Flexible wire-wound fuel assembly axial flow-induced vibration experimental device and simulation method

Abstract

The invention discloses an axial flow-induced vibration experimental device and a simulation method for a flexible wire-wound fuel assembly model, comprising: a wave flow water tank, which is used to store experimental water and can generate waves and water flow to cause the wire-wound fuel assembly model to vibrate in a flow-induced manner; two support frames are provided, which are respectively installed on the upstream side and the downstream side of the wave flow water tank; vertical poles extending into the wave flow water tank are vertically installed on the two support frames; the wire-wound fuel assembly model, one end of which is connected to the lower end of the upstream pole through a universal coupling, and the other end is connected to the lower end of the downstream pole through a steel wire rope; a tensioner for applying axial force to the wire-wound fuel assembly model and a tension sensor for monitoring the tensioning force are installed in the middle of the steel wire rope.

Description

Technical Field

[0001] The present invention relates to the technical field of flow-induced vibration simulation experiments, and in particular to an experimental device and simulation method for axial flow-induced vibration of a flexible wire-wound fuel assembly model. Background Art

[0002] Flow-induced vibration refers to the phenomenon that when a fluid flows past a solid, it exerts an alternating fluid force on the solid surface, causing the solid to move reciprocally. The reciprocating movement of the solid in turn changes the fluid flow pattern, and further changes the fluid force acting on the solid surface. This phenomenon of interaction between the fluid and the solid is called flow-induced vibration.

[0003] Flow-induced vibration will cause the structure to be abraded and worn due to micro-amplitude vibration, or cause the structure to be damaged due to large-amplitude vibration.

[0004] In sodium-cooled fast reactors and lead-bismuth fast reactors, the fuel rods in the wire-wound fuel assembly are mainly positioned and guided by the wire-wound. Sodium and lead-bismuth metals have a high density, and the wire-wound fuel assembly has a low mass ratio. When the coolant flows through the wire-wound fuel assembly, strong turbulent fluctuations are generated. The turbulent axial flow (the axial flow refers to the direction of the turbulent flow being consistent with the axis direction of the fuel rod) causes the assembly to vibrate, and further causes fretting wear and vibration fatigue between the structure and the constraint.

[0005] Since the wire-wound fuel assembly is more complex than a single circular tube and a polygonal column, the number of wire-wound turns, the pitch, and the relative size of the wire-wound are variable, resulting in more complex flow around the wire-wound fuel assembly compared to flow around a circular tube. Numerical simulation needs to consider the applicability of the turbulence model, and numerical simulation is difficult.

[0006] Due to the complexity of the wire-wound fuel assembly, there are few reports on the simulation of flow-induced vibration of the wire-wound fuel assembly caused by axial flow, as well as research on fretting wear and vibration fatigue. Currently, there is a lack of relevant simulation experimental devices and synchronous measurement means for studying the axial flow-induced vibration of the flexible wire-wound fuel assembly, and it is impossible to simulate and study the influencing factors of axial flow-induced vibration. Summary of the Invention

[0007] The purpose of the present invention is to provide an experimental device and simulation method for axial flow-induced vibration of a flexible wire-wound fuel assembly model, so as to solve the technical problem that in the prior art, there is a lack of relevant experimental devices and synchronous measurement means for studying the axial flow-induced vibration of the flexible wire-wound fuel assembly model, and it is impossible to simulate and study the influencing factors of axial flow-induced vibration.

[0008] To solve the above technical problem, the present invention specifically provides an experimental device for axial flow-induced vibration of a flexible wire-wound fuel assembly model, including:

[0009] A wave flume for storing experimental water and capable of generating waves and / or water flow to cause flow-induced vibration of the wire-wound fuel assembly model;

[0010] There are two support frames, which are respectively installed on the upstream side and the downstream side of the wave flume; vertical poles extending into the wave flume are installed on both of the two support frames.

[0011] A wire-wound fuel assembly model is connected to the two poles at both ends through flexible connectors respectively, so that the wire-wound fuel assembly can generate fluid-induced vibration.

[0012] A tensioner for applying an axial force to the wire-wound fuel assembly model and a tension sensor for monitoring the magnitude of the tension force are installed on one of the flexible connectors.

[0013] An anemometer is arranged on the upstream side of the wire-wound fuel assembly model for measuring the far-field incoming flow velocity of the wave flume.

[0014] A wave height gauge is arranged on the upstream side of the wire-wound fuel assembly model for measuring wave data.

[0015] A laser particle image velocimeter is arranged below the wave flume and can illuminate from bottom to top to measure the flow field around the wire-wound fuel assembly model.

