CN117054267A - Test device and method for measuring liquid impact load at top of water storage tank of nuclear power plant - Google Patents

Abstract

Test device for liquid impact load on the top of a water storage tank in a nuclear power plant, including a scaled-down water tank model, a uniaxial hydraulic vibration table, a water pressure sensor, a force sensor, and a high-speed camera. The bottom of the scaled-down water tank model is fixed on a uniaxial hydraulic vibration table. platform, with a through hole on the side wall for fixing the built-in impact top plate; the lower part of the force sensor is fixed on the built-in impact top plate, and the upper part is fixed on the L-shaped stainless steel bracket, which is fixed to the water tank model through transverse bolts on the side wall; the water pressure sensor is installed on the built-in impact top plate. The invention can accurately measure the impact load of liquid sloshing on the top plate of the water tank; can change the protruding arrangement of the top plate as needed; can measure the distribution of the impact load on the top; and has strong economy.

Description

Test device and method for measuring liquid impact load on top of water storage tanks in nuclear power plants

Technical field

The invention belongs to the technical field of nuclear power energy, and specifically belongs to a test device and test method for measuring the impact load of liquid on the top of a water storage tank in a nuclear power plant.

Background technique

Water storage tanks in nuclear power plants are key equipment in the field of nuclear energy and have a variety of important functions to ensure the safe and stable operation of nuclear power plants and respond to emergencies (such as passive containment cooling water tanks, spent fuel pools and auxiliary water tanks, etc. ). These water storage tanks play an indispensable role in the safety system and daily operations of nuclear power plants, covering many key aspects such as cooling, pressure control, and radioactive material control. First, water storage tanks play a vital role in the cooling systems in nuclear power plants. Stable operation of nuclear reactors requires maintaining a suitable temperature range to prevent overheating and fuel damage. As part of the cooling system, the water storage tank stores coolant, usually water, to provide a cooling effect when needed to maintain a stable operating temperature of the nuclear reactor. Its cooling function is crucial to the normal operation of nuclear power plants. Water storage tanks also play an important role in emergency response at nuclear power plants. These water storage tanks can play a key role in the event of an accident or emergency at a nuclear power plant. For example, they can be used to absorb coolant and relieve pressure, helping to control the situation and prevent the accident from getting worse. This emergency response capability is crucial to respond to emergencies and maintain the safety and stability of nuclear power plants. In addition, water storage tanks play an important role in controlling radioactive materials. Radioactive materials produced by nuclear power plants require effective control and management to prevent radiation exposure to the environment and personnel. The water storage tank is used to collect, store and treat wastewater containing radioactive materials to ensure that it does not leak into the environment, thereby maintaining the safety of the environment around the nuclear power plant. The water storage tank can also be used as part of the backup water supply system to ensure that the nuclear power plant can still obtain enough coolant or fire-fighting water in an emergency to maintain the operation of key equipment. In addition, they help maintain the operational stability of nuclear power plants and avoid problems such as temperature rise and pressure increase, thereby ensuring the normal operation of equipment.

Under seismic conditions, liquids in nuclear power plant storage tanks can slosh. When the frequency of external excitation is close to the sloshing frequency of the liquid, the liquid in the water tank resonates, causing large sloshing, which may cause damage to the top of the water tank. Nuclear power plants usually need to maintain the safety and stability of equipment under various conditions to ensure the normal operation of nuclear reactions. Liquid shock may interfere with the normal operation of a nuclear power plant and may even cause equipment failure or leakage of radioactive materials, thereby increasing the risk of accidents. There is a lack of relevant research on liquid impact loads at home and abroad. In addition, in new nuclear power plants, some passive safety water tanks have large spans. In order to enhance their structural rigidity, reinforcing beams are placed on the top of the water tanks. This reinforced beam will be partially immersed in water, and the impact of the protrusions (beams) contained on the top on the liquid impact load is currently unclear.

The existing technology discloses a study on the sloshing characteristics of the AP1000 containment cooling water tank under long-period earthquakes ("Nuclear Power Engineering", Volume 36, Issue 5, October 2015, Zeng Xiaojia et al.). This document establishes an experimental model and uses a shaking table to In the simulation experiment, three sinusoidal waves with the same frequency as the water sloshing were selected as excitations to measure the impact force at each position of the top cover at different liquid depths. By comparing with the calculation method proposed by Lu Daogang, the feasibility and accuracy of the calculation method were further proved. . At the same time, it can be concluded that the calculation result is relatively small when the vibration amplitude is small, and is relatively large when the vibration amplitude is large, which is conservative to a certain extent. However, this prior art cannot accurately measure the impact load of the liquid sloshing on the top plate of the water tank, cannot change the protruding arrangement of the top plate as needed, and cannot measure the distribution of the impact load on the top.

