Verification device capable of reducing pipeline flow-induced vibration

Abstract

The present invention discloses a verification device capable of reducing pipeline flow-induced vibration, comprising: a replaceable test section, a measuring system and a fluid conveying mechanism; the replaceable test section is a section of pipeline with a super-hydrophobic surface loaded on the inner wall, and the replaceable test section is connected to the fluid conveying mechanism; the fluid conveying mechanism is used to convey fluid into the replaceable test section according to a determined fluid flow condition; the measuring system is used to measure the flow-induced vibration parameters generated when the fluid flows through the replaceable test section. By using this device to test the influence of a pipeline loaded with a super-hydrophobic surface on reducing pipeline flow-induced vibration, a super-hydrophobic surface capable of effectively reducing flow-induced vibration is obtained in the early stage of pipeline design, and the pipeline is pre-designed accordingly, thereby obtaining a pipeline design scheme capable of effectively reducing pipeline flow-induced vibration, making pipeline engineering more efficient and economical.

Description

Technical Field

[0001] The invention relates to the technical field of fluid mechanics and vibration mechanics, and in particular to a verification device capable of reducing pipeline flow-induced vibration. Background Art

[0002] Pipeline vibration caused by fluid flow is called flow-induced vibration. The mechanisms that cause flow-induced vibration mainly include vortex-induced vibration, turbulent buffeting, fluid elastic instability and acoustic resonance (collectively referred to as the excitation frequency of fluid flow). When the excitation frequency of fluid flow in the pipeline is equal to or close to the natural vibration frequency of the pipeline, pipeline resonance is induced. Since resonance will amplify tiny vibrations, its harmfulness increases. The natural vibration frequency of the pipeline depends on the elastic modulus and density of the pipeline material, while the excitation frequency of fluid flow changes with the flow state of the fluid.

[0003] At present, the methods for reducing pipeline flow-induced vibration at home and abroad mainly include: using analytical calculations and experimental research to determine the structural design to avoid causing pipeline resonance, or increasing the natural vibration frequency of the pipeline by adding or adjusting supports, changing the pipeline wall thickness and material to avoid the excitation frequency, or reducing the flow rate in the inlet and outlet areas and adding dampers to reduce the excitation frequency, thereby avoiding resonance. However, the above methods have defects, and it is necessary to propose new methods and corresponding pipelines that can reduce pipeline flow-induced vibration.

[0004] However, the prior art lacks effective experimental verification means for the method of pipeline flow-induced vibration and the corresponding pipeline. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a verification device capable of reducing pipeline flow-induced vibration in view of the above-mentioned deficiencies in the prior art, for verifying a method capable of reducing pipeline flow-induced vibration and the corresponding effect of reducing pipeline flow-induced vibration.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A verification device capable of reducing pipeline flow-induced vibration comprises: a replaceable test section, a measurement system and a fluid delivery mechanism;

[0008] The replaceable test section is a section of pipe with a super-hydrophobic surface loaded on the inner wall, and the replaceable test section is connected to the fluid conveying mechanism;

[0009] The fluid delivery mechanism is used to deliver fluid into the replaceable test section according to the determined fluid flow working condition;

[0010] The measuring system is used to measure the flow-induced vibration parameters generated when the fluid flows through the replaceable test section.

[0011] Preferably, the measurement system comprises: a measurement component and a signal processing device;

[0012] The measuring assembly is arranged on the replaceable test section and is used to measure the flow-induced vibration parameters when the fluid flows through the replaceable test section;

[0013] The signal processing device is electrically connected to the measuring component and is used to receive the measured flow-induced vibration parameters and record the measurement results.

[0014] Preferably, the flow-induced vibration parameters include: fluid flow rate and vibration intensity;

[0015] The measuring component comprises: a flow sensor and a vibration signal collector;

[0016] The flow sensor is arranged in the replaceable test section and is used to measure the flow rate of the fluid passing through the replaceable test section to check the flow condition of the fluid flowing through the replaceable test section;

[0017] The vibration signal collector is arranged on the outer wall of the replaceable test section, and is used to collect the vibration signal when the fluid flows through the replaceable test section, so as to obtain the vibration intensity when the fluid flows through the replaceable test section.

[0018] Preferably, two flow sensors are provided, one at each end of the replaceable test section, to check whether the flow rate of the fluid flowing through the replaceable test section reaches a constant value;

[0019] A plurality of vibration signal collectors are arranged around the middle of the outer wall of the replaceable test section, and the vibration intensity of the replaceable test section is obtained according to the average value of the vibration signals measured by the plurality of vibration signal collectors.

[0020] Preferably, the signal processing equipment includes: a signal conditioner, a data acquisition analyzer;

[0021] The input end of the signal conditioning instrument is connected to the flow sensor and the vibration signal sensor, and the output end thereof is connected to the data acquisition and analysis instrument, and is used to condition the fluid flow signal of the flow sensor and the vibration signal collected by the vibration signal collector, and then send them to the data acquisition and analysis instrument;

[0022] The data acquisition and analysis instrument is used to collect and analyze the adjusted fluid flow signal and vibration signal.

[0023] Preferably, the fluid delivery mechanism comprises: a fluid delivery pipeline and a drive guide assembly;

[0024] The fluid delivery pipeline is connected to the replaceable test section and forms a circulation pipeline for the circulation of the fluid;

[0025] The driving and guiding assembly is arranged on the fluid conveying pipeline, and is used for driving and guiding the fluid to circulate in the circulation pipeline and achieve the fluid flow working condition.

