Power stability augmentation method for rotor system of centrifugal compressor

Abstract

The invention discloses a dynamic stability augmentation method for a rotor system of a centrifugal compressor, the rotor system comprises a rotor part, a bearing part and a sealing part, and the dynamic stability augmentation method comprises the following steps: establishing a finite element analysis model of a rotor-bearing system based on a design scheme of the rotor part and the bearing part; optimizing a rotor part and a bearing part based on a finite element analysis model; establishing a finite element analysis model of the rotor-bearing-sealing system based on the rotor part, the bearing part and the sealing part; optimizing a sealing element based on the rotor-bearing-sealing system model; and obtaining the rotor system after power stability augmentation. By optimizing each part in the rotor system, namely the rotor part, the bearing part and the sealing part, on one hand, the dynamic stability of the rotor system can be effectively improved, and on the other hand, the vibration problems such as collision and abrasion of the rotor and the stator can be avoided.

Description

Technical Field

[0001] This invention relates to the field of rotor system technology, and in particular to a method for power stabilization of a centrifugal compressor rotor system. Background Technology

[0002] Centrifugal compressors used in gas storage facilities need to have characteristics such as high pressure rating, high medium density, large displacement, high speed, and wide speed range. This increases the difficulty of designing and analyzing centrifugal compressors, resulting in poorer rotor dynamic characteristics, and especially in terms of stability, failing to meet the requirements of relevant standards.

[0003] In related technologies, for centrifugal compressors used in gas storage facilities with lower pressure, the conventional rotor design ensures that the stability of the rotor-bearing-sealing system (hereinafter referred to as the rotor system) meets the requirements of API 617 standards. The stability of the rotor system is closely related to the unit pressure. With the increasing demand for unit pressure over time, the current market requirement for the highest unit pressure is 40 MPa. Under current technical solutions, the stability of the rotor system no longer meets the requirements of API 617 standards. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] In view of this, the present invention provides a method for dynamic stabilization of a centrifugal compressor rotor system, wherein by optimizing each component of the rotor system, namely the rotor component, bearing component and seal component, the dynamic stability of the rotor system can be effectively improved on the one hand, and vibration problems such as rotor-stator rubbing can be avoided on the other hand.

[0006] Specifically, the following technical solutions are included: This invention provides a method for dynamic stabilization of a centrifugal compressor rotor system, the rotor system comprising rotor components, bearing components, and seals, the method comprising: Based on the design schemes of the rotor and bearing components, a finite element analysis model of the rotor-bearing system is established. Based on the finite element analysis model, optimize the rotor component and the bearing component; Based on the rotor component, the bearing component, and the seal component, a finite element analysis model of the rotor-bearing-seal system is established. Based on the rotor-bearing-seal system model, optimize the seal; The rotor system after obtaining dynamic stabilization.

[0007] Optionally, optimizing the rotor component and the bearing component includes: Based on the finite element analysis model, the rigidity index of the rotor component is optimized; Based on the finite element analysis model, damping natural frequency analysis is carried out to obtain the first-order positive precession logarithmic decay rate of the rotor-bearing system. Based on the first-order positive precession logarithmic decay rate, determine whether to replace the bearing.

[0008] Optionally, optimizing the rigidity of the rotor component includes: Undamped natural frequency analysis was performed on the rotor-bearing system to obtain the natural frequency of the rotor under rigid support. The CSR value of the rotor component is obtained based on the natural frequency under the rigid support and the maximum continuous rotational speed of the rotor component. Determine whether the CSR value is not greater than the first threshold. If yes, proceed to the next step; otherwise, re-obtain the design scheme of the rotor component. Obtain the first-order positive precession logarithmic decay rate.

[0009] Optionally, the CSR value = the maximum continuous rotational speed of the rotor / the first natural frequency under the rigid support.

[0010] Optionally, the first threshold is 2.5.

[0011] Optionally, optimizing the bearing component includes: Damped natural frequency analysis was performed on the rotor-bearing system to obtain the damped natural frequency values ​​and logarithmic decay rate of the rotor-bearing system at different orders; Based on the damping natural frequency values ​​of different orders and the logarithmic decay rate, the first first-order positive precession logarithmic decay rate is obtained; Determine whether the first-order positive precession logarithmic decay rate is not less than the second threshold. If yes, proceed to the next step; otherwise, re-obtain the design scheme of the bearing component. Establish the rotor-bearing-seal system model.

