Device and method for measuring wall sliding speed of lead-bismuth lubricant

Abstract

The invention discloses a device and method for measuring the wall sliding speed of a lead-bismuth lubricant. The device comprises a rotatable cylindrical shaft neck, a fixedly mounted thin-wall bearing and an annular gap which is formed between the rotatable cylindrical shaft neck and the thin-wall bearing and is used for accommodating a liquid lead-bismuth lubricant liquid film, wherein the thin-wall bearing is a fixed bearing which is provided with a thin-wall structure and can bear high temperature and corrosion of a lead-bismuth lubricant, and the thin-wall bearing and the cylindrical shaft neck jointly form a closed cavity of a lubricant liquid film; the device further comprises two distance measuring sensors, a rotating speed sensor, an angular velocity sensor, eight temperature sensors, a liquid level height observation instrument and a temperature control system. According to the method, the stress condition of a lubricant liquid film unit body in the lead-bismuth bearing is analyzed in detail, a fluid unit momentum conservation equation is established, a complete speed distribution function is obtained by combining given boundary conditions, and the sliding speed of the opposite wall surface is calculated according to data acquired by a measuring device.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of bearing lubricant property measurement, and particularly relates to a device and method for measuring wall surface slip speed of lead bismuth lubricant. BACKGROUND

[0002] In the field of nuclear power, the safety of nuclear main pump is extremely important, and the lower end guide bearing thereof is in a high-pressure fluid cavity and has a significant pressure difference, so that the traditional radial sliding bearing is difficult to meet the requirements. The lead bismuth bearing has potential advantages in specific nuclear engineering and high-temperature scenarios, but due to the high density of the alloy, the working environment at high temperature, strong radiation and corrosive environment (such as the temperature in the lead bismuth reactor can reach hundreds of degrees and the lubricant is affected by radiation), challenges are brought to the design and operation.

[0003] During the operation of the lead bismuth bearing, the lubricant slip phenomenon is critical and complex. On the one hand, high shear force under special working conditions makes the lubricant molecular layer close to the solid surface difficult to completely move with the surface to produce relative slip; on the other hand, high temperature changes the viscosity to affect the flow characteristics, radiation destroys the molecular structure to affect the rheological property, and high pressure affects the lubricity, which all make the slip phenomenon more complex.

[0004] At present, the traditional method for measuring the slip speed of the lubricant of the sliding bearing under ordinary working conditions has limited progress under the special working conditions of the lead bismuth bearing. The optical measurement technology is difficult to be applied to the high-temperature, strong radiation and corrosive environment; the accuracy of the CFD numerical simulation needs to be improved, and the calculation cost is high and the time is long; the experimental measurement method has deviation due to the difficulty in simulating the actual working conditions. Therefore, it is urgent to develop a special method for quickly measuring and calculating the slip speed of the lubricant of the lead bismuth bearing to deeply understand the flow characteristics thereof under special working conditions, so as to improve the working stability of the lead bismuth bearing. SUMMARY

[0005] The application aims to solve the problems of large deviation and complicated calculation of the slip speed of the lead bismuth bearing under special working conditions, and provides a device and method for measuring the wall surface slip speed of the lead bismuth lubricant, which establishes the momentum conservation equation of the fluid unit by analyzing the stress condition of the lubricant liquid film unit in the lead bismuth bearing in detail, solves the complete speed distribution function in combination with the given boundary conditions, and calculates the slip speed relative to the wall according to the data collected by the measuring device.

[0006] In order to achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0007] A device for measuring the wall slip velocity of a lead-bismuth lubricant comprises a rotatable cylindrical journal, a fixedly mounted thin-walled bearing, and an annular gap formed therebetween for accommodating a liquid lead-bismuth lubricant film. The thin-walled bearing is a fixed bearing with a thin-walled structure capable of withstanding high temperatures and corrosion by the lead-bismuth lubricant, and together with the cylindrical journal forms a sealed cavity for the lubricant film.

[0008] The device also includes: two distance sensors, installed on the upper part of the thin-walled bearing sealing cover, for measuring the radial distance between the cylindrical journal and the thin-walled bearing relative to the central axis; a speed sensor, installed at the output end of the motor, for measuring the real-time speed of the motor; an angular velocity sensor, directly installed on the base of the cylindrical journal, for measuring the actual rotational angular velocity of the cylindrical journal; and eight temperature sensors, evenly distributed at different heights on the inner wall of the thin-walled bearing, for measuring the operating temperature of the liquid film at different locations.

