Critical speed determination method, apparatus, device, and storage medium

Abstract

The present application relates to the technical field of hydraulic equipment, and discloses a critical speed determination method, device, equipment and storage medium, the present application analyzes the dynamic characteristics of the target pumped storage unit, determines the dynamic characteristic coefficient of the target pumped storage unit, constructs the unbalanced mass force model, the unbalanced magnetic pull model and the unbalanced water pressure model of the target pumped storage unit, constructs the rotor system motion model of the target pumped storage unit based on the dynamic characteristic coefficient, the unbalanced mass force model, the unbalanced magnetic pull model and the unbalanced water pressure model, determines the modal frequency corresponding to multiple rotating speeds based on the rotor system motion model, and determines the critical speed based on the modal frequency. Coupling the dynamic characteristic model of the guide bearing and the sealing, the unbalanced mass force, the unbalanced magnetic pull and the unbalanced water pressure and other excitation force models makes the rotor system motion model more practical and ensures the accuracy of the calculated critical speed.

Description

Technical Field

[0001] This invention relates to the field of hydraulic equipment technology, specifically to a method, apparatus, equipment, and storage medium for determining critical rotational speed. Background Technology

[0002] The core component of a pumped-storage unit, the rotor, mainly consists of a generator motor, a water pump turbine, and a main shaft. When the operating speed of the pumped-storage unit approaches or reaches the rotor's natural frequency, resonance occurs, significantly increasing the rotor's vibration amplitude. This speed is the rotor's critical speed. When resonance occurs, the rotor experiences abnormal vibration and stress concentration, posing a risk of unit damage. Therefore, a method is needed to accurately calculate the critical speed to prevent resonance during operation and ensure the stability and safety of the pumped-storage unit. Summary of the Invention

[0003] In view of this, the present invention provides a method, apparatus, device and storage medium for determining critical speed, so as to accurately calculate critical speed.

[0004] In a first aspect, the present invention provides a method for determining a critical rotational speed, the method comprising:

[0005] The dynamic characteristics of the target pumped storage unit are analyzed to determine the dynamic characteristic coefficients of the target pumped storage unit, including the dynamic characteristic coefficients of the guide bearing and the annular seal.

[0006] Construct unbalanced mass force model, unbalanced magnetic pull force model and unbalanced water pressure model for the target pumped storage unit;

[0007] Based on the dynamic characteristic coefficients, unbalanced mass force model, unbalanced magnetic pull force model and unbalanced water pressure model, a rotor system motion model of the target pumped storage unit is constructed.

[0008] Based on the rotor system motion model, the modal frequencies corresponding to multiple rotational speeds are determined respectively;

[0009] The critical rotational speed is determined based on the modal frequencies.

[0010] In one optional implementation, the dynamic characteristics of the target pumped-storage unit are analyzed to determine the dynamic characteristic coefficients of the target pumped-storage unit, including:

[0011] Based on the preset analysis algorithm, the oil film force of the guide bearing of the target pumped storage unit is analyzed to obtain the oil film stiffness coefficient and the oil film damping coefficient. The dynamic characteristic coefficient of the guide bearing includes the oil film stiffness coefficient and the oil film damping coefficient.

[0012] In one optional implementation, the dynamic characteristics of the target pumped-storage unit are analyzed to determine the dynamic characteristic coefficients of the target pumped-storage unit, including:

[0013] Based on the relationship between the sealing force of the annular seal of the target pumped storage unit and its displacement, velocity, and acceleration, the sealing force components acting on the rotor in the first and second directions are determined, and the dynamic characteristic coefficient of the annular seal is obtained.

[0014] In one alternative implementation, an unbalanced mass force model of the target pumped-storage unit is constructed, including:

[0015] The unbalanced mass is obtained based on rotor dynamic balancing tests.

[0016] Based on the unbalanced mass, rotor eccentricity, and initial phase, the unbalanced mass force components of the rotor in the first and second directions are constructed respectively, resulting in an unbalanced mass force model.

[0017] In one alternative implementation, an unbalanced magnetic pull model of the target pumped-storage unit is constructed, including:

[0018] Based on the Maxwell stress integral of the generator motor of the target pumped-storage unit, an unbalanced magnetic pull model is obtained.

[0019] In one alternative implementation, an unbalanced water pressure model for the target pumped-storage unit is constructed, including:

[0020] The unbalanced water pressure component in the first direction is obtained by integrating the water pressure acting on the impeller in the first direction.

[0021] The unbalanced water pressure component in the second direction is obtained by integrating the water pressure acting on the runner.

[0022] In one optional implementation, a rotor system motion model of the target pumped-storage unit is constructed based on dynamic characteristic coefficients, an unbalanced mass force model, an unbalanced magnetic pull model, and an unbalanced water pressure model, including:

[0023] Based on the unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model, the external force model in the rotor system motion model is determined.

[0024] A motion model of the rotor system is constructed based on the dynamic characteristic coefficients and the external force model.