[0016] A plurality of fiber Bragg gratings are arranged in the wire-wound fuel assembly model, and a number of grating measurement points are evenly distributed on each fiber for measuring the strain at the corresponding position of the wire-wound fuel assembly model, so as to obtain the vibration information of the wire-wound fuel assembly model through modal inversion calculation.

[0017] The anemometer, the wave height gauge, the laser particle image velocimeter, the fiber Bragg gratings and the tension sensor are all connected to the data acquisition card on the measurement computer.

[0018] The tension force, strain, incoming flow velocity, flow field around the object and wave data are connected to the measurement computer through a fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system for synchronous measurement, which is convenient for fluid-structure coupling analysis.

[0019] The vibration information includes vibration position, vibration frequency, vibration mode and amplitude.

[0020] The wave data includes wave period and wave height.

[0021] As a preferred scheme of the present invention, one end of the wire-wound fuel assembly model is connected to the lower end of the pole on the upstream side through a universal coupling, and the other end is connected to the lower end of the pole on the downstream side through a steel wire rope.

[0022] The tensioner and the tension sensor are both installed on the steel wire rope.

[0023] As a preferred embodiment of the present invention, a pulley is fixedly installed at the lower end of the vertical rod on the downstream side, and the steel wire rope passes around the pulley and is connected to the support frame on the downstream side;

[0024] Both the tensioner and the tension sensor are installed on the steel wire rope between the pulley and the support frame.

[0025] As a preferred embodiment of the present invention, both of the vertical rods can adjust their installation heights on the support frame to adjust the gap between the wire-wound fuel assembly model and the wave flume.

[0026] As a preferred embodiment of the present invention, the wire-wound fuel assembly model includes a copper tube inside, a silica gel tube wrapped around the copper tube, and a silica gel strip wire wound around the silica gel tube;

[0027] Four fiber Bragg gratings are evenly bonded circumferentially on the outer wall of the copper tube and are wrapped by the silica gel tube.

[0028] As a preferred embodiment of the present invention, the shape, geometric dimensions, number of screw heads, and pitch of the silica gel strip can all be adjusted to study the influence of wire winding on flow-induced vibration.

[0029] As a preferred embodiment of the present invention, the side wall of the wave flume is made of transparent glass, the bottom surface is a concrete rigid wall surface, and a light-transmitting glass is installed at the position of the concrete rigid wall corresponding to the laser particle image velocimeter.

[0030] To solve the above technical problems, the present invention further provides a method for simulating the axial flow-induced vibration of a flexible wire-wound fuel assembly model. Using the above-mentioned experimental device for the axial flow-induced vibration of a flexible wire-wound fuel assembly model, the method includes the following steps:

[0031] S001. Drain the water in the wave flume, install the experimental device in the wave flume, and adjust the distance between the wire-wound fuel assembly model and the wave flume to a suitable gap ratio;

[0032] S002. Add water to the wave flume to the experimental water depth, and apply a tensile force to the wire-wound fuel assembly model through the tensioner;

[0033] S003. Measure the natural frequency and damping ratio of the wire-wound fuel assembly model;

[0034] S004. Use the wave flume to generate waves and water flow, change the wave parameters or increase the flow velocity according to a preset rule, and synchronously collect the strain data, tensile force data, oncoming flow velocity data, flow-around flow field data, and wave data of the wire-wound fuel assembly model;

[0035] S005. Adjust the tensioner to change the axial force on the wire-wound fuel assembly model, and repeat steps S001 to S004 while keeping the gap ratio and the wire-wound fuel assembly model unchanged to study the influence of the axial force on the axial flow-induced vibration characteristics; or,

[0036] Change the cross-sectional shape, geometric dimensions, number of screw heads, and / or pitch of the silicone strip wire-winding, and repeat steps S001 to S004 while keeping the gap ratio and the axial force unchanged to study the influence of the wire-winding on the axial flow-induced vibration; or,

[0037] Adjust the installation height of the wire-wound fuel assembly model to change the gap ratio, and repeat steps S001 to S004 while keeping the wire-wound fuel assembly model and the tension force unchanged to study the influence of the gap ratio on the axial flow-induced vibration.

[0038] S006. Obtain the vibration information of the wire-wound fuel assembly model through modal inversion calculation, where the vibration information includes the vibration position, vibration frequency, vibration mode, and amplitude size;

[0039] S007. Connect to a measurement computer through a fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system to synchronously measure the tension, strain, oncoming flow velocity, circumferential flow field, and wave data, and perform fluid-structure coupling analysis.