[0009] The device also includes a liquid level observation instrument, which uses optical measurement methods to assist in measuring the liquid level at different radial positions; and is connected to a temperature control system. The temperature control system has two built-in heating devices located on both sides of the thin-walled bearing, which are used to control and adjust the initial temperature of the lead-bismuth lubricant according to the temperature sensed by the temperature sensor.

[0010] A further improvement of the present invention is that the mating end faces of the cylindrical journal and the thin-walled bearing, as well as the lead-out interface portions of all sensors and the liquid level observation instrument, are sealed with high-temperature-resistant and corrosion-resistant sealing materials.

[0011] A further improvement of the present invention is that, during measurement, lead-bismuth lubricant is filled into the annular gap between the cylindrical journal and the thin-walled bearing to ensure that the liquid film thickness is uniform and no bubbles are mixed in.

[0012] A further improvement of the present invention is that during measurement, after filling is completed, the coaxiality of the cylindrical journal and the thin-walled bearing, as well as the installation position of each sensor, are calibrated to ensure that they are in normal working condition and the accuracy of the measurement data is ensured.

[0013] A further improvement of the present invention is that a liquid injector is used to fill the annular gap between the cylindrical journal and the thin-walled bearing with lead-bismuth lubricant.

[0014] A method for measuring the wall slip velocity of a lead-bismuth lubricant, comprising:

[0015] Step one: check the sealing condition of the measuring device, open the motor to drive the cylindrical journal to rotate at rated angular velocity after starting the heating device; the distance sensor, speed sensor, angular velocity sensor and temperature sensor measure the radius of the cylindrical journal, the radius of the thin-walled bearing, the motor speed, the actual rotation angular velocity of the cylindrical journal, the radial liquid level and the temperature parameters at different positions in real time; at the same time, through the online monitoring system after computer data acquisition and processing, the working condition parameters in the measuring device are monitored and controlled in real time through the programmable logic controller, so as to ensure that it always maintains in the high temperature and high pressure environment of the actual operation of lead bismuth bearing;

[0016] Step two: connect the data acquisition system to the measuring device, and the data acquisition system acquires the steady-state data measured by the sensor in step one in real time; the data acquisition system is built-in liquid lead bismuth density and dynamic viscosity calculation formula;

[0017] Step three: first, the data collected in step two is checked, and the effective data within the error range is stored; second, the stored effective data is signal amplified and filtered; finally, the processed cylindrical journal radius, thin-walled bearing radius, cylindrical journal actual rotation angular velocity, radial liquid level and temperature measurement data at different positions are used as input parameters in the lubricant wall slip speed calculation formula;

[0018] Step four: according to the static characteristic parameter values of lead bismuth bearing obtained by collecting and processing in step three, the motion analysis of liquid film unit is carried out under the cylindrical coordinate reference system (r, θ, z), and the stress condition of liquid film in the circumferential direction is analyzed;

[0019] Step five: take a small liquid film unit, calculate its stress condition in the circumferential direction, in addition to considering the viscous force caused by fluid shear, the inertia effect generated by the fluid unit rotating with the cylindrical journal also needs to be considered;

[0020] Step six: under the cylindrical coordinate reference system, according to the stress analysis of step five, the circumferential momentum conservation equation of liquid film unit is established; by integrating the momentum conservation equation, the velocity distribution function of lead bismuth lubricant in the liquid film is obtained;

[0021] Step seven: based on the velocity distribution function v(r) obtained in step six, and combined with the set boundary conditions, the lead bismuth lubricant slip speed v s (r) of the cylindrical journal wall and the thin-walled bearing wall is calculated respectively;

[0022] Step eight: under different working condition parameters, steps one to seven are repeated, and the lubricant wall slip speed under the corresponding working condition is calculated; the slip speed result calculated by step seven is compared with the theoretical calculation value, so as to verify the accuracy and effectiveness of the measuring device;

[0023] Step nine: if the comparison result of step eight shows that the error of both exceeds the preset threshold range, then re-perform the measurement until the measurement result meets the accuracy requirement;

[0024] Step ten: when the error of the slip velocity result calculated in step nine and the theoretically calculated value meets the preset threshold range, the lead bismuth lubricant wall surface slip velocity measurement result meeting the measurement accuracy is obtained.