[0025] In a second aspect, the present invention provides a critical speed determining device, the device comprising:

[0026] The characteristic coefficient determination module is used to analyze the dynamic characteristics of the target pumped storage unit and determine the dynamic characteristic coefficients of the target pumped storage unit. The dynamic characteristic coefficients include the dynamic characteristic coefficients of the guide bearing and the dynamic characteristic coefficients of the annular seal.

[0027] The first model construction module is used to construct the unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model of the target pumped storage unit.

[0028] The second model construction module is used to construct the rotor system motion model of the target pumped storage unit based on the dynamic characteristic coefficient, unbalanced mass force model, unbalanced magnetic pull model and unbalanced water pressure model.

[0029] The modal frequency determination module is used to determine the modal frequencies corresponding to multiple rotational speeds based on the rotor system motion model.

[0030] The critical speed determination module is used to determine the critical speed based on the modal frequency.

[0031] Thirdly, the present invention provides a computer device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the critical speed determination method of the first aspect or any corresponding embodiment described above.

[0032] Fourthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to perform the critical speed determination method of the first aspect or any corresponding embodiment thereof.

[0033] Fifthly, the present invention provides a computer program product, including computer instructions for causing a computer to execute the critical speed determination method of the first aspect or any corresponding embodiment thereof.

[0034] The critical speed determination method provided in this invention analyzes the dynamic characteristics of the target pumped-storage unit to obtain the dynamic characteristic coefficients of the guide bearing and the annular seal. This allows for full consideration of the influence of the annular seal and fluid-induced additional effects on the critical speed during calculation. Simultaneously, it constructs unbalanced mass force, unbalanced magnetic pull, and unbalanced water pressure models for the target pumped-storage unit. Based on these models, a rotor system motion model is built, coupling the guide bearing and seal dynamic characteristic models with the excitation force models such as unbalanced mass force, unbalanced magnetic pull, and unbalanced water pressure. This makes the constructed rotor system motion model more realistic and ensures the accuracy of the calculated critical speed. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a flowchart illustrating the critical speed determination method according to an embodiment of the present invention;

[0037] Figure 2 This is a flowchart illustrating another method for determining the critical speed according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the equivalent model of the guide bearing in the critical speed determination method according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the bearing bush distribution in the critical speed determination method according to an embodiment of the present invention;

[0040] Figure 5 This is a flowchart illustrating another method for determining the critical speed according to an embodiment of the present invention;

[0041] Figure 6 This is a flowchart illustrating yet another critical speed determination method according to an embodiment of the present invention;

[0042] Figure 7 This is a structural block diagram of the critical speed determining device according to an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] The core component of a pumped-storage unit, the rotor, mainly consists of a generator motor, a water pump turbine, and a main shaft. When the operating speed of the pumped-storage unit approaches or reaches the rotor's natural frequency, resonance occurs, and the rotor vibration amplitude increases significantly. This speed is the rotor's critical speed. When resonance occurs, the rotor experiences abnormal vibration and stress concentration, posing a risk of damage to the unit.

[0046] In related technologies, the guide bearing is typically treated as a rigid support in the calculation of critical speed, or the dynamic characteristic coefficient of the guide bearing is considered as an eight-parameter model to improve the accuracy of the critical speed. In practical engineering applications, after the structural design of the pumped-storage unit is completed, only a few specific bearing stiffness values ​​are usually selected to test the critical speed to assess whether the design has sufficient safety margin. However, the rotor system of an actual pumped-storage unit is very complex. Its critical speed is affected not only by the dynamic characteristics of the guide bearing and the annular seal, but also by factors such as residual unbalanced mass, generator unbalanced magnetic pull, fluid excitation force, and rotor shaft misalignment. Therefore, the calculation of critical speed in related technologies cannot closely match the actual design of the pumped-storage unit, and the calculated critical speed is not accurate enough.

[0047] Based on this, embodiments of the present invention provide a method for determining critical speed. The method includes: analyzing the dynamic characteristics of a target pumped-storage unit to determine the dynamic characteristic coefficients of the target pumped-storage unit, wherein the dynamic characteristic coefficients include the dynamic characteristic coefficients of the guide bearing and the annular seal; constructing an unbalanced mass force model, an unbalanced magnetic pull model, and an unbalanced water pressure model of the target pumped-storage unit; constructing a rotor system motion model of the target pumped-storage unit based on the dynamic characteristic coefficients, the unbalanced mass force model, the unbalanced magnetic pull model, and the unbalanced water pressure model; determining the modal frequencies corresponding to multiple speeds based on the rotor system motion model; and determining the critical speed based on the modal frequencies. Therefore, by analyzing the dynamic characteristics of the target pumped-storage unit, the dynamic characteristic coefficients of the guide bearing and the annular seal of the target pumped-storage unit are obtained. This allows the influence of the annular seal and the additional fluid effect on the critical speed to be fully considered during the calculation of the critical speed. At the same time, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model of the target pumped-storage unit are constructed. Based on the dynamic characteristic coefficients, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model, a rotor system motion model of the target pumped-storage unit is constructed. This couples the dynamic characteristic models of the guide bearing and seal with the excitation force models such as unbalanced mass force, unbalanced magnetic pull force, and unbalanced water pressure, making the constructed rotor system motion model more realistic and ensuring the accuracy of the calculated critical speed.

