generated by fluid flow. Then analyze the variation relationship between the vibration amplitude of the local model and the turbulent vortex intensity, and it can be known that the larger the turbulent vortex intensity, the larger the vibration amplitude; then analyze the variation relationship between the fretting wear of the local model and the vibration amplitude of the local model, and it can be known that the larger the vibration amplitude, the larger the fretting wear.

[0039] The effect of the present invention is as follows: Since the superhydrophobic surface is loaded on the local model in the method of the present invention; the superhydrophobic surface has good drag reduction performance; after numerically simulating the fluid flow of the steam generator and analyzing the change of the load generated by the fluid flow on the steam generator, the influence of the superhydrophobic surface on the fluid under the excitation of the load can be clarified, so as to clarify the structural response and fretting wear change of the steam generator. In practical applications, the fretting wear of the steam generator can be reduced by adjusting the characterization of the superhydrophobic surface according to the analysis.

[0040] Those skilled in the art should understand that the method and system of the present invention are not limited to the embodiments in the specific implementation manners. The above specific description is only for explaining the purpose of the present invention and is not used to limit the present invention. Other implementation manners obtained by those skilled in the art according to the technical solution of the present invention also belong to the scope of the technical innovation of the present invention. The protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for reducing fretting wear of a steam generator, characterized in that It includes the following steps: Step (1): Establish a local model for the location where fretting wear occurs in the steam generator, and the local model is a heat transfer tube model; Step (2): Load a superhydrophobic surface onto the local model, including: Load a superhydrophobic surface onto the pipeline of the local model; Load a superhydrophobic surface onto the anti-vibration strip of the local model; Load a superhydrophobic surface onto the support plate of the local model; Step (3): Conduct a numerical simulation of the fluid flow in the steam generator; Step (4): Analyze the change in the load generated by the fluid flow on the steam generator, including: Determine the gas-liquid ratio of the superhydrophobic surface; Determine the turbulence vortex intensity generated by the fluid flow; Determine the structural response generated by the steam generator; Step (5): Analyze the structural response and fretting wear change of the steam generator under the excitation of the load, including: Analyze the variation relationship between the turbulence vortex intensity and the gas-liquid ratio; Analyze the variation relationship between the vibration amplitude of the local model and the turbulence vortex intensity; Analyze the variation relationship between the fretting wear of the local model and the vibration amplitude of the local model.

2. The method for reducing fretting wear of a steam generator according to claim 1, characterized in that, The gas-liquid ratio GF of the superhydrophobic surface = (P - W) / P, where P is the length of the topography period in the microstructure of the superhydrophobic surface, and W is the contact length between the liquid and the solid within the topography period.

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