[0026] Preferably, the fluid delivery pipeline comprises in sequence: a first connecting section, a driving section, an expansion section, a flow guide section, a contraction section, and a second connecting section;

[0027] The replaceable test section is a straight tube;

[0028] The first connecting section adopts an L-shaped tube with a 90° bend, one end of which is connected to one end of the replaceable test section, and the other end is connected to one end of the driving section;

[0029] The driving section adopts an L-shaped tube with a 90° bend, and the other end of the L-shaped tube is connected to the narrow end of the expansion section;

[0030] The expansion section is a trumpet-shaped pipe, and its wide end is connected to the diversion section;

[0031] The diversion section is a U-shaped tube with 90° bends at both ends, and the other end is connected to the wide end of the contraction section;

[0032] The contraction section contracts in a funnel shape, and a narrow end thereof is connected to the second connecting section;

[0033] The second connecting section is a straight tube, and the other end of the second connecting section is connected to the other end of the replaceable test section opposite to the first connecting section.

[0034] Preferably, the length of the expansion section is greater than or equal to the sum of the lengths of the replaceable test section, the second connecting section and the contraction section;

[0035] A pressure balancing seam is provided at the connection between the second connecting section and the contraction section, for balancing the pressure of the fluid during circulation.

[0036] Preferably, the driving and guiding assembly comprises: a driving element, a guide vane and a honeycomb;

[0037] The driving element is used to drive the fluid to circulate;

[0038] The guide vanes and the honeycomb are used to guide and adjust the flow state of the fluid flowing to the replaceable test section, so that the Reynolds number of the fluid flow in the replaceable test section is a constant value under the drive of the driving element.

[0039] Preferably, the drive element comprises an impeller;

[0040] The impeller is disposed in the driving section, and the impeller is connected to a motor, and the motor drives the impeller to rotate, so that the impeller drives the fluid to flow;

[0041] The speed of the impeller is controlled by adjusting the output power of the motor, thereby adjusting the speed of the fluid flow.

[0042] The present invention provides a verification device for reducing flow-induced vibration of a pipeline. A measurement system is set in a replaceable test section to measure and analyze flow-induced vibration parameters generated when a fluid flows through the replaceable test section. The device is used to test the influence of a pipeline loaded with a super-hydrophobic surface on reducing flow-induced vibration of the pipeline. A super-hydrophobic surface that can effectively reduce flow-induced vibration is obtained in the early stage of pipeline design, and the pipeline is pre-designed accordingly, thereby obtaining a pipeline design scheme that can effectively reduce flow-induced vibration of the pipeline, making the pipeline project more efficient and economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flow chart of a method for reducing pipeline flow-induced vibration related to an embodiment of the present invention;

[0044] Figure 2 Schematic diagram of a super-hydrophobic surface with a regular microstructure involved in an embodiment of the present invention;

[0045] Figure 3 The curve diagram of the effect of gas-liquid ratio GF on the flow velocity of the fluid near the inner wall of the pipeline obtained by numerical simulation method;

[0046] Figure 4 The graph showing the effect of the gas-liquid ratio GF on the turbulent eddy intensity of the fluid flowing in the pipeline obtained by numerical simulation method;

[0047] Figure 5 A schematic diagram of the structure of a verification device capable of reducing pipeline flow-induced vibration;

[0048] Figure 6 for Figure 5 Schematic diagram of the circulation pipeline connection structure of the device. DETAILED DESCRIPTION

[0049] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0050] In the description of the present invention, it should be noted that the directions or positional relationships indicated by “upper” and the like are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0051] In the description of the present invention, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0052] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connect", "set", "install", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] What the present invention claims to protect is a verification device capable of reducing flow-induced vibration of a pipeline. For ease of understanding, a method capable of reducing flow-induced vibration of a pipeline and a corresponding pipeline are first introduced in detail.

[0054] The technical problem to be solved by the embodiment of the present invention is to verify the effectiveness of avoiding the resonance of the pipeline caused by the flow of fluid in the pipeline, that is, to verify the effectiveness of reducing the flow-induced vibration of the pipeline. In order to prevent the pipeline from resonating, the excitation frequency of the fluid flow in the pipeline should be unequal to or close to the natural vibration frequency of the pipeline. The embodiment of the present invention adopts the measure of changing the flow state of the fluid in the pipeline to reduce the excitation frequency, so as to achieve the goal of making the excitation frequency of the fluid flow in the pipeline avoid the natural vibration frequency of the pipeline.

[0055] Research has found that super-hydrophobic surfaces can affect turbulent flow, and turbulent vortices can cause pipeline vibrations. When turbulent flow increases, pipe wall vibrations increase, and thus, super-hydrophobic surfaces affect pipeline flow-induced vibrations. Therefore, there is a possibility of loading super-hydrophobic surfaces on the inner wall of the pipeline to reduce pipeline vibrations caused by fluid flow in the pipeline, thereby reducing the damage caused by pipeline vibrations. The design method of pre-loading super-hydrophobic surfaces on the inner wall of the pipeline is conducive to reducing engineering costs and improving engineering construction efficiency.

[0056] Therefore, the technical idea of ​​the method and pipeline related to the present invention that can reduce pipeline flow-induced vibration is: by adding a super-hydrophobic surface on the inner wall surface of the pipeline, the super-hydrophobic surface can be used to improve the stability of the fluid flow in the pipeline, thereby reducing the excitation frequency of the fluid flow in the pipeline. When the fluid flows in the pipeline, its excitation frequency is always lower than the natural vibration frequency of the pipeline, which can effectively avoid causing pipeline resonance. In order to verify the effectiveness of the method and pipeline, it is necessary to provide a corresponding verification device that can reduce pipeline flow-induced vibration to verify that the pipeline flow-induced vibration of the pipeline with the super-hydrophobic surface loaded on the inner wall is reduced.

[0057] First, if Figure 1 As shown, a method related to the present invention for reducing pipeline flow-induced vibration comprises the following steps:

[0058] S1. Determine the natural vibration frequency of the pipeline.

[0059] Specifically, the natural vibration frequency of the pipeline is determined by the elastic modulus and density of the pipeline material. In this embodiment 1, the natural vibration frequency of the pipeline is obtained by field measurement of a determined pipeline, calculation using empirical formulas according to relevant specifications, or numerical simulation calculation using finite element software.

