Method and device for testing rigidity and damping of turbine guide bearing of rotating machinery of nuclear power plant

Abstract

The invention relates to the field of nuclear main pump testing, in particular to a method and a device for testing rigidity and damping of a turbine guide bearing of rotating machinery of a nuclear power plant. According to the method, cold-state gap measurement, static measurement and hot gap measurement are carried out; performing dynamic measurement; based on parameters measured by the sensor, the rigidity and damping of the water lubricated bearing are solved through a rotor dynamic balance equation; constructing a liquid film fluid calculation model of the experiment table water guide bearing, substituting the measured pressure data into the calculation model to obtain axial and circumferential pressure distribution curves of a liquid film of a cylinder of the water guide bearing, and obtaining liquid film forces of the water guide bearing in different states; and comparing the rigidity and damping obtained by the dynamic balance equation of the rotor with the rigidity and damping obtained by the calculation model, eliminating the rigidity and damping with the deviation greater than 5% between the two methods under the same working condition, and averaging the residual values to obtain the final damping and rigidity. The method is high in measurement precision and convenient in measurement.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear main pump testing, in particular to a method and device for testing the stiffness and damping of water guide bearings of rotating machinery in nuclear power plants. BACKGROUND

[0002] Sliding bearings are widely used as support components of important rotating machinery in nuclear power plants. Water guide bearings (sliding bearings with water as the flow medium) with guiding function are very important in shafting support systems. The dynamic characteristics of water guide bearings are key factors affecting the stability of rotating machinery, especially the load-carrying capacity and stability problems, and the water film formation and rupture problems. One of the key steps to solve the above problems is to accurately grasp the dynamic characteristic parameters of water guide bearings, including stiffness and damping parameters, in order to effectively cope with the above challenges. However, in nuclear power plants, when the key rotating machinery equipment operates in a high-temperature, high-pressure and water medium environment, it is difficult to implement traditional stiffness and damping experimental test methods, and simulation calculation methods lack measured values for calibration, making it difficult to evaluate their errors. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a method and device for testing the stiffness and damping of water guide bearings of rotating machinery in nuclear power plants, which has high measurement accuracy and is convenient to measure.

[0004] The present application provides a device for testing the stiffness and damping of water guide bearings of rotating machinery in nuclear power plants, comprising: a cylinder component,

[0005] The cylinder component is a floating component, comprising a cylinder and a cylinder end cover;

[0006] The cylinder has a cylinder end cover at each end, and a rotating shaft is assembled in the cylinder, with the rotating shaft passing through the cylinder end cover; the cylinder has an inlet in the middle and two outlets on both sides;

[0007] The two ends of the rotating shaft are matched with bearings, and the bearings are fixed on a bearing seat;

[0008] The bearing seat is fixed on a common base;

[0009] The exciter is in contact with the cylinder;

[0010] The displacement sensor is in contact with the cylinder end cover, and the tension sensor and the pressure sensor are in contact with the cylinder.

[0011] In one embodiment of the present application, the cylinder is designed with an inlet in the middle and two outlets on both sides, forming two symmetrical groups of water guide bearings.

[0012] In one embodiment of the present application, the common base is also provided with an exciter support,

[0013] One end of the vibrator is fixed to the vibrator bracket, and the other end is in contact with the cylinder;

[0014] The vibration exciter bracket is provided with a pulley block, the pulley block comprising at least one pulley, and a steel wire rope is wound around the pulley;

[0015] One end of the steel wire rope is connected to the standard block, and the other end is connected to the tension sensor.

[0016] In a specific embodiment of the present invention, the inlet of the cylinder is designed with a rectifying cavity.

[0017] The present invention provides a method for testing the stiffness and damping of a water-guided bearing of a rotating machinery in a nuclear power plant, comprising the following steps:

[0018] Step 1: Perform cold gap measurement, static measurement and hot gap measurement;

[0019] Step 2: Perform dynamic measurements;

[0020] Step 3: Based on the parameters measured by the sensor, the stiffness K and damping C of the water-lubricated bearing are solved through the rotor dynamics equilibrium equation;

[0021] Step 4: Construct a liquid film fluid calculation model of the experimental bench water guide bearing in MATLAB, and bring the measured pressure data into the calculation model to obtain the axial and circumferential pressure distribution curves of the liquid film of the water guide bearing cylinder, and obtain the liquid film force of the water guide bearing under different states;

[0022] Step 5: Compare the stiffness and damping obtained from the rotor dynamics equilibrium equation with the stiffness and damping obtained from the calculation model. Using the stiffness and damping obtained from the calculation model as a benchmark, eliminate the stiffness and damping values ​​between the two methods under the same working conditions that deviate by more than 5%. Average the remaining values ​​to obtain the final damping and stiffness.