[0025] Further improvement of the present application is that in step two, the density ρ and dynamic viscosity μ calculation formula of the built-in liquid lead bismuth are as follows:

[0026]

[0027] In the formula, A, B, C and D are constants related to the composition and characteristics of lead bismuth alloy.

[0028] Further improvement of the present application is that in step five, the expressions of the force F c related to the rotational inertia and the viscous force F μ are as follows:

[0029]

[0030] In the formula, dm is the unit mass, ds is the unit area, r direction width dr, θ direction angle dθ, and z direction height H;

[0031] In the steady state, the circumferential momentum conservation equation of the liquid film unit is as follows:

[0032]

[0033] Further improvement of the present application is that in step six, the integral constant determined by the integral function and the boundary condition and the function expression of the velocity distribution are as follows:

[0034]

[0035] The integral constant C is calculated by using the velocity boundary condition v| r＝A = 0, and the velocity distribution expression is obtained by substituting it into expression (3):

[0036]

[0037] Further improvement of the present application is that in step seven, the calculation method of the lubricant slip velocity is obtained by splitting the velocity when the wall surface has no slip as follows:

[0038] v θ (a) = ωa (6)

[0039]

[0040] In the formula: v θ (a) The ideal velocity of the wall surface when the rigid body rotates without slip.

[0041] Compared with the prior art, the application has at least the following beneficial technical effects:

[0042] The device and method for measuring the wall surface slip velocity of the lead bismuth lubricant provided by the application consider the high density and high temperature influence of the lead bismuth bearing under special working conditions, adopt the combination of theoretical analysis and actual measurement, on the one hand, establish a precise physical model, and solve the velocity distribution by using the momentum conservation equation; on the other hand, use the data acquisition system and computer processing program to obtain high-precision measurement results, and avoid the problems of poor applicability, low precision and high numerical calculation cost of the traditional measurement method under the special working conditions of the lead bismuth bearing. In summary, the application has the following advantages:

[0043] 1. The device and method for measuring the wall surface slip velocity of the lead bismuth lubricant provided by the application fill the blank of the bearing measurement method under this working condition, and provide a complete and effective system method for measuring the slip velocity of the lead bismuth bearing.

[0044] 2. Compared with the CFD numerical work or experimental measurement method, the method provided by the application significantly improves the solving efficiency under the premise that the physical meaning of each parameter is clear, and is conducive to solving the problems of poor applicability, low precision and high numerical calculation cost of the existing measurement method. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0046] Figure 1 Flow chart of the lead bismuth bearing lubricant slip velocity measurement method.

[0047] Figure 2 Schematic diagram of the lead bismuth lubricant wall surface slip velocity system measurement device, wherein 1 is a liquid level observation instrument, 2 is a heating device, 3 is a distance measuring sensor, 4 is a bevel gear box, 5 is a primary shaft coupling, 6 is a speed sensor, 7 is a secondary shaft coupling, 8 is a motor, 9 is a gear reduction box, 10 is a thin wall bearing, 11 is a cylindrical journal, 12 is an angular velocity sensor, and 13 is a temperature sensor.

[0048] Figure 3 Overall calculation model diagram of the application.

[0049] Figure 4 Fig. 3 is a schematic diagram of the liquid level distribution when the wall slip velocity is different for different angular velocities.

[0050] Figure 5 Fig. 4 is a comparison diagram of the wall slip velocity distribution for different wall observation heights. DETAILED DESCRIPTION

[0051] Hereinafter, only certain exemplary embodiments will be described simply. As can be recognized by those skilled in the art, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0052] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0053] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0054] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection, or communication; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] In the present application, unless specifically stated and limited otherwise, the "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "on", "above" and "over" of a first feature to a second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is higher in horizontal height than the second feature. The "under", "below" and "underneath" of a first feature to a second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the first feature is lower in horizontal height than the second feature.

[0056] It should be understood that the terms "comprises" and "comprising", when used in this specification and the following claims, indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0057] It should also be understood that the terms used in the present specification and the following claims are merely for the purpose of describing particular embodiments and do not intend to limit the present application. As used in the present specification and the following claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0058] It should further be understood that the term "and / or" used in the present specification and the following claims are intended to mean one or more of the associated listed items and all possible combinations of these items unless the context clearly indicates otherwise.