[0040] As a preferred solution of the present invention, the method for measuring the natural frequency and damping ratio of the wire-wound fuel assembly model is:

[0041] Apply a known displacement excitation to the wire-wound fuel assembly model and then release it to make the wire-wound fuel assembly model perform free decay vibration;

[0042] Record the change of the vibration strain of the wire-wound fuel assembly model with time;

[0043] Match the theoretically predicted response with the experimental record to find the unknown damping ratio;

[0044] The damping ratio ζ = ln(A i / A i+n ) / 2πn, where A i and A i+n are the strains corresponding to the i-th and (i + n)-th wave peaks of the free decay vibration strain vs. time curve;

[0045] Perform spectral analysis on the change of the vibration strain of the wire-wound fuel assembly model with time to obtain the natural frequency.

[0046] As a preferred solution of the present invention, the method for the modal inversion calculation is:

[0047] First, it is assumed that the structural vibration displacement can be expressed as a linear superposition of a series of natural modes. According to the strain information at different discrete points, the displacement information of any point on the cylindrical structure can be obtained:

[0048]

[0049] where y(z,t) is the lateral displacement, w n (t) is the weight coefficient, φ n (z) is the mode function, n is the modal order of the structure. For the boundary conditions of simply supported at both ends, φ n (z) can be expressed as:

[0050]

[0051] Furthermore, the curvature and strain have the following relationship:

[0052]

[0053] Based on this, the vibration displacement of any point on the wire-wound fuel assembly model can be obtained, and then the vibration frequency and vibration mode can be obtained.

[0054] The present invention has the following beneficial effects compared with the prior art:

[0055] By connecting both ends of the wire-wound fuel assembly model to the vertical rods extending into the wave flume through flexible connectors, and using the wave flume to generate waves and water flows, the wire-wound fuel assembly model can be caused to have axial flow-induced vibration. Then, through the flow-around flow field and wave data, the fluid-structure-soil coupling multi-physical parameter synchronous testing and real-time monitoring system, the measurement computer, and various measuring instruments, the tensile force, strain, oncoming flow velocity, flow-around flow field, and wave data can be collected, and fluid-structure coupling analysis can be carried out to study the influencing factors of axial flow-induced vibration. And according to the experimental results, the influencing factors can be adjusted and controlled to reduce the vibration amplitude, make the vibration be in the low-order mode, and reduce fretting wear and vibration fatigue. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0057] Figure 1 It is the front view schematic diagram of the experimental device for axial flow-induced vibration of the wire-wound fuel assembly model in the embodiment of the present invention;

[0058] Figure 2Schematic three-dimensional structure diagram of the experimental device for axial flow-induced vibration of the wire-wound fuel assembly model in the embodiments of the present invention;

[0059] Figure 3 Cross-sectional schematic diagram of the round-section three-headed wire-wound fuel assembly model in the embodiments of the present invention;

[0060] Figure 4 Cross-sectional schematic diagram of the square-section four-headed wire-wound fuel assembly model in the embodiments of the present invention;

[0061] Figure 5 Schematic three-dimensional structure diagram of the wire-wound fuel assembly model in the embodiments of the present invention;

[0062] Figure 6 Schematic structure diagram of the universal coupling in the embodiments of the present invention.

[0063] The reference numerals in the figure are respectively represented as follows:

[0064] 1 - wave flume, 2 - wire-wound fuel assembly model, 3 - support frame, 4 - vertical rod, 5 - tensioner, 6 - tension sensor, 7 - current meter, 8 - wave height meter, 9 - laser particle image velocimeter, 10 - fiber Bragg grating, 11 - copper tube, 12 - silicone tube, 13 - silicone strip wire winding, 14 - universal coupling, 15 - steel wire rope, 16 - pulley, 17 - light-transmitting glass, 18 - cross beam. Specific embodiments

[0065] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0066] The present invention specifically provides an experimental device for axial flow-induced vibration of a flexible wire-wound fuel assembly model, including:

[0067] A wave flume 1 for storing experimental water and capable of generating waves and / or water flow to cause flow-induced vibration of the wire-wound fuel assembly model 2; it can generate waves or water flow separately, or generate waves and water flow simultaneously.

[0068] The length of the wave flume 1 is 52 m. Utilizing the advantage of the length of the wave flume 1, a wire-wound fuel assembly model 2 with a long aspect ratio greater than 100 can be arranged along the wave flow direction to study the axial flow-induced vibration of the flexible wire-wound fuel assembly model.

[0069] Support frames 3, there are two of them, respectively installed on the upstream side and the downstream side of the wave flume 1; on both of the two support frames 3, there are vertically installed vertical rods 4 extending into the wave flume 1;

[0070] Wound wire fuel assembly model 2, both ends are respectively connected to the two vertical rods 4 through flexible connectors, so that the wound wire fuel assembly can generate fluid-induced vibration;

[0071] On one of the flexible connectors, there is installed a tensioner 5 for applying an axial force to the wound wire fuel assembly model 2, and a tension sensor 6 for monitoring the magnitude of the tension force;

[0072] Flow velocity meter 7, is arranged on the upstream side of the wound wire fuel assembly model 2, and is used to measure the far-field incoming flow velocity of the wave flume 1;

[0073] Wave height meter 8, is arranged on the upstream side of the wound wire fuel assembly model 2, and is used to measure wave data, and the wave data includes wave period and wave height.