[0060] S2. Obtaining a value of a characteristic parameter of the super-hydrophobic surface that enables an excitation frequency of the fluid flowing in the pipeline to avoid a natural vibration frequency of the pipeline.

[0061] Specifically, the characteristic parameters of the super-hydrophobic surface include: gas-liquid ratio GF or effective slip length L.

[0062] Specifically, the characteristic parameters of the super-hydrophobic surface are used to characterize the super-hydrophobic performance of the super-hydrophobic surface, and are usually expressed by the gas-liquid ratio GF (gas fraction) or the effective slip length L. Figure 2 The super-hydrophobic surface with regular microstructure shown in the figure is used to illustrate the characteristic parameter of its surface - gas-liquid ratio GF. GF is defined as: GF = (PW) / P, where P is the length of the morphological period in the regular super-hydrophobic surface microstructure, and W is the contact length between the liquid and the solid within the morphological period.

[0063] It is known from existing research that there is a monotonic correlation between GF and L, and they are equivalent, so the embodiments of the present invention can choose to use either the gas-liquid ratio GF or the effective slip length L as the characteristic quantity of the super-hydrophobic surface to study its relationship with the pipeline flow-induced vibration. In the analysis of the subsequent embodiments of this specification, only the gas-liquid ratio GF is used for illustration, but it should be understood that all places where the gas-liquid ratio GF is used can also use the effective slip length L for calculation or expression, and the two can be replaced.

[0064] Specifically, before obtaining the value of the characteristic parameter of the super-hydrophobic surface that can make the excitation frequency of the fluid flow in the pipeline avoid the natural vibration frequency of the pipeline, the method also includes: determining the structural parameters of the pipeline and the fluid flow conditions in the pipeline; under the structural parameters and the fluid flow conditions in the pipeline, obtaining the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the excitation frequency of the fluid flow in the pipeline.

[0065] Specifically, after step S1, the natural vibration frequency of the pipeline has been determined. To obtain the value of the characteristic parameter of the super-hydrophobic surface that can make the excitation frequency of the fluid flow in the pipeline avoid the natural vibration frequency of the pipeline, it is necessary to know the influence of the characteristic parameter of the super-hydrophobic surface on the excitation frequency of the fluid flow. Through the study of the embodiments of the present invention, it is found that there is a monotonic relationship between the characteristic parameter of the super-hydrophobic surface and the excitation frequency of the fluid flow in the pipeline. According to the monotonic relationship, a suitable value of the characteristic parameter can be selected so that when the fluid flows through the super-hydrophobic surface having the value of the characteristic parameter, its excitation frequency is always lower than the natural vibration frequency of the pipeline.

[0066] Specifically, the method of obtaining the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the excitation frequency of the fluid flow in the pipeline comprises: using finite volume method software as a numerical simulation tool to simulate a pipeline having the structural parameters; setting the values ​​of the characteristic parameters of a plurality of different super-hydrophobic surfaces; obtaining the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the fluid flow parameters in the pipeline under the condition of obtaining the corresponding fluid flow parameters in the pipeline under the condition of the value of the characteristic parameters of each super-hydrophobic surface by simulating the fluid flowing in the pipeline having the super-hydrophobic surface and the set characteristic parameter values; and obtaining the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the fluid flow parameters in the pipeline according to the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the fluid flow parameters in the pipeline, and the monotonic relationship between the known fluid flow parameters in the pipeline and the excitation frequency of the fluid flow in the pipeline.

[0067] Specifically, the flow of fluid in the pipeline is studied by using the direct numerical simulation method, and the relationship between the superhydrophobic surface characteristics and the pipeline flow-induced vibration is explored based on the simulation results. The direct numerical simulation method uses the finite volume method software as a numerical simulation tool to directly simulate the fluid flow in the pipeline. It can better simulate the fluid flow in the pipeline, and the simulation results are highly accurate.

[0068] Specifically, the numerical simulation tool specifically adopts ANSYS Fluent; the pipeline structure parameters include: the diameter of the pipeline, the length of the pipeline; the fluid flow conditions in the pipeline include: the fluid flow rate at the pipeline inlet, the pipeline operating pressure, temperature, fluid density, and fluid viscosity coefficient; the fluid flow parameters in the pipeline include: the flow velocity near the inner wall of the pipeline, and the turbulent vortex intensity; the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the fluid flow parameters in the pipeline includes: the characteristic parameters of the super-hydrophobic surface are positively correlated with the flow velocity near the inner wall of the pipeline, and the characteristic parameters of the super-hydrophobic surface are inversely correlated with the turbulent vortex intensity; the monotonic relationship between the fluid flow parameters in the pipeline and the excitation frequency of the fluid flow in the pipeline includes: the flow velocity near the inner wall of the pipeline is inversely correlated with the excitation frequency of the fluid flow in the pipeline, and the turbulent vortex intensity is positively correlated with the excitation frequency of the fluid flow in the pipeline; the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the excitation frequency of the fluid flow in the pipeline is: the characteristic parameters of the super-hydrophobic surface are inversely correlated with the excitation frequency of the fluid flow in the pipeline.

[0069] Specifically, the finite volume method software uses ANSYS Fluent. In the numerical simulation tool, the fluid flow in the pipeline is simulated, and the relevant numerical values ​​of the simulated fluid flow are set according to the on-site operating condition data in projects such as nuclear power plants, that is, the pipeline structure parameters and the fluid flow conditions in the pipeline are obtained from the project site, and the simulation operation is performed after the pipeline structure parameters and the fluid flow conditions in the pipeline are input into the numerical simulation tool.

[0070] In actual pipeline applications, the pipeline structural parameters and the fluid flow conditions in the pipeline must meet the performance requirements of the pipeline transporting the fluid. Both will affect the flow state of the fluid in the pipeline, thereby affecting the frequency of the fluid flow exciting the pipeline. In a specific application example, the pipeline is a cooling water pipeline of a nuclear power plant. The diameter of the pipeline is generally 150mm. The flow velocity in the pipeline is about 10m / s during operation. Based on this as the calculation basis, the turbulent vortex intensity inside the pipeline is 4000 without loading the super-hydrophobic surface.