[0012] Optionally, the second threshold is 0.2.

[0013] Optionally, optimizing the seal includes: Based on the rotor component, the bearing component, and the seal component, a first rotor-bearing-seal system model is established. Based on the first rotor-bearing-seal system model, the second first-order positive precession logarithmic decay rate is obtained; Determine whether the second first-order positive precession logarithmic decay rate is not less than the third threshold. If yes, directly obtain the rotor system; otherwise, proceed to the next step. Replace the seals and rebuild the second rotor-bearing-seal system model.

[0014] Optionally, optimizing the seal includes: Based on the second rotor-bearing-seal system model, the third first-order positive precession logarithmic decay rate is obtained; Determine whether the third first-order positive precession logarithmic decay rate is not less than the third threshold. If it is, directly obtain the rotor system; otherwise, re-establish the finite element analysis model of the rotor-bearing system.

[0015] Optionally, the third threshold is 0.1.

[0016] The present invention provides a method for dynamic stabilization of a centrifugal compressor rotor system. This method includes establishing an initial finite element analysis model of the rotor-bearing system based on the initial design schemes of the rotor and bearing components; optimizing the rotor and bearing components based on the finite element analysis model; then establishing a rotor-bearing-seal system based on the optimized rotor and bearing components and the initial seals; and finally optimizing the seals based on the rotor-bearing-seal system. In other words, the rotor, bearing, and seal components in the rotor system are all optimized to ensure that each component contributes to the stability of the rotor system, thereby enabling the rotor system to achieve good dynamic stability even under high-pressure operation. Simultaneously, it avoids causing other vibration problems by focusing on optimizing one component, thus improving the reliability of the rotor system.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a simplified flowchart illustrating a dynamic stabilization method according to an embodiment of the present invention. Figure 2 This is a flowchart illustrating the optimization of the rigidity index of a rotor component according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the process for optimizing a bearing component according to an embodiment of the present invention; Figure 4This is a schematic diagram illustrating the specific process of a dynamic stabilization method according to an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Before providing a further detailed description of the embodiments of the present invention, the directional terms used in the embodiments of the present invention, such as "upper part", "lower part" and "side part", are not intended to limit the scope of protection of the present invention.

[0022] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0023] Figure 1 This is a simplified flowchart illustrating a dynamic stabilization method according to an embodiment of the present invention.

[0024] like Figure 1 As shown, one embodiment of the present invention provides a method for dynamic stabilization of a centrifugal compressor rotor system. The rotor system includes rotor components, bearing components, and seals. The dynamic stabilization method includes: Step 1: Based on the design schemes of the rotor and bearing components, establish a finite element analysis model of the rotor-bearing system; Step 2: Optimize rotor components and bearing components based on the finite element analysis model; Step 3: Based on the rotor components, bearing components, and seal components, establish a finite element analysis model of the rotor-bearing-seal system; Step 4: Optimize the seals based on the rotor-bearing-seal system model; Step 5: Obtain the rotor system after power stabilization.

[0025] The dynamic stability enhancement method involves establishing an initial finite element analysis model of the rotor-bearing system based on the initial design schemes of the rotor and bearing components. Then, based on this model, the rotor and bearing components are optimized. Next, using the optimized rotor and bearing components, along with the initial seals, a rotor-bearing-seal finite element analysis model is established. Finally, the seals are optimized according to the rotor-bearing-seal system. In other words, the rotor, bearing, and seal components in the rotor system are all optimized to ensure that each contributes to the stability of the rotor system. This allows the rotor system to achieve good dynamic stability even when operating under high-voltage conditions. Furthermore, it avoids causing other vibration problems by focusing on optimizing a single component, thus improving the reliability of the rotor system.