[0074] Laser particle image velocimeter 9, is arranged below the wave flume 1, and can illuminate from bottom to top to measure the flow field around the wound wire fuel assembly model 2;

[0075] Fiber Bragg gratings 10, there are multiple ones arranged inside the wound wire fuel assembly model 2, and several grating measuring points are evenly distributed on each optical fiber, and are used to measure the strain at the corresponding position of the wound wire fuel assembly model 2, so as to obtain the vibration information of the wound wire fuel assembly model 2 through modal inversion calculation; the vibration information includes vibration position, vibration frequency, vibration mode and amplitude size;

[0076] The Fiber Bragg grating 10 measures strain and inverses vibration displacement, which has the advantages of small volume, high measurement accuracy, no interference to the structure, etc.

[0077] The flow velocity meter 7, the wave height meter 8, the laser particle image velocimeter 9, the fiber Bragg grating 10, and the tension sensor 6 are all connected to the data acquisition card on the measurement computer;

[0078] The tension, strain, incoming flow velocity, flow field around the object, and wave data are connected to the measurement computer through the fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system for synchronous measurement, which is convenient for fluid-structure coupling analysis.

[0079] The fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system is an existing technology, and the method in CN200410033634.3 can be referred to, and will not be elaborated here.

[0080] In summary, by connecting both ends of the wire-wound fuel assembly model 2 to the vertical rod 4 extending into the wave flume 1 through flexible connectors, and using the wave flume 1 to generate waves and water currents, the wire-wound fuel assembly model 2 can be caused to undergo axial flow-induced vibration. Then, through the flow-around flow field and wave data, the fluid-structure-soil coupling multi-physical parameter synchronous testing and real-time monitoring system, the measurement computer, and various measuring instruments, the tensile force, strain, oncoming flow velocity, flow-around flow field, and wave data can be collected, and fluid-structure coupling analysis can be carried out to facilitate the study of the influencing factors of axial flow-induced vibration.

[0081] Furthermore, the wire-wound fuel assemblies are arranged closely, prone to flow blockage, and high turbulence is also one of the difficulties in simulation. Therefore, in the present invention, the simulation starts from a single wire-wound fuel assembly to explore the factors affecting the axial flow-induced vibration of the wire-wound fuel assembly.

[0082] Furthermore, the two flexible connectors are respectively set as a universal coupling 14 and a steel wire rope 15. One end of the wire-wound fuel assembly model 2 is connected to the lower end of the vertical rod 4 on the upstream side through the universal coupling 14, and the other end is connected to the lower end of the vertical rod 4 on the downstream side through the steel wire rope 15;

[0083] The tensioner 5 and the tension sensor 6 are both installed on the steel wire rope 15. The tension of the steel wire rope 15 on the wire-wound fuel assembly model 2 can be adjusted through the tensioner 5, that is, the axial force applied to the wire-wound fuel assembly model 2 can be adjusted. The magnitude of the axial force can be detected in real time through the tension sensor 6 to facilitate the study of the influence of the axial force on the axial flow-induced vibration of the wire-wound fuel assembly model 2.

[0084] At the same time, when studying other influencing factors, this axial force adjustment feedback mechanism can easily adjust the axial force to remain unchanged.

[0085] The specific implementation process of studying the influence of the axial force on the axial flow-induced vibration is as follows:

[0086] S001. Drain the water in the wave flume 1, install the experimental device in the wave flume 1, and adjust the distance between the wire-wound fuel assembly model 2 and the wave flume 1 to an appropriate gap ratio;

[0087] S002. Add water to the wave flume 1 to the experimental water depth, and apply a tensile force to the wire-wound fuel assembly model 2 through the tensioner 5;

[0088] S003. Measure the natural frequency and damping ratio of the wire-wound fuel assembly model 2;

[0089] S004. Use the wave flume 1 to generate waves and water currents, change the wave parameters or increase the flow velocity according to a preset rule, and synchronously collect the strain data, tensile force data, oncoming flow velocity data, flow-around flow field data, and wave data of the wire-wound fuel assembly model 2;

[0090] S005. Adjust the tensioner 5 to change the axial force on the wire-wound fuel assembly model 2. Repeat steps S001 to S004 while keeping the gap ratio and the wire-wound fuel assembly model 2 unchanged, and study the influence of the axial force on the axial flow-induced vibration characteristics.

