A method and device for evaluating the state of a marine gas turbine blade

Abstract

The embodiment of the present application provides a method and a device for evaluating the state of a marine gas turbine blade. Through the data validity judgment algorithm and the data cleaning algorithm, the problem of false triggering caused by factors such as the complex tip end face morphology of the rotor blade of the marine gas turbine, surface pollution and scaling of the tip and timing sensors is solved; through the rotational speed matrix solving algorithm, the problem of calculating the rotational speed under all working conditions is solved; through the blade vibration calculation algorithm, the problem of comprehensively and accurately calculating the transient displacement and the steady-state displacement is solved; through the reconstruction analysis of the blade transient displacement and the steady-state displacement into the blade stress and comparison with the state stress threshold, the blade state evaluation is realized. Compared with the prior art, the present invention improves the engineering applicability of the tip timing technology in the vibration monitoring and state evaluation of the rotor blade of the marine gas turbine, and has the evaluation ability under all working conditions and higher accuracy.

Description

Technical Field

[0001] This application relates to the technical field of rotor blade state assessment and health management in marine gas turbine compressors and turbines, and particularly relates to a method and device for assessing the state of marine gas turbine blades. Background Art

[0002] The blade is the core component for energy conversion in a marine gas turbine, and its safe operation is extremely important. Dynamically monitoring the vibration of the blade and conducting state assessment are necessary steps to grasp the health status and functional characteristics of the blade, and play an important fundamental role in improving its operation reliability and fault tracing and root cause elimination. After years of development, a gas turbine dynamic monitoring system mainly based on casing vibration, combined with oil, gas path, and performance parameters, has been able to diagnose most faults and has functions such as warning, alarm, and indication. However, it is difficult to monitor and assess the blade state.

[0003] The tip timing method is the mainstream method for online monitoring of blade vibration and has been widely studied and developed in recent years. In this method, several tip timing sensors are installed on the casing to measure the moment when the blade reaches the sensor. According to the difference between the theoretical arrival moment and the actual arrival moment and the rotational speed, the blade vibration displacement is calculated. Further analysis of the vibration displacement sequence can be used to evaluate the operating state of the blade. Due to its advantages such as non-intrusive measurement, simple system structure, convenient sensor installation, and low measurement cost, this technology has received attention and recognition from the industrial and academic circles. However, when this technology is applied to the state assessment of marine gas turbine rotor blades, the following deficiencies exist:

[0004] (1) In the basic principle of the tip timing technology, it is assumed that the rotational speed is constant within one revolution of the blade. However, the starting, speed increase and decrease, and sudden stop of a marine gas turbine are often processes with rapid speed changes, and its operating conditions include variable speed conditions and constant speed conditions. The current technology cannot meet the monitoring requirements for all operating conditions.

[0005] (2) This technology only considers the transient displacement caused by the modal vibration mode during blade resonance. During the operation of marine gas turbine blades, there are also steady displacements caused by aerodynamic loads, centrifugal loads, thermal loads, and corrosion deformation. The current technology cannot meet the comprehensive monitoring requirements for transient displacement and steady displacement.

[0006] (3) The tip end surface morphology of the marine gas turbine rotor blade is complex, and the tip and the surface of the timing sensor are easily affected by factors such as pollution and fouling, resulting in missing data or false triggering of redundant data in the tip timing signal. The false triggering affects the accuracy of the vibration displacement calculation result.

[0007] Therefore, the blade vibration displacement calculated by the current technology is inaccurate and incomplete, which cannot meet the engineering requirements for the state assessment of the rotor blades of a marine gas turbine. Summary of the Invention

[0008] In view of this, the purpose of this application is to provide a method and device for assessing the state of marine gas turbine blades, so as to comprehensively monitor and evaluate the state of the rotor blades of the gas turbine under all working conditions. Through the data validity judgment algorithm and the data cleaning algorithm, the problem of mis-triggering of the tip timing signal is solved; through the rotational speed matrix solving algorithm, the problem of calculating the rotational speed under all working conditions is solved; through the blade vibration displacement calculation algorithm, the comprehensive calculation problems of transient displacement and steady-state displacement are solved; through the reconstruction analysis of the blade transient displacement and steady-state displacement into dynamic stress and steady-state stress, the stress of the blade is obtained and compared with the state stress threshold, and finally the blade state assessment is realized. Furthermore, the applicability and accuracy of the tip timing technology in the state assessment of the rotor blades of marine gas turbines are improved.