[0026] Specifically, the stability of a rotor system fundamentally depends on two factors: the rigidity of the rotor components themselves and the damping characteristics of the seals within the rotor system. Therefore, by improving the stability of each component individually, a significant improvement in the overall stability of the rotor system can be achieved while maintaining stability in each component. This approach makes improving stability in each component easier and more feasible, reducing the difficulty of the improvement. Thus, by analyzing the stability of the rotor-bearing system using finite element analysis, if the stability does not meet requirements, both the rotor and bearing components need to be redesigned to improve the stability of the rotor-bearing system. If the stability meets requirements, the damping characteristics of the seals are analyzed to optimize their damping effect. If the damping effect is insufficient, the seal damping design is reworked. Finally, if the damping effect meets requirements, the resulting rotor system meets the stability requirements of a high-voltage generator set.

[0027] In one feasible implementation, optimizing the rotor components and bearing components includes: Based on the finite element analysis model, the rigidity index of the rotor component is optimized. Based on the finite element analysis model, damping natural frequency analysis is carried out to obtain the first-order positive precession logarithmic decay rate of the rotor-bearing system; Based on the first-order positive precession logarithmic decay rate, determine whether to replace the bearing.

[0028] In traditional designs, there are no requirements for the rigidity of the rotor components themselves. This application sets forth clear requirements for the rigidity of the rotor components themselves. When the rigidity meets the requirements, it can contribute to the overall stability of the rotor system. This reduces the difficulty for subsequent components to contribute to the overall stability of the rotor system.

[0029] It should be noted that traditional designs do not require damping of bearing components. After analysis, it was found that the original design had a low contribution of bearing components to the rotor system damping. Therefore, it is necessary to replace the bearings or optimize the data of the bearing components to improve their contribution to the stability of the rotor system, as detailed below.

[0030] It is understandable that by conducting damped natural frequency analysis on the finite element analysis model of the rotor, the first-order positive precession frequency and its corresponding logarithmic decay rate can be obtained.

[0031] Figure 2 This is a flowchart illustrating the optimization of the rigidity index of a rotor component according to an embodiment of the present invention.

[0032] In one feasible implementation, such as Figure 2 As shown, the optimized rigidity parameters of the rotor components include: Step 201: Perform undamped natural frequency analysis on the rotor-bearing system to obtain the natural frequency of the rotor components under rigid support. Step 202: Based on the natural frequency under rigid support and the maximum continuous speed of the rotor component, obtain the CSR value of the rotor component; Step 203: Determine whether the CSR value is not greater than the first threshold. If yes, proceed to the next step; otherwise, re-obtain the rotor component design scheme and return to step 1. Step 204: Obtain the first-order positive precession logarithmic decay rate.

[0033] This application specifies the rigidity index of the rotor components, with a CSR value not exceeding a first threshold. Specifically, a finite element model is established for the rotor-bearing system (without seals), and undamped natural frequency analysis is performed to obtain the natural frequencies of the rotor components under rigid support. The CSR value of the rotor is further obtained based on the maximum continuous rotational speed of the rotor components (known data). Analysis of multiple units and field application results show that a higher CSR value indicates poorer rotor rigidity. When the CSR value exceeds the first threshold, even with subsequent applications of damping seals, it is difficult to achieve an ideal stability index for the rotor system. Therefore, a clear requirement for rotor component rigidity is established at the initial design stage of the rotor system. This reduces the difficulty of improving the stability of subsequent components, distributing the challenge of improving rotor stability to each component, thus increasing the feasibility of improving rotor system stability while reducing the overall difficulty.

[0034] Specifically, if the CSR value of the obtained rotor component is not greater than the first threshold, the bearing analysis and evaluation can proceed. If the CSR value of the rotor component is greater than the first threshold, the rotor component needs to be redesigned. The redesigned rotor can improve the rigidity of the rotor component and meet the rotor CSR value requirements by shortening the span (i.e., shortening the distance between the two bearings of the rotor), increasing the diameter of the shaft, or reducing the mass of additional components such as impellers, bushings, and balance discs.

