A Monitoring Method and System for Centrifugal Impellers Based on Siamese Degradation Model

Abstract

The present invention relates to the technical field of operating state monitoring of large rotating machinery equipment, and specifically provides a monitoring method and system for a centrifugal impeller based on a twin reduced-order model. The centrifugal impeller is configured with full-circumference blades, and the monitoring method includes: collecting the tip vibration signals of the full-circumference blades to obtain the original vibration data; preprocessing the original vibration data to obtain the tip vibration data; processing the tip vibration data based on the non-keyphasor reference method to obtain the tip vibration displacement; performing non-linear least squares curve fitting on the tip vibration displacement to identify the dynamic parameters of each independent blade in the full-circumference blades; constructing a twin reduced-order model of the centrifugal impeller, and determining the update parameters of the twin reduced-order model based on the dynamic parameters; updating the twin reduced-order model based on the update parameters to obtain a digital model; and monitoring the centrifugal impeller based on the digital model. The present invention has a relatively small response calculation load, is relatively easy to extract detuning parameters, and has high real-time performance and accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of operation status monitoring, diagnosis, operation and maintenance of large rotating machinery equipment, and particularly to a monitoring method and system for centrifugal impellers based on a twin reduced-order model. Background Art

[0002] Centrifugal compressors have the advantages of high single-stage pressure ratio, wide operating range, and compact structure. They are the core power equipment in important fields such as petrochemical, natural gas, coal chemical, and aerospace, and play a very important role in the national economy and national defense construction.

[0003] In recent years, dozens of accidents have occurred at home and abroad where the centrifugal impellers of centrifugal compressors failed, resulting in excessive vibration and fracture of the blades, causing huge economic losses to enterprises and serious social impacts. According to public reports and fault statistical analysis at home and abroad, the vast majority of centrifugal impeller failures are caused by unsteady fluid excitation-induced impeller vibration and high-cycle fatigue damage. As the core working component of a centrifugal compressor, the centrifugal impeller often operates under conditions of high tip tangential velocity and high aerodynamic load. With the improvement of aerodynamic design parameters, the unsteady loads and pulsating airflows borne by the centrifugal impeller are continuously intensifying, resulting in frequent fatigue failures of the impeller.

[0004] The use of online monitoring methods can monitor the vibration response of the blades in real time. However, the vibration at the tip or a point on the blade surface is difficult to comprehensively reflect the overall response of the centrifugal impeller. Affected by processing errors and operating wear, the centrifugal impeller will inevitably have detuning. The destruction of the structural cyclic symmetry characteristics will have an adverse impact on the blade vibration, and for specific detuning forms and aerodynamic load conditions, the vibration response may change sharply, and the initial model is no longer applicable to the centrifugal impeller entity in long-term service. Existing twin models for centrifugal impeller health monitoring have problems such as large response calculation load, difficult extraction of detuning parameters, and lack of linkage mechanism in the digital model, making it difficult to meet the monitoring requirements such as operation and maintenance diagnosis and online fatigue assessment of centrifugal impellers. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the problems of large response calculation load, difficult extraction of detuning parameters, and lack of linkage mechanism in the twin models for monitoring centrifugal impellers in the prior art, and provide a monitoring method and system for centrifugal impellers based on a twin reduced-order model, which has a linkage mechanism, a relatively small response calculation load, is easy to extract detuning parameters, and has high real-time performance and accuracy.

[0006] In a first aspect, to solve the above technical problem, the present invention provides a monitoring method for a centrifugal impeller based on a twin reduced-order model. The centrifugal impeller is configured with full-circumference blades. The monitoring method includes the following steps:

[0007] Collect the tip vibration signals of the full - circumference blades to obtain the original vibration data;

[0008] Pre - process the original vibration data to obtain the tip vibration data;

[0009] Process the tip vibration data based on the key - phaseless reference method to obtain the tip vibration displacement;

[0010] Perform non - linear least - squares curve fitting on the tip vibration displacement to identify the dynamic parameters of each independent blade in the full - circumference blades;

[0011] Construct the twin reduced - order model of the centrifugal impeller, and determine the update parameters of the twin reduced - order model based on the dynamic parameters;

[0012] Update the twin reduced - order model based on the update parameters to obtain the digital model;

[0013] Monitor the centrifugal impeller based on the digital model;

[0014] Among them, the steps of constructing the twin reduced - order model of the centrifugal impeller include:

[0015] Divide the centrifugal impeller into a first sub - structure and a second sub - structure by using the mixed interface method:

[0016] The first sub - structure corresponds to the overall coordinated impeller, and the model of the first sub - structure is generated by using the coordinated modes in the harmonic nominal modal subset;

[0017] The second sub - structure corresponds to the mistuned blades, and the model of the second sub - structure introduces a mass mistuning model or a stiffness mistuning model;

[0018] Construct the twin reduced - order model of the centrifugal impeller based on the model of the first sub - structure and the model of the second sub - structure.

[0019] In an embodiment of the present invention, collecting the tip vibration signals of the full - circumference blades to obtain the original vibration data includes the following steps:

[0020] Perform modal analysis on the centrifugal impeller by using the block Lanczos method to obtain the impeller mode;

[0021] Install tip - timing sensors circumferentially on the end wall casing of the centrifugal impeller based on the impeller mode;

[0022] Collect the tip vibration signals of the full - circumference blades based on the tip - timing sensors to obtain the original vibration data.

