Pumped storage unit, vibration avoidance operation method and system, and computer system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-11
- Publication Date
- 2026-08-11
AI Technical Summary
而且长短叶片可能在高速旋转时叶片表面形成大小不等的周期性涡旋，引发叶片高频振动进而影响转轮整体的固有频率
[0017]本申请提供的抽水蓄能机组的避振运行方法，在机组实际运行阶段之前通过仿真确定机组的轴向间隙和径向间隙对机组模态参数的影响，确定用于在实际运行阶段安装抽水蓄能机组的设计参数，从而提前避免或减轻共振现象对结构带来的破坏。
Smart Images
Figure CN122543898A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of hydraulic machinery vibration and control technology, and in particular to a pumped storage unit, a vibration isolation operation method and system, and a computer system. Background Technology
[0002] With the optimization of my country's energy structure and the development of smart grids, hydropower, especially pumped storage technology, is ushering in new plans and opportunities.
[0003] These large pumped-storage units have the following advantages: good speed adaptability, adjustable input power during pump operation, improved operating performance during turbine operation, rapid adjustment of active / reactive power, and good stable operation capability. For long-short blade runners, also known as split-flow runners, short blades are added between adjacent long blade channels to improve the internal flow pattern, resulting in significant advantages in improving the efficiency of turbines and pumps.
[0004] Given the existing operational and turbine structure characteristics of pumped storage power stations, ensuring the stable operation of the turbines is becoming increasingly important and has become a key area of research and development in the industry. Common factors affecting the operational stability of pumped storage power station turbines include, but are not limited to, the following: Due to the high-speed and variable operating conditions, the rotational frequency of the runner, the centrifugal force generated by the long and short blades, and the influence of the fluid, low-frequency resonance occurs throughout the runner. Torsional vibration may also occur due to excessively high runner speed. Furthermore, the long and short blades may form periodic vortices of varying sizes on their surfaces during high-speed rotation, causing high-frequency blade vibration and thus affecting the natural frequency of the entire runner.
[0005] In summary, the natural frequency variation of the long and short blade runners in pumped storage power stations is more complex. Therefore, more methods are needed to effectively control their natural frequency in order to achieve structural vibration reduction and optimize stability. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of related technologies and provide a pumped storage unit, a vibration-damping operation method and system, and a computer system.
[0007] In a first aspect, embodiments of this application provide a vibration-damping operation method for a pumped storage unit, comprising: A fluid-structure interaction model of a pumped-storage unit is established, comprising a fluid model and a structural solid model of the pumped-storage unit in an aquatic environment. The pumped-storage unit includes a long-short blade impeller, an impeller chamber, a main shaft, a top cover, and a seat ring. The long-short blade impeller includes an upper crown, a lower ring, and multiple long-short blades fixed between the upper crown and the lower ring. The impeller chamber is located between the top cover and the seat ring. The long-short blade impeller is located within the impeller chamber and connected to the main shaft. The gap between the long-short blade impeller and the sidewall of the impeller chamber is a radial gap, the gap between the upper crown and the top cover is a first axial gap, and the gap between the lower ring and the seat ring is a second axial gap. Based on different operating conditions of the pumped storage unit, the radial clearance, the first axial clearance, and the second axial clearance are adjusted by simulation, and the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under each operating condition is determined. The values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under each operating condition are determined as the design parameters of the pumped storage unit under the corresponding operating condition; and the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions are determined as the target design parameters of the pumped storage unit during the actual operation phase. During the actual operation of the pumped storage unit, if the operating conditions are fixed, the pumped storage unit will be installed using the design parameters corresponding to those operating conditions. If the operating conditions are not fixed during the actual operation of the pumped storage unit, the target design parameters will be used to install the pumped storage unit.
[0008] Optionally, the step of adjusting the values of the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: Keeping two of the radial clearance, the first axial clearance, and the second axial clearance constant, the value of the third clearance is adjusted to determine the influence of different values of the third clearance on the modal parameters of the pumped storage unit under various operating conditions.
[0009] Optionally, the step of adjusting the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the impact of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: Keeping one of the radial clearance, the first axial clearance, and the second axial clearance constant, the values of the other two are adjusted to determine the influence of different combinations of these two values on the modal parameters of the pumped storage unit under various operating conditions.
[0010] Optionally, the step of adjusting the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the impact of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: Adjust the values of the radial clearance, the first axial clearance, and the second axial clearance to determine the influence of different combinations of these three values on the modal parameters of the pumped storage unit under various operating conditions.
[0011] Optionally, determining the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under each operating condition, as the design parameters of the pumped storage unit under the corresponding operating condition, includes: Determine the hydraulic excitation frequency of the pumped storage unit under the current operating conditions based on its operating conditions. Based on the different values of the radial clearance, the first axial clearance, and the second axial clearance, the corresponding natural frequency of the pumped storage unit is determined. From the different values of the radial clearance, the first axial clearance, and the second axial clearance, a set of values is selected such that the difference between the corresponding natural frequency and the hydraulic excitation frequency does not exceed the safety margin threshold, and these values are used as the design parameters.