Contents of the invention

The object of the present invention is to provide a test device and method for measuring the impact load of liquid on the top of a water storage tank in a nuclear power plant, which can measure the impact load of the liquid on the top of the entire water tank due to liquid sloshing, and at the same time determine the distribution of the impact load of the liquid. , it is also possible to explore the influence of the protrusion (beam) on the top of the water tank on the liquid impact load.

A test device for liquid impact load on the top of a water storage tank in a nuclear power plant, including a scaled-down water tank model, a uniaxial hydraulic vibration table, a water pressure sensor, and a force sensor. The characteristics are: the bottom of the scaled-down water tank model (1) is fixed on a uniaxial To the hydraulic vibration table (11), there is a through hole (10) on the side wall for fixing the built-in impact top plate (5); the lower part of the force sensor (4) is fixed on the built-in impact top plate (5), and the upper part is fixed on the built-in impact top plate (5). On the L-shaped stainless steel bracket (3), the L-shaped stainless steel bracket is fixed on the side wall of the water tank model through transverse bolts (2); the water pressure sensor is installed on the built-in impact top plate;

During the test, a uniaxial hydraulic vibration table (11) was used to excite the scaled water tank model (1). The liquid inside the water tank sloshed, causing the liquid to impact the built-in top plate. The force sensor measured the impact force of the fluid. Time history curve, the distribution of liquid impact pressure on the top plate is measured by the water pressure sensor.

The invention also discloses a test method for liquid impact load on the top of a water storage tank in a nuclear power plant using the above experimental device, which is characterized by:

1) Install the scaled test model of the nuclear power plant water storage tank on the table of the uniaxial hydraulic vibration table, and use bolts to firmly connect the bottom of the model to the vibration table;

2) Install the water pressure sensor on the side wall of the model;

3) Inject water into the water tank model to make the water level reach the test requirements;

4) If necessary, secure the top protrusion to the built-in impact top plate with bolts;

5) Install the force sensor and pressure sensor on the built-in impact top plate;

6) Fix the built-in impact top plate to the side wall of the water tank model through L-shaped stainless steel brackets and transverse bolts;

7) Fix the waterproof wide-angle high-speed camera on the top side wall of the model through the suction cup;

8) Turn on the vibration table control system and water cooling system, and set the vibration parameters;

9) Connect the sensor to the data collection system and turn on the relevant sensor;

10) Turn on the data collector and set the collection parameters;

11) Start the test, apply external vibration excitation to the model, and record the force at each measuring point

Time history curves of sensors and water pressure sensors;

12) After the liquid returns to calmness, repeat step 11 and repeat the test 3 times. The final measurement result is the average of the 3 tests to reduce random errors.

13) Drain all the water in the model and keep other settings consistent with steps 9 and 10 (as a control group to exclude the impact of external incentives on the model);

14) Repeat step 11 once and record the test data.

beneficial effects

1) Able to accurately measure the impact load of liquid sloshing on the roof of the water tank;

2) The arrangement of the roof protrusion can be changed as needed;

3) The distribution of impact load on the top can be measured;

4) It has strong economic efficiency.

Description of the drawings

Figure 1 is a schematic diagram of the test device for liquid impact load on the top of the water storage tank in a nuclear power plant;

Figure 2 is a schematic diagram of the built-in impact top plate;

Figure 3 is a schematic diagram of the data collection device of the present invention;

Figure 4 shows the calculation domain of the test model potential function, in which (a) is a perspective view of the calculation domain; (b) is a top view of the calculation domain;

Figure 5 is the external excitation acceleration time history curve of the embodiment;

Figure 6 is the time history curve of the resultant force of the roof liquid impact load;

Figure 7 shows the time history curve of the pressure distribution of the liquid impact load on the roof;

Among them: 1-scale water storage tank model, 2-lateral fixing bolts, 3-L-shaped stainless steel bracket, 4-force sensor, 5-built-in impact roof plate, 6-top plate water pressure sensor, 7-top protrusion model, 8- Longitudinal fixing bolts of the protrusion, 9-side wall water pressure sensor, 10-top plate transverse fixing hole, 11-uniaxial hydraulic vibration table, 12-waterproof wide-angle high-speed camera; 13-force sensor fixing bolt hole, 14-top protrusion Object fixing bolt hole (oblique), 15-the connection hole between the stainless steel frame and the acrylic body, 16-top protrusion fixing bolt hole (forward), 17-top plate water pressure sensor hole, 18-stainless steel frame, 19-acrylic body ; 20-Strain data conditioner, 21-Data acquisition instrument.