[0071] After inputting the corresponding pipeline structure parameters and the relevant values ​​of the fluid flow conditions in the pipeline into the numerical simulation tool, the values ​​of the characteristic parameters of different super-hydrophobic surfaces are set, and it is assumed that the super-hydrophobic surface with the value of the characteristic parameter is loaded on the inner wall of the pipeline, and the corresponding in-pipe fluid flow parameters under the values ​​of the characteristic parameters of the super-hydrophobic surface are calculated in the numerical simulation tool to obtain the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the in-pipe fluid flow parameters. In the aforementioned specific application examples, the super-hydrophobic surface characteristic parameter selects the gas-liquid ratio GF, and its values ​​are respectively taken as 0.25, 0.5, and 0.75 to calculate the changes in the flow velocity and turbulent eddy intensity near the inner wall of the pipeline corresponding to the gas-liquid ratio GF of the super-hydrophobic surface for the above-mentioned values, and some of the results are as follows. Figure 3 and 4 shown.

[0072] Specifically, in Figure 3 Middle: The horizontal axis represents the length of the pipe X, and the vertical axis represents the average flow velocity near the inner wall of the pipe from Figure 3 It can be observed that as the gas-liquid ratio GF increases, the flow velocity near the inner wall increases. According to fluid mechanics theory, fluid flow is divided into longitudinal flow and transverse flow in terms of movement direction. The longitudinal flow is along the axial direction (i.e., the flow direction), and the transverse flow is perpendicular to the axial direction. Even when the flow velocity is not large, the transverse flow will cause the vibration of the pipeline. The increase in the flow velocity (the velocity of the longitudinal flow) means that the transverse flow decreases, and the excitation frequency of the fluid flow in the pipeline decreases, thereby reducing the pipeline flow-induced vibration.

[0073] Specifically, in Figure 4 Middle: The horizontal axis represents the gas-liquid ratio GF, and the vertical axis represents the turbulent eddy intensity (vorticitymagnitude). Figure 4 It can be observed that the turbulent vortex intensity in the pipeline decreases with the increase of the gas-liquid ratio GF. Specifically, the turbulent vortex intensity is 3500 when the gas-liquid ratio is 0.25, the turbulent vortex intensity is 2650 when the gas-liquid ratio is 0.5, and the turbulent vortex intensity is 2010 when the gas-liquid ratio is 0.75. The turbulent vortex intensity is the main inducing factor of turbulent buffeting. Therefore, its reduction means that the excitation frequency of the fluid flow in the pipeline is reduced, thereby reducing the flow-induced vibration of the pipeline.

[0074] From the above analysis, it can be seen that the influence of fluid flow parameters such as the flow velocity near the inner wall of the pipeline and the turbulent vortex intensity value on the flow-induced vibration will decrease with the increase of the gas-liquid ratio GF. It can be seen that the characteristic parameters of the super-hydrophobic surface are monotonically related to the excitation frequency of the fluid flow in the pipeline, and are still monotonically related to the pipeline flow-induced vibration. The gas-liquid ratio GF or the effective slip length L of the super-hydrophobic surface is also monotonically related to the natural vibration frequency of the pipeline that needs to be avoided. Specifically, the lower the natural vibration frequency of the pipeline, the larger the gas-liquid ratio GF or the effective slip length L of the super-hydrophobic surface that needs to be set can be obtained by establishing a relationship table or curve diagram between the characteristic parameter GF of the super-hydrophobic surface and the natural vibration frequency of the pipeline that needs to be avoided, so as to obtain the value of the characteristic parameter of the super-hydrophobic surface that can make the excitation frequency of the fluid flow in the pipeline avoid the natural vibration frequency of the pipeline.

[0075] Specifically, according to the above analysis, the addition of the super-hydrophobic surface changes the state of the fluid flow in the pipeline, reduces the impact of turbulent flow on the pipeline, and makes the fluid flow in the pipeline tend to a stable state, thereby being able to reduce the excitation frequency. Under certain flow conditions and the pipeline's own conditions, a super-hydrophobic surface with appropriate characteristic parameters is selected to avoid the natural vibration frequency of the pipeline, so that the excitation frequency of the fluid flow in the pipeline is always lower than the natural vibration frequency of the pipeline, thereby avoiding resonance between the two. Under the same conditions, due to the monotonic relationship between the characteristic parameters of the super-hydrophobic surface and the pipeline flow-induced vibration, although the characteristic parameters of the super-hydrophobic surface can be selected as large as possible, considering practical factors such as processing costs, try to select appropriate characteristic parameter values ​​according to the natural vibration frequency of the pipeline.

[0076] S3. Loading a super hydrophobic surface having the characteristic parameter value onto the inner wall surface of the pipeline, so that the pipeline resonance will not be induced when the fluid in the pipeline flows.

[0077] Specifically, the step of loading a super-hydrophobic surface having the value of the characteristic parameter onto the inner wall surface of the pipe comprises: etching the inner wall surface of the pipe to form a super-hydrophobic surface having the value of the characteristic parameter; or attaching or spraying a super-hydrophobic material onto the inner wall surface of the pipe to form a super-hydrophobic surface having the value of the characteristic parameter.

[0078] Specifically, the loading method may be to etch the inner wall surface of the pipe to form the super-hydrophobic surface, such as directly processing the inner wall of the pipe to form a super-hydrophobic surface having the value of the characteristic parameter using laser, electro-etching or other processes; or, attaching or spraying a super-hydrophobic material on the inner wall surface of the pipe to form the super-hydrophobic surface, wherein the super-hydrophobic material is a material having the value of the characteristic parameter, i.e., having a certain value of the gas-liquid ratio GF or the effective slip length L.