[0012] Optionally, determining the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions, as the target design parameters for the pumped storage unit during actual operation, includes: The hydraulic excitation frequency of the pumped storage unit under each operating condition is determined based on the different operating conditions of the pumped storage unit. Based on the different values of the radial clearance, the first axial clearance, and the second axial clearance, the corresponding natural frequency of the pumped storage unit is determined. From the different values of the radial clearance, the first axial clearance, and the second axial clearance, a set of values is selected such that the difference between the corresponding natural frequency and each of the hydraulic excitation frequencies does not exceed the safety margin threshold, and these values are used as the target design parameters.
[0013] Optionally, the modal parameters include natural frequencies and mode shapes; The determination of the values of the radial clearance, the first axial clearance, and the second axial clearance, which enable the pumped storage unit to operate most stably under all operating conditions, as the target design parameters for the pumped storage unit during actual operation, includes: Set the first axial clearance and the second axial clearance to be the same, and establish a first function for the natural frequency to change with the first axial clearance under different values and a second function for the mode shape to change with the first axial clearance. A third function relating the natural frequency to the radial clearance at different values and a fourth function relating the mode shape to the radial clearance are established. By comparing and analyzing the influence of the first axial clearance and the radial clearance on the modal parameters of the pumped storage unit under the same mode, the weights of each part of the first function, the second function, the third function and the fourth function are obtained, and a comprehensive function of the modal parameters of the pumped storage unit is established. Based on the comprehensive function and the operating parameters of each operating condition, a set of values for the radial clearance, the first axial clearance, and the second axial clearance that can make the pumped storage unit operate most stably under all operating conditions is determined as the target design parameters.
[0014] Secondly, embodiments of this application provide a vibration isolation operation system for a pumped storage unit, comprising: a modeling and analysis unit and a control unit electrically connected to the modeling and analysis unit; The modeling and analysis unit is configured to perform the following operations: A fluid-structure interaction model of a pumped-storage unit is established, comprising a fluid model and a structural solid model of the pumped-storage unit in an aquatic environment. The pumped-storage unit includes a long-short blade impeller, an impeller chamber, a main shaft, a top cover, and a seat ring. The long-short blade impeller includes an upper crown, a lower ring, and multiple long-short blades fixed between the upper crown and the lower ring. The impeller chamber is located between the top cover and the seat ring. The long-short blade impeller is located within the impeller chamber and connected to the main shaft. The gap between the long-short blade impeller and the sidewall of the impeller chamber is a radial gap, the gap between the upper crown and the top cover is a first axial gap, and the gap between the lower ring and the seat ring is a second axial gap. Based on different operating conditions of the pumped storage unit, the radial clearance, the first axial clearance, and the second axial clearance are adjusted by simulation, and the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under each operating condition is determined. The control unit is configured to perform the following operations: The values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under each operating condition are determined as the design parameters of the pumped storage unit under the corresponding operating condition; and the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions are determined as the target design parameters of the pumped storage unit during the actual operation phase. During the actual operation of the pumped storage unit, if the operating conditions are fixed, the pumped storage unit will be installed using the design parameters corresponding to those operating conditions. If the operating conditions are not fixed during the actual operation of the pumped storage unit, the target design parameters will be used to install the pumped storage unit.
[0015] Thirdly, embodiments of this application provide a pumped storage unit, which is installed according to the method described in the first aspect.
[0016] Fourthly, embodiments of this application provide a computer system including one or more processors and a memory, the memory storing computer program instructions that, when executed by the processor, implement the method described in the first aspect.
[0017] The vibration isolation operation method for pumped storage units provided in this application determines the influence of the axial and radial clearances of the unit on the modal parameters of the unit through simulation before the actual operation stage, and determines the design parameters for installing the pumped storage unit during the actual operation stage, thereby avoiding or mitigating the damage to the structure caused by resonance in advance.
[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0020] Figure 1 This is a flowchart of the vibration isolation operation method for pumped storage units provided in this embodiment.
[0021] Figure 2 This is a simplified schematic diagram of the pumped storage unit provided in this embodiment.
[0022] Figure 3 and Figure 4 These are the natural frequency and added mass coefficient of the structure under different axial clearances provided in this embodiment.
[0023] Figure 5 These are the 1ND mode vibration modes of the structure under different axial clearances provided in this embodiment.
[0024] Figure 6 and Figure 7 These are the natural frequency and added mass coefficient of the structure under different radial clearances provided in this embodiment.
[0025] Figure 8 and Figure 9 These are the 1ND mode vibration modes of the structure under different radial clearances provided in this embodiment.
[0026] Figure 10 This is a diagram illustrating the establishment method of the comprehensive evaluation model for the rotor modal parameters provided in this embodiment.
[0027] Figure 11 This is a diagram showing the selection method of the combination of roller clearance values provided in this embodiment.
[0028] Figure 12 This is a structural block diagram of the vibration isolation operation system of the pumped storage unit provided in this embodiment. Detailed Implementation
[0029] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.
[0030] To better understand the technical solution of this application, the pumped storage unit, vibration isolation operation method and system, and computer system of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementation methods can be combined with each other.