[0023] In an embodiment of the present invention, pre - processing the original vibration data to obtain the tip vibration data includes the following steps:

[0024] First, obtain the initialized rotational frequency parameter based on the first m tip pulse count sequences in the original vibration data :

[0025] ;

[0026] wherein is the j-th tip pulse count sequence, is the (j - 1)-th tip pulse count sequence, is the counter fundamental frequency;

[0027] Then, calculate the theoretical pulse count interval :

[0028] ;

[0029] wherein is the number of tip timing sensors;

[0030] Next, obtain the tip vibration data based on the actual pulse count interval of the tip vibration, and the actual pulse count interval needs to satisfy:

[0031] .

[0032] In an embodiment of the present invention, processing the tip vibration data based on the keyless reference method to obtain the tip vibration displacement includes the following steps:

[0033] Convert the tip vibration data into a tip arrival timing sequence;

[0034] Determine the timing reference signal based on the tip arrival timing sequence;

[0035] Calculate the rotation period and rotational frequency corresponding to each rotation of the centrifugal impeller based on the timing reference signal;

[0036] Obtain the ideal arrival time based on the rotation period or the rotational frequency;

[0037] Obtain the tip vibration displacement based on the ideal arrival time.

[0038] In an embodiment of the present invention, the steps of constructing the twin reduced-order model of the centrifugal impeller include:

[0039] Determine the update parameters of the twin reduced-order model based on the dynamic parameters, and the update parameters include the damping ratio. The steps of determining the damping ratio include:

[0040] Construct the damping matrix of each independent blade of the centrifugal impeller using the Rayleigh damping model :

[0041] ;

[0042] Set the constant mass damping coefficient to zero, so that the damping matrix is independent of the mass matrix , and the damping matrix is only proportional to the harmonic stiffness matrix ; The constant stiffness damping coefficient is:

[0043] ;

[0044] Wherein, is the angular frequency corresponding to the resonance speed of the centrifugal impeller, is the damping ratio of each independent blade of the centrifugal impeller.

[0045] In an embodiment of the present invention, based on the dynamic parameters, the update parameters of the twin reduced-order model are determined, and the update parameters include the detuning deviation. The steps of determining the detuning deviation include:

[0046] ;

[0047] Wherein, is the natural frequency of the k-th blade, is the ideal harmonic blade frequency.

[0048] In an embodiment of the present invention, the steps of updating the twin reduced-order model based on the update parameters include:

[0049] Regard the update of the twin reduced-order model as a decision-making problem, and the correction criterion of the decision-making problem is:

[0050] ;

[0051] ;

[0052] Wherein, represents the overall deviation degree of the parameter group of the single dynamic parameter of each independent blade; represents the pulse index, and the pulse index is used to evaluate the maximum deviation degree of the single dynamic parameter; is the number of tip-timing sensors; is the first decision threshold; is the second decision threshold; Denote the update parameters of the twin reduced-order model; Denote the dynamics parameter identification result corresponding to the update parameters ; Σ represents summation; ‖ represents taking the absolute value.

[0053] In one embodiment of the present invention, the steps of monitoring the centrifugal impeller based on the digital model include:

[0054] Calculating a three-dimensional response field based on the digital model;

[0055] Introducing cyclic coordinates to the three-dimensional response field and performing a transformation from the cyclic coordinates to physical coordinates to obtain the motion equation;

[0056] Obtaining the modal participation factors of the independent blades based on the motion equation;

[0057] Characterizing the state indicators of the centrifugal impeller based on the modal participation factors, where the state indicators include three-dimensional full-field vibration displacement and strain; when the state indicators are within the set range, the monitoring result of the centrifugal impeller is normal; when the state indicators are not within the set range, the monitoring result of the centrifugal impeller is abnormal.

[0058] In a second aspect, to solve the above technical problems, the present invention also provides a centrifugal impeller monitoring system based on a twin reduced-order model. The centrifugal impeller is configured with full-circumference blades. The monitoring system includes:

[0059] An acquisition module that acquires the tip vibration signals of the full-circumference blades to obtain the original vibration data;

[0060] A first processing module that preprocesses the original vibration data to obtain the tip vibration data;

[0061] A second processing module that processes the tip vibration data based on the keyphaseless reference method to obtain the tip vibration displacement;

[0062] A parameter identification module that performs non-linear least squares curve fitting on the tip vibration displacement to identify the dynamics parameters of the independent blades in the full-circumference blades;

[0063] A model construction module that constructs the twin reduced-order model of the centrifugal impeller and determines the update parameters of the twin reduced-order model based on the dynamics parameters;

[0064] A model update module that updates the twin reduced-order model based on the update parameters to obtain a digital model;

[0065] A monitoring module that monitors the centrifugal impeller based on the digital model;

[0066] Among them, the steps of constructing the twin reduced-order model of the centrifugal impeller include:

[0067] Dividing the centrifugal impeller into a first sub-structure and a second sub-structure by using the mixed interface method:

[0068] The first sub-structure corresponds to the overall coordinated impeller, and the model of the first sub-structure is generated by using the coordinated modes in the coordinated nominal mode subset;

[0069] The second sub-structure corresponds to the mistuned blades, and the model of the second sub-structure introduces a mass mistuning model or a stiffness mistuning model;

[0070] Constructing the twin reduced-order model of the centrifugal impeller based on the model of the first sub-structure and the model of the second sub-structure.

