Self-balancing multi-stage pump axial force stabilizing device and method based on leakage control

Abstract

The application relates to the technical field of energy-saving pumps, in particular to a self-balancing multi-stage pump axial force stabilizing device and method based on leakage control, which comprises the following steps: obtaining radial and axial vibration data, lift data and flow data at the outlets of positive and negative impellers of a multi-stage pump in a current operation process; obtaining unstable characteristic values of each period according to the frequency difference of the radial and axial vibration data, the complexity of the axial vibration data, the flow data fluctuation characteristics at the outlets of the positive and negative impellers and the correlation between vibration abnormalities and flow abnormalities, and obtaining an evaluation coefficient in the current operation process in combination with the change amplitude of the lift data, so as to judge whether the adjustment rate of a leakage switch valve needs to be reduced in the next operation process. The application can accurately evaluate the stability of the axial force of the multi-stage pump, and then adjust the adjustment rate of the leakage switch valve, thereby improving the stability of the axial force of the multi-stage pump.

Description

Technical Field

[0001] This application relates to the field of energy-saving pump technology, specifically to a device and method for stabilizing the axial force of a self-balancing multistage pump based on leakage control. Background Technology

[0002] Self-balancing multistage pumps are high-efficiency, stable, and easy-to-maintain pumps. Their design achieves axial force self-balancing through a symmetrically arranged impeller structure, significantly improving operational reliability. They are commonly used in high-rise building water supply, long-distance water transmission, or industrial circulating water systems. Their stable axial force plays a crucial role in reducing frictional losses between the impeller and guide vanes, thus improving pump operating efficiency.

[0003] During operation, the axial force generated by a multistage pump mainly originates from two aspects: first, the asymmetry of the impeller structure leads to uneven pressure distribution on the cover plate surface; second, the change in direction of the liquid flowing through the impeller causes the liquid to impact the impeller, generating a reaction force. Existing self-balancing multistage pumps typically achieve axial force stability control based on structural characteristics. However, during operation, due to dimensional deviations between the impeller and the shaft, the axial forces generated during impeller rotation cannot completely cancel each other out, resulting in the instability of the axial force in the self-balancing multistage pump. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this application is to provide a device and method for stabilizing the axial force of a self-balancing multistage pump based on leakage control. The specific technical solution adopted is as follows:

[0005] In a first aspect, embodiments of this application provide a method for stabilizing the axial force of a self-balancing multistage pump based on leakage control, the method comprising the following steps:

[0006] Acquire radial vibration data, axial vibration data, head data, and flow rate data at the positive and negative impeller outlets of the self-balancing multistage pump during its current operation.

[0007] The entire data acquisition time during the current operation is divided into multiple time periods. The main frequency difference coefficient of each time period is obtained based on the frequency difference between radial and axial vibration data in each time period. The negative impact coefficient of each time period is obtained by combining the number of abrupt change points in the spectrum of axial vibration data in each time period, the dispersion of the frequencies corresponding to all abrupt change points, and the dispersion of axial vibration data in each time period and its neighboring time periods.

[0008] Based on the degree of difference between the flow data at the positive and negative impeller outlets in each time period, and the degree of random fluctuation of the flow data at the positive and negative impeller outlets, the flow anomaly coefficient for each time period is obtained. Combined with the correlation between the negative impact coefficient and the flow anomaly coefficient of each time period and its neighboring time periods, as well as the negative impact coefficient of each time period, the unstable characteristic value of each time period is obtained.

[0009] Based on the differences between the variation ranges of all unstable characteristic values ​​and all head data during the current operation, the evaluation coefficients for the current operation are obtained, and then it is determined whether the adjustment rate of the relief switch valve needs to be reduced in the next operation.

[0010] Preferably, the dominant frequency difference coefficient for each time period refers to the absolute difference between the frequencies corresponding to the largest amplitude values ​​in the spectrum diagrams of the radial vibration data and axial vibration data for each time period.