[0031] See Figure 1 As shown, an embodiment of this application provides a vibration-damping operation method for a pumped storage unit, including: Step S1: Establish a fluid-structure interaction model for the pumped-storage unit. This model includes a fluid model and a structural solid model of the pumped-storage unit in an aquatic environment. Specifically, it combines... Figure 2The diagram shows a simplified schematic of a pumped-storage hydroelectric unit. The unit includes a long-short blade impeller 10, an impeller chamber 20, a main shaft 30, a top cover 40, and a seat ring 50. The long-short blade impeller includes an upper crown 11, a lower ring 12, and multiple long-short blade combinations fixed between the upper crown 11 and the lower ring 12. The impeller chamber 20 is located between the top cover 40 and the seat ring 50. The long-short blade impeller 10 is disposed within the impeller chamber 20 and connected to the main shaft 30. The gap between the long-short blade impeller 10 and the sidewall of the impeller chamber 20 is a radial gap dr; the gap between the upper crown 11 and the top cover 40 is a first axial gap da1; and the gap between the lower ring 12 and the seat ring 50 is a second axial gap da2. The impeller chamber 20 can contain fluid, such as water. Optionally, the multiple long-short blade combinations may include five long blades and five short blades, or other combinations. Optionally, a full-flow fluid model and structural solid model of the unit can be established using 3D CAD software and finite element analysis software (finite element preprocessing software, such as ANSYS and COMSOL), and the model can be meshed with high quality to complete high-precision modeling.
[0032] Step S2: Based on different operating conditions of the pumped storage unit, the radial clearance, the first axial clearance, and the second axial clearance are adjusted through simulation, and the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under each operating condition is determined.
[0033] It should be noted that, due to the influence of added mass, the modal characteristics of long and short blade runners are more complex. In this case, the magnitude of the aforementioned gaps has a more complex impact on the runner's inherent modal characteristics, potentially inducing a unique resonance mechanism. Vibration-damping structures are designed along the radial outer edges of the runner's upper crown and lower ring to alter the radial gap and thus affect the runner's natural frequency. This application primarily studies the influence of different radial and axial gaps on the runner's inherent modes. Specifically, based on different operating conditions, the runner's outer edge can be modified to change different gap dimensions, thereby affecting the added mass coefficient, natural frequency, and mode shape of the runner's inherent modes, thus avoiding or mitigating the damage caused by resonance.
[0034] First, since the axial force is relatively greater during the operation of the runner, and the runner's modes are mainly axial vibrations, especially in runners with long and short blades, due to the presence of periodic vortices of varying sizes, the runner is prone to axial vibrations due to uneven water flow. The natural frequency and mode shape of different modes of the runner can be changed by symmetrically changing the axial clearance.
[0035] Secondly, when the turbine operating speed of a pumped storage unit is related to its natural frequency, thus causing resonance, radial vibration will also increase significantly, potentially leading to structural damage during operation. Simultaneously, the blade size relationship between long and short blades will also cause radial imbalance between the runner and blades during operation. Therefore, the natural frequency of the runner can be adjusted to cope with different operating conditions by symmetrically changing the radial clearance.
[0036] It should be clarified that the closer the impeller structure is to the side wall of the impeller chamber, the greater the added mass effect. Consequently, when the axial and radial clearances of the impeller are changed, the natural frequencies and mode shapes under different modes will also change. This application mainly provides a solution from two aspects: changing the axial and radial clearances, while considering the influence of rotational speed changes under different clearance conditions.
[0037] Then, considering the changes in operating conditions of the unit during actual operation of the power station under different axial and radial clearance conditions, the influence of three factors, namely "different operating conditions, axial clearance, and radial clearance", on the runner structure is comprehensively analyzed. Combining the internal hydraulic excitation characteristics of the unit, the optimal function under the influence of multiple factors is established for different operating conditions with the vibration isolation of the runner and other key structural components as the goal, so as to achieve safe and stable operation of the long and short blade runners of the pumped storage power station.
[0038] Step S3 involves determining the set of radial clearance, first axial clearance, and second axial clearance values that ensure the most stable operation of the pumped-storage unit under each operating condition. These values are then used as the design parameters for the pumped-storage unit under the corresponding operating condition. It is understood that by simulating and adjusting the combination of radial clearance, first axial clearance, and second axial clearance variables, the influence of different values of these clearances on the modal parameters of the pumped-storage unit under various operating conditions can be determined. Thus, under each operating condition, the set of radial clearance, first axial clearance, and second axial clearance values that ensure the most stable operation of the pumped-storage unit can be selected as the design parameters for that operating condition.
[0039] The values of the radial clearance, the first axial clearance, and the second axial clearance, which ensure the most stable operation of the pumped-storage unit under all operating conditions, are determined and used as the target design parameters for the pumped-storage unit during actual operation. Understandably, by simulating and adjusting the combinations of radial clearance, the first axial clearance, and the second axial clearance, the influence of different values of these clearances on the modal parameters of the pumped-storage unit under various operating conditions can be determined. Thus, the set of radial clearance, the first axial clearance, and the second axial clearance values that ensure the most stable operation of the pumped-storage unit under different operating conditions can be selected; that is, the optimal fixed clearance dimensions that are compatible with vibration damping under all operating conditions, are used as the design parameters for the pumped-storage unit under that operating condition.