[0059] Various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clarity and some details may be omitted. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality may be deviated due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0060] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0061] Embodiment 1

[0062] As Figure 2As shown, the present invention provides a device for measuring the wall slip velocity of a lead-bismuth lubricant. The main structure of the device includes a rotatable cylindrical journal 11 and a fixed thin-walled bearing 10. An annular gap is formed between the two to accommodate the liquid lead-bismuth lubricant film. The cylindrical journal 11 is driven by a motor 8 and can rotate about its central axis. Its relative position with the thin-walled bearing 10 must meet dimensional design requirements to ensure uniform distribution of the liquid film thickness. The thin-walled bearing 10 is a specially designed bearing with a thin-walled structure and can withstand the high temperatures and corrosive environment of the lead-bismuth lubricant that the lead-bismuth bearing may face during actual operation. It and the cylindrical journal 11 together form a closed cavity for the lubricant film. The output end of the motor 8 is connected to a gear reducer 9 via a secondary coupling 7. The output end of the gear reducer 9 is connected to a bevel gearbox 4 via a primary coupling 5. The output end of the bevel gearbox 4 meshes with the cylindrical journal 11 and can rotate about its central axis.

[0063] like Figure 2 As shown, the measuring device is equipped with multiple types of high-precision sensors, including:

[0064] Two distance measuring sensors 3: installed on the upper part of the sealing cover of the thin-walled bearing 10, used to measure the radial distances a and A between the cylindrical journal 11 and the thin-walled bearing 10 relative to the central axis in real time, which is crucial for determining the liquid film thickness.

[0065] 1 speed sensor 6: installed at the output end of the motor 8, used to accurately measure the real-time speed v of the motor m , through the known transmission ratio, the theoretical angular velocity of the cylindrical journal can be indirectly calculated.

[0066] 1 angular velocity sensor 12: directly mounted on the base of the cylindrical journal 11, used to directly measure the actual rotational angular velocity ω of the cylindrical journal 11, ensuring accurate acquisition of motion parameters.

[0067] 8 temperature sensors 13: These sensors are evenly distributed at different heights on the inner wall of the thin-walled bearing 10 and are used to measure the operating temperature T of the liquid film at different radial and axial positions, considering that temperature has a significant impact on the properties of the lead-bismuth lubricant (such as viscosity).

[0068] In the measuring device, a liquid level observer 1 is installed. The observer measures the liquid level H at different radial positions by an optical measurement method, which helps to monitor the integrity and morphology of the liquid film. At the same time, the measuring device is connected with a temperature control system. The temperature control system is internally provided with two heating devices 2, which are respectively located on both sides of the thin-wall bearing 10, and are used to accurately control and adjust the initial temperature T0 of the lead-bismuth lubricant according to the temperature sensed by the temperature sensor 13, so as to simulate the actual working conditions. The sealing of the entire measuring device is crucial, especially the mating end faces of the cylindrical shaft neck 11 and the thin-wall bearing 10, and the lead-out line interfaces of all sensors and the liquid level observer 1, which are prone to leakage, are sealed with high-temperature-resistant and corrosion-resistant sealing materials to effectively prevent the oxidation and leakage of the lead-bismuth lubricant and ensure the stability and safety of the measuring environment.

[0069] Before starting the measurement, a special liquid filler is used to accurately fill the liquid lead-bismuth lubricant in the annular gap between the cylindrical shaft neck 11 and the thin-wall bearing 10. This process needs to be strictly controlled to ensure that the liquid film thickness is uniform and no air bubbles are mixed in, because air bubbles can seriously affect the flow characteristics of the liquid film and the measurement results. After filling, the coaxiality of the cylindrical shaft neck 11 and the thin-wall bearing 10 is accurately calibrated to ensure that the center lines of the two are aligned to ensure the uniformity of the liquid film gap. At the same time, the installation positions of all sensors are finally checked and calibrated to ensure that they are in the best working state and ensure the accuracy and reliability of the subsequent measurement data.

[0070] Example 2

[0071] As shown in Figure 1 The method for measuring the wall slip velocity of lead-bismuth lubricant provided by the application comprises the following steps:

[0072] Step one: After filling and calibration, check the overall sealing condition of the measuring device to ensure that there is no risk of leakage. Then, start the heating device 2 to heat the lubricant to the preset temperature, and start the motor 8 to drive the cylindrical shaft neck 11 to rotate at the rated angular velocity to simulate the actual bearing working state. In this process, the distance sensor 3, the rotation speed sensor 6, the angular velocity sensor 12 and the temperature sensor 13 will measure the key parameters in real time, including the radius of the cylindrical shaft neck 11, the radius of the thin-wall bearing 10, the motor rotation speed, the actual rotation angular velocity of the cylindrical shaft neck 11, the radial liquid level and the temperature at different positions. At the same time, through the online monitoring system after computer data acquisition processing, the working condition parameters in the device are monitored and controlled in real time through the programmable logic controller (PLC) to ensure that they always remain in the high-temperature and high-pressure environment required by the actual operation of the lead-bismuth bearing, providing a stable premise for accurate measurement.