[0011] Preferably, the formula for calculating the negative impact coefficient for each time period is as follows: In the formula, Let be the negative impact coefficient for the i-th time period; The dominant frequency difference coefficient for the i-th time period; Let be the mean of the standard deviations of the axial vibration data for the i-th time period and all its nearest neighbor time periods; Let be the axial frequency complexity for the i-th time period; This is a preset constant.

[0012] Preferably, the axial frequency complexity of each time period refers to the product of the number of abrupt changes in the spectrum of the axial vibration data of each time period and the standard deviation of the frequencies corresponding to all abrupt change locations.

[0013] Preferably, the formula for calculating the flow anomaly coefficient for each time period is as follows: In the formula, Let be the traffic anomaly coefficient for the i-th time period. Let be the mean of the coefficients of determination corresponding to the fitted curves of the flow rate data at the positive and negative impeller outlets during the i-th time period. denoted as the SBD distance between the flow data at the positive and negative impeller outlets during the i-th time period.

[0014] Preferably, the formula for calculating the unstable characteristic values ​​of each time period is: In the formula, Let be the unstable characteristic value of the i-th time period. Let be the correlation coefficient between the negative impact sequence and the abnormal traffic sequence in the i-th time period, and exp() be an exponential function with the natural constant e as the base. Let be the negative impact coefficient for the i-th time period. Let be the traffic anomaly coefficient for the i-th time period.

[0015] Preferably, the negative impact sequence and the flow anomaly sequence for each time period refer to the sequence composed of the negative impact coefficients and flow anomaly coefficients of each time period and all its neighboring time periods arranged in ascending order of time.

[0016] Preferably, the evaluation coefficient in the current operation process refers to the ratio of the range of unstable characteristic values ​​for all time periods in the current operation process to the range of all head data.

[0017] Preferably, the specific process for determining whether the adjustment rate of the relief switch valve needs to be reduced in the next operation is as follows: if the normalized result of the evaluation coefficient in the current operation is greater than or equal to the preset instability threshold, then it is determined that the adjustment rate of the relief switch valve needs to be reduced in the next operation; otherwise, it is determined that the adjustment rate of the relief switch valve does not need to be reduced in the next operation.

[0018] Secondly, embodiments of this application also provide an axial force stabilization device for a self-balancing multistage pump based on leakage control, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any of the above-described methods for stabilizing the axial force of a self-balancing multistage pump based on leakage control.

[0019] This application has at least the following beneficial effects:

[0020] This application proposes an axial force stabilization device and method for a self-balancing multistage pump based on discharge control. By deeply analyzing the characteristics of radial and axial coupled vibration during the operation of the self-balancing multistage pump, and the complexity of axial vibration data, a negative impact coefficient is constructed to provide a preliminary assessment of the axial force stability. By analyzing the flow rate variation characteristics at the positive and negative impeller outlets, a flow rate anomaly coefficient is constructed to further evaluate the stability of the axial force of the self-balancing multistage pump from a flow rate perspective. By considering the correlation between abnormal flow rate variations and coupled vibration, and the influence of operating load on axial force stability, an evaluation coefficient is calculated for the current operating process, enabling accurate assessment of the instability of the axial force of the self-balancing multistage pump. Based on the obtained evaluation coefficient, the adjustment rate of the discharge switch valve is optimized, improving the stability of the axial force of the self-balancing multistage pump. Attached Figure Description

[0021] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A flowchart illustrating the steps of a self-balancing multistage pump axial force stabilization method based on discharge control, provided in one embodiment of this application.

[0023] Figure 2 A flowchart illustrating the acquisition of evaluation coefficients during the current operation process, provided as an embodiment of this application. Detailed Implementation

[0024] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the self-balancing multi-stage pump axial force stabilization device and method based on leakage control proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] The following description, in conjunction with the accompanying drawings, details the specific scheme of the axial force stabilization device and method for a self-balancing multistage pump based on leakage control provided in this application.