[0040] Step S4: During the actual operation of the pumped storage unit, if the operating conditions are fixed, the pumped storage unit is installed using the design parameters corresponding to those operating conditions. In this way, installing the unit with the clearance dimensions corresponding to the design parameters under each operating condition provides the best vibration damping effect for the structure, and can prevent or mitigate the damage to the structure caused by resonance in advance.
[0041] During the actual operation of pumped storage units, if the operating conditions are not fixed, the target design parameters are used for installation. Thus, when the operating conditions of the unit vary, using the optimal clearance dimensions of the target design parameters, which are compatible with vibration damping under all operating conditions, provides the best vibration damping effect on the structure under each operating condition, and can prevent or mitigate the damage to the structure caused by resonance in advance.
[0042] It should be noted that the optimal design parameters for each operating condition, as well as the optimal target design parameters compatible with all operating conditions, can be stored in a database. Alternatively, a data model can be designed and trained, and all the simulation data mentioned above can be input into it. During actual operation, once the current operating condition is determined, the current operating parameters can be input into the data model, or the optimal design parameters corresponding to the current operating condition can be determined directly through a lookup table.
[0043] Understandably, due to the rigidity of large components and assembly limitations, the axial and radial clearances of pumped storage units are fixed after leaving the factory and cannot be changed in real time, making real-time fine-tuning impossible during operation. Therefore, this application, through the aforementioned technical solution, determines the optimal clearance of the impeller through preliminary numerical simulation and design optimization. By adjusting the combination of clearance variables in the simulation software during the impeller design or machining modification stage through numerical simulation, a set of optimal fixed clearance dimensions that can accommodate vibration damping under all operating conditions is found.
[0044] During the design phase (numerical simulation to determine clearance): Before the unit leaves the factory or the runner is replaced, multiphysics numerical simulation (fluid-structure interaction simulation) is used to simulate various typical operating conditions and the most unfavorable operating conditions throughout the unit's entire life cycle. Different axial / radial clearance variables are substituted into the simulation software to calculate the corresponding Hi function values, thereby selecting a set of fixed clearance dimensions with the best overall vibration damping effect, which is used to guide the outer edge modification of the runner and the final assembly in the factory.
[0045] During the operation phase: After the unit is actually put into operation, displacement sensors and vibration sensors can be deployed to monitor the current operating conditions, modes, and factory-preset actual clearances in real time. This allows for verification of the accuracy of the initial numerical simulations, correction of simulation boundary conditions, and monitoring for abnormal changes in clearances after long-term operation (deterioration causing the Hi function value to deviate from safety specifications), thereby enabling early warning of resonance risks.
[0046] The vibration-damping operation method for pumped-storage units provided in this application determines the impact of axial and radial clearances on the unit's modal parameters through simulation before the actual operation phase. This determines the design parameters for installing the pumped-storage unit during actual operation, thereby avoiding or mitigating structural damage caused by resonance. The method optimizes the unit's structure itself, specifically the dimensions of each clearance, to improve operational stability. By altering the axial and radial clearances of the runner within a certain range during the design phase, and then installing the unit using the determined optimal design parameters during actual operation, the method effectively avoids resonance by staggering the excitation modes and the runner's natural modal frequencies.
[0047] In some optional implementations, step S2 above, which involves adjusting the values of the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: keeping the values of two of the radial clearance, the first axial clearance, and the second axial clearance constant, adjusting the value of the third, and determining the influence of different values of the third on the modal parameters of the pumped storage unit under various operating conditions. It can be understood that this method can be considered as a one-dimensional, one-variable operating condition, using the controlled variable method to study the design of the runner outer edge under a single variable (axial or radial clearance) variation.
[0048] For example, see Figures 3 to 5As shown, with the first and second axial clearances set to be the same and the radial clearance dr = 2 mm kept constant, the influence of axial clearance on the unit's modal characteristics is analyzed. It can be observed that as the axial clearance decreases, the natural frequencies of the unit gradually decrease, while the added mass coefficient gradually increases; the smaller the distance, the more sensitive the frequency change. Furthermore, taking the 1ND mode shape as an example, the influence of different axial clearances on the unit's mode shape is analyzed. The results show that different axial clearances result in different 1ND mode shapes, and the modal displacement increases with increasing axial clearance.
[0049] See Figure 6 and Figure 7 As shown, the first and second axial clearances are set to be the same, and the axial clearance da = 2 mm is kept constant. The modal characteristics of the structure under different radial clearances are analyzed. It can be seen that for smaller radial clearances, the changes in the unit's natural frequency and added mass coefficient are significantly affected by the distance. As the radial distance further increases, the natural frequency and added mass coefficient remain basically unchanged.
[0050] See Figure 8 and Figure 9 As shown, six values with relatively small radial clearances are selected to demonstrate the modal displacements of the 1ND structure in the same mode. The results show that a small radial clearance does affect the modal displacements of the 1ND, but the difference is very small. As the radial clearance size increases, the modal displacements of the 1ND remain essentially unchanged.