[0071] The above technical solution of the present invention has the following beneficial effects compared with the prior art:

[0072] The present invention provides a monitoring method and system for a centrifugal impeller based on a twin reduced-order model, determines the update parameters of the twin reduced-order model based on dynamic parameters, establishes a virtual-real interactive parameter fusion mechanism, realizes the coupling linkage between the tip vibration signal and the twin reduced-order model, has a relatively small response calculation load, is relatively easy to extract the mistuning parameters, and has high real-time performance and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] In order to make the content of the present invention easier to be clearly understood, the present invention will be further described in detail below according to the specific embodiments of the present invention and in conjunction with the accompanying drawings.

[0074] Figure 1 It is a step flow chart of a monitoring method for a centrifugal impeller based on a twin reduced-order model in a preferred embodiment of the present invention;

[0075] Figure 2 It is a pulse signal diagram of the original vibration data without preprocessing in a preferred embodiment of the present invention;

[0076] Figure 3 It is a pulse signal diagram of the tip vibration data obtained by preprocessing in a preferred embodiment of the present invention;

[0077] Figure 4 It is a diagram of the calculation result of the tip vibration displacement of the No. 11 blade in a preferred embodiment of the present invention;

[0078] Figure 5 It is a diagram of the frequency identification result of each independent blade in a preferred embodiment of the present invention;

[0079] Figure 6 It is a fitting result diagram of the No. 3 blade and the No. 12 blade in a preferred embodiment of the present invention;

[0080] Figure 7 Schematic diagram of the twin reduced-order model of the centrifugal impeller in the preferred embodiment of the present invention;

[0081] Figure 8 Flow chart of a centrifugal impeller monitoring system based on a twin reduced-order model in an embodiment of the present invention. Specific embodiments

[0082] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0083] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0084] In the embodiments of the present application, descriptions such as "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of these features.

[0085] The online monitoring method can be used to monitor the vibration response of the blade in real time, but the vibration at the tip or a point on the blade surface is difficult to comprehensively reflect the overall response of the centrifugal impeller; affected by processing errors and operating wear, the centrifugal impeller will inevitably be detuned. The destruction of the structural cyclic symmetry characteristics will have an adverse effect on the blade vibration, and for specific detuning forms and aerodynamic load conditions, the vibration response may change sharply, and the initial model is no longer applicable to the centrifugal impeller entity in long-term service. The existing twin models for centrifugal impeller health monitoring have problems such as large response calculation load, difficult extraction of detuning parameters, and lack of linkage mechanism in the digital model, which are difficult to meet the monitoring requirements such as operation and maintenance diagnosis and online fatigue assessment of centrifugal impellers.

[0086] The inventors of the present application considered that: centrifugal impeller online monitoring and operation and maintenance assessment belong to the problems of real-time update and digital model linkage. The method of virtual-real fusion can provide a solution for the accurate assessment of the vibration response of the centrifugal impeller and the early warning of dangerous failure parts. However, limited by the number of channels, it is difficult to comprehensively identify and obtain the vibration response parameters of the detuned impeller by strain testing. At the same time, the additional strain will also affect the actual structural dynamics system. Therefore, a non-contact vibration measurement technology is selected, such as using a tip-timing sensor to obtain the vibration signals of the full-circumference blades; then identifying the dynamic parameters, and then carrying out linkage update with the twin reduced-order model to establish a virtual-real interactive parameter fusion mechanism.

[0087] Therefore, the embodiments of the present application provide a centrifugal impeller monitoring method and system based on a twin reduced-order model.

[0088] Embodiment 1

[0089] This embodiment provides a centrifugal impeller monitoring method based on a twin reduced-order model. The centrifugal impeller is configured with full-circumference blades. For this monitoring method, please refer to Figure 1 as shown, including:

[0090] Step S1, collect the tip vibration signals of the full-circumference blades to obtain the original vibration data;

[0091] Step S2, preprocess the original vibration data to obtain the tip vibration data;

[0092] Step S3, process the tip vibration data based on the keyphaseless reference method to obtain the tip vibration displacement;

[0093] Step S4, perform non-linear least squares curve fitting on the tip vibration displacement to identify the dynamic parameters of each independent blade in the full-circumference blades;

[0094] Step S5, construct the twin reduced-order model of the centrifugal impeller, and determine the update parameters of the twin reduced-order model based on the dynamic parameters;

[0095] Step S6, update the twin reduced-order model based on the update parameters to obtain a digital model;

[0096] Step S7, monitor the centrifugal impeller based on the digital model;

[0097] Among them, the steps of constructing the twin reduced-order model of the centrifugal impeller include:

[0098] Divide the centrifugal impeller into a first sub-structure and a second sub-structure by using the mixed interface method:

[0099] The first sub-structure corresponds to the overall coordinated impeller, and the model of the first sub-structure is generated by using the coordinated modes in the harmonic nominal mode subset;

[0100] The second sub-structure corresponds to the mistuned blades, and the model of the second sub-structure introduces a mass mistuning model or a stiffness mistuning model;

[0101] Construct the twin reduced-order model of the centrifugal impeller based on the model of the first sub-structure and the model of the second sub-structure.

[0102] A monitoring method for centrifugal impellers based on a twin reduced-order model provided in this embodiment: (1) Determine the update parameters of the twin reduced-order model based on dynamic parameters, establish a virtual-real interaction parameter fusion mechanism, realize the coupled linkage between the tip vibration signal and the twin reduced-order model, and improve the consistency between the physical entity and the twin reduced-order model; (2) The response calculation load is small, the detuning parameters are relatively easy to extract, and the real-time performance and accuracy are high, and it can be applied to the full-field online monitoring and fatigue assessment of the dynamics of high-speed centrifugal impellers.