[0027] Please see Figure 1 The diagram illustrates a flowchart of a method for stabilizing the axial force of a self-balancing multistage pump based on leakage control, according to an embodiment of this application. The method includes the following steps:

[0028] Step 1: Obtain radial vibration data, axial vibration data, head data, and flow rate data at the positive and negative impeller outlets of the self-balancing multistage pump during its current operation.

[0029] Self-balancing multistage pumps are highly efficient and energy-saving devices. By optimizing impeller and flow channel design, they mitigate the increased energy consumption caused by axial force imbalance during the operation of traditional multistage pumps. Utilizing advanced sealing technology and an intelligent control system, self-balancing multistage pumps not only significantly improve pump operating efficiency and reduce energy consumption but also extend equipment lifespan. This aligns perfectly with the core concepts of energy conservation, emission reduction, and optimized resource utilization advocated by the high-efficiency energy-saving industry. The multistage pump is driven by an electric motor or diesel engine, which rotates the impeller at high speed. Liquid enters the inlet end, where it is pressurized stage by stage under the action of the positive impeller. It then flows through double-sided transition pipes to the secondary inlet end, where it is further pressurized under the action of the negative impeller, and finally discharged downstream. To monitor the axial force state of the self-balancing multistage pump, this application installs a vibration sensor on the pump shaft to acquire radial and axial vibration data of the self-balancing multistage pump during current operation. In this embodiment, the acquisition frequency is set to 500 Hz. Flow sensors are installed at the positive and negative impeller outlets to acquire flow data at the positive and negative impeller outlets during current operation. Head data of the self-balancing multistage pump during current operation is also acquired based on the multistage pump control system. The data acquisition time interval for both flow data and head data is 0.1 seconds.

[0030] Step 2: Divide the entire data acquisition time during the current operation into multiple time periods; obtain the dominant frequency difference coefficient of each time period based on the frequency difference between radial and axial vibration data in each time period, and obtain the negative impact coefficient of each time period by combining the number of abrupt change points in the spectrum diagram of axial vibration data in each time period, the dispersion of the frequencies corresponding to all abrupt change points, and the dispersion of axial vibration data in each time period and its neighboring time periods.

[0031] The axial force stabilization device of a self-balancing multistage pump is mainly based on the symmetrical arrangement of impellers. Specifically, the multistage pump consists of a pump body, a bearing rotor, a balancing device, and a power unit. The pump body is the outer shell of the self-balancing multistage pump, and its main function is to contain the liquid and provide the necessary structural support for the pump's operation. The bearing rotor is the core part of the pump, containing multiple impellers. The impellers, through high-speed rotation, transfer mechanical energy to the liquid, giving the liquid kinetic and potential energy. The impellers, including both positive and negative impellers, are arranged symmetrically facing each other, ensuring that the axial forces generated by the positive and negative impellers are opposite in direction and similar in magnitude, thus canceling each other out and achieving automatic axial force balance. The balancing device further bears the residual axial force to ensure the smooth operation of the rotor. In the power unit, the pump rotor and motor are connected via a coupling, providing the power source for the pump's operation.

[0032] However, in practical applications of high-efficiency and energy-saving industries, excessive clearance between the impeller and shaft may affect the alignment of the guide vanes, leading to uneven axial force distribution. Furthermore, the liquid velocity and pressure distribution within the impeller may change due to operating conditions, further increasing the instability of the axial force. This application analyzes and evaluates the axial force of a multistage pump based on these characteristics.