Detailed ways

Example 1

The test device for studying the impact load of liquid on the top of a water storage tank in a nuclear power plant according to the present invention mainly includes:

1) A scaled model used to simulate a water storage tank in a nuclear power plant, with the bottom fixed on a uniaxial hydraulic vibration table;

2) The uniaxial hydraulic vibration test system is used to provide the external excitation required for the test;

3) Six force sensors are fixed on the built-in impact top plate;

4) Six water pressure sensors are installed on the built-in impact top plate.

The main structure of the test device is shown in Figure 1. The bottom of the scaled water tank model (1) is bolted to the uniaxial hydraulic vibration table (11), and a φ10 top plate transverse fixing hole (10) is opened on its side wall for fixing the built-in impact top plate. The built-in impact top plate (5) consists of two parts, namely a stainless steel frame (18) and an acrylic (plexiglass) body (19), which are fixedly connected by bolts. The lower part of the force sensor (4) is fixed to the bolt hole on the built-in impact top plate (5), and the upper part is fixed on the L-shaped stainless steel bracket (3) through bolts. The L-shaped stainless steel bracket is fixed on the side wall of the water tank model through transverse fixing bolts (2). The roof water pressure sensor (6) is installed in the reserved hole (17) of the built-in impact roof through a threaded connection. The side wall water pressure sensor (9) is also installed on the side wall of the model through threads. In addition, the top protrusion model (7) is fixed on the built-in impact top plate through the protrusion longitudinal fixing bolts (8) (it can be decided whether to install the top protrusion according to the test requirements).

During the test, a uniaxial hydraulic vibration table was used to excite the water storage tank model. The liquid inside the water tank sloshed, causing the liquid to impact the built-in roof. The time history curve of the fluid impact force could be measured through six force sensors. , the distribution of liquid impact pressure on the top plate can be measured through six water pressure sensors. A wide-angle high-speed camera (12) can also be used to record the distribution of the impact surface when the liquid impacts the top plate.

The force sensor 4 is connected to the strain data conditioner 20 through a cable, and the strain data conditioner 20 is connected to the data acquisition instrument 21 through a cable. During the test, the force sensor 4 converts the impact load of the liquid into an electrical signal through the strain data conditioner 20 and amplifies it, and the data collector 21 collects and records the processed electrical signal. The roof water pressure sensor 6 directly converts the liquid impact pressure into an electrical signal, and the data collector 21 collects and records the electrical signal. The data collector 21 can transmit the collected and recorded signals to the data analysis computer, thereby summarizing and further analyzing the data.

Example 2

The steps of the test method for studying the impact load of liquid on the top of a water storage tank in a nuclear power plant according to the present invention are as follows:

1) Install the scaled test model of the nuclear power plant water storage tank on the table of the uniaxial hydraulic vibration table, and use bolts to firmly connect the bottom of the model to the vibration table;

2) Install the water pressure sensor on the side wall of the model;

3) Inject water into the water tank model to make the water level reach the test requirements;

4) If necessary, secure the top protrusion to the built-in impact top plate with bolts;

5) Install the force sensor and pressure sensor on the built-in impact top plate;

6) Fix the built-in impact top plate to the side wall of the water tank model through L-shaped stainless steel brackets and transverse bolts;

7) Fix the waterproof wide-angle high-speed camera on the top side wall of the model through the suction cup;

8) Connect the sensor to the data collection system and turn on the relevant sensor;

9) Turn on the uniaxial hydraulic vibration table control system and water cooling system, and set the vibration parameters;

10) Turn on the data collector, set the collection parameters, and start sampling;

11) Start the test, apply external vibration excitation to the model, and record the time history curves of the force sensor and water pressure sensor at each measuring point;

12) Repeat the content of step 11 and repeat the test 3 times. The final measurement result is the average of the 3 tests to reduce random errors.

13) Drain all the water in the model and keep other settings consistent with steps 9 and 10 (as a control group to exclude the impact of external incentives on the model);

14) Repeat step 11 once and record the test data.

During the test, the displacement function X of the external excitation applied through the uniaxial hydraulic vibration table can be expressed as: In the formula, A is the displacement amplitude of the external excitation, f is the frequency of the external excitation, and t is the time.