[0073] Step 2: The measuring device is connected to the data acquisition system via a dedicated data line. After the cylindrical journal 11 rotates stably and the working parameters reach a steady state, the data acquisition system collects the steady-state data measured by each sensor in step 1 in real time, including the cylindrical radius a, the thin wall radius A, the motor speed v m , cylindrical angular velocity ω, radial liquid level height H, and operating temperature T at different locations. These data are the basis for subsequent calculations. The data acquisition system has pre-built formulas for calculating the density ρ and dynamic viscosity μ of liquid lead-bismuth. These formulas are functions of the liquid film operating temperature T and can be directly interpolated into the slip velocity calculation formula when needed. Specifically, the formulas for calculating the lead-bismuth density and dynamic viscosity are as follows:

[0074]

[0075] Where: A, B, C, D are constants related to the composition and properties of lead-bismuth alloy.

[0076] Step 3: First, conduct a preliminary check on the original system data collected in step 2. In this stage, the preset logical algorithm is mainly used to eliminate abnormal data points that obviously deviate from the normal range, and only retain the valid data within the error range to ensure data quality. Secondly, the necessary signal amplification and filtering processing is performed on the stored valid data to eliminate random noise in the measurement process and further improve the availability of the data. Finally, the key measurement data such as the radius of the cylindrical journal 11, the radius of the thin-walled bearing 10, the actual rotational angular velocity of the cylindrical journal 11, the radial liquid level and the temperature at different positions after the above processing are used as input parameters in the lubricant wall slip velocity calculation formula (Equation 6, Equation 7) in step 7 to prepare for subsequent precise calculations.

[0077] Step 4: Based on the static characteristic parameter values ​​of the lead-bismuth bearing collected and processed in step 3, the motion analysis of the liquid film unit is carried out in the cylindrical coordinate reference system (r, θ, z). The focus of this stage is to analyze the force on the liquid film in the circumferential direction, laying the foundation for the subsequent establishment of the momentum conservation equation. Figure 3 As shown, it is the overall calculation model diagram of the present invention.

[0078] Step 5: Take a small liquid film unit (width dr in the r direction, angle dθ in the θ direction, height H in the z direction) and calculate its circumferential force. Among them, the force F related to the rotational inertia is mainly considered. c and the viscous force F μ The expression is as follows:

[0079]

[0080] Where: dm is the unit mass and ds is the unit area.

[0081] In the steady state case, the liquid film unit circumferential momentum conservation equation is as follows:

[0082]

[0083] Step six: in the cylindrical coordinate reference system, according to the force analysis of the liquid film unit in step five, the liquid film unit circumferential momentum conservation equation is established. The equation is simplified (approximate common factor) and then integrated to solve. Through integral solution, the velocity distribution function of lead bismuth lubricant in the liquid film is finally obtained:

[0084]

[0085] Using the velocity boundary condition v| r＝A = 0, the integral constant C is calculated and substituted into expression (3) to obtain the velocity distribution expression:

[0086]

[0087] Step seven: based on the lead bismuth lubricant velocity distribution function obtained in step six, and combined with the set boundary conditions, the slip velocity of the lead bismuth lubricant at the wall surface of the cylindrical journal 11 and the thin-walled bearing 10 is calculated respectively. The specific calculation method is obtained by splitting the ideal velocity when the wall surface has no slip, that is, formula 6 and formula 7. By splitting the velocity when the wall surface has no slip, the slip velocity calculation method is as follows:

[0088] v θ (a) = ωa (6)

[0089]

[0090] In the formula: v θ (a) is the ideal velocity when the wall surface has no slip during rigid body rotation.