[0033] First, with the increasing complexity of operating conditions, the vibration problem of multistage pumps is becoming more and more apparent. This includes not only radial vibration caused by impeller rotation, but also axial force generated by the interaction between each impeller stage and the liquid. Furthermore, radial and axial vibrations interact and influence each other. Specifically, due to the rigidity of the shaft and the characteristics of the support system, the energy of axial vibration may be transferred to the radial direction, further aggravating the amplitude of radial vibration. Conversely, radial vibration can easily cause asymmetry in impeller arrangement, resulting in dynamic changes in axial force and affecting axial vibration. Therefore, there is a certain coupling effect between the two. The closer the frequencies of radial and axial vibrations are, and the more complex the frequency and amplitude variations of axial vibration, the greater the negative impact of the coupled radial and axial vibrations on the axial force stability of the self-balancing multistage pump. In view of this, the vibration characteristics of the shaft are analyzed as follows.

[0034] This application divides the entire data acquisition time during the current operation into preset durations as a time period. In this embodiment, the preset duration is set to 2 seconds, where s is the unit of time (seconds). Taking the radial and axial vibration data of the i-th time period as an example, the spectrum diagrams of the radial and axial vibration data within the i-th time period are obtained using Fast Discrete Fourier Transform (FFT). Typically, the radial vibration response of the shaft is mainly concentrated around a certain frequency, while the vibration response at other frequencies is relatively small. The axial vibration response, in addition to the main frequency, also exhibits a certain frequency distribution at other frequency locations. Therefore, the absolute difference between the frequencies corresponding to the largest amplitude values ​​in the spectrum diagrams of the radial and axial vibration data of the i-th time period is taken as the dominant frequency difference coefficient of the i-th time period, denoted as [missing value]. This is used to characterize the frequency difference between radial and axial vibrations. The resulting... The smaller the value, the closer the main frequencies of vibration in different directions of the shaft are during that period.

[0035] Furthermore, for the spectrum of axial vibration data, since most frequencies correspond to low amplitudes, while a small number of frequencies have higher amplitudes, this application employs the SOS detection algorithm to obtain the locations of abrupt change points in the spectrum of axial vibration data. The more unbalanced the axial force of the multi-stage pump, the more complex the frequency variation of the axial vibration. Therefore, the product of the number of abrupt change points in the spectrum of the axial vibration data for the i-th time period and the standard deviation of the frequencies corresponding to all abrupt change point locations is denoted as the axial frequency complexity for the i-th time period, and is written as [formula missing]. The result The larger the value, the more complex the axial vibration frequency in the i-th time period.

[0036] Furthermore, instability of axial force can cause large displacement of the shaft in the axial direction, significantly increasing the fluctuation of axial vibration. Taking the N preceding time periods of the i-th time period as the nearest neighbor time periods of the i-th time period, and setting the value of N to the range [8,10], in this embodiment N is taken as 8, then the mean of the standard deviations of the axial vibration data of the i-th time period and its N preceding time periods is calculated, denoted as . The result The larger the value, the more complex the amplitude fluctuation of the axial vibration.

[0037] As a preferred embodiment, the negative impact coefficient for each time period is obtained based on the dominant frequency difference coefficient for each time period, the number of abrupt change points in the spectrum of axial vibration data for each time period, the dispersion of frequencies corresponding to all abrupt change points, and the dispersion of axial vibration data for each time period and its neighboring time periods. This coefficient is used to characterize the negative impact of radial and axial coupled vibration on the axial force stability of the self-balancing multistage pump within each time period.

[0038] In this embodiment, the negative impact coefficient of the i-th time period is denoted as... Its expression is: In the formula, Let be the negative impact coefficient for the i-th time period; The dominant frequency difference coefficient for the i-th time period; Let be the mean of the standard deviations of the axial vibration data for the i-th time period and all its nearest neighbor time periods; Let be the axial frequency complexity for the i-th time period; This is a preset constant used to prevent the denominator from being zero. Its value range is [0.001, 0.1], and in this embodiment, it is 0.01.

[0039] income This reflects the extent to which coupled vibration negatively impacts the axial force stability of a self-balancing multistage pump. The larger the value, the greater the negative impact of the radial and axial coupled vibration on the axial force stability of the self-balancing multistage pump during the i-th time period.