Regarding the phenomenon of liquid sloshing, when the external excitation frequency is far away from the natural vibration frequency of the liquid, the amplitude of liquid sloshing is significantly reduced and no impact load will be produced on the top plate; only when the external excitation frequency is close to the frequency of the liquid's natural vibration plate, will the liquid undergo significant sloshing? The shaking phenomenon causes impact load on the roof of the water tank. Therefore, it is crucial to determine the natural frequency of the liquid in the tank.

For a regular-shaped water tank, a theoretical formula is used to calculate the natural frequency of the liquid inside it. In this experimental model, the potential function method is used to describe the free vibration of the liquid, and the calculation domain is shown in Figure 4(a)(b).

The Laplace equation of the liquid free vibration velocity potential function Φ is:

Boundary conditions:

Putting equations (2) to (5) into equation (1), through mathematical derivation, the calculation formula for the natural frequency of liquid can be solved as:

In the formula, ξ _mn is the positive root of the determinant △ _m/2α = J' _m/2α Y' _m/2α (kξ)-J' _m/2α (kξ)Y' _m/2α (ξ) = 0, J and Y are the Bessel functions of the first and second types respectively, k=b/a, b is the inner radius of the ring fan-shaped water tank, a is the outer radius of the ring fan-shaped water tank; g is the gravity acceleration, and h is the liquid depth. In this experiment, we took the first-order sloshing frequency in the radial direction of the model (i.e. m=0, n=1, ξ _mn =6.78), and used equation (6) to calculate the natural vibration frequency of the liquid in the model as 1.65Hz.

Example 3

Measure the liquid impact load on the top of the water tank under a certain set of working conditions, as shown in Figure 5.

Table 1 working condition parameters:

Installation of bench

1) First, install the scaled test model of the nuclear power plant water storage tank on the table of the uniaxial hydraulic vibration table, and use bolts to firmly connect the bottom of the model to the vibration table;

2) Install the water pressure sensor on the side wall of the model;

3) Inject water into the water tank model to make the water level reach the test requirements;

4) Install the force sensor and pressure sensor on the built-in impact top plate;

5) Fix the built-in impact top plate on the side wall of the water tank model through the L-shaped stainless steel bracket and transverse bolts. You can use a level to check whether the top plate is level and keep the distance between the bottom of the impact top plate and the liquid level at 60mm;

6) Fix the waterproof wide-angle high-speed camera on the top side wall of the model through the suction cup.

Operation of collection instruments and sensors before testing:

1) Connect relevant sensors to the data collection system;

2) Open and set the data collector parameters;

3) Turn on the uniaxial hydraulic vibration table control system, set the vibration waveform to sinusoidal pulse wave, wave number to 3, displacement amplitude to 12mm, and vibration frequency to 1.65Hz.

4) Click the "online monitoring mode" of the data collection system to monitor the test data in real time;

5) Click the "Sampling" button of the data collection system to start collecting test data.

Test operation:

1) Click "Run" on the vibration table control system to start the test;

2) Observe the data on the liquid impact load on the roof collected by the acquisition system at the end of each test, and stop the test after the external excitation ends;

3) After the liquid returns to calmness, repeat steps 1 to 2 twice, and record the test data each time; 4) Drain all the water in the model, and keep other settings consistent with the water condition (do nothing here) The reason for the water test: External excitation will have a certain impact on the model, and we are only concerned about the impact of liquid sloshing on the model. Therefore, we conduct a test without water and record the test data to eliminate the impact of external excitation on the model);

5) Repeat steps 1 to 2 once and record the test data.

data processing:

The sensors on the built-in top plate of this experiment include six force sensors and six pressure sensors. By summing the data of the six force sensors, the resultant force of the liquid impact load on the top of the water storage tank can be obtained, as shown in the figure below. Next, in order to eliminate the influence of external excitation on the test, it is necessary to subtract the resultant force value of the water test from the water-free test to obtain the roof impact load caused by liquid sloshing. In the data obtained by the force sensor, the tensile force is a positive value and the pressure is a negative value. Due to the way the force sensor is fixed, when the liquid impacts the top plate, the top plate will fall downward, thus generating an impact pulling force (the positive peak in the figure). Therefore, in data analysis, you can ignore the spikes with positive signs and focus only on the pressure peaks on the top plate, that is, the spikes with negative signs, as shown in Figure 5.

Through the data of the water pressure sensor, the distribution of liquid impact load on the top of the water storage tank can be obtained, as shown in the figure below. In addition, with the help of a camera arranged above the model, the impact surface caused by the sloshing of the liquid can be photographed and recorded, and the impact area of the liquid on the top plate can be estimated based on the image captured by the camera and the simulation calculation results. Next, multiply the measured pressure by the impact area at the same place to get the impact force on the roof at that location, which can be described by the following formula:

F=∑P _i ·S _i

In the formula: F is the resultant force of the impact on the roof, P _i is the measured pressure data at the i-th water pressure measuring point on the roof, and S _i is the impact area of the liquid at the i-th water pressure measuring point on the built-in roof.