[0048] According to an embodiment of the present invention, a method for determining critical speed is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0049] This embodiment provides a method for determining critical rotational speed, which can be used in hydraulic machinery. Figure 1 This is a flowchart illustrating the critical speed determination method according to an embodiment of the present invention, as shown below. Figure 1 As shown, the process includes the following steps:

[0050] Step S101: Analyze the dynamic characteristics of the target pumped-storage unit and determine the dynamic characteristic coefficient of the target pumped-storage unit.

[0051] In this embodiment of the invention, the dynamic characteristic coefficient of the target pumped storage unit includes the dynamic characteristic coefficient of the guide bearing and the dynamic characteristic coefficient of the annular seal in the target pumped storage unit.

[0052] The dynamic characteristic coefficients of the guide bearing are used to quantify the stiffness and damping response of the oil film force to small rotor disturbances. They typically include four stiffness coefficients and four damping coefficients. Various methods, such as the finite difference method, finite element method, numerical simulation, and experimental testing, can be used to analyze the dynamic characteristics of the guide bearing and obtain its dynamic characteristic coefficients. The dynamic characteristic coefficients of the annular seal are used to characterize the response of the turbulent fluid within the sealing gap to rotor vibration. They typically include two stiffness coefficients, two damping coefficients, and two mass coefficients. The relationship between the sealing force of the annular seal and displacement, velocity, and acceleration can be analyzed to obtain the dynamic characteristic coefficients of the annular seal.

[0053] Step S102: Construct the unbalanced mass force model, unbalanced magnetic pull model, and unbalanced water pressure model of the target pumped storage unit.

[0054] In this embodiment of the invention, due to factors such as material defects, bending deformation and processing precision, the rotor often has a certain mechanical imbalance, which generates unbalanced mass force, unbalanced magnetic pull force and unbalanced water pressure, etc.

[0055] The unbalanced mass force is the centrifugal force generated by the uneven distribution of rotor mass. When the center of mass deviates from the axis of rotation, the centrifugal force causes periodic vibration, thus affecting the critical speed. An unbalanced mass force model for the target pumped-storage unit can be constructed based on the principle of centrifugal force. The unbalanced magnetic pull is the unidirectional magnetic attraction generated by the asymmetry between the rotor and stator magnetic fields in the generator motor. This leads to increased rotor vibration, thus affecting the critical speed. An unbalanced magnetic pull model for the target pumped-storage unit can be constructed based on Maxwell's stress tensor or finite element analysis. The unbalanced water pressure is the resultant force generated by uneven pressure distribution on both sides of the flow channel or impeller in fluid mechanics, i.e., in a water pump turbine. This causes axial or radial vibration, thus affecting the critical speed. An unbalanced water pressure model for the target pumped-storage unit can be constructed based on fluid mechanics, through pressure integration or momentum theorem analysis.

[0056] Step S103: Based on the dynamic characteristic coefficient, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model, construct the rotor system motion model of the target pumped storage unit.

[0057] In this embodiment of the invention, the rotor system motion model is used to describe the dynamic behavior of the target pumped-storage unit, mainly involving the dynamic behavior of the rotor under inertial force, elastic force, damping force, and external excitation. This model is used to analyze key dynamic characteristics such as critical speed, stability, and unbalanced response. Specifically, the unbalanced mass force model, unbalanced magnetic pull model, and unbalanced water pressure model are used as external excitations for the target pumped-storage unit, and combined with dynamic characteristic coefficients, to construct the rotor system motion model of the target pumped-storage unit.

[0058] Step S104: Based on the rotor system motion model, determine the modal frequencies corresponding to multiple rotational speeds.

[0059] In this embodiment of the invention, the modal frequency is the natural frequency of the system under a specific vibration mode. When the rotor speed is equal to or close to the modal frequency, the system resonates, and the rotor speed at this point is the critical speed. Therefore, the critical speed can be determined based on the relationship between the rotational speed and the modal frequency. Accordingly, based on the rotor system motion model, the rotor system motion model is analyzed and solved at different rotational speeds to obtain multiple modal frequencies corresponding to different rotational speeds.

[0060] Step S105: Determine the critical speed based on the modal frequency.

[0061] In this embodiment of the invention, a Campbell plot of the modal frequency as a function of rotational speed can be fitted based on the modal frequencies corresponding to multiple rotational speeds obtained by solving. In the Campbell plot, the intersection point of the modal frequency curve and the rotational speed line is determined to obtain the critical rotational speed.