[0040] Step 3: Based on the degree of difference between the flow data at the positive and negative impeller outlets in each time period, and the degree of random fluctuation of the flow data at the positive and negative impeller outlets, obtain the flow anomaly coefficient for each time period. Combine the correlation between the negative impact coefficient and the flow anomaly coefficient of each time period and its neighboring time periods, as well as the negative impact coefficient of each time period, to obtain the unstable characteristic value of each time period.

[0041] Furthermore, the instability of the axial force may be caused by changes in the operating state of the positive and negative impellers. In this case, the flow rates at the outlets of the positive and negative impellers will exhibit significant random fluctuations and inconsistent abnormalities, and the degree of this abnormality will increase with the increase of the coupled vibration influence. This is because after the impeller undergoes displacement or vibration in the axial direction, the gap between the impeller and the guide vanes changes, and this change in gap will alter the flow path and velocity distribution of the liquid, thus causing flow rate fluctuations.

[0042] Therefore, a quadratic polynomial fitting technique is used to fit the flow rate data at the outlet positions of the positive and negative impellers in the i-th time period. If the axial force is relatively stable, the velocity change is relatively smooth, and the random variation component of the velocity is small, then the goodness of fit between the obtained data and its fitting curve is better. The mean value of the coefficient of determination corresponding to the fitting curves of the flow rate data of the positive and negative impellers in the i-th time period is denoted as... The result The smaller the value, the more likely the flow rate data at the positive and negative impeller outlets in the i-th time period will exhibit significant random fluctuations. Under normal conditions, although there is a certain difference between the flow rates at the positive and negative impeller outlets, the flow rate fluctuations caused by changes in operating load are relatively similar. The liquid output from the positive impeller will be further pressurized at the negative impeller, resulting in a certain time-varying characteristic between the flow rates at the positive and negative impeller outlets. Therefore, the SBD (Shape-Based Distance) distance between the flow rate data at the positive and negative impeller outlets in the i-th time period is calculated and denoted as [missing value]. The result The larger the value, the more inconsistent the flow rate changes at the positive and negative impeller outlets.

[0043] As a preferred implementation, the flow anomaly coefficient for each time period is obtained based on the degree of difference between the flow data at the positive and negative impeller outlets in each time period, as well as the degree of random fluctuation of the flow data at the positive and negative impeller outlets. This coefficient is used to characterize the degree of anomaly of the flow data at the positive and negative impeller outlets in each time period.

[0044] In this embodiment, the traffic anomaly coefficient for the i-th time period is denoted as... Its expression is: In the formula, Let be the traffic anomaly coefficient for the i-th time period. Let be the mean of the coefficients of determination corresponding to the fitted curves of the flow rate data at the positive and negative impeller outlets during the i-th time period. denoted as the SBD distance between the flow data at the positive and negative impeller outlets during the i-th time period.

[0045] income The larger the value, the greater the degree of anomaly in the flow data of the positive and negative impeller outlets during the i-th time period.

[0046] The above analysis shows that under the unstable axial force state of a multi-stage pump, the degree of abnormality in flow rate changes increases with the increase of the coupled vibration influence, and the positive correlation between the two becomes more significant. Therefore, the negative impact coefficients and flow rate anomaly coefficients of the i-th time period and all its nearest neighbor time periods are arranged in ascending order of time to obtain the negative impact sequence and flow rate anomaly sequence of the i-th time period. The correlation coefficient between the two sequences is then denoted as... , The larger the value, the more significant the correlation between the degree of abnormality in flow rate changes and the characteristics of coupled vibration effects.

[0047] As a preferred embodiment, based on the flow anomaly coefficient and negative impact coefficient of each time period, as well as the correlation between the negative impact coefficient and flow anomaly coefficient of each time period and its neighboring time periods, the unstable characteristic value of each time period is obtained, which is used to characterize the degree of instability of the axial force of the self-balancing multistage pump in each time period.