[0023] In a specific embodiment of the present invention, step 1 specifically includes:

[0024] Step 1-1: Perform cold gap measurement;

[0025] The cold clearance measurement is used to estimate the average clearance of the water guide bearing, and does not set the clearance limit for the water guide bearing alignment under no-load conditions;

[0026] Step 1-2: After reaching steady-state operation close to the nominal test conditions, perform static measurements;

[0027] The static measurements include water medium pressure, rotor relative displacement, water medium temperature and rotational speed. A set of multiple data points are recorded within 60-120 seconds. The data under the test conditions is taken as the average of the multiple data points. After the data collection is completed, a confidence interval is calculated for each measurement.

[0028] Step 1-3: After reaching the highest load test state, perform thermal clearance measurement;

[0029] The thermal clearance data obtained from the thermal clearance measurement is used to determine the water-guided bearing center and the average bearing clearance parameters, and then calculate the eccentricity, attitude angle and dimensionless dynamic coefficient.

[0030] In a specific embodiment of the present invention, the rotor dynamics balance equation is

[0031]

[0032] Where, f1 and f2 are the horizontal and vertical forces on the water-guided bearing respectively; M is the mass of the rotor; C 11 and C 22 , are the damping in the horizontal and vertical directions respectively; K 11 and K 22 are the stiffness in the horizontal and vertical directions respectively; C 12 and C 21 are the cross damping in the horizontal and vertical directions respectively; K 12 and K 21 are the cross stiffness in the horizontal and vertical directions respectively; X1 is the horizontal displacement of the rotor; Y1 is the vertical displacement of the rotor; X2 is the horizontal displacement of the water-guide bearing cylinder; Y2 is the vertical displacement of the water-guide bearing cylinder. is the first-order differential of X1; is the first-order differential of X2; is the first-order differential of Y1; is the first-order differential of Y2; is the second-order differential of X1; is the second-order differential of X2; is the second-order differential of Y1; is the second-order differential of Y2.

[0033] In a specific embodiment of the present invention, the dynamic measurement method is:

[0034] Apply exciting forces to the cylinder in the axial and radial directions respectively. During each excitation process, record the response of the cylinder in two orthogonal directions simultaneously.

[0035] The excitation frequency increases gradually from 0 Hz to 1000 Hz in steps of 10 Hz, and the time domain raw data of pressure pulsation, shaft displacement, dynamic force and static force are collected synchronously at high frequency by sensors.

[0036] In a specific embodiment of the present invention, the raw data is divided into a plurality of data sets, each data set comprising a plurality of vibration records;

[0037] The average value of each data set was calculated and compared, and the confidence interval was recorded to evaluate the repeatability of the measurement results.

[0038] In a specific embodiment of the present invention, in step 2, the dynamic measurement is performed for different working conditions, and the number of measurements for the same working condition is no less than 10 times.

[0039] Compared with the prior art, the method and device for testing the stiffness and damping of water-guided bearings of nuclear power plant rotating machinery of the present invention overcome the limitation of traditional testing methods that cannot measure the damping stiffness of important rotating machinery (main pumps, main feedwater pumps, etc.) in nuclear power plants under high temperature, high pressure, and aqueous media environments. It has the following beneficial effects:

[0040] (1) The device of the present invention has a simple structure and is easy to operate, making it easier to perform bearing testing in complex environments and reducing operational difficulty and cost;

[0041] (2) The present invention can accurately obtain the dynamic parameters of the water-guided bearing, including stiffness and damping values, by measuring the cold and hot clearances, combined with dynamic measurement and signal processing;

[0042] (3) The present invention can accurately grasp the dynamic characteristic parameters of the water-guided bearing, which helps to optimize the design and maintenance of rotating machinery and improve the stability and reliability of key nuclear power equipment, thereby extending the service life of the equipment and improving the economy of nuclear power units. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Fig. 1 A schematic diagram showing the structure of a measuring device for testing the damping and stiffness of water-guided bearings of rotating machinery in nuclear power plants;

[0044] Fig. 2 It shows the schematic diagram of the bracket and base system;

[0045] In the figure,

[0046] 1 is the cylinder component, 2 is the rotor component, 3 is the base component, 4 is the load application unit, 5 is the sensor unit, 1-1 is the cylinder, 1-2 is the cylinder end cover, 2-1 is the rotating shaft, 2-2 is the bearing, 2-3 is the locking nut, 3-1 is the common base, 3-2 is the bearing seat, 4-1 is the exciter, 4-2 is the standard mass block, 4-3 is the pulley block, 4-4 is the wire rope, 4-5 is the exciter bracket, 5-1 is the displacement sensor, 5-2 is the tension sensor, and 5-3 is the pressure sensor. DETAILED DESCRIPTION

[0047] In order to further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than for limiting the present invention.