[0079] Specifically, after the super-hydrophobic surface having the value of the characteristic parameter is loaded on the inner wall surface of the pipe so that the pipe resonance will not be caused when the fluid flows in the pipe, the method further includes: connecting the pipe loaded with the super-hydrophobic surface to a verification device capable of reducing the flow-induced vibration of the pipe, the verification device comprising a measurement system, the measurement system being used to measure the flow-induced vibration parameters of the pipe; conveying fluid into the pipe and controlling the fluid to flow in the pipe according to a determined fluid flow condition; and recording the flow-induced vibration parameters of the pipe through the measurement system to verify that the pipe loaded with the super-hydrophobic surface can reduce the flow-induced vibration of the pipe.

[0080] Specifically, the verification device capable of reducing pipeline flow-induced vibration is as follows: Figure 5 and Figure 6 As shown, first Figure 5 As shown, the pipe loaded with the super-hydrophobic surface is used as a replaceable test section 1, and a measuring system 2 is connected thereto, which is then connected to a fluid conveying mechanism 3 to form a replaceable test section 1. Figure 6 In the circulation pipeline shown, the fluid conveying mechanism 3 conveys fluid to the replaceable test section 1, and controls the fluid flow conditions in the replaceable test section 1 to meet the test requirements. When the fluid flow conditions in the replaceable test section 1 meet the test requirements, the measurement system 2 records the corresponding flow-induced vibration parameters, and specifically can directly measure the vibration intensity of the replaceable test section 1, and judge whether the pipeline loaded with the super-hydrophobic surface can reduce the flow-induced vibration of the pipeline according to the magnitude of the vibration intensity.

[0081] In a specific application example, as mentioned above, the pipeline is a cooling water pipeline of a nuclear power plant, the diameter of the pipeline is 150 mm, and the fluid flow in the replaceable test section 1 is controlled by the fluid conveying mechanism 3 to achieve a Reynolds number of 8E+05 or other values ​​for the fluid flow in the pipeline, and the flow velocity condition of 10 m / s is met, and the vibration signal is recorded.

[0082] In the method for reducing pipeline flow-induced vibration related to the present invention, the structural vibration problem is converted into a fluid flow problem by linking the superhydrophobic surface characteristics with the flow-induced vibration problem, and the pipeline flow-induced vibration is reduced by adding a superhydrophobic surface to the inner wall surface of the pipeline. As the superhydrophobicity of the superhydrophobic surface is enhanced, the turbulent vortex intensity is reduced, thereby reducing the excitation intensity from the source, and the structural vibration caused by the fluid flow in the pipeline is reduced by changing the boundary conditions of the fluid flow. When the natural frequency of the pipeline is known in advance, the excitation frequency of the pipeline is adjusted by adjusting the characteristic parameters of the superhydrophobic surface of the inner wall of the pipeline to avoid the natural frequency of the pipeline, thereby reducing the strong flow-induced vibration caused by resonance, thereby providing a pipeline engineering design method that is easier to implement, more efficient and economical than the prior art.

[0083] More specifically, the method of the present invention has the following beneficial effects compared with the prior art:

[0084] 1) Compared with analytical calculation, this method directly simulates the turbulent flow in the pipeline, so it can describe the pipeline flow more realistically and accurately;

[0085] 2) Compared with the experimental research method, this method avoids the error sources such as pump noise, pipeline buckling and pipeline supports that may be introduced during the experiment;

[0086] 3) Compared with the method of adding or adjusting supports, the present invention does not need to change the existing design of the pipeline in the project, and does not need to add or change supports, thus reducing project costs and time, making it more economical and convenient;

[0087] 4) Compared with the method of changing the pipe wall thickness and material, the present invention does not need to replace the pipe material or re-construction, but only needs to process the inner wall surface of the pipe before construction, thus saving more time and construction costs;

[0088] 5) Compared with the method of reducing the flow rate in the inlet and outlet areas, it can reduce the design and calculation costs in the early and late stages of the project;

[0089] 6) Compared with adding a damper, the present invention does not need to significantly increase the weight of the system and is not restricted by external temperature.

[0090] Second, a pipeline capable of reducing flow-induced vibration related to the present invention comprises a pipeline body and a super-hydrophobic surface;

[0091] The super-hydrophobic surface is loaded on the inner wall surface of the pipeline, and the super-hydrophobic surface has a characteristic parameter value that can make the excitation frequency of the fluid flowing in the pipeline avoid the natural vibration frequency of the pipeline, so that the pipeline resonance will not be caused when the fluid flows in the pipeline.

[0092] Optionally, the characteristic parameters include: gas-liquid ratio GF or effective slip length L.

[0093] Specifically, the microstructure of the super-hydrophobic surface is divided into regular and irregular types. In the present embodiment, the super-hydrophobic surface can be a regular or irregular microstructure, but it must have a certain gas-liquid ratio GF value or a certain effective slip length L value. In industry, in order to reduce manufacturing costs, its microstructure is generally irregular. For a super-hydrophobic surface with an irregular microstructure, its characteristic parameters can also be expressed by the gas-liquid ratio GF or the effective slip length L.

[0094] Optionally, the super-hydrophobic surface is loaded on the inner wall surface of the pipe, including: etching the inner wall surface of the pipe to form a super-hydrophobic surface having the value of the characteristic parameter; or attaching or spraying a super-hydrophobic material on the inner wall surface of the pipe to form a super-hydrophobic surface having the value of the characteristic parameter.

[0095] In a specific embodiment, the super-hydrophobic surface is loaded on the inner wall surface of the pipe, including two loading methods: etching on the inner wall surface of the pipe to form the super-hydrophobic surface, such as using laser, electro-etching and other processes to directly process the inner wall of the pipe to form a super-hydrophobic surface with the value of the characteristic parameter; in another specific embodiment, attaching or spraying a super-hydrophobic material on the inner wall surface of the pipe to form the super-hydrophobic surface; the super-hydrophobic material uses a material with the value of the characteristic parameter.

[0096] Optionally, the values ​​of the characteristic parameters of the super-hydrophobic surface are determined with reference to the aforementioned method capable of reducing pipeline flow-induced vibration.