[0091] S006. Obtain the vibration information of the wire-wound fuel assembly model 2 through modal inversion calculation. The vibration information includes the vibration position, vibration frequency, vibration mode, and amplitude size.

[0092] S007. Connect to the measurement computer through the fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system to synchronously measure the tension, strain, oncoming flow velocity, circumferential flow field, and wave data, and conduct fluid-structure coupling analysis.

[0093] Furthermore, if the wire rope 15 only has the length from the end of the wire-wound fuel assembly to the end of the vertical pole 4, it will make the installation space of the tensioner 5 and the tension sensor 6 very narrow and is not convenient for subsequent adjustment of the axial force.

[0094] Therefore, in the present invention, a pulley 16 is fixedly installed at the lower end of the vertical pole 4 on the downstream side, and the wire rope 15 bypasses the pulley 16 and is connected to the support frame 3 on the downstream side.

[0095] Both the tensioner 5 and the tension sensor 6 are installed on the wire rope 15 between the pulley 16 and the support frame 3.

[0096] The pulley 16 can convert the tension in other directions into the tension in the horizontal direction, so that the direction of the axial force remains unchanged.

[0097] In this way, the installation space of the tensioner 5 and the tension sensor 6 can be increased, and the operation space for subsequent adjustment of the axial force can also be increased.

[0098] Furthermore, both vertical poles 4 can adjust their installation heights on the support frame 3 to adjust the gap between the wire-wound fuel assembly model 2 and the wave flume 1, so as to facilitate the study of the influence of the gap size on the axial flow-induced vibration of the wire-wound fuel assembly.

[0099] The specific implementation process for studying the influence of the gap ratio on the axial flow-induced vibration is as follows:

[0100] S001. Drain the water in the wave flume 1, install the experimental device in the wave flume 1, and adjust the distance between the wire-wound fuel assembly model 2 and the wave flume 1 to an appropriate gap ratio.

[0101] S002. Add water to the wave flume 1 to the experimental water depth, and apply a tension to the wire-wound fuel assembly model 2 through the tensioner 5.

[0102] S003. Measure the natural frequency and damping ratio of the wire-wound fuel assembly model 2.

[0103] S004. Generate waves and water currents using the wave flume 1, change the wave parameters or increase the flow velocity according to a preset rule, and synchronously collect the strain data, tensile force data, oncoming flow velocity data, circumferential flow field data, and wave data of the wire-wound fuel assembly model 2.

[0104] S005. Adjust the installation height of the wire-wound fuel assembly model 2, change the clearance ratio, repeat steps S001 - S004, keep the wire-wound fuel assembly model 2 and the tension force unchanged, and study the influence of the clearance ratio on the axial flow-induced vibration.

[0105] S006. Obtain the vibration information of the wire-wound fuel assembly model 2 through modal inversion calculation. The vibration information includes the vibration position, vibration frequency, vibration mode, and amplitude size.

[0106] S007. Connect the measurement computer through the fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system to synchronously measure the tensile force, strain, oncoming flow velocity, circumferential flow field, and wave data, and perform fluid-structure coupling analysis.

[0107] It can be understood that there are various ways to adjust the height of the vertical rod 4 on the support frame 3. For example, a plurality of fixing holes are evenly arranged at equal intervals on the vertical rod 4, and different fixing holes are fixed to the support frame 3 through screws, so as to realize the adjustment of the installation height of the vertical rod 4.

[0108] Or, the vertical rod 4 is slidably connected to the support frame 3, and the vertical rod 4 is driven to move up and down through a cylinder, a telescopic rod, etc.

[0109] Furthermore, in the present invention, the wire-wound fuel assembly model 2 includes a copper tube 11 inside, a silica gel tube 12 wrapped outside the copper tube 11, and a silica gel strip wire winding 13 wound outside the silica gel tube 12.

[0110] Among them, four fiber Bragg gratings 10 are evenly bonded circumferentially on the outer wall of the copper tube 11 and are wrapped by the silica gel tube 12.

[0111] Furthermore, the shape, geometric dimensions, number of screw heads, and pitch of the silica gel strip can all be adjusted to study the influence of the wire winding on the flow-induced vibration.

[0112] The specific implementation process of studying the influence of the silica gel strip on the axial flow-induced vibration is as follows:

[0113] S001. Drain the water in the wave flume 1, install the experimental device in the wave flume 1, and adjust the distance between the wire-wound fuel assembly model 2 and the wave flume 1 to a suitable clearance ratio.

[0114] S002. Add water to the wave flume 1 to the experimental water depth, and apply a tensile force to the wire-wound fuel assembly model 2 through the tensioner 5.