[0048] In this embodiment, the unstable characteristic value of the i-th time period is denoted as Its expression is: In the formula, Let be the unstable characteristic value of the i-th time period. Let be the correlation coefficient between the negative impact sequence and the abnormal traffic sequence in the i-th time period, and exp() be an exponential function with the natural constant e as the base. Let be the negative impact coefficient for the i-th time period. Let be the traffic anomaly coefficient for the i-th time period. The obtained... The larger the value, the more significant the abnormal state of coupled vibration and flow changes during that period, as well as the more pronounced the positive correlation between them, making it difficult to meet the industry's requirements for high efficiency and energy saving.

[0049] Step 4: Based on the differences between the variation ranges of all unstable characteristic values ​​and all head data during the current operation, obtain the evaluation coefficient for the current operation, and then determine whether it is necessary to reduce the regulation rate of the relief switch valve in the next operation.

[0050] Furthermore, the operating conditions of multistage pumps are complex and variable during use, requiring adjustments to the head according to actual needs. A higher head results in a greater operating load on the multistage pump, and under poor operating conditions, axial force instability is more likely to occur. During each run of the multistage pump, the greater the change in head data that causes a significant shift in the unstable characteristic value, the more pronounced the axial force instability.

[0051] Therefore, the ratio of the range of unstable characteristic values ​​to the range of all head data for all time periods during the current operation of the multistage pump is calculated and used as the evaluation coefficient for the current operation. A larger evaluation coefficient indicates that the axial force of the self-balancing multistage pump is more likely to become unstable with increasing operating load during the current operation. The process for obtaining the evaluation coefficient for the current operation is as follows: Figure 2 As shown.

[0052] Furthermore, since the axial force stability of a self-balancing multistage pump is closely related to the discharge control, specifically, the faster the adjustment rate of the discharge switch valve during discharge control, the greater the change in the force between the liquid and the impeller, which easily exacerbates the axial instability of the self-balancing multistage pump. Therefore, if the evaluation coefficient during the current operation is higher, the adjustment rate of the discharge switch valve needs to be reduced more during discharge control.

[0053] This application sets a preset instability threshold as follows: (In this embodiment) Using a value of 0.7, the evaluation coefficients during the current operation are normalized using the tanh function. If the normalization result is greater than or equal to the preset instability threshold, it indicates that the axial force stability of the self-balancing multistage pump is poor. In this case, the adjustment rate of the relief valve needs to be reduced to x% of the original adjustment rate in the next operation to improve the stability of the axial force of the self-balancing multistage pump. In this embodiment, x is set to 80. Otherwise, it is determined that there is no need to reduce the adjustment rate of the relief valve in the next operation, and relief control is performed according to the original rate of change in the multistage pump control system to ensure equipment operating efficiency. This helps to compensate for the instability of the axial force of the self-balancing multistage pump and can better meet the needs of the high-efficiency and energy-saving industry.

[0054] Based on the same inventive concept as the above methods, this application also provides an axial force stabilizing device for a self-balancing multistage pump based on leakage control, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-described methods for stabilizing the axial force of a self-balancing multistage pump based on leakage control.

[0055] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments of this specification have been described above. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0056] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0057] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A method for stabilizing the axial force of a self-balancing multistage pump based on discharge control, characterized in that, The method includes the following steps: Acquire radial vibration data, axial vibration data, head data, and flow rate data at the positive and negative impeller outlets of the self-balancing multistage pump during its current operation. The entire data acquisition time during the current operation is divided into multiple time periods. The main frequency difference coefficient of each time period is obtained based on the frequency difference between radial and axial vibration data in each time period. The negative impact coefficient of each time period is obtained by combining the number of abrupt change points in the spectrum of axial vibration data in each time period, the dispersion of the frequencies corresponding to all abrupt change points, and the dispersion of axial vibration data in each time period and its neighboring time periods. Based on the degree of difference between the flow data at the positive and negative impeller outlets in each time period, and the degree of random fluctuation of the flow data at the positive and negative impeller outlets, the flow anomaly coefficient for each time period is obtained. Combined with the correlation between the negative impact coefficient and the flow anomaly coefficient of each time period and its neighboring time periods, as well as the negative impact coefficient of each time period, the unstable characteristic value of each time period is obtained. Based on the differences between the variation ranges of all unstable characteristic values ​​and all head data during the current operation, the evaluation coefficients for the current operation are obtained, and then it is determined whether the adjustment rate of the relief switch valve needs to be reduced in the next operation.