[0051] Building upon this, further considering the dynamic changes in unit speed during startup and peak shaving, which can be viewed as dynamic single-variable operating conditions, a vibration damping control design coupled with single clearance variation and speed can be obtained. Thus, the influence of different values of the single variable axial or radial clearance on the modal parameters of the pumped storage unit under various operating conditions can be determined.
[0052] In some optional implementations, step S2 above, which involves adjusting the radial clearance, the first axial clearance, and the second axial clearance through simulation and determining the impact of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped-storage unit under various operating conditions, includes: keeping one of the radial clearance, the first axial clearance, and the second axial clearance constant, adjusting the values of the other two, and determining the impact of different combinations of these two values on the modal parameters of the pumped-storage unit under various operating conditions. This approach can be understood as a multi-dimensional, multi-variable operating condition, allowing for the study of a comprehensive vibration damping design under the synergistic optimization of "axial + radial" dual clearances. Furthermore, considering dynamic changes in unit speed during startup and peak shaving, this can be considered a full-dimensional dynamically coupled operating condition, leading to a vibration damping control design under simultaneous dynamic changes in "dual clearances + speed load." Thus, the impact of different values of the dual variables of axial and radial clearances on the modal parameters of the pumped-storage unit under various operating conditions can be determined.
[0053] In some optional implementations, step S2 above, which involves adjusting the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the impact of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: adjusting the values of the radial clearance, the first axial clearance, and the second axial clearance, and determining the impact of different combinations of these three values on the modal parameters of the pumped storage unit under various operating conditions. This approach can be understood as a multi-dimensional, multi-variable operating condition, allowing for the study of a comprehensive vibration damping design under the coordinated optimization of "axial + radial" multi-clearances. Furthermore, considering the dynamic changes in unit speed during startup and peak shaving, this can be considered a full-dimensional dynamically coupled operating condition, leading to a vibration damping control design under the simultaneous dynamic changes of "dual clearances + speed load." Thus, the impact of different values of the axial clearance and radial clearance on the modal parameters of the pumped storage unit under various operating conditions can be determined.
[0054] Based on the above analysis, the effects of various numerical combinations of axial and radial clearances on the natural frequencies and mode shapes of the structure can be determined according to different operating conditions.
[0055] In some optional implementations, the modal parameters include natural frequencies. Step S3 above, determining the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under each operating condition, as design parameters for the pumped storage unit under the corresponding operating condition, includes: Step S31A: Determine the hydraulic excitation frequency of the pumped storage unit under its current operating conditions based on the unit's operating status. Optionally, monitor the unit's current operating speed N in real time and calculate the current primary hydraulic excitation frequency f based on the hydraulic design. e Hydraulic excitation frequency f e =k×N / 60, where k is the excitation order, which is determined by the number of rotor blades and the number of moving guide vanes.
[0056] Step S32A: Determine the natural frequencies of the pumped storage unit based on the different values of the radial clearance, the first axial clearance, and the second axial clearance. Optionally, acoustic-structure interaction modal analysis can be used to calculate the natural frequencies of the unit's fluid-structure interaction model in an aquatic environment under different clearance combinations.
[0057] Step S33A: From the different values of the radial clearance, the first axial clearance, and the second axial clearance, select a set of values that ensure the difference between the corresponding natural frequency and the hydraulic excitation frequency does not exceed a safety margin threshold, and use these values as the design parameters. It is understood that comparing the natural frequency with the hydraulic excitation frequency, when the following conditions are met... (Equation 1) assumes that the current combination of clearance values will allow the unit to operate most stably under the current operating conditions. Where f e Let f be the hydraulic excitation frequency. n The inherent frequency, δ This is a safety margin threshold. Optionally, the safety margin threshold ranges from 5% to 15%, preferably 10%, and this threshold can be dynamically adjusted based on the unit's historical vibration intensity data, structural importance, or operational experience.
[0058] In some optional implementations, the modal parameters include natural frequencies. Step S3 above, determining the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions, as the target design parameters for the pumped storage unit during actual operation, includes: Step S31B: Determine the hydraulic excitation frequency of the pumped storage unit under different operating conditions. Optionally, monitor the current operating speed N of the unit in real time and calculate the current main hydraulic excitation frequency f based on the hydraulic design. e Hydraulic excitation frequency f e =k×N / 60, where k is the excitation order, which is determined by the number of rotor blades and the number of moving guide vanes.
[0059] Step S32B: Determine the natural frequencies of the pumped storage unit based on the different values of the radial clearance, the first axial clearance, and the second axial clearance. Optionally, acoustic-structure interaction modal analysis can be used to calculate the natural frequencies of the unit's fluid-structure interaction model in an aquatic environment under different clearance value combinations.
[0060] Step S33B: From the different values of the radial clearance, the first axial clearance, and the second axial clearance, select a set of values such that the difference between the corresponding natural frequency and each of the hydraulic excitation frequencies does not exceed a safety margin threshold, and use these values as the target design parameters. It is understood that comparing the natural frequency with the hydraulic excitation frequency, when the following conditions are met... (Equation 1) assumes that the current combination of clearance values allows the unit to operate most stably under all operating conditions. Where f e Let f be the hydraulic excitation frequency. n The inherent frequency, δ This is a safety margin threshold. Optionally, the safety margin threshold ranges from 5% to 15%, preferably 10%, and this threshold can be dynamically adjusted based on the unit's historical vibration intensity data, structural importance, or operational experience.