[0103] Next, a monitoring method for centrifugal impellers based on a twin reduced-order model provided in this embodiment will be introduced in detail:

[0104] Specifically, the centrifugal impeller is configured with full-circumference blades.

[0105] Among them, "full-circumference blades" means that the blades on the centrifugal impeller are evenly distributed around the hub and cover the entire circumference of the centrifugal impeller.

[0106] Step S1: Collect the tip vibration signals of the full-circumference blades to obtain the original vibration data.

[0107] Specifically, selecting the tip vibration signals with significant modal vibrations for monitoring can improve the signal quality.

[0108] Step S101, perform modal analysis on the centrifugal impeller using the Block Lanczos method to obtain the impeller mode;

[0109] Optionally, the above impeller mode includes the tip mode displacement and the modal strain field.

[0110] Step S102, install tip timing sensors circumferentially on the end wall casing of the centrifugal impeller based on the impeller mode;

[0111] Optionally, the above tip timing sensors are one or more; the above tip timing sensors are installed on the channel cover side of the centrifugal impeller and flush with the wall surface; the base frequency of the counter acquisition card of the above tip timing sensors is set to 80 MHz.

[0112] Step S103, collect the tip vibration signals of the full-circumference blades based on the tip timing sensors to obtain the original vibration data.

[0113] Optionally, use a laser emission box to provide the laser light source for measurement.

[0114] When each independent blade in the above-mentioned full - circumference blade rotates past the above-mentioned tip - timing sensor, the tip profile of each independent blade dynamically reflects the laser, and the tip vibration signal of each independent blade is fed back to the acquisition module of the above-mentioned tip - timing sensor in the form of trigger pulses in real time. Subsequently, the counter acquisition card of the above-mentioned tip - timing sensor obtains the arrival sequence of each independent blade.

[0115] Step S2: Pre - process the original vibration data to obtain tip vibration data.

[0116] Step S201: Obtain the initial rotational frequency parameter based on the first m tip - pulse counting sequences in the original vibration data :

[0117] ;

[0118] Among them, is the j - th tip - pulse counting sequence, is the (j - 1) - th tip - pulse counting sequence, is the counter base frequency, represents summation.

[0119] Meanwhile, it is necessary to verify whether the above - mentioned initial rotational frequency parameter is within the normal operating speed range of the centrifugal impeller:

[0120] When is satisfied, the above - mentioned initial rotational frequency parameter is within the normal operating speed range of the centrifugal impeller; when is not satisfied, the above - mentioned initial rotational frequency parameter is not within the normal operating speed range of the centrifugal impeller, and it is necessary to search sequentially backward along the above - mentioned first m tip - pulse counting sequences until an initial rotational frequency parameter that satisfies is obtained; among them, is the set minimum rotational frequency value, is the set maximum rotational frequency value.

[0121] Step S202: Taking into account the timing pulse intervals when each independent blade is not vibrating, calculate the theoretical pulse counting interval :

[0122] ;

[0123] Among them, is the number of the above - mentioned tip - timing sensors.

[0124] Step S203: Based on the actual pulse counting interval Obtain the tip vibration data, and the actual pulse counting interval shall satisfy:

[0125] ;

[0126] Specifically, the tip vibration data obtained thereby can reduce the influence of abnormal pulses and interference noise.

[0127] Exemplarily, taking a semi-open centrifugal impeller configured with 19 independent blades as the monitoring object, in a working environment of high rotational speed and high pressure, the test results without the above-mentioned preprocessing are shown in Figure 2 as shown, wherein the irregular black vertical lines in the longitudinal axis direction represent the influence brought by abnormal pulses and noise interference; the test results obtained after the above-mentioned preprocessing are shown in Figure 3 as shown.

[0128] It can be seen that, compared with the original vibration data without the above-mentioned preprocessing, the tip vibration data obtained after the above-mentioned preprocessing is more accurate and effective.

[0129] Step S3: Process the tip vibration data based on the keyphaseless reference method to obtain the tip vibration displacement.

[0130] Affected by the machining error of the end wall casing, the installation and positioning error of the tip timing sensor, etc., there are deviations in the interval angles of the independent blades. During the vibration calculation process, a keyphasor signal needs to be used as a vibration-free reference. However, in practice, it is difficult to install a keyphasor sensor on large energy equipment. Even if the above-mentioned keyphasor sensor is installed, the keyphasor sensor is easily affected by the vibration of the base, which will instead bring large errors to the amplitude calculation of each independent blade.

[0131] Therefore, the embodiment of the present application adopts the keyphaseless reference method to process the tip vibration data:

[0132] Step S301, convert the tip vibration data into a tip arrival timing sequence.

[0133] Specifically, read the tip pulse counting sequence obtained by the above counter acquisition card , and then based on the above counter base frequency convert it into a tip arrival timing sequence ;

[0134] wherein, k represents the k-th blade among the independent blades, i represents the i-th tip timing sensor, and n represents the n-th rotation of the centrifugal impeller.

[0135] Step S302, determine a timing reference signal based on the tip arrival timing sequence.