[0035] It should be noted that finite element analysis is an analytical method, which can be divided into two types based on the content of the analysis: undamped natural frequency analysis and damped natural frequency analysis. The dynamic characteristics of bearings and seals both include stiffness and damping terms. If the damping term is not considered in the analysis, it is called undamped natural frequency analysis; if it includes the damping term, it is called damped natural frequency analysis. Undamped natural frequency analysis also has its advantages. Because the analysis does not consider damping, the analysis time is shorter, allowing for quick determination of some preliminary indicators in the preliminary design stage. The natural frequency of the rotor under rigid support can be obtained by assuming the bearing stiffness is infinite. The natural frequency of the rotor under rigid support refers to the maximum natural frequency that the rotor itself can reach, i.e., the upper limit of the natural frequency (of all orders). The significance of this value is that if the upper limit of the rotor's natural frequency cannot meet a certain indicator, then the preliminary design of the rotor is unsuccessful. The maximum continuous speed of the rotor refers to the maximum speed at which the compressor rotor can operate for a long time; this is a known value.

[0036] In one feasible implementation, the CSR value is calculated as the maximum continuous rotational speed of the rotor divided by the first natural frequency under rigid support.

[0037] Rotors with an operating speed greater than their first natural frequency are typically called flexible rotors. Rotors with an operating speed less than their first natural frequency are called rigid rotors. Two data points related to the CSR value are: maximum continuous speed (the maximum operating speed) and the first natural frequency of rigid support (the maximum first natural frequency). Therefore, the value calculated using these two data points, i.e., the CSR value, is a more reasonable choice for assessing rigidity.

[0038] In one feasible implementation, the first threshold is 2.5.

[0039] It should be noted that the first threshold is 2.5, a value derived from the API 617 standard. In the API standard, a CSR value less than 2.5 is an important indicator for determining whether a rotor's first-level stability is acceptable. Generally, a CSR value higher than 2.5 indicates high rotor flexibility, while a CSR value lower than 2.5 indicates high rotor rigidity. Highly flexible rotors are prone to instability, while highly rigid rotors are less prone to instability. Based on the API standard and engineering experience, 2.5 can be used as a preliminary indicator for judging rotor rigidity.

[0040] Figure 3 This is a schematic diagram of the process for optimizing a bearing component according to an embodiment of the present invention; In one feasible implementation, such as Figure 3 As shown, the optimized bearing components include: Step 205: Perform damped natural frequency analysis on the rotor-bearing system to obtain the damped natural frequency values ​​and logarithmic decay rate of different orders of the rotor-bearing system; Step 206: Based on the damping natural frequency values ​​and logarithmic decay rates of different orders, obtain the first first-order positive precession logarithmic decay rate; Step 207: Determine whether the first-order positive precession logarithmic decay rate is not less than the second threshold. If yes, proceed to the next step; otherwise, re-obtain the design scheme of the bearing component and return to step 1. Step 3: Establish a rotor-bearing-seal system model.

[0041] Specifically, damped natural frequency analysis considers the stiffness and damping characteristics of the rotor structure, bearings, and seals, and then conducts an analysis encompassing the entire system. The analysis yields the natural frequencies (for each order) and logarithmic decay rates. The logarithmic decay rate and damping coefficient are indicators of the strength of the rotor system's damping. Damped natural frequency analysis is performed on the rotor-bearing system to obtain the damped natural frequency values ​​and corresponding logarithmic decay rates for different orders. The first-order positive precession logarithmic decay rate is evaluated. If the first-order positive precession logarithmic decay rate of the rotor-bearing system is less than a second threshold, it indicates that the bearing component's contribution to the rotor system's damping is low, requiring bearing replacement or optimization of bearing data to improve the bearing component's contribution to the rotor system's stability.

[0042] It should be noted that, generally speaking, the analysis of damped natural frequencies can simultaneously yield damped natural frequency values ​​of multiple orders and their corresponding logarithmic decay rates. Here, only the first-order damped natural frequency value and its corresponding logarithmic decay rate are extracted. The API standard specifies that rotor stability is evaluated based on the logarithmic decay rate at the first-order damped natural frequency, so the order and corresponding logarithmic decay rate must be selected. The logarithmic decay rate obtained after damped natural frequency analysis of the rotor-bearing system is higher than that obtained after damped natural frequency analysis of the rotor-bearing-seal system. This is because the addition of the seal system increases the airflow excitation force, leading to a decrease in the logarithmic decay rate. The API standard requires the logarithmic decay rate of the rotor-bearing-seal system to be greater than 0.1. However, during the rotor-shaft system design phase, before the seal system is introduced, empirical engineering data is needed to determine the requirements for the rotor-bearing system. Taking a threshold of 0.2 for the logarithmic decay rate, and considering the seal system, the estimated value is above 0.1. Stability is determined by logarithmic decay rate or damping, which is a direct parameter related to system damping. The greater the damping, i.e. the greater the logarithmic decay rate, the stronger the system stability.