[0061] In some alternative implementations, the modal parameters include natural frequencies and mode shapes. (Combined with...) Figure 10 As shown, step S3 above, determining the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions, as the target design parameters for the pumped storage unit during actual operation, includes: Step S31C: Set the first axial clearance and the second axial clearance to be the same (hereinafter referred to as axial clearance), and establish a first function for the natural frequency to change with the first axial clearance under different values, and a second function for the mode shape to change with the first axial clearance. Optionally, combine the frequency descent rate and the added mass coefficient to establish a function Fa for the natural frequency to change with the axial clearance. Based on the modal displacement change, establish a function Da for the mode shape to change with the axial clearance.
[0062] Step S32C: Establish a third function for the natural frequency to vary with the radial clearance under different values, and a fourth function for the mode shape to vary with the radial clearance. Optionally, combine the frequency descent rate and the added mass coefficient to establish a function Fr for the natural frequency to vary with the radial clearance. Based on the modal displacement variation, establish a function Dr for the mode shape to vary with the axial clearance.
[0063] Step S33C: Compare and analyze the influence of the first axial clearance and the radial clearance on the modal parameters of the pumped storage unit under the same mode, obtain the weights w of each part of the first function, the second function, the third function and the fourth function, and establish the comprehensive function Hi function of the modal parameters of the pumped storage unit as a comprehensive evaluation model of the runner modal parameters coupled by multiple factors.
[0064] Step S31C: Based on the comprehensive function and the operating parameters for each operating condition, determine the values of the radial clearance, the first axial clearance, and the second axial clearance that ensure the most stable operation of the pumped storage unit under all operating conditions, and use these values as the target design parameters. Thus, vibration damping measures are implemented by considering the hydraulic excitation characteristics under different operating conditions. By designing different clearance dimensions for the long and short blade impeller structure, the impeller's natural frequency and mode shape are adjusted, and the added mass effect of the surrounding fluid is controlled, achieving staggered excitation modes and impeller natural modes under different operating conditions, thereby achieving structural vibration damping.
[0065] Understandably, the early design phase's study of the patterns in each axis is precisely to provide a quantitative basis for the final control strategy. Based on the different sensitivity characteristics of axial / radial clearances, the following approach—a "multi-gradient clearance collaborative optimization design strategy oriented towards the dominant operating condition"—can be adopted as the core control method during the design phase: 1. Axial Clearance Optimization Strategy (Large-Range Coarse Frequency Adjustment): Since the turbine runner primarily vibrates axially, and its natural frequencies are extremely sensitive to changes in axial clearance (the smaller the clearance, the faster the frequency drops), a coarse adjustment strategy focusing on "changing the axial clearance" is adopted when the predicted hydraulic excitation frequency is high and a significant shift from the natural frequency is urgently needed. By appropriately increasing the axial clearance, the natural frequencies can be significantly increased, quickly escaping the low-frequency resonance region.
[0066] 2. Radial Clearance Optimization Strategy (Local Flow Division and Fine-tuning): Since the natural frequency and added mass coefficient are only sensitive when the radial clearance is small, and basically remain unchanged after increasing to a certain extent, a "small-range fine-tuning" strategy can be adopted for the radial clearance. The focus is on controlling it within the sensitive size range (such as the smaller value range in numerical simulations) to fine-tune modes of specific orders, while also taking into account the radial imbalance caused by the varying blade lengths.
[0067] 3. Multi-condition compromise optimization strategy: If the unit needs to take into account multiple complex operating conditions such as water pumps and water turbines, the Hi function is used to perform a weighted solution for the entire life cycle, and the fixed gap numerical combination that minimizes the overall resonance risk is obtained through a comprehensive evaluation process.
[0068] Furthermore, combined Figure 11As shown, when selecting a combination of gap values, you can determine whether the current combination of gap values is too large or too small, and to what extent it needs to be adjusted, using the following methods: 1. Boundary Input: Based on the actual operating conditions of the power plant, the system directly extracts the current rotational speed, flow rate, and operating conditions. Based on the load dynamic function γ(ω) (considering the influence of rotational speed, flow rate changes, and operating load variations such as the added mass system), the uncontrollable external hydraulic excitation frequency under the current operating conditions is directly locked.
[0069] 2. Difference Judgment: The structural natural frequency fn under the preset gap is calculated by numerical simulation. If the first constraint condition is met and fn < fe, it means that the structural natural frequency is too close to the excitation source. Since the smaller the gap, the lower the natural frequency, it is judged that the gap is too small. Conversely, if the frequency difference does not meet the standard and fn > fe, it is judged that the gap is too large.
[0070] 3. Based on the above size determination, the gap is substituted into the comprehensive function for multi-factor optimization iteration. The final suitable level is the termination condition, and it must simultaneously satisfy the frequency safety offset rate and the complete convergence of the function value, reaching the appropriate safety specification value under this operating condition.