[0115] S003. Measure the natural frequency and damping ratio of the wire-wound fuel assembly model 2;

[0116] S004. Use the wave flume 1 to generate waves and water flow, change the wave parameters or increase the flow velocity according to a preset rule, and synchronously collect the strain data, tensile force data, oncoming flow velocity data, flow-around flow field data, and wave data of the wire-wound fuel assembly model 2;

[0117] S005. Change the cross-sectional shape (circular, square, rectangular, etc.), geometric dimensions, number of wire heads (3 heads, 4 heads, or other numbers), and / or pitch (single change or compound change) of the silica gel strip wire winding 13, repeat steps S001 - S004, keep the gap ratio and axial force unchanged, and study the influence of the wire winding on the axial flow-induced vibration;

[0118] S006. Obtain the vibration information of the wire-wound fuel assembly model 2 through modal inversion calculation, and the vibration information includes the vibration position, vibration frequency, vibration mode, and amplitude size;

[0119] S007. Connect the measurement computer through the fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system to synchronously measure the tensile force, strain, oncoming flow velocity, flow-around flow field, and wave data, and conduct fluid-structure coupling analysis.

[0120] Furthermore, the side wall of the wave flume 1 is made of transparent glass, the bottom surface is a concrete rigid wall surface, and a light-transmitting glass 17 is installed at the position of the laser particle image velocimeter 9 corresponding to the concrete rigid wall surface, so as to facilitate the laser particle image velocimeter 9 to shine light from bottom to top.

[0121] At the same time, in order to facilitate the installation of the support frame 3 on the side wall of the wave flume 1 made of transparent glass, cross beams 18 are installed at the tops of both sides in the length direction of the wave flume 1, and the support frame 3 is installed on the cross beams 18.

[0122] To solve the above technical problems, the present invention further provides a simulation method for axial flow-induced vibration of a flexible wire-wound fuel assembly model, using the above experimental device for axial flow-induced vibration of a flexible wire-wound fuel assembly model, including the following steps:

[0123] S001. Drain the water in the wave flume 1, install the experimental device in the wave flume 1, and adjust the distance between the wire-wound fuel assembly model 2 and the wave flume 1 to an appropriate gap ratio;

[0124] S002. Add water to the wave flume 1 to the experimental water depth, and apply a tensile force to the wire-wound fuel assembly model 2 through the tensioner 5;

[0125] S003. Measure the natural frequency and damping ratio of the wire-wound fuel assembly model 2;

[0126] S004. Generate waves and water currents using the wave flume 1, change the wave parameters or increase the flow velocity according to a preset rule, and simultaneously collect the strain data, tensile force data, oncoming flow velocity data, flow field data around the wire-wound fuel assembly model 2, and wave data;

[0127] S005. Adjust the tensioner 5 to change the axial force on the wire-wound fuel assembly model 2, repeat steps S001 - S004, keep the clearance ratio and the wire-wound fuel assembly model 2 unchanged, and study the influence of the axial force on the axial flow-induced vibration characteristics; or,

[0128] Change the cross-sectional shape, geometric dimensions, number of screw heads, and / or pitch of the silica gel strip wire-wound 13, repeat steps S001 - S004, keep the clearance ratio and the axial force unchanged, and study the influence of the wire-wound on the axial flow-induced vibration; or,

[0129] Adjust the installation height of the wire-wound fuel assembly model 2 to change the clearance ratio, repeat steps S001 - S004, keep the wire-wound fuel assembly model 2 and the tension force unchanged, and study the influence of the clearance ratio on the axial flow-induced vibration.

[0130] S006. Obtain the vibration information of the wire-wound fuel assembly model 2 through modal inversion calculation, and the vibration information includes the vibration position, vibration frequency, vibration mode, and amplitude size;

[0131] S007. Connect the measurement computer through the fluid-structure-soil coupling multi-physical parameter synchronous test and real-time monitoring system to synchronously measure the tensile force, strain, oncoming flow velocity, flow field around the wire-wound, and wave data, and conduct fluid-structure coupling analysis.

[0132] As a preferred solution of the present invention, the method for measuring the natural frequency and damping ratio of the wire-wound fuel assembly model 2 is:

[0133] Apply a known displacement excitation to the wire-wound fuel assembly model 2 and then release it to make the wire-wound fuel assembly model 2 perform free decay vibration;

[0134] Record the change of the vibration strain of the wire-wound fuel assembly model 2 with time;

[0135] Match the theoretically predicted response with the experimental record to find the unknown damping ratio;

[0136] The damping ratio ζ = ln(A i / A i+n ) / 2πn, where A i and A i+n are the strains corresponding to the i-th and (i + n)-th wave peaks of the curve of the free decay vibration strain changing with time;

[0137] Conduct spectral analysis on the change of the vibration strain of the wire-wound fuel assembly model 2 with time to obtain the natural frequency.