[0062] The critical speed determination method provided in this invention includes: analyzing the dynamic characteristics of a target pumped-storage unit to determine the dynamic characteristic coefficients of the target pumped-storage unit, wherein the dynamic characteristic coefficients include the dynamic characteristic coefficients of the guide bearing and the annular seal; constructing an unbalanced mass force model, an unbalanced magnetic pull model, and an unbalanced water pressure model of the target pumped-storage unit; constructing a rotor system motion model of the target pumped-storage unit based on the dynamic characteristic coefficients, the unbalanced mass force model, the unbalanced magnetic pull model, and the unbalanced water pressure model; determining the modal frequencies corresponding to multiple speeds based on the rotor system motion model; and determining the critical speed based on the modal frequencies. Therefore, by analyzing the dynamic characteristics of the target pumped-storage unit, the dynamic characteristic coefficients of the guide bearing and the annular seal of the target pumped-storage unit are obtained. This allows the influence of the annular seal and the additional fluid effect on the critical speed to be fully considered during the calculation of the critical speed. At the same time, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model of the target pumped-storage unit are constructed. Based on the dynamic characteristic coefficients, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model, a rotor system motion model of the target pumped-storage unit is constructed. This couples the dynamic characteristic models of the guide bearing and seal with the excitation force models such as unbalanced mass force, unbalanced magnetic pull force, and unbalanced water pressure, making the constructed rotor system motion model more realistic and ensuring the accuracy of the calculated critical speed.

[0063] This embodiment provides a method for determining critical rotational speed, which can be used in hydraulic machinery. Figure 2 This is a flowchart illustrating another critical speed determination method according to an embodiment of the present invention, as shown below. Figure 2 As shown, the process includes the following steps:

[0064] Step S201: Analyze the dynamic characteristics of the target pumped-storage unit and determine the dynamic characteristic coefficient of the target pumped-storage unit.

[0065] In this embodiment of the invention, the dynamic characteristics of the target pumped-storage unit are analyzed, including the dynamic characteristics of the guide bearing and the dynamic characteristics of the annular seal. Specifically, step S201 includes the following steps:

[0066] Step S2011: Based on the preset analysis algorithm, the oil film force of the guide bearing of the target pumped storage unit is analyzed to obtain the oil film stiffness coefficient and the oil film damping coefficient.

[0067] In this embodiment of the invention, the dynamic characteristic coefficients of the guide bearing include the oil film stiffness coefficient and the oil film damping coefficient. Figure 3 This is a schematic diagram of the equivalent model of the guide bearing in the critical speed determination method according to an embodiment of the present invention, as shown below. Figure 3As shown, the radial force of the guide bearing can be decomposed into components in the first and second directions using the following formula (1):

[0068] Formula (1)

[0069] in, 、 These are the components of the radial force of the guide bearing in the first and second directions, respectively. Here is the oil film stiffness matrix; Here is the oil film damping matrix; 、 These are displacement vector components; , Let be the velocity vector components. The first direction is the X-direction, and the second direction is the Y-direction.

[0070] In this embodiment of the invention, based on Figure 3 The equivalent model of the guide bearing shown employs a preset analysis algorithm to analyze the oil film force, oil film stiffness coefficient, and oil film damping coefficient of the guide bearing. The preset analysis algorithm can include numerical simulation methods, analytical calculation methods, and experimental testing methods, etc., and is not specifically limited here.

[0071] In one optional implementation, when using numerical simulation for analysis, a three-dimensional thermo-elasto-fluidic calculation model of the guide bearing is constructed, and the physical parameters such as the material density, elastic modulus, and Poisson's ratio of the guide bearing of the target pumped storage unit are input into the three-dimensional thermo-elasto-fluidic calculation model to perform three-dimensional thermo-elasto-fluidic numerical simulation, thereby obtaining the oil film pressure. The oil film force of the guide bearing is obtained by integrating the oil film pressure, and the dynamic characteristic coefficient is obtained by differentiating the oil film force of the guide bearing.

[0072] In an alternative implementation, when using analytical calculation methods for analysis, the Reynolds equation for a finite-length bearing can be constructed and solved using the finite difference method to obtain the oil film pressure, as shown in the following formula (2):

[0073] Formula (2)

[0074] in, The coordinates of the rotor circumference. The coordinates are in the radial direction of the rotor; Oil film pressure; The vortex velocity is the shaft diameter. For fluid dynamic viscosity; For time.

[0075] Figure 4 This is a schematic diagram of the bearing bush distribution in the critical speed determination method according to an embodiment of the present invention, as shown below. Figure 4 As shown, after obtaining the oil film pressure, the oil film pressure is integrated to obtain the oil film force of each bearing in the guide bearing, as shown in the following formula (3):

[0076] Formula (3)

[0077] in, For the first The bearing bush provides oil film force to the rotating shaft; For the first The area of ​​the bearing block.