[0136] Specifically, the timing reference signal and are respectively as follows:

[0137] ;

[0138] Step S303: Calculate the rotation period and rotational frequency corresponding to each rotation of the centrifugal impeller based on the timing reference signal.

[0139] Specifically, the rotation period corresponding to each rotation of the centrifugal impeller and the rotational frequency are respectively as follows:

[0140] .

[0141] Step S304: Obtain the ideal arrival time based on the rotation period or the rotational frequency.

[0142] Specifically, the ideal arrival time of each independent blade is:

[0143] ;

[0144] wherein, represents the number of revolutions that the centrifugal impeller has rotated.

[0145] Step S305: Obtain the tip vibration displacement based on the ideal arrival time.

[0146] Specifically, the tip vibration displacement is:

[0147] ;

[0148] wherein, is the rotational angular frequency of the centrifugal impeller, is the radius of gyration at the tip measurement point of the centrifugal impeller blade, is the pi.

[0149] Exemplarily, taking the semi-open centrifugal impeller configured with 19 independent blades as the monitoring object, and taking the vibration amplitude of the 11th blade of the centrifugal impeller as an example, the calculation result of the tip vibration displacement obtained by the above non-key phase reference method is shown in Figure 4 as shown.

[0150] Step S4: Perform non-linear least squares curve fitting on the tip vibration displacement to identify the dynamic parameters of each independent blade in the full-circle blades.

[0151] Optionally, use the Levenberg-Marquardt algorithm to perform non-linear least squares curve fitting.

[0152] Specifically, the dynamic parameters of each independent blade include the natural frequency , displacement amplitude , phase , damping ratio , constant C, resonance order .

[0153] Under the undersampling condition, the dynamic parameter equations of each independent blade are as follows:

[0154] ;

[0155] ;

[0156] ;

[0157] ;

[0158] Among them, is the frequency, is the quality factor, is the calculation intermediate variable, is the installation interval angle of the above-mentioned tip-timing sensor, is the initial phase.

[0159] Exemplarily, taking the semi-open centrifugal impeller with 19 independent blades configured above as the monitoring object, the above-mentioned non-linear least squares curve fitting is performed, and taking the frequency as an example, the frequency identification results of each independent blade are shown in Figure 5 .

[0160] Exemplarily, please refer to Figure 6 . Taking the No. 3 blade and the No. 12 blade of the centrifugal impeller as examples, the fitting waveform of the normalized tip amplitude is in good agreement with the original point set. Then, the dynamic parameters identified based on this will be relatively accurate; among them, represents the instantaneous rotational speed of the above-mentioned centrifugal impeller, represents the highest rotational speed of the above-mentioned centrifugal impeller.

[0161] Step S5: Construct a twin reduced-order model of the centrifugal impeller, and determine the update parameters of the twin reduced-order model based on the dynamic parameters.

[0162] Step S501, construct a twin reduced-order model of the centrifugal impeller:

[0163] Preferably, the centrifugal impeller is divided into a first sub-structure and a second sub-structure by using the Hybrid interface method to achieve the "reduction order" of the existing twin model;

[0164] The first sub-structure corresponds to the overall coordinated impeller, and the model of the first sub-structure is generated by using the coordinated modes in the Subset of Nominal Modes (SNM).

[0165] The second sub-structure corresponds to the mistuned blades, and the model of the second sub-structure introduces a mass mistuning model or a stiffness mistuning model.

[0166] Based on the models of the first sub-structure and the second sub-structure, a twin reduced-order model of the centrifugal impeller is constructed.

[0167] Preferably, a stiffness mistuning model is introduced Construct the model of the second sub-structure above:

[0168] ;

[0169] Wherein, represents the coordinated stiffness matrix, represents the mistuned stiffness.

[0170] Furthermore, a Rayleigh damping model is used to construct the damping matrix of each independent blade of the centrifugal impeller :

[0171] ;

[0172] Set the constant mass damping coefficient to zero, so that the damping matrix is independent of the mass matrix , and the damping matrix is only proportional to the coordinated stiffness matrix ; The constant stiffness damping coefficient is:

[0173] ;

[0174] Wherein, is the angular frequency corresponding to the resonance speed of the centrifugal impeller.

[0175] Furthermore, using the regular mode set obtained by normalizing the mass matrix to perform modal coordinate transformation on the coordinated impeller corresponding to the first sub-structure, and obtaining a mistuned twin reduced-order model of the centrifugal impeller:

[0176] ;

[0177] Wherein, is the angular frequency, is the identity matrix, is the unit complex number, is the system generalized stiffness matrix of the above harmonic impeller, is the displacement in the modal coordinate system, is the load of the centrifugal impeller, and the superscript represents the transpose.

[0178] Furthermore, the normal modes of the cantilever blade based on the Craig-Bampton method are used for mapping. At this time, the detuning term can be expressed as:

[0179] ;

[0180] ;

[0181] ;

[0182] wherein, is the number of independent blades of the above centrifugal impeller, is the diagonal matrix function, is the modal participation factor of the k-th blade; the detuning parameter represents the deviation of the r-th main modal frequency of the k-th blade.

[0183] Furthermore, ignoring the coupling between modes and the boundary influence, the above detuned centrifugal impeller twin reduced-order model is correspondingly simplified to:

[0184] ;

[0185] wherein, is the main modal set.

[0186] Exemplarily, the centrifugal impeller twin reduced-order model constructed by the above steps is shown in Figure 7 wherein, the second sub-structure includes 19 independent blades, which are uniformly arranged on the first sub-structure.