[0043] Understandably, the primary purpose of redesigning the bearing components, i.e., replacing the bearing, is to improve its damping. Based on theoretical analysis or relevant engineering experience, measures such as reducing the bearing pad width and increasing the bearing clearance can improve bearing damping, which is beneficial to stability. However, this will reduce the bearing stiffness, affecting other parameters such as the rotor's critical speed. Therefore, it is necessary to re-analyze whether the bearing meets the requirements in relation to other parameters. Commonly used bearing optimization techniques to improve damping parameters include reducing the bearing pad width and increasing the bearing mounting clearance, both of which can improve the bearing's damping.

[0044] In one feasible implementation, the second threshold is 0.2.

[0045] It should be noted that the second threshold is a value determined based on engineering experience from the analysis of multiple high-voltage units and on-site operation. It is used to constrain the contribution of the rotor-bearing system to stability. If the first-order positive precession logarithmic decay rate is less than this value, the stability may not meet requirements after further considering the sealing system. Based on the analysis of multiple high-voltage units and on-site operation experience, the second threshold is set at 0.2. If the first-order positive precession logarithmic decay rate is higher than this value, the stability analysis of the rotor-bearing-sealing system is more likely to meet requirements after considering the sealing system. If the first-order positive precession logarithmic decay rate is lower than this value, it indicates that the rotor-bearing system's contribution to unit stability is insufficient. Significantly increasing the logarithmic decay rate by improving the sealing system is difficult, which would lead to unit design failure. Therefore, in this case, the bearing components need to be redesigned.

[0046] In one feasible implementation, optimizing the seal includes: Step 401: Based on the rotor components, bearing components, and seal components, establish a first rotor-bearing-seal system model; Step 402: Based on the first rotor-bearing-seal system model, obtain the second first-order positive precession logarithmic decay rate; Step 403: Determine whether the second first-order positive precession logarithmic decay rate is not less than the third threshold. If yes, directly obtain the rotor system; otherwise, proceed to the next step. Step 404: Replace the seals and rebuild the second rotor-bearing-seal system model.

[0047] Specifically, the seal includes the seal body and the anti-swirl device. The seal is typically located at the impeller mouth ring and balance disc of the rotor system, and uses stator tooth seals. Because stator tooth seals are easier to manufacture and have lower costs compared to damping seals, thus improving the economics of the rotor system, they are chosen as the modeling basis for the first rotor-bearing-seal configuration.

[0048] It should be noted that, due to the relatively high pressure of the gas storage unit, anti-swirling devices can be installed at both the impeller inlet seal and the balance disc seal to improve the stability of the rotor system. Specifically, based on the above, a first rotor-bearing-seal system model is established, and damping natural frequency analysis is performed. By obtaining the damping natural frequency values ​​and corresponding logarithmic decay rates of different orders of the rotor-bearing-seal system, the second first-order positive precession logarithmic decay rate is obtained for evaluation. If the second first-order positive precession logarithmic decay rate of the rotor-bearing-seal system is less than a third threshold, it indicates that the seal contributes little to the damping of the rotor system. In this case, the balance disc is replaced with a damping seal and an anti-swirling device. The third first-order positive precession logarithmic decay rate is then recalculated.

[0049] In one feasible implementation, optimizing the seal includes: Step 405: Based on the second rotor-bearing-seal system model, obtain the third first-order positive precession logarithmic decay rate; Step 406: Determine whether the third first-order positive precession logarithmic decay rate is not less than the third threshold. If yes, directly obtain the rotor system; otherwise, re-establish the finite element analysis model of the rotor-bearing system.