[0048] The embodiment of the present application discloses a device for testing the stiffness and damping of water guide bearing of rotating machinery in nuclear power plant, which comprises Figs. 1-2 as shown, including:

[0049] cylinder component 1, rotor component 2, base component 3, load applying unit 4 and sensor unit 5;

[0050] The cylinder component 1 is a floating component, and there is no assembly relationship with other stator components;

[0051] The cylinder component 1 comprises a cylinder 1-1 and a cylinder end cover 1-2;

[0052] The rotor component 2 comprises a rotating shaft 2-1, a bearing 2-2 and a locking nut 2-3;

[0053] The base component 3 comprises a common base 3-1 and a bearing seat 3-2;

[0054] The load applying unit 4 comprises a vibration exciter 4-1, a standard mass block 4-2, a pulley block 4-3, a steel wire rope 4-4 and a vibration exciter support 4-5;

[0055] The sensor unit 5 comprises a displacement sensor 5-1, a tension sensor 5-2 and a pressure sensor 5-3.

[0056] The diameter gap formed by the assembly of the cylinder 1-1 of the cylinder component 1 and the rotating shaft 2-1 of the rotor component 2 is a water guide bearing diameter gap, the cylinder 1-1 is designed with one inlet in the middle and two outlets on both sides, thereby forming two symmetrical water guide bearings, so that the axial force formed by the fluid pressure in the cylinder 1-1 is balanced under the floating state of the cylinder component 1.

[0057] The inlet of the cylinder 1-1 is designed with a flow regulating cavity, so that the inlet fluid can enter the water guide bearing uniformly in the circumferential direction.

[0058] Both ends of the cylinder 1-1 are provided with the cylinder end cover 1-2, and the rotating shaft 2-1 penetrates through the cylinder end cover 1-2;

[0059] The cylinder end cover 1-2 is designed with a seal, and no other shaft seal is additionally used in the device, so as to avoid the influence of the installation of the shaft seal on the floating state of the cylinder component 1.

[0060] The rotating shaft 2-1 is matched with the bearing at both ends, and the bearing 2-2 is fixed on the bearing seat 3-2 of the base component 3; the bearing 2-2 and the bearing seat 3-2 are fixed through the locking nut 2-3;

[0061] The bearing seat 3-2 and the vibration exciter support 4-5 are arranged on the common base 3-1;

[0062] The exciting vibrator 4-1 in the load applying unit 4 is fixed at one end on the exciting vibrator support 4-5 and in contact with the cylinder 1-1 of the cylinder component 1, and the pulley block 4-3 is also installed on the exciting vibrator support 4-5.

[0063] The pulley block 4-3 comprises at least one pulley on which the steel wire rope 4-4 is wound;

[0064] The steel wire rope 4-4 is connected at one end to the standard mass 4-2 and at the other end to the tension sensor 5-2.

[0065] The sensor unit 5 is entirely installed on the cylinder component 1; specifically, the displacement sensor 5-1 is in contact with the cylinder end cover 1-2, and the tension sensor 5-2 and the pressure sensor 5-3 are both in contact with the cylinder 1-1.

[0066] The embodiment of the present application also discloses a method for testing the stiffness and damping of a water guide bearing of a rotating machine in a nuclear power plant, comprising the following steps:

[0067] Step 1: cold gap measurement, static measurement and hot gap measurement are performed;

[0068] Step 1-1: cold gap measurement is performed;

[0069] The cold gap measurement is used to estimate the average gap of the water guide bearing and set the gap limit under the centering of the water guide bearing without load;

[0070] Step 1-2: after reaching a steady state operation close to the nominal test condition, static measurement is performed;

[0071] The static measurement comprises parameters such as the water medium pressure P measured by the pressure sensor 5-3, the relative position (x, y) of the rotor measured by the displacement sensor 5-1, the water medium temperature (T) and the rotating speed (N), a plurality of data points are recorded within 60-120 seconds, the data under the test condition is taken as the average value of the plurality of data points, and a confidence interval is calculated for each measurement after the data acquisition is completed.