[0187] Step S502, determining the update parameters of the twin reduced-order model based on the dynamic parameters:

[0188] Preferably, the update parameters include the detuning deviation, and this detuning deviation corresponds to the above detuning parameter , and the steps for determining the detuning deviation include:

[0189] First, determine the detuning parameter based on the identification results of the dynamic parameters of each independent blade;

[0190] Furthermore, the proportional detuning is quantified by the elastic modulus perturbation:

[0191] ;

[0192] Among them, is the equivalent elastic modulus of the k-th blade, and the nominal elastic modulus of each of the above independent blades is updated through the mistuning coefficient of the k-th blade , so as to correct the natural frequency parameters of each of the above independent blades.

[0193] Therefore, the stiffness mistuning of the k-th blade can be expressed as:

[0194] ;

[0195] Among them, is the nominal stiffness matrix.

[0196] Furthermore, the above mistuning parameter is simplified:

[0197] ;

[0198] Furthermore, a mistuning deviation is introduced to represent :

[0199] ;

[0200] Among them, the mistuning deviation is dimensionless, is the natural frequency of the k-th blade, is the frequency of the ideal harmonic blade.

[0201] Through the above steps, the mistuning parameter can be extracted more easily, improving the real-time performance and accuracy.

[0202] Step S6: Update the twin reduced-order model based on the updated parameters to obtain a digital model.

[0203] Preferably, regarding the update of the twin reduced-order model as a decision-making problem, the correction criterion of the decision-making problem is:

[0204] ;

[0205] ;

[0206] Among them, represents the overall deviation degree of the parameter group of the single dynamic parameters of each of the above independent blades; represents the pulse index, and the pulse index is used to evaluate the maximum deviation degree of the single dynamic parameters of each of the above independent blades; is the number of tip timing sensors; is the first determination threshold; is the second determination threshold; represents the update parameter of the twin reduced-order model; represents the same as the update parameter corresponding dynamic parameter identification result; Σ represents summation; ‖ represents taking the absolute value.

[0207] Preferably, the above update parameter is the damping ratio or the detuning deviation .

[0208] Specifically, by updating the twin reduced-order model of the centrifugal impeller through the above steps, a virtual-real interaction parameter fusion mechanism is established, realizing the coupling linkage between the tip vibration signal and the twin reduced-order model, thereby obtaining a digital model consistent with the physical entity.

[0209] Step S7: Monitor the centrifugal impeller based on the digital model.

[0210] Step S701, calculate the three-dimensional response field based on the digital model.

[0211] Because the above digital model is consistent with the physical entity, the above three-dimensional response field coincides with the actually collected tip vibration displacement.

[0212] Step S702, introduce cyclic coordinates to the three-dimensional response field and perform a transformation from the cyclic coordinates to physical coordinates to obtain the motion equation;

[0213] Specifically, from the cyclic coordinates to the physical coordinates the transformation is:

[0214] ;

[0215] where is the real-valued Fourier matrix, is the direct product operator.

[0216] Specifically, the above motion equation is: ;

[0217] where represents the pseudo-block diagonal matrix, is the set of impeller pitch diameter harmonics of the centrifugal impeller, represents the harmonic number as when the real-valued circumferential principal mode set.

[0218] Step S703: Obtain the modal participation factors of each independent blade based on the motion equation;

[0219] Specifically, when the harmonic number is the participation factors of the above-mentioned independent blades in the corresponding cyclic symmetric mode are:

[0220] ;

[0221] represents the blade part in the real-valued circumferential main mode set ;

[0222] is the generalized stiffness matrix of the cantilever blade;

[0223] is the nominal stiffness matrix of the above-mentioned cantilever blade;

[0224] is the main mode set.

[0225] Furthermore, the modal participation factors of the above-mentioned independent blades are:

[0226] ;

[0227] where is the k-th row of the above-mentioned real-valued Fourier matrix .

[0228] Step S704: Characterize the state indicators of the centrifugal impeller based on the modal participation factors , where the state indicators include three-dimensional full-field vibration displacement and strain; when the state indicators are within the set range, the monitoring result of the centrifugal impeller is normal; when the state indicators are not within the set range, the monitoring result of the centrifugal impeller is abnormal.

[0229] Specifically, when the monitoring result of the above-mentioned centrifugal impeller is abnormal, it indicates that the centrifugal impeller faces the risk of fatigue failure.

[0230] By monitoring the centrifugal impeller through the above steps, the response calculation load can be reduced, and the real-time performance and accuracy can be improved.

[0231] Embodiment 2

[0232] This embodiment provides a monitoring system for a centrifugal impeller based on a twin reduced-order model. The centrifugal impeller is configured with full-circumference blades. Please refer to Figure 8 as shown, including:

[0233] The acquisition module 100 acquires the tip vibration signals of the full - circumference blades to obtain the original vibration data;

[0234] The first processing module 200 pre - processes the original vibration data to obtain the tip vibration data;

[0235] The second processing module 300 processes the tip vibration data based on the key - phaseless reference method to obtain the tip vibration displacement;

[0236] The parameter identification module 400 performs non - linear least - squares curve fitting on the tip vibration displacement to identify the dynamic parameters of each independent blade in the full - circumference blades;

[0237] The model construction module 500 constructs the twin reduced - order model of the centrifugal impeller and determines the update parameters of the twin reduced - order model based on the dynamic parameters;