[0138] As a preferred embodiment of the present invention, the method of modal inversion calculation is as follows:

[0139] First, it is assumed that the structural vibration displacement can be expressed as a linear superposition of a series of natural modes. According to the strain information at different discrete points, the displacement information of any point on the cylindrical structure can be obtained:

[0140]

[0141] where y(z, t) is the lateral displacement, w n (t) is the weight coefficient, φ n (z) is the mode function, n is the modal order of the structure. For the boundary conditions of simply supported at both ends, φ n (z) can be expressed as:

[0142]

[0143] Furthermore, the relationship between curvature and strain is as follows:

[0144]

[0145] Based on this, the vibration displacement of any point on the wire-wound fuel assembly model 2 can be obtained, and then the vibration frequency and vibration mode can be obtained.

[0146] Through the above method, the effects of axial force, clearance ratio, cross-sectional shape, geometric dimensions, number of screw heads and pitch of the wire winding on the axial flow-induced vibration can be studied. The purpose is to adjust and control each influencing factor according to the experimental results to reduce the vibration amplitude, make the vibration in the low-order mode, and reduce fretting wear and vibration fatigue.

[0147] The above embodiments are only exemplary embodiments of the present application and are not used to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present application, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present application.

Claims

1. A flexible wire-wound fuel assembly model axial flow-induced vibration experimental device, characterized in that: include: A wave and flow water tank (1) is used to store experimental water and is capable of generating waves and / or water flow to cause the wound wire fuel assembly model (2) to undergo flow-induced vibration; Two support frames (3) are provided, which are respectively installed on the upstream side and the downstream side of the wave flow water tank (1); and vertical poles (4) extending into the wave flow water tank (1) are vertically installed on the two support frames (3); The wire-wound fuel assembly model (2) has two ends connected to the two upright poles (4) via flexible connectors, so that the wire-wound fuel assembly model (2) can generate flow-induced vibration; A tensioner (5) for applying an axial force to the wire-wound fuel assembly model (2) and a tension sensor (6) for monitoring the magnitude of the tensioning force are installed on one of the flexible connecting members; A flow meter (7), arranged at the upstream side of the wire-wound fuel assembly model (2), for measuring the far-field incoming flow velocity of the wave flow tank (1); A wave height meter (8), arranged at the upstream side of the wire-wound fuel assembly model (2), for measuring wave data; A laser particle image velocimeter (9) is arranged below the wave flow tank (1) and is capable of illuminating from bottom to top to measure the flow field of the wound wire fuel assembly model (2); A plurality of optical fiber Bragg gratings (10) are arranged in the wire-wound fuel assembly model (2), and a plurality of grating measuring points are evenly distributed on each optical fiber, and are used to measure the strain at a corresponding position of the wire-wound fuel assembly model (2), so as to obtain vibration information of the wire-wound fuel assembly model (2) through modal inversion calculation; The velocity meter (7), the wave height meter (8), the laser particle image velocimeter (9), the fiber grating (10), and the tension sensor (6) are all connected to a data acquisition card on a measuring computer; The vibration information includes vibration position, vibration frequency, vibration mode and amplitude; The wave data includes wave period and wave height; The wire-wound fuel assembly model (2) comprises an internal copper tube (11), a silicone tube (12) wrapped outside the copper tube (11), and a silicone strip wire (13) wound outside the silicone tube (12); Four optical fiber gratings (10) are evenly bonded to the outer wall of the copper tube (11) in the circumferential direction and are wrapped by the silicone tube (12).

2. A flexible wire-wound fuel assembly model axial flow-induced vibration experimental device according to claim 1, characterized in that: One end of the wire-wound fuel assembly model (2) is connected to the lower end of the vertical rod (4) on the upstream side through a universal coupling (14), and the other end is connected to the lower end of the vertical rod (4) on the downstream side through a steel wire rope (15); The tensioner (5) and the tension sensor (6) are both installed on the steel wire rope (15).

3. A flexible wire-wound fuel assembly model axial flow-induced vibration experimental device according to claim 2, characterized in that: A pulley (16) is fixedly mounted on the lower end of the vertical pole (4) on the downstream side, and the steel wire rope (15) passes over the pulley (16) and is connected to the support frame (3) on the downstream side; The tensioner (5) and the tension sensor (6) are both installed on the steel wire rope (15) between the pulley (16) and the support frame (3).

4. The axial flow-induced vibration experimental device of a flexible wire-wound fuel assembly model according to claim 3 is characterized in that: The two vertical rods (4) are both capable of adjusting their installation heights on the support frame (3) to adjust the gap between the wire-wound fuel assembly model (2) and the wave flow water tank (1).