[0071] This application, through the aforementioned technical solution, selects a more focused and universally applicable approach without altering any of the original hardware structure of the unit. Only during the design modification stage, through numerical simulation calculations, minor adjustments are made to the outer edge machining dimensions of the upper crown and lower ring of the runner, thereby determining a set of fixed clearance numerical combinations that provide optimal vibration damping under all operating conditions.
[0072] An embodiment of this application provides a pumped storage unit, which is installed according to the vibration-damping operation method of the pumped storage unit described above.
[0073] The pumped storage unit provided in this application determines the impact of axial and radial clearances on the unit's modal parameters through simulation before the actual operation phase. This determines the design parameters for installing the pumped storage unit during actual operation, thereby avoiding or mitigating structural damage caused by resonance. The unit's structure itself, specifically the dimensions of each clearance, is optimized to improve operational stability. By altering the axial and radial clearances of the runner within a certain range during the design phase, and then installing the unit using the determined optimal design parameters during actual operation, the excitation modes and the runner's natural modal frequencies are staggered, reducing resonance.
[0074] The embodiments of this application also provide a computer system, including one or more processors and a memory, wherein the memory stores computer program instructions, and when the instructions are executed by the processor, the above-described vibration-avoidance operation method of the pumped storage unit is implemented.
[0075] See Figure 12 As shown, an embodiment of this application also provides a vibration isolation operation system for a pumped storage unit, including: a modeling and analysis unit 60 and a control unit 70 electrically connected to the modeling and analysis unit 60.
[0076] The modeling and analysis unit 60 is configured to perform the following operations: A fluid-structure interaction model of a pumped-storage unit is established, comprising a fluid model and a structural solid model of the pumped-storage unit in an aquatic environment. The pumped-storage unit includes a long-short blade impeller, an impeller chamber, a main shaft, a top cover, and a seat ring. The long-short blade impeller includes an upper crown, a lower ring, and multiple long-short blades fixed between the upper crown and the lower ring. The impeller chamber is located between the top cover and the seat ring. The long-short blade impeller is located within the impeller chamber and connected to the main shaft. The gap between the long-short blade impeller and the sidewall of the impeller chamber is a radial gap, the gap between the upper crown and the top cover is a first axial gap, and the gap between the lower ring and the seat ring is a second axial gap. Based on different operating conditions of the pumped storage unit, the radial clearance, the first axial clearance, and the second axial clearance are adjusted by simulation, and the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under each operating condition is determined. The control unit 70 is configured to perform the following operations: The values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under each operating condition are determined as the design parameters of the pumped storage unit under the corresponding operating condition; and the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions are determined as the target design parameters of the pumped storage unit during the actual operation phase. During the actual operation of the pumped storage unit, if the operating conditions are fixed, the pumped storage unit will be installed using the design parameters corresponding to those operating conditions. If the operating conditions are not fixed during the actual operation of the pumped storage unit, the target design parameters will be used to install the pumped storage unit.
[0077] The vibration isolation system for pumped storage units provided in this application determines the impact of axial and radial clearances on the unit's modal parameters through modeling and analysis unit simulation before the actual operation phase. The control unit then determines the design parameters for installing the pumped storage unit during actual operation, thereby preventing or mitigating structural damage caused by resonance. The system optimizes the unit's structure itself, specifically the dimensions of each clearance, to improve operational stability. By altering the axial and radial clearances of the runner within a certain range during the design phase, and employing the determined optimal design parameters for unit installation during actual operation, the system effectively avoids resonance by aligning the excitation modes with the runner's natural modal frequencies.
[0078] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A method of vibration avoidance operation of a pumped storage unit, characterized by, include: A fluid-structure interaction model of a pumped-storage unit is established, comprising a fluid model and a structural solid model of the pumped-storage unit in an aquatic environment. The pumped-storage unit includes a long-short blade impeller, an impeller chamber, a main shaft, a top cover, and a seat ring. The long-short blade impeller includes an upper crown, a lower ring, and multiple long-short blades fixed between the upper crown and the lower ring. The impeller chamber is located between the top cover and the seat ring. The long-short blade impeller is located within the impeller chamber and connected to the main shaft. The gap between the long-short blade impeller and the sidewall of the impeller chamber is a radial gap, the gap between the upper crown and the top cover is a first axial gap, and the gap between the lower ring and the seat ring is a second axial gap. Based on different operating conditions of the pumped storage unit, the radial clearance, the first axial clearance, and the second axial clearance are adjusted by simulation, and the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under each operating condition is determined. The values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under each operating condition are determined as the design parameters of the pumped storage unit under the corresponding operating condition; and the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions are determined as the target design parameters of the pumped storage unit during the actual operation phase. During the actual operation of the pumped storage unit, if the operating conditions are fixed, the pumped storage unit will be installed using the design parameters corresponding to those operating conditions. If the operating conditions are not fixed during the actual operation of the pumped storage unit, the target design parameters will be used to install the pumped storage unit.
2. The method of claim 1, wherein, The process of adjusting the values of the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the impact of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: Keeping two of the radial clearance, the first axial clearance, and the second axial clearance constant, the value of the third clearance is adjusted to determine the influence of different values of the third clearance on the modal parameters of the pumped storage unit under various operating conditions.