According to a test device and method provided by the present invention for measuring the impact load of liquid on the top of a water storage tank in a nuclear power plant, by changing different water level depths, different arrangements of top protrusions, and different excitation methods for testing, different water level depths can be determined , the different arrangements of the top protrusions and the magnitude of the impact load on the liquid at the top of the nuclear power plant water storage tank under different external conditions provide support and basis for the design of the nuclear power plant water storage tank.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and descriptions is only the principle of the present invention. The present invention may also have various modifications without departing from the spirit and scope of the present invention. changes and improvements that fall within the scope of the claimed invention. The scope of protection required for the present invention is defined by the appended claims and their equivalents.

Claims (5)

1. The utility model provides a test device of nuclear power plant's storage water tank top liquid impact load, includes scale water tank model, unipolar fluid pressure type shaking table, water pressure strong sensor, force transducer, characterized by: the bottom of the scaled water tank model (1) is fixed on a single-axial hydraulic vibrating table (11), and a through hole (10) is formed in the side wall for fixing the built-in impact top plate (5); the lower part of the force sensor (4) is fixed on a built-in impact top plate (5), the upper part of the force sensor is fixed on an L-shaped stainless steel bracket (3), and the L-shaped stainless steel bracket is fixed on the side wall of the water tank model through a transverse bolt (2); the water pressure Jiang Chuangan device is arranged on the built-in impact top plate and the side wall of the model;

in the test process, excitation is applied to the scaled water tank model (1) through the uniaxial hydraulic vibration table (11), liquid in the water tank shakes, so that the liquid impacts the built-in top plate, a time course curve of the impact force of the liquid is measured through the force sensor, and the distribution condition of the impact pressure of the liquid on the top plate is measured through the water pressure intensity sensor.

2. The test device for the top liquid impact load of a water storage tank of a nuclear power plant according to claim 1, wherein the test device comprises: the built-in impact top plate (5) consists of two parts, namely a stainless steel frame (18) and an acrylic body (19), which are fixedly connected through bolts.

3. The test device for the top liquid impact load of a water storage tank of a nuclear power plant according to claim 1, wherein the test device comprises: according to experimental requirements, the top protrusion model (7) is fixed on the built-in impact top plate through a longitudinal fixing bolt (8).

4. The test device for the top liquid impact load of a water storage tank of a nuclear power plant according to claim 1, wherein the test device comprises: the force sensor and the water pressure intensity sensor are fixed on the built-in impact top plate, the time course curve of the fluid impact force can be measured through six force sensors, and the distribution condition of the liquid impact pressure on the top plate can be measured through six water pressure intensity sensors; the distribution of the impact surface when the liquid impacts the top plate is recorded by a wide angle high speed camera (12).

5. A method for testing the top liquid impact load of a water storage tank of a nuclear power plant, which is based on the device for testing the top liquid impact load of the water storage tank of the nuclear power plant according to any one of claims 1 to 4, and is characterized in that: the method comprises the following steps:

1) The method comprises the steps of installing a nuclear power plant water storage tank scaling test model on a table top of a single-axis hydraulic vibration table, and fixedly connecting the bottom of the model with the vibration table top by bolts;

2) Installing a water pressure strong sensor on the side wall of the model;

3) Injecting water into the water tank model to enable the water level to meet the test requirement;

4) If necessary, fixing the top protrusion to the built-in impact top plate by bolts;

5) Mounting a force sensor and a pressure sensor to a built-in impact top plate;

6) The built-in impact top plate is fixed on the side wall of the water tank model through an L-shaped stainless steel bracket and a transverse bolt;

7) Fixing a waterproof wide-angle high-speed camera on the side wall of the top of the model through a sucker;

8) Connecting the sensor with a data acquisition system;

9) Opening a data acquisition instrument, and setting acquisition parameters;

10 Opening a control system and a water cooling system of the vibrating table, and setting vibration parameters;

11 Starting the test, applying external vibration excitation to the model, and recording time course curves of the force sensor and the water pressure intensity sensor of each measuring point;

12 Repeating the content of the step 11 after the liquid is calm, repeating the test for 3 times, and taking the average value of the 3 tests as the final measurement result to reduce random errors;

13 All the water in the model is drained and other settings are kept consistent with steps 9 and 10;

14 Repeating step 11 once and recording test data.