[0050] Specifically, replace the balance disk with a damping seal and a counter-rotating flow device. The stator tooth seal and the counter-rotating flow device are still formed at the impeller mouth ring. Establish a second rotor-bearing-seal system model and conduct a damping natural frequency analysis. By obtaining the damping natural frequency values and the corresponding logarithmic decrements of different orders of the rotor-bearing, obtain the logarithmic decrement of the third first-order forward precession for evaluation. If the logarithmic decrement of the third first-order forward precession of the rotor-bearing-seal system is less than the third threshold again, the rotor system needs to be redesigned and re-analyzed. Otherwise, the specific model of the rotor system can be determined for production.

[0051] It should be noted that there is a step before the rotor system is redesigned, namely steps 404 and 405. The seals need to be optimized and improved, such as adding a counter-rotating flow device or changing to a damping seal. If the requirements are still not met, it means that the stability of the rotor system does not meet the requirements when the seal system is optimal. Redesign can apply damping bearings, electromagnetic bearings, and the impeller can use titanium alloy materials with lower density, etc., but this will increase the manufacturing cost.

[0052] In a feasible implementation, the third threshold is 0.1.

[0053] It should be noted that if the logarithmic decrement of the second first-order forward precession is greater than this value, the stability of the rotor passes; if the logarithmic decrement of the second first-order forward precession is less than this value, it fails. This value is from the API617 standard and is the value specified in the standard for determining whether the rotor stability is qualified.

[0054] In summary, the dynamic stability enhancement method for the centrifugal compressor rotor system of the present application respectively puts forward stability requirements for the rotor parts, bearing parts, and seal parts, and gives the unit characteristics of the high-pressure gas storage reservoir. In the stability analysis, reasonable contribution requirements are put forward for each component in the rotor-bearing-seal system, rather than an average contribution index, further improving the feasibility and reliability of stability enhancement. By analyzing each component one by one, the components that do not meet the requirements can be quickly located, facilitating the improvement of each component of the rotor system during the analysis process and shortening the design cycle. The rotor system designed by the dynamic stability enhancement method of the present application enables the stability index of the gas storage reservoir unit to meet the requirements of the API617 standard, and the stability index is greatly improved, which is more conducive to the long-term safe and stable operation of the unit.

[0055] Figure 4 It is a specific flow schematic diagram of the dynamic stability enhancement method according to an embodiment of the present invention.

[0056] Specifically, as Figure 4As shown, the dynamic stabilization method includes: Step 1, establishing a finite element analysis model of the rotor-bearing system based on the design schemes of the rotor and bearing components; Step 201, performing undamped natural frequency analysis on the rotor-bearing system to obtain the natural frequency of the rotor under rigid support; Step 202, obtaining the CSR value of the rotor based on the natural frequency under rigid support and the maximum continuous rotational speed (known value) of the rotor; Step 203, determining whether the CSR value is not greater than the first threshold; if yes, proceed to Step 205; otherwise, re-obtain the rotor design scheme and return to Step 1; Step 205, performing damped natural frequency analysis on the rotor-bearing system to obtain the damped natural frequency values ​​and logarithmic decay rates of different orders of the rotor-bearing system; Step 206, obtaining the first-order positive precession logarithmic decay rate based on the damped natural frequency values ​​and logarithmic decay rates of different orders; Step 207, determining the first-order positive precession logarithmic decay rate. If the logarithmic decay rate is not less than the second threshold, proceed to step 401; otherwise, re-obtain the bearing component design scheme and return to step 1. Step 401: Based on the rotor component, bearing component, and seal, establish a first rotor-bearing-seal system model. Step 402: Based on the first rotor-bearing-seal system model, obtain the second first-order positive precession logarithmic decay rate. Step 403: Determine if the second first-order positive precession logarithmic decay rate is not less than the third threshold; if yes, proceed directly to step 5; otherwise, proceed to step 404. Step 404: Replace the seal and re-establish the second rotor-bearing-seal system model. Step 405: Based on the second rotor-bearing-seal system model, obtain the third first-order positive precession logarithmic decay rate. Step 406: Determine if the third first-order positive precession logarithmic decay rate is not less than the third threshold; if yes, proceed directly to step 5; otherwise, return to step 1. Step 5: The rotor system design is complete.

[0057] Comparative Example Table 1 compares the rotor stability indices of centrifugal compressors used in gas storage facilities at different pressure levels under two different schemes. Table 1. Comparison of rotor stability indices for centrifugal compressors of different pressure levels used in gas storage facilities under two different schemes.