3. The method of claim 1, wherein, The process of adjusting the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the impact of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: Keeping one of the radial clearance, the first axial clearance, and the second axial clearance constant, the values of the other two are adjusted to determine the influence of different combinations of these two values on the modal parameters of the pumped storage unit under various operating conditions.
4. The method of claim 1, wherein, The process of adjusting the radial clearance, the first axial clearance, and the second axial clearance through simulation, and determining the impact of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under various operating conditions, includes: Adjust the values of the radial clearance, the first axial clearance, and the second axial clearance to determine the influence of different combinations of these three values on the modal parameters of the pumped storage unit under various operating conditions.
5. The method according to any one of claims 1-4, characterized in that, The determination of the values of the radial clearance, the first axial clearance, and the second axial clearance, which enable the pumped storage unit to operate most stably under each operating condition, as the design parameters of the pumped storage unit under the corresponding operating condition, includes: Determine the hydraulic excitation frequency of the pumped storage unit under the current operating conditions based on its operating conditions. Based on the different values of the radial clearance, the first axial clearance, and the second axial clearance, the corresponding natural frequency of the pumped storage unit is determined. From the different values of the radial clearance, the first axial clearance, and the second axial clearance, a set of values is selected such that the difference between the corresponding natural frequency and the hydraulic excitation frequency does not exceed the safety margin threshold, and these values are used as the design parameters.
6. The method according to any one of claims 1-4, characterized in that, The determination of the values of the radial clearance, the first axial clearance, and the second axial clearance, which enable the pumped storage unit to operate most stably under all operating conditions, as the target design parameters for the pumped storage unit during actual operation, includes: The hydraulic excitation frequency of the pumped storage unit under each operating condition is determined based on the different operating conditions of the pumped storage unit. Based on the different values of the radial clearance, the first axial clearance, and the second axial clearance, the corresponding natural frequency of the pumped storage unit is determined. From the different values of the radial clearance, the first axial clearance, and the second axial clearance, a set of values is selected such that the difference between the corresponding natural frequency and each of the hydraulic excitation frequencies does not exceed the safety margin threshold, and these values are used as the target design parameters.
7. The method according to any one of claims 1 to 4, characterized in that, The modal parameters include natural frequencies and mode shapes; The determination of the values of the radial clearance, the first axial clearance, and the second axial clearance, which enable the pumped storage unit to operate most stably under all operating conditions, as the target design parameters for the pumped storage unit during actual operation, includes: Set the first axial clearance and the second axial clearance to be the same, and establish a first function for the natural frequency to change with the first axial clearance under different values and a second function for the mode shape to change with the first axial clearance. A third function relating the natural frequency to the radial clearance at different values and a fourth function relating the mode shape to the radial clearance are established. By comparing and analyzing the influence of the first axial clearance and the radial clearance on the modal parameters of the pumped storage unit under the same mode, the weights of each part of the first function, the second function, the third function and the fourth function are obtained, and a comprehensive function of the modal parameters of the pumped storage unit is established. Based on the comprehensive function and the operating parameters of each operating condition, a set of values for the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions is determined as the target design parameters.
8. A vibration isolation operation system for a pumped storage unit, characterized in that, include: A modeling and analysis unit and a control unit electrically connected to the modeling and analysis unit; The modeling and analysis unit is configured to perform the following operations: A fluid-structure interaction model of a pumped-storage unit is established, comprising a fluid model and a structural solid model of the pumped-storage unit in an aquatic environment. The pumped-storage unit includes a long-short blade impeller, an impeller chamber, a main shaft, a top cover, and a seat ring. The long-short blade impeller includes an upper crown, a lower ring, and multiple long-short blades fixed between the upper crown and the lower ring. The impeller chamber is located between the top cover and the seat ring. The long-short blade impeller is located within the impeller chamber and connected to the main shaft. The gap between the long-short blade impeller and the sidewall of the impeller chamber is a radial gap, the gap between the upper crown and the top cover is a first axial gap, and the gap between the lower ring and the seat ring is a second axial gap. Based on different operating conditions of the pumped storage unit, the radial clearance, the first axial clearance, and the second axial clearance are adjusted by simulation, and the influence of different values of the radial clearance, the first axial clearance, and the second axial clearance on the modal parameters of the pumped storage unit under each operating condition is determined. The control unit is configured to perform the following operations: The values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under each operating condition are determined as the design parameters of the pumped storage unit under the corresponding operating condition; and the values of the radial clearance, the first axial clearance, and the second axial clearance that enable the pumped storage unit to operate most stably under all operating conditions are determined as the target design parameters of the pumped storage unit during the actual operation phase. During the actual operation of the pumped storage unit, if the operating conditions are fixed, the pumped storage unit will be installed using the design parameters corresponding to those operating conditions. If the operating conditions are not fixed during the actual operation of the pumped storage unit, the target design parameters will be used to install the pumped storage unit.
9. A pumped storage unit characterized by The pumped storage unit is installed according to any one of the methods described in claims 1-7.
10. A computer system, characterized by It includes one or more processors and a memory, the memory storing computer program instructions that, when executed by the processor, implement the method as described in any one of claims 1-7.