[0078] Based on the oil film force of each bearing bush in the guide bearing, the force is decomposed in the first and second directions to obtain the radial force components of the guide bearing acting in the first and second directions, as shown in the following formula (4):

[0079]

[0080] Formula (4)

[0081] in, The radial force component of the guide bearing acting in the first direction. The radial force component of the guide bearing acting in the second direction; For the guide bearing angle; This refers to the number of guide shaft bearings.

[0082] Based on the derivatives of the radial force components acting on the guide bearing in the first and second directions, the oil film stiffness coefficient and oil film damping coefficient of the guide bearing are obtained, as shown in the following formula (5):

[0083]

[0084] Formula (5)

[0085] in, This is the oil film stiffness coefficient. This represents the oil film damping coefficient.

[0086] In one optional implementation, when using experimental testing methods for analysis, oil film pressure measuring points are installed on the bearing pads of the guide bearing. The oil film pressure is obtained by testing the oil film pressure measuring points, the oil film force of the guide bearing is obtained by integrating the oil film pressure, and the dynamic characteristic coefficient is obtained by differentiating the oil film force of the guide bearing.

[0087] Step S2012: Based on the relationship between the sealing force of the annular seal of the target pumped storage unit and its displacement, velocity, and acceleration, determine the sealing force components acting on the rotor in the first and second directions, and obtain the dynamic characteristic coefficient of the annular seal.

[0088] In this embodiment of the invention, the relationship between the sealing force of the annular seal and the displacement and velocity disturbance is shown in the following formula (6):

[0089] Formula (6)

[0090] in, The force exerted by the sealing fluid on the rotor in the first direction, The force exerted by the sealing fluid on the rotor in the second direction; Principal stiffness coefficient, This is the cross stiffness coefficient; The principal damping coefficient, This is the cross-damping coefficient; Main quality coefficient; , These are displacement vector components; , These are velocity vector components; , These are the acceleration vector components.

[0091] At the initial moment, that is t When = 0, = 0, = 0, = 0, , = 0, .in, This represents the displacement of the vortex center. The rotor whirl velocity is given. Based on this analysis, the dynamic characteristic coefficient of the annular seal is obtained as shown in the following formula (7):

[0092]

[0093] Formula (7)

[0094] Step S202 involves constructing the unbalanced mass force model, unbalanced magnetic pull model, and unbalanced water pressure model for the target pumped-storage unit. For details, please refer to [link to relevant documentation]. Figure 1 Step S102 of the illustrated embodiment will not be described again here.

[0095] Step S203: Based on the dynamic characteristic coefficients, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model, construct the rotor system motion model of the target pumped-storage unit. For details, please refer to [link to relevant documentation]. Figure 1 Step S103 of the illustrated embodiment will not be described again here.

[0096] Step S204: Based on the rotor system motion model, determine the modal frequencies corresponding to multiple rotational speeds. For details, please refer to [link to relevant documentation]. Figure 1 Step S104 of the illustrated embodiment will not be described again here.

[0097] Step S205: Determine the critical speed based on the modal frequencies. For details, please refer to [link to relevant documentation]. Figure 1 Step S105 of the illustrated embodiment will not be described again here.

[0098] The critical speed determination method provided by this invention analyzes the dynamic characteristics of the target pumped-storage unit to obtain the dynamic characteristic coefficients of the guide bearing and the annular seal of the target pumped-storage unit. Thus, the influence of the annular seal and the additional fluid effect on the critical speed is fully considered in the calculation process of the critical speed, ensuring the accuracy of the calculated critical speed.

[0099] This embodiment provides a method for determining critical rotational speed, which can be used in hydraulic machinery. Figure 5 This is a flowchart illustrating another method for determining the critical speed according to an embodiment of the present invention, as shown below. Figure 5 As shown, the process includes the following steps:

[0100] Step S501: Analyze the dynamic characteristics of the target pumped-storage unit and determine its dynamic characteristic coefficients. For details, please refer to [link to relevant documentation]. Figure 1 Step S101 of the illustrated embodiment will not be described again here.

[0101] Step S502: Construct the unbalanced mass force model, unbalanced magnetic pull model, and unbalanced water pressure model of the target pumped storage unit.

[0102] In this embodiment of the invention, unbalanced mass force models, unbalanced magnetic pull force models, and unbalanced water pressure models of the target pumped-storage unit are constructed respectively. Specifically, step S502 may include the following steps:

[0103] Step S5021: Obtain the unbalanced mass.

[0104] Step S5022: Based on the unbalanced mass, the rotor's eccentricity, and the initial phase, construct the unbalanced mass force components of the rotor in the first and second directions respectively to obtain the unbalanced mass force model.

[0105] In this embodiment of the invention, steps S5021 and S5022 are used to construct an unbalanced mass force model. The unbalanced mass is obtained based on a rotor dynamic balancing test. After obtaining the unbalanced mass, the unbalanced mass force components of the rotor in the first and second directions are constructed based on the centrifugal force formula to obtain the unbalanced mass force model, as shown in the following formula (8):

[0106]

[0107] Formula (8)

[0108] in, This refers to the unbalanced mass force component of the rotor in the first direction. The unbalanced mass force component of the rotor in the second direction; This represents the maximum unbalanced mass. It is the eccentric moment; This is the initial phase.