[0072] Step 1-3: after reaching the highest load test state, hot gap measurement is performed;

[0073] The hot gap data measured by the hot gap measurement are used to determine the center (x o , y o ) of the water guide bearing and the average bearing gap parameter, and further calculate the eccentricity, the attitude angle and the dimensionless dynamic coefficient.

[0074] Step 2: dynamic measurement is performed;

[0075] Specifically, a standard mass block 4-2 is used to give the cylinder 1-1 a standard static tension through a pulley block 4-3, a steel wire rope 4-4, and a tension sensor 5-2. An exciter 4-1 applies an excitation force to the cylinder 1-1 in the x and y directions, respectively, and the response of the cylinder 1-1 is recorded in both orthogonal directions simultaneously during each excitation process. The response of the cylinder 1-1 is superimposed by a plurality of sine waveforms of different frequencies. The excitation frequency is gradually increased from 0 Hz to 1000 Hz at a step of 10 Hz, and the time-domain raw data of pressure pulsation (P), shaft displacement, dynamic force (F1), and static force (F2) are synchronously collected by the sensor unit displacement sensor 5-1, tension sensor 5-2, and pressure sensor 5-3.

[0076] The shaft displacement includes axial displacement and radial displacement;

[0077] The x direction is axial, and the y direction is radial;

[0078] The data is divided into a plurality of data sets, and each data set contains a plurality of vibration records. Finally, the average value of each data set is calculated respectively for comparison and recording within the confidence interval to evaluate the repeatability of the measurement results.

[0079] Step 3: Based on the parameters measured by the sensor, the stiffness K and the damping C of the water-lubricated bearing are solved by the following rotor dynamics balance equation;

[0080]

[0081] In the formula, f1 and f2 are the horizontal and vertical forces of the water-lubricated bearing, respectively; M is the rotor mass; C 11 and C 22 are the horizontal and vertical dampings, respectively; K 11 and K 22 are the horizontal and vertical stiffnesses, respectively; C 12 and C 21 are the horizontal and vertical cross dampings, respectively; K 12 and K 21 are the horizontal and vertical cross stiffnesses, respectively; X1 is the horizontal displacement of the rotor; Y1 is the vertical displacement of the rotor; X2 is the horizontal displacement of the water-lubricated bearing cylinder; and Y2 is the vertical displacement of the water-lubricated bearing cylinder. is the first-order derivative of X1; is the first-order derivative of X2; is the first-order derivative of Y1; is the first-order derivative of Y2; is the second-order derivative of X1; is the second-order derivative of X2; is the second-order derivative of Y1; is the second-order derivative of Y2;

[0082] Step 4: Construct a liquid film fluid calculation model of the experimental bench water guide bearing in MATLAB, and input the pressure data P measured by the pressure sensor 5-3 into the calculation model to obtain the axial and circumferential pressure distribution curves of the liquid film of the water guide bearing cylinder, and obtain the liquid film force of the water guide bearing under different states;

[0083] Step 5: Compare the damping and stiffness thus obtained with the damping and stiffness obtained by solving the rotor dynamics equilibrium equation principle above. Carry out no less than 10 test measurements under the same working condition. Take the damping and stiffness obtained by the liquid film fluid calculation principle as the benchmark, eliminate the damping and stiffness with large deviations between the two methods under the same working condition, and take the average value of the two methods on this basis. In this way, the errors introduced by different methods are balanced to obtain more accurate damping and stiffness.

[0084] The large deviation refers to a deviation greater than 5%.

[0085] The present invention can carry out stiffness and damping test experiments on various sliding bearings by adjusting different water-guided bearing clearance values, aspect ratios and other parameters. The sliding bearing circulation medium includes but is not limited to water, and the application scenarios include but are not limited to the field of nuclear power engineering.

[0086] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0087] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for testing the stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants, characterized in that: include: Cylinder parts, The cylinder component is a floating component, including a cylinder and a cylinder end cover; The cylinder is provided with cylinder end covers at both ends, a rotating shaft is assembled in the cylinder, and the rotating shaft passes through the cylinder end covers; There is an inlet in the middle of the cylinder and outlets on both sides; Both ends of the rotating shaft are matched with bearings, and the bearings are fixed on the bearing seats; The bearing seat is fixed on the common base; The vibrator is in contact with the cylinder; The displacement sensor is in contact with the end cover of the cylinder, and the tension sensor and the pressure sensor are both in contact with the cylinder.