2. The axial force stabilization method for a self-balancing multi-stage pump based on leakage control as described in claim 1, characterized in that, The dominant frequency difference coefficient for each time period refers to the absolute difference between the frequencies corresponding to the largest amplitude values ​​in the spectrum diagrams of radial and axial vibration data for each time period.

3. The axial force stabilization method for a self-balancing multistage pump based on leakage control as described in claim 1, characterized in that, The formula for calculating the negative impact coefficient for each time period is as follows: In the formula, Let be the negative impact coefficient for the i-th time period; The dominant frequency difference coefficient for the i-th time period; Let be the mean of the standard deviations of the axial vibration data for the i-th time period and all its nearest neighbor time periods; Let be the axial frequency complexity for the i-th time period; This is a preset constant.

4. The axial force stabilization method for a self-balancing multistage pump based on leakage control as described in claim 3, characterized in that, The axial frequency complexity for each time period refers to the product of the number of abrupt changes in the spectrum of axial vibration data for each time period and the standard deviation of the frequencies corresponding to all abrupt change locations.

5. The method for stabilizing the axial force of a self-balancing multistage pump based on leakage control as described in claim 1, characterized in that, The formula for calculating the flow anomaly coefficient for each time period is as follows: In the formula, Let be the traffic anomaly coefficient for the i-th time period. Let be the mean of the coefficients of determination corresponding to the fitted curves of the flow rate data at the positive and negative impeller outlets during the i-th time period. denoted as the SBD distance between the flow data at the positive and negative impeller outlets during the i-th time period.

6. The method for stabilizing the axial force of a self-balancing multistage pump based on leakage control as described in claim 1, characterized in that, The formulas for calculating the unstable characteristic values ​​for each time period are as follows: In the formula, Let be the unstable characteristic value of the i-th time period. Let be the correlation coefficient between the negative impact sequence and the abnormal traffic sequence in the i-th time period, and exp() be an exponential function with the natural constant e as the base. Let be the negative impact coefficient for the i-th time period. Let be the traffic anomaly coefficient for the i-th time period.

7. The axial force stabilization method for a self-balancing multistage pump based on leakage control as described in claim 6, characterized in that, The negative impact sequence and flow anomaly sequence for each time period refer to the sequence composed of the negative impact coefficients and flow anomaly coefficients of each time period and all its neighboring time periods arranged in ascending order of time.

8. The method for stabilizing the axial force of a self-balancing multistage pump based on leakage control as described in claim 1, characterized in that, The evaluation coefficient in the current operation process refers to the ratio of the range of unstable characteristic values ​​for all time periods in the current operation process to the range of all head data.

9. The method for stabilizing the axial force of a self-balancing multistage pump based on leakage control as described in claim 1, characterized in that, The specific process for determining whether the adjustment rate of the relief switch valve needs to be reduced in the next operation is as follows: if the normalized result of the evaluation coefficient in the current operation is greater than or equal to the preset instability threshold, then it is determined that the adjustment rate of the relief switch valve needs to be reduced in the next operation. Conversely, it is determined that there is no need to reduce the adjustment rate of the relief switch valve during the next operation.

10. An axial force stabilizing device for a self-balancing multi-stage pump based on leakage control, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the self-balancing multistage pump axial force stabilization method based on leakage control as described in any one of claims 1-9.

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