[0109] Step S5023: Perform Maxwell stress integration based on the generator motor of the target pumped-storage unit to obtain the unbalanced magnetic pull model.

[0110] In this embodiment of the invention, step S5023 is used to construct an unbalanced magnetic pull model. Specifically, Maxwell stress integrals are performed on the generator motor of the target pumped-storage unit to obtain the unbalanced magnetic pull model, as shown in the following formula (9):

[0111] Formula (9)

[0112] in, This is due to unbalanced magnetic pull; The length of the generator motor rotor. The diameter of the generator motor rotor; The magnetic permeability of air; The fundamental magnetomotive force coefficient of the air gap; It is the excitation current; This represents the average length of the air gap. This is the rotor eccentricity.

[0113] Step S5024: Integrate the water pressure acting on the impeller in the first direction to obtain the unbalanced water pressure component in the first direction.

[0114] Step S5025: Integrate the water pressure acting on the runner in the second direction to obtain the unbalanced water pressure component in the second direction.

[0115] In this embodiment of the invention, steps S5024 and S5025 are used to construct an unbalanced water pressure model. Specifically, the water pressure of the impeller in the first and second directions is integrally calculated to obtain the unbalanced water pressure components in the first and second directions, as shown in the following formula (10):

[0116]

[0117] Formula (10)

[0118] in, Let be the projection of the area of ​​the infinitesimal element on the inner surface of the wheel onto the normal plane in the first direction. The projection of the area of ​​the infinitesimal element on the inner surface of the wheel onto the normal plane in the second direction; The unbalanced water pressure component in the first direction. This represents the unbalanced water pressure component in the second direction.

[0119] Step S503: Based on the dynamic characteristic coefficients, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model, construct the rotor system motion model of the target pumped-storage unit. For details, please refer to [link to relevant documentation]. Figure 1 Step S103 of the illustrated embodiment will not be described again here.

[0120] Step S504: Based on the rotor system motion model, determine the modal frequencies corresponding to multiple rotational speeds. For details, please refer to [link to relevant documentation]. Figure 1 Step S104 of the illustrated embodiment will not be described again here.

[0121] Step S505: Determine the critical speed based on the modal frequencies. For details, please refer to [link to relevant documentation]. Figure 1 Step S105 of the illustrated embodiment will not be described again here.

[0122] The critical speed determination method provided in this invention constructs an unbalanced mass force model, an unbalanced magnetic pull force model, and an unbalanced water pressure model for the target pumped-storage unit. Based on the dynamic characteristic coefficients, the unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model, a rotor system motion model of the target pumped-storage unit is constructed. This couples the guide bearing and sealing dynamic characteristic model with the excitation force models such as unbalanced mass force, unbalanced magnetic pull force, and unbalanced water pressure, making the constructed rotor system motion model more realistic and ensuring the accuracy of the calculated critical speed.

[0123] This embodiment provides a method for determining critical rotational speed, which can be used in hydraulic machinery. Figure 6 This is a flowchart illustrating a method for determining a critical speed according to an embodiment of the present invention, as shown below. Figure 6 As shown, the process includes the following steps:

[0124] Step S601: Analyze the dynamic characteristics of the target pumped-storage unit and determine its dynamic characteristic coefficients. For details, please refer to [link to relevant documentation]. Figure 1 Step S101 of the illustrated embodiment will not be described again here.

[0125] Step S602: Construct the unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model for the target pumped-storage unit. For details, please refer to [link to relevant documentation]. Figure 1Step S102 of the illustrated embodiment will not be described again here.

[0126] Step S603: Based on the dynamic characteristic coefficient, unbalanced mass force model, unbalanced magnetic pull force model, and unbalanced water pressure model, construct the rotor system motion model of the target pumped storage unit.

[0127] Specifically, step S603 includes:

[0128] Step S6031: Based on the unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model, determine the external force model in the rotor system motion model.

[0129] In this embodiment of the invention, the motion model of the rotor system can be represented by the following formula (11):

[0130] Formula (11)

[0131] in, For the quality matrix, Here is the damping matrix. Here is the stiffness matrix. This is a gyroscope matrix; The rotor vortex velocity; For the generalized displacement vector of the rotor system, For the generalized velocity vector of the rotor system, The generalized acceleration vector of the rotor system; This refers to the generalized external force acting on the rotor system.

[0132] In this embodiment of the invention, the generalized external forces on the rotor system are defined as unbalanced mass force, unbalanced magnetic pull force, and unbalanced water pressure. The unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model are added together to obtain the external force model of the rotor system motion model.

[0133] Step S6032: Based on the dynamic characteristic coefficients and the external force model, construct the rotor system motion model.