[0097] Optionally, the pipeline is also connected to a verification device capable of reducing flow-induced vibration of the pipeline, the verification device comprising a measurement system, the measurement system being used to measure flow-induced vibration parameters of the pipeline; conveying fluid into the pipeline and controlling the fluid to flow in the pipeline according to determined fluid flow conditions; and recording the flow-induced vibration parameters of the pipeline through the measurement system to verify that the pipeline can reduce flow-induced vibration.

[0098] In the pipeline capable of reducing flow-induced vibration related to the present invention, the flow-induced vibration of the pipeline is reduced by adding a super-hydrophobic surface on the inner wall surface of the pipeline. The super-hydrophobic surface has the ability to make the excitation frequency of the fluid flow in the pipeline avoid the value of the characteristic parameter corresponding to the inherent vibration frequency of the pipeline, thereby reducing the structural vibration caused by the fluid flow in the pipeline. The pipeline related to the present invention can be pre-designed for the pipeline, so that the project has higher efficiency and economy.

[0099] Embodiment 1:

[0100] like Figure 5 and 6 As shown, embodiment 1 of the present invention provides a verification device capable of reducing pipeline flow-induced vibration, comprising: a replaceable test section 1, a measurement system 2 and a fluid delivery mechanism 3;

[0101] The replaceable test section 1 is a section of pipe with a super-hydrophobic surface on the inner wall, and the replaceable test section 1 is connected to the fluid conveying mechanism 3;

[0102] The fluid delivery mechanism 3 is used to deliver fluid into the replaceable test section 1 according to the determined fluid flow working conditions;

[0103] The measuring system 2 is used to measure the flow-induced vibration parameters generated when the fluid flows through the replaceable test section 1 .

[0104] Specifically, the replaceable test section 1 is a section of pipe obtained by a method capable of reducing flow-induced vibration of a pipe as described above, or a section of a pipe capable of reducing flow-induced vibration as described above. The verification device is used to verify that the pipe obtained as described above can reduce flow-induced vibration of the pipe. The pipe obtained as described above is selected as the replaceable test section 1 for verification test. The flow-induced vibration parameter directly reflects the vibration intensity of the pipe when the fluid flows in the pipe. The reduction in the vibration intensity achieves the effect of reducing the flow-induced vibration of the pipe.

[0105] Optionally, the measurement system 2 includes: a measurement component 21 and a signal processing device 22;

[0106] The measuring component 21 is arranged on the replaceable test section 1, and is used to measure the flow-induced vibration parameters when the fluid flows through the replaceable test section 1;

[0107] The signal processing device 22 is electrically connected to the measuring component 21 and is used to receive the measured flow-induced vibration parameters and record the measurement results.

[0108] Specifically, the measurement system measures the flow-induced vibration parameters of the pipeline through the measurement component 21, and receives and records the measurement results through the signal processing device 22. By enriching and improving the measurement data records, a more accurate relationship between the characteristic parameters of the super-hydrophobic surface and the flow-induced vibration of the pipeline can be obtained, providing effective empirical data for pipeline engineering design.

[0109] Optionally, the flow-induced vibration parameters include: fluid flow rate and vibration intensity;

[0110] The measuring component 21 includes: a flow sensor 211 and a vibration signal collector 212;

[0111] The flow sensor 211 is disposed in the replaceable test section 1 and is used to measure the flow rate of the fluid passing through the replaceable test section 1 to check the flow condition of the fluid flowing through the replaceable test section 1;

[0112] The vibration signal collector 212 is disposed on the outer wall of the replaceable test section 1 , and is used to collect vibration signals when the fluid flows through the replaceable test section 1 , so as to obtain the vibration intensity when the fluid flows through the replaceable test section 1 .

[0113] Specifically, after the flow sensor 211 verifies that the flow condition of the fluid flowing through the replaceable test section 1 meets the test requirements, the vibration signal collector 212 collects the vibration intensity of the replaceable test section 1 and sends the vibration intensity to the signal processing device 22 .

[0114] Optionally, two flow sensors 211 are provided, one at each end of the replaceable test section 1, to check whether the flow rate of the fluid flowing through the replaceable test section 1 reaches a constant value;

[0115] A plurality of vibration signal collectors 212 are provided, which are arranged around the middle of the outer wall of the replaceable test section 1 , and the vibration intensity of the replaceable test section 1 is obtained according to the average value of the vibration signals measured by the plurality of vibration signal collectors 212 .

[0116] Specifically, first, the fluid flow rates at the inlet and outlet positions of the replaceable test section are measured respectively according to the two flow sensors 211, and the flow velocity of the fluid before and after flowing through the replaceable test section 1 is calculated according to the fluid flow rate. The vibration signal is not collected until the flow velocities before and after are consistent and reach a constant value. The vibration signal collector 212 can use an acceleration sensor, which is surrounded by the middle of the pipeline, and the vibration intensity of the pipeline is obtained by calculating the average value.

[0117] Optionally, the signal processing device 22 includes: a signal conditioner 221 and a data acquisition analyzer 222;

[0118] The input end of the signal conditioner 221 is connected to the flow sensor 211 and the vibration signal sensor 212, and the output end thereof is connected to the data acquisition analyzer 222, and is used to condition the fluid flow signal of the flow sensor 211 and the vibration signal collected by the vibration signal collector 212, and then send them to the data acquisition analyzer 222;

[0119] The data acquisition and analysis instrument 222 is used to collect and analyze the adjusted fluid flow signal and vibration signal.

[0120] Specifically, the signal processing device 22 also includes a computer 223, which is connected to a data acquisition analyzer 222. The data acquisition analyzer 222 converts analog signals into digital signals and sends them to the computer 223. The computer 223 combines the received signals with the values ​​of the corresponding characteristic parameters of the super-hydrophobic surface to give a flow-induced vibration measurement and analysis result of the replaceable test section 1. By using pipes with different values ​​of the characteristic parameters as the replaceable test section 1 for multiple tests, the measurement and analysis results of the flow-induced vibration and super-hydrophobic surface characteristic parameters of the replaceable test section 1 can be given.