2. The device for testing the stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 1, characterized in that: The cylinder is designed with an inlet in the middle and two outlets on both sides, forming two symmetrical sets of water-guided bearings.

3. The device for testing the stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 1, characterized in that: The common base is also provided with a vibration exciter bracket, One end of the vibrator is fixed to the vibrator bracket, and the other end is in contact with the cylinder; The vibration exciter bracket is provided with a pulley block, the pulley block comprising at least one pulley, and a steel wire rope is wound around the pulley; One end of the steel wire rope is connected to the standard block, and the other end is connected to the tension sensor.

4. The device for testing the stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 1, characterized in that: The inlet of the cylinder is designed with a rectifying cavity.

5. A method for testing the stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants, characterized in that: The following steps are involved: Step 1: Perform cold gap measurement, static measurement and hot gap measurement; Step 2: Perform dynamic measurements; Step 3: Based on the parameters measured by the sensor, the stiffness K and damping C of the water-lubricated bearing are solved through the rotor dynamics equilibrium equation; Step 4: Construct a liquid film fluid calculation model of the experimental bench water guide bearing in MATLAB, and bring the measured pressure data into the calculation model to obtain the axial and circumferential pressure distribution curves of the liquid film of the water guide bearing cylinder, and obtain the liquid film force of the water guide bearing under different states; Step 5: Compare the stiffness and damping obtained from the rotor dynamics equilibrium equation with the stiffness and damping obtained from the calculation model. Using the stiffness and damping obtained from the calculation model as a benchmark, eliminate the stiffness and damping values ​​between the two methods under the same working conditions that deviate by more than 5%. Average the remaining values ​​to obtain the final damping and stiffness.

6. The method for testing stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 5, characterized in that: The step 1 specifically includes: Step 1-1: Perform cold gap measurement; The cold clearance measurement is used to estimate the average clearance of the water guide bearing, and does not set the clearance limit for the water guide bearing alignment under no-load conditions; Step 1-2: After reaching steady-state operation close to the nominal test conditions, perform static measurements; The static measurements include water medium pressure, rotor relative displacement, water medium temperature and rotational speed. A set of multiple data points are recorded within 60-120 seconds. The data under the test conditions is taken as the average of the multiple data points. After the data collection is completed, a confidence interval is calculated for each measurement. Step 1-3: After reaching the highest load test state, perform thermal clearance measurement; The thermal clearance data obtained from the thermal clearance measurement is used to determine the center of the water-guided bearing and the average bearing clearance parameters, and then calculate the eccentricity, attitude angle and dimensionless dynamic coefficient.

7. The method for testing stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 5, characterized in that: The rotor dynamics equilibrium equation is Where, f1 and f2 are the horizontal and vertical forces on the water-guided bearing respectively; M is the mass of the rotor; C 11 and C 22 , are the damping in the horizontal and vertical directions respectively; K 11 and K 22 are the stiffness in the horizontal and vertical directions respectively; C 12 and C 21 are the cross damping in the horizontal and vertical directions respectively; K 12 and K 21 are the cross stiffness in the horizontal and vertical directions respectively; X1 is the horizontal displacement of the rotor; Y1 is the vertical displacement of the rotor; X2 is the horizontal displacement of the water-guide bearing cylinder; Y2 is the vertical displacement of the water-guide bearing cylinder. is the first-order differential of X1; is the first-order differential of X2; is the first-order differential of Y1; is the first-order differential of Y2; is the second-order differential of X1; is the second-order differential of X2; is the second-order differential of Y1; is the second-order differential of Y2.

8. The method for testing stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 5, characterized in that: The dynamic measurement method is: Apply exciting forces to the cylinder in the axial and radial directions respectively. During each excitation process, record the response of the cylinder in two orthogonal directions simultaneously. The excitation frequency increases gradually from 0 Hz to 1000 Hz in steps of 10 Hz, and the time domain raw data of pressure pulsation, shaft displacement, dynamic force and static force are collected synchronously at high frequency by sensors.

9. The method for testing stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 6, characterized in that: The raw data is divided into multiple data sets, each data set contains multiple vibration records; The average value of each data set was calculated and compared, and the confidence interval was recorded to evaluate the repeatability of the measurement results.

10. The method for testing stiffness and damping of water-guided bearings of rotating machinery in nuclear power plants according to claim 5, characterized in that: In step 2, the dynamic measurement is performed for different working conditions, and the number of measurements for the same working condition is no less than 10.

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