[0134] In this embodiment of the invention, the dynamic characteristic coefficients are embedded in the rotor system motion model in the form of a corresponding matrix, and the external force model is embedded in the rotor system motion model in the form of external forces to obtain the rotor system motion model.

[0135] Step S604: Based on the rotor system motion model, determine the modal frequencies corresponding to multiple rotational speeds. For details, please refer to [link to relevant documentation]. Figure 1 Step S104 of the illustrated embodiment will not be described again here.

[0136] Step S605: Determine the critical speed based on the modal frequencies. For details, please refer to [link to relevant documentation]. Figure 1Step S105 of the illustrated embodiment will not be described again here.

[0137] The critical speed determination method provided in this invention constructs an unbalanced mass force model, an unbalanced magnetic pull force model, and an unbalanced water pressure model for the target pumped-storage unit. Based on the dynamic characteristic coefficients, the unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model, a rotor system motion model of the target pumped-storage unit is constructed. This couples the guide bearing and sealing dynamic characteristic model with the excitation force models such as unbalanced mass force, unbalanced magnetic pull force, and unbalanced water pressure, making the constructed rotor system motion model more realistic and ensuring the accuracy of the calculated critical speed.

[0138] This embodiment also provides a critical speed determining device, which is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0139] This embodiment provides a critical speed determination device, such as... Figure 7 As shown, it includes:

[0140] The characteristic coefficient determination module 701 is used to analyze the power characteristics of the target pumped storage unit and determine the power characteristic coefficient of the target pumped storage unit. The power characteristic coefficient includes the power characteristic coefficient of the guide bearing and the power characteristic coefficient of the annular seal.

[0141] The first model construction module 702 is used to construct the unbalanced mass force model, unbalanced magnetic pull force model and unbalanced water pressure model of the target pumped storage unit;

[0142] The second model construction module 703 is used to construct the rotor system motion model of the target pumped storage unit based on the dynamic characteristic coefficient, unbalanced mass force model, unbalanced magnetic pull model and unbalanced water pressure model.

[0143] The modal frequency determination module 704 is used to determine the modal frequencies corresponding to multiple rotational speeds based on the rotor system motion model.

[0144] The critical speed determination module 705 is used to determine the critical speed based on the modal frequency.

[0145] In one optional implementation, the characteristic coefficient determination module 701 includes:

[0146] The oil film force analysis unit is used to analyze the oil film force of the guide bearing of the target pumped storage unit based on a preset analysis algorithm, and obtain the oil film stiffness coefficient and oil film damping coefficient. The dynamic characteristic coefficients of the guide bearing include the oil film stiffness coefficient and the oil film damping coefficient.

[0147] In one optional implementation, the characteristic coefficient determination module 701 includes:

[0148] The sealing force analysis unit is used to determine the sealing force components acting on the rotor in the first and second directions based on the relationship between the sealing force and displacement, velocity and acceleration of the annular seal of the target pumped storage unit, and to obtain the dynamic characteristic coefficient of the annular seal.

[0149] In one alternative implementation, the first model building module 702 includes:

[0150] The unbalanced mass acquisition unit is used to acquire the unbalanced mass, which is obtained based on rotor dynamic balancing tests.

[0151] The unbalanced mass force model building unit is used to construct the unbalanced mass force components of the rotor in the first and second directions based on the unbalanced mass, the rotor's eccentricity, and the initial phase, respectively, to obtain the unbalanced mass force model.

[0152] In one alternative implementation, the first model building module 702 includes:

[0153] The unbalanced magnetic pull model construction unit is used to perform Maxwell stress integration on the generator motor of the target pumped-storage unit to obtain the unbalanced magnetic pull model.

[0154] In one alternative implementation, the first model building module 702 includes:

[0155] The first unbalanced water pressure calculation unit is used to perform integral calculation on the water pressure acting on the runner in the first direction to obtain the unbalanced water pressure component in the first direction.

[0156] The second unbalanced water pressure calculation unit is used to perform integral calculations on the water pressure acting on the runner in the second direction to obtain the unbalanced water pressure component in the second direction.

[0157] In one alternative implementation, the second model building module 703 includes:

[0158] The external force model construction unit is used to determine the external force model in the rotor system motion model based on the unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model.

[0159] The rotor system motion model construction unit is used to construct the rotor system motion model based on the dynamic characteristic coefficients and the external force model.

[0160] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0161] In this embodiment, the critical speed determination device is presented in the form of a functional unit. Here, a unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that execute one or more software or fixed programs, and / or other devices that can provide the above functions.

[0162] This invention also provides a computer device having the above-described features. Figure 8 The device for determining the critical speed shown.

[0163] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of a computer device provided in an optional embodiment of the present invention, such as... Figure 8 As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 8 Take a processor 10 as an example.

[0164] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0165] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0166] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0167] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0168] The computer device also includes a communication interface 30 for communicating with other devices or communication networks.

[0169] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code, which, when accessed and executed by the computer, processor, or hardware, implements the methods shown in the above embodiments.