[0121] Optionally, the fluid delivery mechanism 3 comprises: a fluid delivery pipeline 31 and a driving guide assembly 32;

[0122] The fluid delivery pipeline 31 is connected to the replaceable test section 1 and forms a circulation pipeline for the fluid to circulate;

[0123] The driving and guiding assembly 32 is disposed on the fluid delivery pipeline 31 and is used to drive and guide the fluid to circulate in the circulation pipeline and achieve the fluid flow working condition.

[0124] Specifically, the fluid flow operating conditions include determining the fluid flow velocity in the pipeline based on the actual diameter of the pipeline, and the Reynolds number of the fluid flow in the pipeline, requiring that the velocity of the water flow when reaching the replaceable test section 1 is constant, and the Reynolds number is 8E+05 or other values. Since the purpose of the present invention is to measure the vibration parameters of the pipeline itself of the replaceable test section 1, the present invention only needs to control the flow conditions flowing through the replaceable test section 1 to achieve the purpose of the present invention. Therefore, whether the fluid circulates is not a necessary condition of the present invention, but the design scheme of circulating flow is conducive to continuous measurement.

[0125] Optionally, the fluid delivery pipeline 31 includes in sequence: a first connecting section 311, a driving section 312, an expansion section 313, a flow guiding section 314, a contraction section 315, and a second connecting section 316;

[0126] The replaceable test section 1 is a straight tube;

[0127] The first connecting section 311 is an L-shaped tube with a 90° bend, one end of which is connected to one end of the replaceable test section 1, and the other end is connected to one end of the driving section 312;

[0128] The driving section 312 is an L-shaped tube with a 90° bend, and the other end thereof is connected to the narrow end of the expansion section 313;

[0129] The expansion section 313 is a trumpet-shaped pipe, and its wide end is connected to the guide section 314;

[0130] The flow guide section 314 is a U-shaped tube with two ends bent at 90 degrees, and the other end is connected to the wide end of the contraction section 315;

[0131] The contraction section 315 contracts in a funnel shape, and its narrow end is connected to the second connection section 316;

[0132] The second connecting section 316 is a straight tube, and the other end of the second connecting section 316 is connected to the other end of the replaceable test section 1 opposite to the first connecting section 311 .

[0133] Optionally, the length of the expansion section 313 is greater than or equal to the sum of the lengths of the replaceable test section 1, the second connecting section 316 and the contraction section 315;

[0134] A pressure balancing seam 317 is provided at the connection between the second connecting section 316 and the contraction section 315 to balance the pressure of the fluid during circulation.

[0135] Specifically, the expansion section 313 is installed relative to the replaceable test section 1, the second connecting section 316 and the contraction section 315, and its length is greater than or equal to the sum of the lengths of the three. The 90° bends of all pipes are set to circular arc bends.

[0136] Optionally, the driving guide assembly 32 includes: a driving element 321, a guide vane 322 and a honeycomb 323;

[0137] The driving element 321 is used to drive the fluid to circulate;

[0138] The guide vanes 322 and the honeycomb 323 are used to guide and adjust the flow state of the fluid flowing to the replaceable test section 1, so that under the drive of the driving element 321, the Reynolds number of the fluid flow in the replaceable test section 1 is a constant.

[0139] Optionally, the driving element 321 includes an impeller 3211;

[0140] The impeller 3211 is disposed in the driving section 312, and the impeller 3211 is connected to a motor 3212, and the motor 3212 drives the impeller 3211 to rotate, so that the impeller 3211 drives the fluid to flow;

[0141] The speed of the impeller 3211 is controlled by adjusting the output power of the motor 3212, thereby adjusting the speed of the fluid flow.

[0142] Specifically, the impeller 3211 is arranged at one end where the driving section 312 is connected to the first connecting section 311, the motor 3212 is arranged outside the pipeline of the driving section 312, and is connected to the impeller 3211 to drive the impeller 3211 to rotate, the guide blades 322 include two groups, and the two groups of guide blades 322 are respectively arranged at two 90° bends of the guide section 314, so as to guide the fluid after expansion and deceleration in the expansion section 313 to smoothly pass through the two 90° bends of the guide section, each group of guide blades 322 includes a plurality of inwardly bent arc blades, and are distributed from the outer angle to the inner angle of the 90° bend of the guide section 314, and the honeycomb 323 is arranged at the wide end of the contraction section 315.

[0143] The method of using the verification device is as follows: first, select the pipe loaded with the super-hydrophobic surface to be verified, and use it as a replaceable test section 1 to connect the fluid delivery mechanism 3 to form a circulation pipe, and connect it to the measurement system 2, start the motor 3212 to drive the impeller 3211 to rotate, and drive the fluid in the circulation pipe to flow and circulate according to the determined fluid flow conditions. The flow sensor 211 measures the fluid flow at both ends of the replaceable test section 1, and transmits the data to the signal processing device 22. When the flow rate is constant, the vibration sensor 212 measures the pipe vibration of the replaceable test section 1. By recording the flow-induced vibration parameters of the pipe measured by the vibration sensor 212, it is verified that the pipe loaded with the super-hydrophobic surface can reduce the flow-induced vibration of the pipe, and finally transmit the data to the computer 223 of the signal processing device 22 for storage and recording.

[0144] Embodiment 1 of the present invention provides a verification device capable of reducing pipeline flow-induced vibration. By setting a measurement system in a replaceable test section 1, the flow-induced vibration parameters generated when the fluid flows through the replaceable test section 1 are measured and analyzed, thereby providing a simple, convenient, economical and reliable experimental verification device. The pipeline flow-induced vibration parameters are obtained through experimental measurement results to test pipeline performance.