[0058] The API 617 standard determines stability based on the magnitude of the first-order positive precession logarithmic decay rate of the rotor system. A logarithmic decay rate greater than 0.1 indicates that the rotor system meets the stability requirements, while a rate less than 0.1 indicates that it does not. In other words, a larger first-order positive precession logarithmic decay rate indicates better stability. As shown in Table 1, when the unit's maximum pressure is 15 MPa, the stability analysis results of both schemes meet the API 617 standard requirements, but the results of the new technology scheme are superior. When the unit's maximum pressure is 40 MPa, the analysis results of the relevant technical schemes do not meet the API 617 standard requirements, while the analysis results of the new technology scheme meet the standard requirements. In conclusion, the stability indicators of the new technology scheme are better than the requirements of the API 617 standard, which is more conducive to the long-term safe and stable operation of the unit.

[0059] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "a plurality" refers to two or more unless otherwise expressly defined.

[0060] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for dynamic stabilization of a centrifugal compressor rotor system, the rotor system comprising rotor components, bearing components, and seals, characterized in that, The dynamic stabilization method includes: Based on the design schemes of the rotor and bearing components, a finite element analysis model of the rotor-bearing system is established. Based on the finite element analysis model, optimize the rotor component and the bearing component; Based on the rotor component, the bearing component, and the seal component, a finite element analysis model of the rotor-bearing-seal system is established. Based on the rotor-bearing-seal system model, optimize the seal; The rotor system after obtaining dynamic stabilization.

2. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 1, characterized in that, Optimizing the rotor component and the bearing component includes: Based on the finite element analysis model, the rigidity index of the rotor component is optimized; Based on the finite element analysis model, damping natural frequency analysis is carried out to obtain the first-order positive precession logarithmic decay rate of the rotor-bearing system. Based on the first-order positive precession logarithmic decay rate, determine whether to replace the bearing.

3. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 2, characterized in that, Optimizing the rigidity of the rotor component includes: Undamped natural frequency analysis was performed on the rotor-bearing system to obtain the natural frequency of the rotor under rigid support. The CSR value of the rotor component is obtained based on the natural frequency under the rigid support and the maximum continuous rotational speed of the rotor component. Determine whether the CSR value is not greater than the first threshold. If yes, proceed to the next step; otherwise, re-obtain the design scheme of the rotor component. Obtain the first-order positive precession logarithmic decay rate.

4. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 3, characterized in that, The CSR value = the maximum continuous speed of the rotor / the first natural frequency under the rigid support.

5. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 3, characterized in that, The first threshold is 2.

5.

6. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 2, characterized in that, The optimization of the bearing component includes: Damped natural frequency analysis was performed on the rotor-bearing system to obtain the damped natural frequency values ​​and logarithmic decay rate of the rotor-bearing system at different orders; Based on the damping natural frequency values ​​of different orders and the logarithmic decay rate, the first first-order positive precession logarithmic decay rate is obtained; Determine whether the first-order positive precession logarithmic decay rate is not less than the second threshold. If yes, proceed to the next step; otherwise, re-obtain the design scheme of the bearing component. Establish the rotor-bearing-seal system model.

7. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 6, characterized in that, The second threshold is 0.

2.

8. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 1, characterized in that, Optimizing the seal includes: Based on the rotor component, the bearing component, and the seal component, a first rotor-bearing-seal system model is established. Based on the first rotor-bearing-seal system model, the second first-order positive precession logarithmic decay rate is obtained; Determine whether the second first-order positive precession logarithmic decay rate is not less than the third threshold. If yes, directly obtain the rotor system; otherwise, proceed to the next step. Replace the seals and rebuild the second rotor-bearing-seal system model.

9. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 8, characterized in that, Optimizing the seal includes: Based on the second rotor-bearing-seal system model, the third first-order positive precession logarithmic decay rate is obtained; Determine whether the third first-order positive precession logarithmic decay rate is not less than the third threshold, and try to directly obtain the rotor system; otherwise, re-establish the finite element analysis model of the rotor-bearing system.

10. The method for dynamic stabilization of a centrifugal compressor rotor system according to claim 9, characterized in that, The third threshold is 0.1.

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