[0170] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0171] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A method for determining critical rotational speed, characterized in that, The method includes: The dynamic characteristics of the target pumped-storage unit are analyzed to determine the dynamic characteristic coefficient of the target pumped-storage unit, wherein the dynamic characteristic coefficient includes the dynamic characteristic coefficient of the guide bearing and the dynamic characteristic coefficient of the annular seal. Construct unbalanced mass force model, unbalanced magnetic pull force model and unbalanced water pressure model for the target pumped storage unit; Based on the aforementioned dynamic characteristic coefficients, the unbalanced mass force model, the unbalanced magnetic pull model, and the unbalanced water pressure model, a rotor system motion model of the target pumped storage unit is constructed. Based on the rotor system motion model, the modal frequencies corresponding to multiple rotational speeds are determined respectively; Based on the modal frequencies, the critical rotational speed is determined; The construction of the unbalanced mass force model of the target pumped-storage unit includes: obtaining the unbalanced mass, which is obtained based on the rotor dynamic balancing test; and constructing the unbalanced mass force components of the rotor in the first and second directions based on the unbalanced mass, the rotor's eccentricity and initial phase, respectively, to obtain the unbalanced mass force model. Constructing the unbalanced magnetic pull model of the target pumped-storage unit includes: performing Maxwell stress integral based on the generator motor of the target pumped-storage unit to obtain the unbalanced magnetic pull model; Constructing the unbalanced water pressure model of the target pumped storage unit includes: integrating the water pressure acting on the runner in a first direction to obtain the unbalanced water pressure component in the first direction; and integrating the water pressure acting on the runner in a second direction to obtain the unbalanced water pressure component in the second direction.

2. The method according to claim 1, characterized in that, The analysis of the power characteristics of the target pumped-storage unit, and the determination of the power characteristic coefficients of the target pumped-storage unit, includes: Based on a preset analysis algorithm, the oil film force of the guide bearing of the target pumped storage unit is analyzed to obtain the oil film stiffness coefficient and the oil film damping coefficient. The dynamic characteristic coefficient of the guide bearing includes the oil film stiffness coefficient and the oil film damping coefficient.

3. The method according to claim 1, characterized in that, The analysis of the power characteristics of the target pumped-storage unit, and the determination of the power characteristic coefficients of the target pumped-storage unit, includes: Based on the relationship between the sealing force of the annular seal of the target pumped storage unit and its displacement, velocity, and acceleration, the sealing force components acting on the rotor in the first and second directions are determined, and the dynamic characteristic coefficient of the annular seal is obtained.

4. The method according to claim 1, characterized in that, The process of constructing a rotor system motion model for the target pumped-storage unit based on the dynamic characteristic coefficients, the unbalanced mass force model, the unbalanced magnetic pull model, and the unbalanced water pressure model includes: Based on the unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model, the external force model in the rotor system motion model is determined. Based on the dynamic characteristic coefficients and the external force model, the motion model of the rotor system is constructed.

5. A critical speed determining device, characterized in that, The device includes: The characteristic coefficient determination module is used to analyze the power characteristics of the target pumped storage unit and determine the power characteristic coefficient of the target pumped storage unit, wherein the power characteristic coefficient includes the power characteristic coefficient of the guide bearing and the power characteristic coefficient of the annular seal. The first model construction module is used to construct the unbalanced mass force model, the unbalanced magnetic pull force model, and the unbalanced water pressure model of the target pumped storage unit. The second model construction module is used to construct the rotor system motion model of the target pumped storage unit based on the dynamic characteristic coefficients, the unbalanced mass force model, the unbalanced magnetic pull model, and the unbalanced water pressure model. The modal frequency determination module is used to determine the modal frequencies corresponding to multiple rotational speeds based on the rotor system motion model. The critical speed determination module is used to determine the critical speed based on the modal frequency; The first model construction module includes: an unbalanced mass acquisition unit, used to acquire the unbalanced mass, which is obtained based on a rotor dynamic balancing test; and an unbalanced mass force model construction unit, used to construct the unbalanced mass force components of the rotor in the first and second directions based on the unbalanced mass, the rotor's eccentricity and initial phase, respectively, to obtain the unbalanced mass force model. The unbalanced magnetic pull force model construction unit is used to perform Maxwell stress integration based on the generator motor of the target pumped storage unit to obtain the unbalanced magnetic pull force model. The first unbalanced water pressure calculation unit is used to perform integral calculation on the water pressure acting on the impeller in the first direction to obtain the unbalanced water pressure component in the first direction; the second unbalanced water pressure calculation unit is used to perform integral calculation on the water pressure acting on the impeller in the second direction to obtain the unbalanced water pressure component in the second direction.

6. A computer device, characterized in that, include: A memory and a processor are interconnected, the memory storing computer instructions, and the processor executing the computer instructions to perform the critical speed determination method according to any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a computer to perform the critical speed determination method according to any one of claims 1 to 4.

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