[0091] Step eight: in order to evaluate the performance index of the measuring device, the entire measurement and calculation process of steps one to seven needs to be repeated under different working condition parameters (for example, changing the rotational speed of the cylindrical journal, the initial temperature of the lubricant, etc.). After each repetition, the lubricant wall surface slip velocity under the corresponding working condition is calculated. The model calculation results are used to compare and analyze the effectiveness of the measurement data. As shown in Figure 4 , it is a schematic diagram of the liquid surface height distribution when the wall surface slips under different angular velocities; the liquid surface slip velocity at the radial position will change under different observation heights, as shown in Figure 5 , it is a comparison diagram of slip velocity distribution at different wall surface observation heights.

[0092] Step nine: analyze the comparison results in step eight, if the error between the slip velocity result calculated by step seven and the theoretical calculation value exceeds the preset threshold range (for example, set to 10%), it indicates that there may be abnormalities in the measurement or data processing process. At this time, it is necessary to re-execute the measurement stage after step two, which includes re-checking the installation, calibration, data acquisition process and subsequent data processing of the sensor, until the final measurement result meets the preset accuracy requirement.

[0093] Step ten: when the error between the slip velocity result calculated by step seven and the theoretical calculation value in step nine meets the preset threshold range, it is considered that the measurement process is reliable and the data is accurate. At this time, the final measurement result of the lead bismuth lubricant wall slip velocity meeting the measurement accuracy can be obtained.

[0094] In summary, the device and method for measuring the lead bismuth lubricant wall slip velocity provided by the present application considers the high density and high temperature influence of the lead bismuth bearing under special working conditions, adopts the combination of theoretical analysis and actual measurement, on the one hand, establishes a precise physical model, and uses the momentum conservation equation to solve the velocity distribution; on the other hand, uses the data acquisition system and computer processing program to obtain high-precision measurement results, avoiding the problems of poor applicability, low precision and high numerical calculation cost of traditional measurement methods under special working conditions of lead bismuth bearings.

[0095] The basic principles and main features of the present application and the advantages of the present application are shown and described above, and it is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be realized in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims. Any reference signs in the claims should not be considered as limiting the claims involved.

[0096] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand. The above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application, and any modification made on the basis of the technical solutions of the present application falls within the protection scope of the claims of the present application.

Claims

1. A device for measuring the wall slip velocity of a lead-bismuth lubricant, characterized in that: The invention comprises a rotatable cylindrical journal, a fixedly mounted thin-walled bearing, and an annular gap formed therebetween for accommodating a liquid lead-bismuth lubricant film. The thin-walled bearing is a fixed bearing having a thin-walled structure and capable of withstanding high temperatures and corrosion by the lead-bismuth lubricant, and together with the cylindrical journal forms a sealed cavity for the lubricant film. The device also includes: two distance sensors, installed on the upper part of the thin-walled bearing sealing cover, for measuring the radial distance between the cylindrical journal and the thin-walled bearing relative to the central axis; a speed sensor, installed at the output end of the motor, for measuring the real-time speed of the motor; an angular velocity sensor, directly installed on the base of the cylindrical journal, for measuring the actual rotational angular velocity of the cylindrical journal; and eight temperature sensors, evenly distributed at different heights on the inner wall of the thin-walled bearing, for measuring the operating temperature of the liquid film at different locations. The device also includes a liquid level observation instrument, which uses optical measurement methods to assist in measuring the liquid level at different radial positions; and is connected to a temperature control system. The temperature control system has two built-in heating devices located on both sides of the thin-walled bearing, which are used to control and adjust the initial temperature of the lead-bismuth lubricant according to the temperature sensed by the temperature sensor.

2. The device for measuring the wall slip velocity of lead-bismuth lubricant according to claim 1, characterized in that: The mating end faces of the cylindrical journal and the thin-walled bearing, as well as the lead-out interface parts of all sensors and liquid level observation instruments, are sealed with high-temperature resistant and corrosion-resistant sealing materials.

3. The device for measuring the wall slip velocity of lead-bismuth lubricant according to claim 1, characterized in that: During measurement, the lead-bismuth lubricant is filled into the annular gap between the cylindrical journal and the thin-walled bearing to ensure that the liquid film thickness is uniform and no bubbles are mixed in.

4. The device for measuring the wall slip velocity of lead-bismuth lubricant according to claim 3, characterized in that: During measurement, after filling, calibrate the coaxiality of the cylindrical journal and the thin-walled bearing, as well as the installation position of each sensor, so that they are in normal working condition and ensure the accuracy of the measurement data.

5. The device for measuring the wall slip velocity of lead-bismuth lubricant according to claim 3, characterized in that: The lead-bismuth lubricant is filled into the annular gap between the cylindrical journal and the thin-walled bearing using an injector.