5. The axial flow-induced vibration experimental device of a flexible wire-wound fuel assembly model according to claim 1, characterized in that: The shape, geometrical dimensions, number of screw heads and screw pitch of the silicone strip winding wire (13) can be adjusted to study the influence of the winding wire on flow-induced vibration.

6. The axial flow-induced vibration experimental device of a flexible wire-wound fuel assembly model according to claim 5, characterized in that: The side wall of the wave flow water tank (1) is made of transparent glass, and the bottom surface is a concrete rigid wall surface, and a light-transmitting glass (17) is installed on the concrete rigid wall surface at a position corresponding to the laser particle image velocimeter (9).

7. A method for simulating axial flow-induced vibration of a flexible wire-wound fuel assembly model, characterized in that: The axial flow-induced vibration experimental device for a flexible wire-wound fuel assembly model according to claim 6 comprises the following steps: S001, draining the water in the wave flow water tank (1), installing an experimental device in the wave flow water tank (1), and adjusting the distance between the wire wound fuel assembly model (2) and the wave flow water tank (1) to a suitable gap ratio; S002, adding water to the wave flow water tank (1) to a test water depth, and applying tension to the wire-wound fuel assembly model (2) through a tensioner (5); S003, measuring the natural frequency and damping ratio of the wire-wound fuel assembly model (2); S004, using a wave and flow tank (1) to generate waves and water flow, changing wave parameters or increasing flow velocity according to preset rules, and synchronously collecting strain data, tension data, incoming flow velocity data, bypass flow field data and wave data of the wire-wound fuel assembly model (2); S005, adjusting the tensioner (5), changing the axial force on the wire-wound fuel assembly model (2), repeating steps S001 to S004, keeping the gap ratio and the wire-wound fuel assembly model (2) unchanged, and studying the influence of the axial force on the axial flow-induced vibration characteristics; or, Changing the cross-sectional shape, geometric dimensions, number of screw heads and / or pitch of the silicone strip winding wire (13), repeating steps S001 to S004, keeping the gap ratio and axial force unchanged, and studying the influence of the winding wire on the axial flow-induced vibration; or, Adjusting the installation height of the wire-wound fuel assembly model (2), changing the gap ratio, repeating steps S001 to S004, keeping the wire-wound fuel assembly model (2) and the tension force unchanged, and studying the effect of the gap ratio on the axial flow-induced vibration; S006. Obtaining vibration information of the wire-wound fuel assembly model (2) by modal inversion calculation, wherein the vibration information includes vibration position, vibration frequency, vibration mode and amplitude; S007. Through the fluid-solid-soil coupling multi-physical parameter synchronous test and real-time monitoring system connected to the measurement computer to synchronously measure the tension, strain, incoming flow velocity, flow field and wave data, and conduct fluid-solid coupling analysis.

8. A method for simulating axial flow-induced vibration of a flexible wire-wound fuel assembly model according to claim 7, characterized in that: The method for measuring the natural frequency and damping ratio of the wire-wound fuel assembly model (2) is as follows: Applying a known displacement excitation to the wire-wound fuel assembly model (2) and then releasing it, so that the wire-wound fuel assembly model (2) performs free attenuation vibration; Recording the change of the vibration strain of the wire-wound fuel assembly model (2) over time; Match the theoretically predicted response with the experimental record to find the unknown damping ratio; Damping ratio ζ=ln(A i / A i+n ) / 2πn,A i and A i+n is the strain corresponding to the i-th and i+n-th peaks of the free decay vibration strain-time curve; The variation of vibration strain of the wire-wound fuel assembly model (2) with time is analyzed by spectrum analysis to obtain the natural frequency.

9. A method for simulating axial flow-induced vibration of a flexible wire-wound fuel assembly model according to claim 7, characterized in that: The method of modal inversion calculation is: First, it is assumed that the structural vibration displacement can be expressed as a linear superposition of a series of natural modes. According to the strain information of different discrete points, the displacement information of any point in the cylindrical structure can be obtained: where y(z,t) is the lateral displacement, is the modal function, w n (t) is the weight coefficient of each mode, n is the modal order of the structure, L is the length of the flexible wire-wound fuel assembly model, and for the boundary conditions of simple supports at both ends, It can be expressed as: Then the curvature and strain have the following relationship: Among them, ε(z, t) is the strain at the corresponding position of the wire-wound fuel assembly model (2) measured by the grating measurement point, and R is the radius of the copper tube (11), both of which are known quantities. Based on this, the weight coefficient and the vibration displacement of any point on the wire-wound fuel assembly model (2) can be obtained, and then the vibration frequency and vibration mode can be obtained.

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