[0145] The measuring equipment required for this experimental device is relatively common and inexpensive. It is available in general fluid mechanics laboratories and can be compared, repeated, and verified to ensure its correctness and accuracy. This verification device can be used to test the effect of adding a super-hydrophobic surface to a pipe on reducing the flow-induced vibration of the pipe, thereby providing a basis for the early design of a super-hydrophobic surface that effectively reduces the flow-induced vibration of the pipe. This super-hydrophobic surface can then be applied to the inner wall surface of the pipe for pre-design, avoiding the general practice in existing engineering practices of reducing flow-induced vibration by modifying and adjusting the pipe design and construction through on-site feedback, greatly reducing construction costs and later modification costs, saving time, and making the project more efficient and economical.

[0146] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A verification device capable of reducing pipeline flow-induced vibration, characterized in that: include: Replaceable test section, measuring system and fluid delivery mechanism; The replaceable test section is a section of pipe with a super-hydrophobic surface on the inner wall, and the replaceable test section is connected to the fluid delivery mechanism. The inner wall is loaded with a super hydrophobic surface, including: etching the inner wall surface of the pipe to form a super hydrophobic surface; or attaching or spraying a super hydrophobic material on the inner wall surface of the pipe to form a super hydrophobic surface; The fluid delivery mechanism is used to deliver fluid into the replaceable test section according to the determined fluid flow working condition; The measuring system is used to measure the flow-induced vibration parameters generated when the fluid flows through the replaceable test section.

2. The verification device capable of reducing pipeline flow-induced vibration according to claim 1, characterized in that: The measurement system comprises: a measurement component and a signal processing device; The measuring assembly is arranged on the replaceable test section and is used to measure the flow-induced vibration parameters when the fluid flows through the replaceable test section; The signal processing device is electrically connected to the measuring component and is used to receive the measured flow-induced vibration parameters and record the measurement results.

3. The verification device capable of reducing pipeline flow-induced vibration according to claim 2, characterized in that: The flow-induced vibration parameters include: fluid flow rate and vibration intensity; The measuring component comprises: a flow sensor and a vibration signal collector; The flow sensor is arranged in the replaceable test section and is used to measure the flow rate of the fluid passing through the replaceable test section to check the flow condition of the fluid flowing through the replaceable test section; The vibration signal collector is arranged on the outer wall of the replaceable test section, and is used to collect the vibration signal when the fluid flows through the replaceable test section, so as to obtain the vibration intensity when the fluid flows through the replaceable test section.

4. The verification device capable of reducing pipeline flow-induced vibration according to claim 3, characterized in that: Two flow sensors are provided, one at each end of the replaceable test section, to check whether the flow rate of the fluid flowing through the replaceable test section reaches a constant value; A plurality of vibration signal collectors are arranged around the middle of the outer wall of the replaceable test section, and the vibration intensity of the replaceable test section is obtained according to the average value of the vibration signals measured by the plurality of vibration signal collectors.

5. The verification device capable of reducing pipeline flow-induced vibration according to claim 3, characterized in that: The signal processing equipment includes: a signal conditioner and a data acquisition analyzer; The input end of the signal conditioning instrument is connected to the flow sensor and the vibration signal sensor, and the output end thereof is connected to the data acquisition and analysis instrument, and is used to condition the fluid flow signal of the flow sensor and the vibration signal collected by the vibration signal collector, and then send them to the data acquisition and analysis instrument; The data acquisition and analysis instrument is used to collect and analyze the adjusted fluid flow signal and vibration signal.

6. The verification device capable of reducing pipeline flow-induced vibration according to any one of claims 1 to 5, characterized in that: The fluid delivery mechanism comprises: a fluid delivery pipeline and a driving guide assembly; The fluid delivery pipeline is connected to the replaceable test section and forms a circulation pipeline for circulating the fluid; The driving and guiding assembly is arranged on the fluid conveying pipeline, and is used for driving and guiding the fluid to circulate in the circulation pipeline and achieve the fluid flow working condition.

7. The verification device capable of reducing pipeline flow-induced vibration according to claim 6, characterized in that: The fluid delivery pipeline comprises in sequence: a first connecting section, a driving section, an expansion section, a flow guide section, a contraction section, and a second connecting section; The replaceable test section is a straight tube; The first connecting section adopts an L-shaped tube with a 90° bend, one end of which is connected to one end of the replaceable test section, and the other end is connected to one end of the driving section; The driving section adopts an L-shaped tube with a 90° bend, and the other end of the L-shaped tube is connected to the narrow end of the expansion section; The expansion section is a trumpet-shaped pipe, and its wide end is connected to the diversion section; The diversion section is a U-shaped tube with 90° bends at both ends, and the other end is connected to the wide end of the contraction section; The contraction section contracts in a funnel shape, and a narrow end thereof is connected to the second connecting section; The second connecting section is a straight tube, and the other end of the second connecting section is connected to the other end of the replaceable test section opposite to the first connecting section.

8. The verification device capable of reducing pipeline flow-induced vibration according to claim 7, characterized in that: The length of the expansion section is greater than or equal to the sum of the lengths of the replaceable test section, the second connecting section and the contraction section; A pressure balancing seam is provided at the connection between the second connecting section and the contraction section, for balancing the pressure of the fluid during circulation.

9. The verification device capable of reducing pipeline flow-induced vibration according to claim 8, characterized in that: The driving and guiding assembly comprises: a driving element, a guide vane and a honeycomb; The driving element is used to drive the fluid to circulate; The guide vanes and the honeycomb are used to guide and adjust the flow state of the fluid flowing to the replaceable test section, so that the Reynolds number of the fluid flow in the replaceable test section driven by the driving element is a constant value.

10. The verification device capable of reducing pipeline flow-induced vibration according to claim 9, characterized in that: The driving element includes an impeller; The impeller is disposed in the driving section, and the impeller is connected to a motor, and the motor drives the impeller to rotate, so that the impeller drives the fluid to flow; The speed of the impeller is controlled by adjusting the output power of the motor, thereby adjusting the speed of the fluid flow.

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