[0238] The model update module 600 updates the twin reduced - order model based on the update parameters to obtain the digital model;

[0239] The monitoring module 700 monitors the centrifugal impeller based on the digital model;

[0240] Among them, the steps of constructing the twin reduced - order model of the centrifugal impeller include:

[0241] The centrifugal impeller is divided into a first sub - structure and a second sub - structure by using the mixed interface method:

[0242] The first sub - structure corresponds to the overall coordinated impeller, and the model of the first sub - structure is generated by using the coordinated modes in the harmonic nominal mode subset;

[0243] The second sub - structure corresponds to the mistuned blades, and the model of the second sub - structure introduces a mass mistuning model or a stiffness mistuning model;

[0244] Based on the model of the first sub - structure and the model of the second sub - structure, the twin reduced - order model of the centrifugal impeller is constructed.

[0245] For the introduction of a centrifugal impeller monitoring system based on a twin reduced - order model provided in this embodiment, please refer to Embodiment 1, and this embodiment will not be elaborated here.

[0246] A centrifugal impeller monitoring system based on a twin reduced - order model provided in this embodiment has the same beneficial effects as the above - mentioned centrifugal impeller monitoring method based on a twin reduced - order model.

[0247] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0248] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0249] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing devices to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implements the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0250] These computer program instructions can also be loaded onto a computer or other programmable data processing devices, so that a series of operation steps are executed on the computer or other programmable devices to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable devices provide steps for implementing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0251] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to exhaustively list all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A centrifugal impeller monitoring method based on a twin reduced-order model, wherein the centrifugal impeller is equipped with full-circumference blades, characterized in that: The monitoring method comprises the following steps: Collecting the blade tip vibration signal of the full-circumference blade to obtain original vibration data; Preprocessing the original vibration data to obtain blade tip vibration data; Processing the blade tip vibration data based on a keyless phase reference method to obtain a blade tip vibration displacement; Performing nonlinear least square curve fitting on the blade tip vibration displacement to identify the dynamic parameters of each independent blade in the full-circumference blade; Constructing a twin reduced-order model of the centrifugal impeller, and determining update parameters of the twin reduced-order model based on the dynamic parameters; Updating the twin reduced-order model based on the update parameters to obtain a digital model; Monitoring the centrifugal impeller based on the digital model; The step of constructing the twin reduced-order model of the centrifugal impeller includes: The centrifugal impeller is divided into a first substructure and a second substructure by using a mixed interface method: The first substructure corresponds to an integrally coordinated impeller, and a model of the first substructure is generated using a coordinated mode in a harmonic nominal mode subset; The second substructure corresponds to a detuned blade, and a model of the second substructure introduces a mass detuned model or a stiffness detuned model; Constructing a twin reduced-order model of the centrifugal impeller based on the model of the first substructure and the model of the second substructure; Preprocessing the raw vibration data to obtain blade tip vibration data comprises the following steps: First, the initialization frequency parameter is obtained based on the first m blade tip pulse count sequences in the original vibration data. : ； in, is the j-th blade tip pulse counting sequence, is the j-1th blade tip pulse counting sequence, is the counter base frequency, Indicates the sum; in satisfying In the case of Within the normal operating speed range of the centrifugal impeller; In the case of If the centrifugal impeller is not within the normal operating speed range, it is necessary to search backward along the first m blade tip pulse counting sequence until the condition is satisfied. Initialization frequency conversion parameters ;in, is the lowest value of the set frequency. The maximum value of the set rotation frequency; Then, calculate the theoretical pulse count interval : ； in, The number of blade tip timing sensors; Next, based on the actual pulse count interval of blade tip vibration Get blade tip vibration data, the actual pulse count interval Need to meet: ； Processing the blade tip vibration data based on the keyless phase reference method to obtain the blade tip vibration displacement includes the following steps: converting the blade tip vibration data into a blade tip arrival timing sequence; Determine a timing reference signal based on the blade tip arrival timing sequence and : ； Where i represents the i-th blade tip timing sensor, n represents the n-th revolution of the centrifugal impeller, k represents the k-th blade in each independent blade, represents the blade tip arrival timing sequence; Calculate the rotation period corresponding to each rotation of the centrifugal impeller based on the timing reference signal and frequency conversion : ； Obtaining an ideal arrival time based on the rotation period or the rotation frequency : ； in, Indicates the number of revolutions the centrifugal impeller has made; Obtaining blade tip vibration displacement based on the ideal arrival time; The step of updating the twin reduced-order model based on the update parameter comprises: The update of the twin reduced-order model is regarded as a decision problem, and the correction criterion of the decision problem is: ； ； in, Indicates the overall deviation degree of the parameter group of the single dynamic parameter of each independent blade; represents a pulse index, and the pulse index is used to evaluate the maximum deviation degree of the single kinetic parameter; The number of blade tip timing sensors; is the first determination threshold; is the second determination threshold; represents the update parameters of the twin reduced-order model; Represents the update parameters with The corresponding kinetic parameter identification results; Σ represents the sum; ‖ represents the absolute value.

2. A centrifugal impeller monitoring method based on twin reduced-order model according to claim 1, characterized in that: Collecting the blade tip vibration signal of the full-circumference blade to obtain original vibration data includes the following steps: Using the block Lanczos method to perform modal analysis on the centrifugal impeller to obtain the impeller mode; Based on the impeller mode, a blade tip timing sensor is installed in the circumferential direction of the end wall casing of the centrifugal impeller; The blade tip vibration signal of the full-circumference blade is collected based on the blade tip timing sensor to obtain original vibration data.