6. A method for measuring the wall slip velocity of a lead-bismuth lubricant, characterized in that: The method is based on a device for measuring the wall slip velocity of a lead-bismuth lubricant according to any one of claims 3 to 5, comprising: Step 1: Check the sealing condition of the measuring device. After starting the heating device, turn on the motor to drive the cylindrical journal to rotate at the rated angular velocity. The distance sensor, speed sensor, angular velocity sensor, and temperature sensor synchronously measure the cylindrical journal radius, thin-walled bearing radius, motor speed, actual rotational angular velocity of the cylindrical journal, radial liquid level, and temperature parameters at different positions in real time. At the same time, through the online monitoring system after computer data acquisition and processing, the programmable logic controller monitors and controls the operating parameters inside the measuring device in real time to ensure that it always maintains the high temperature and high pressure environment in which the lead-bismuth bearing actually operates. Step 2: The measuring device is connected to a data acquisition system, which collects the steady-state data measured by the sensor in step 1 in real time. The data acquisition system has built-in formulas for calculating the density and dynamic viscosity of liquid lead and bismuth. Step 3: First, check the data collected in step 2 and store valid data within the error range; then amplify and filter the stored valid data; finally, use the processed cylindrical journal radius, thin-walled bearing radius, actual cylindrical journal rotation angular velocity, radial liquid level height, and temperature measurement data at different positions as input parameters in the lubricant wall slip velocity calculation formula; Step 4: Based on the static characteristic parameter values ​​of the lead-bismuth bearing collected and processed in step 3, perform motion analysis on the liquid film unit in the cylindrical coordinate reference system (r, θ, z), focusing on the force on the liquid film in the circumferential direction; Step 5: Take a tiny liquid film unit and calculate its circumferential force. In addition to considering the viscous force caused by fluid shear, it is also necessary to consider the inertial effect caused by the fluid unit rotating with the cylindrical journal; Step 6: In the cylindrical coordinate reference system, based on the force analysis in step 5, establish the circumferential momentum conservation equation of the liquid film unit; by integrating and solving this momentum conservation equation, obtain the velocity distribution function of the lead-bismuth lubricant in the liquid film; Step 7: Based on the velocity distribution function v(r) obtained in step 6 and combined with the set boundary conditions, calculate the sliding velocity v of the lead-bismuth lubricant at the cylindrical journal wall and the thin-walled bearing wall respectively. s (r); Step 8: Repeat steps 1 to 7 under different operating parameters and calculate the lubricant wall slip velocity under the corresponding operating conditions; compare the slip velocity calculated in step 7 with the theoretical calculated value to verify the accuracy and effectiveness of the measurement device; Step 9: If the comparison result in step 8 shows that the error between the two exceeds the preset threshold range, re-measurement is performed until the measurement result meets the accuracy requirement; Step 10: When the error between the slip velocity result calculated in step 9 and the theoretical calculated value meets the preset threshold range, the lead-bismuth lubricant wall slip velocity measurement result that meets the measurement accuracy is obtained.

7. The method for measuring the wall slip velocity of lead-bismuth lubricant according to claim 6, characterized in that: In step 2, the density ρ and dynamic viscosity μ of the built-in liquid lead bismuth are calculated as follows: Where: A, B, C, D are constants related to the composition and properties of lead-bismuth alloy.

8. The method for measuring the wall slip velocity of lead-bismuth lubricant according to claim 7, characterized in that: In step 5, through circumferential force analysis, the force F related to rotational inertia c and the viscous force F μ The expression is as follows: Where: dm is the unit mass, ds is the unit area; r direction width dr, θ direction angle dθ, z direction height H; In steady state, the conservation equation of the circumferential momentum of the liquid film unit is as follows:

9. The method for measuring the wall slip velocity of lead-bismuth lubricant according to claim 8, characterized in that: In step 6, the functional expressions of the integral constant and velocity distribution determined by the integral function and boundary conditions are as follows: Using the velocity boundary condition v| r＝A =0, calculate the integral constant C, and substitute it into expression (3) to obtain the velocity distribution expression:

10. The method for measuring the wall slip velocity of lead-bismuth lubricant according to claim 9, characterized in that: In step 7, the calculation method for the lubricant slip velocity is as follows by decomposing the velocity when the wall has no slip: v θ (a)=ωa (6) Where: v θ (a) is the ideal speed with no wall slip when the rigid body rotates.

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