3. The centrifugal impeller monitoring method based on twin reduced-order model according to claim 1, characterized in that: The steps of constructing the twin reduced-order model of the centrifugal impeller include: The damping matrix of each independent blade of the centrifugal impeller is constructed using the Rayleigh damping model. : ； The constant mass damping coefficient is set to zero so that the damping matrix With the mass matrix Regardless, the damping matrix Only with the harmonic stiffness matrix Proportional; constant stiffness damping coefficient for: ； in, is the angular frequency corresponding to the resonant speed of the centrifugal impeller, is the damping ratio of each independent blade of the centrifugal impeller.

4. The centrifugal impeller monitoring method based on twin reduced-order model according to claim 1, characterized in that: Based on the dynamic parameters, update parameters of the twin reduced-order model are determined, wherein the update parameters include a detuning deviation, and the detuning deviation is determined. The steps include: ； in, is the natural frequency of blade k, For ideally tuned blade frequency.

5. The centrifugal impeller monitoring method based on twin reduced-order model according to claim 1, characterized in that: The step of monitoring the centrifugal impeller based on the digital model comprises: Calculating a three-dimensional response field based on the digital model; Introducing cyclic coordinates into the three-dimensional response field, and transforming the cyclic coordinates into physical coordinates to obtain a motion equation; Obtaining a modal participation factor of each independent blade based on the motion equation; The state index of the centrifugal impeller is characterized based on the modal participation factor, and the state index includes three-dimensional full-field vibration displacement and strain; when the state index is within a set range, the monitoring result of the centrifugal impeller is normal; when the state index is not within the set range, the monitoring result of the centrifugal impeller is abnormal.

6. A centrifugal impeller monitoring system based on a twin reduced-order model, wherein the centrifugal impeller is equipped with full-circumference blades, characterized in that: The monitoring system includes: A collection module collects the tip vibration signal of the full-circle blade to obtain original vibration data; A first processing module pre-processes the original vibration data to obtain blade tip vibration data; A second processing module processes the blade tip vibration data based on a keyless phase reference method to obtain a blade tip vibration displacement; A parameter identification module performs nonlinear least square curve fitting on the blade tip vibration displacement to identify the dynamic parameters of each independent blade in the full-circumference blade; A model building module, constructing a twin reduced-order model of the centrifugal impeller, and determining update parameters of the twin reduced-order model based on the dynamic parameters; A model updating module, which updates the twin reduced-order model based on the update parameters to obtain a digital model; A monitoring module, for monitoring the centrifugal impeller based on the digital model; The step of constructing the twin reduced-order model of the centrifugal impeller includes: The centrifugal impeller is divided into a first substructure and a second substructure by using a mixed interface method: The first substructure corresponds to an integrally coordinated impeller, and a model of the first substructure is generated using a coordinated mode in a harmonic nominal mode subset; The second substructure corresponds to a detuned blade, and a model of the second substructure introduces a mass detuned model or a stiffness detuned model; Constructing a twin reduced-order model of the centrifugal impeller based on the model of the first substructure and the model of the second substructure; Preprocessing the original vibration data to obtain blade tip vibration data includes: First, the initialization frequency parameter is obtained based on the first m blade tip pulse count sequences in the original vibration data. : ； in, is the j-th blade tip pulse counting sequence, is the j-1th blade tip pulse counting sequence, is the counter base frequency, Indicates the sum; in satisfying In the case of Within the normal operating speed range of the centrifugal impeller; In the case of If the centrifugal impeller is not within the normal operating speed range, it is necessary to search backward along the first m blade tip pulse counting sequence until the condition is satisfied. Initialization frequency conversion parameters ;in, is the lowest value of the set frequency. The maximum value of the set rotation frequency; Then, calculate the theoretical pulse count interval : ； in, The number of blade tip timing sensors; Next, based on the actual pulse count interval of blade tip vibration Get blade tip vibration data, the actual pulse count interval Need to meet: ； Processing the blade tip vibration data based on the keyless phase reference method to obtain the blade tip vibration displacement includes: converting the blade tip vibration data into a blade tip arrival timing sequence; Determine a timing reference signal based on the blade tip arrival timing sequence and : ； Where i represents the i-th blade tip timing sensor, n represents the n-th revolution of the centrifugal impeller, k represents the k-th blade in each independent blade, represents the blade tip arrival timing sequence; Calculate the rotation period corresponding to each rotation of the centrifugal impeller based on the timing reference signal and frequency conversion : ； Obtaining an ideal arrival time based on the rotation period or the rotation frequency : ； in, Indicates the number of revolutions the centrifugal impeller has made; Obtaining blade tip vibration displacement based on the ideal arrival time; Updating the twin reduced-order model based on the update parameter includes: The update of the twin reduced-order model is regarded as a decision problem, and the correction criterion of the decision problem is: ； ； in, Indicates the overall deviation degree of the parameter group of the single dynamic parameter of each independent blade; represents a pulse index, and the pulse index is used to evaluate the maximum deviation degree of the single kinetic parameter; The number of blade tip timing sensors; is the first determination threshold; is the second determination threshold; represents the update parameters of the twin reduced-order model; Represents the update parameters with The corresponding kinetic parameter identification results; Σ represents the sum; ‖ represents the absolute value.

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