[0009] An embodiment of this application provides a method for assessing the state of marine gas turbine blades, including:

[0010] Obtain the arrival time of the rotor blade and the arrival time of the key phase;

[0011] Judge the data validity of the arrival time of the blade;

[0012] Clean the mis-triggered data of the arrival time of the blade;

[0013] Solve the rotational speed measurement matrix constructed by the arrival time of the key phase, and then calculate the rotational speed of the rotor blade;

[0014] Calculate the blade vibration displacement based on the arrival time of the blade, the arrival time of the key phase, the blade rotational speed, the tip rotation radius, and the angle between the blade and the key phase;

[0015] Analyze and process the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade;

[0016] Reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and conduct blade state assessment by comparing the stress of the blade with the stress thresholds in different states;

[0017] According to the blade state assessment result, send feedback information. When the blade is in a healthy state, the state warning module does not send a warning message. When the blade is in a sub-healthy state, the state warning module issues a warning. When the blade is in a faulty state, the state warning module issues an alarm.

[0018] In some embodiments, the obtaining the arrival time of the rotor blade and the arrival time of the key phase includes:

[0019] On the casing corresponding to the top of the rotor blade of the marine gas turbine, a tip timing sensor is arranged to measure the moment \(t\) when the blade reaches the tip timing sensor. b,n A keyphasor is set on the rotor of the marine gas turbine, and a keyphasor timing sensor is arranged at the top of the keyphasor to measure the moment \(t\) when the keyphasor reaches the keyphasor timing sensor. o,n The subscript \(b\) represents the blade number, the subscript \(o\) represents the keyphasor, and the subscript \(n\) represents the number of rotation cycles.

[0020] In some embodiments, the determination of the validity of the blade arrival time data includes:

[0021] The period of one rotation of the rotor is:

[0022] \(T = t_{o(n + 1)} - t_{on}\) (1) o,n+1 \(t_{o(n + 1)}\) o,n (1)

[0023] The arrival time window width of each blade within this period is:

[0024]

[0025] \(n\) b is the number of blades;

[0026] The range of the blade arrival time is:

[0027] \(t_{on} + (b - 1)\frac{T}{n} \leq t_b \leq t_{on} + b\frac{T}{n}\) (3) o,n \(t_{on}\) w \(t_b\) b,n \(t_{on}\) o,n \(t_b\) w (3)

[0028] In the above formula, \(t_{on}\) o,n is the arrival time of the keyphasor in the \(n\)th rotation cycle, \(t_{o(n + 1)}\) o,n+1 is the arrival time of the keyphasor in the \((n + 1)\)th rotation cycle, \(n\) b is the number of blades on the measured disk, and \(b\) is the blade number;

[0029] The validity of the blade arrival time data is judged by formula (3).

[0030] In some embodiments, the cleaning of the mis-triggered blade arrival time data includes:

[0031] If there are multiple arrival time signals within the value range of formula (3) or there is no blade arrival time signal, this situation is a mis-trigger of the tip timing signal. The mis-triggered data cleaning method is as follows:

[0032] The rotation frequency of the keyphasor is:

[0033]

[0034] The actual passing frequency between the arrival time signals of two adjacent blades is:

[0035]

[0036] If there are redundant false trigger signals in the blade arrival time signals. The cleaning method for this case is to directly remove the redundant arrival time signals corresponding to this passing frequency;

[0037] If there are missing false trigger signals in the blade arrival time signals. The cleaning method for this case is to supplement the missing arrival time signals according to the keyphasor rotation frequency. The supplement method is:

[0038]

[0039] In the above formula, t b,n is the arrival time of the b-th blade in the n-th rotation cycle, and t b+1,n is the arrival time of the (b + 1)-th blade in the n-th rotation cycle.

[0040] In some embodiments, the method of constructing a rotational speed measurement matrix for the keyphasor arrival time and then calculating the rotational speed of the rotor blade includes:

[0041] In the tip timing technology, the method of calculating the blade rotational speed is:

[0042]

[0043] The rotational speed calculated by formula (7) is the average rotational speed of the blade rotating one circle, which is applicable to the constant speed working condition and not applicable to the variable speed working condition; the rotational speed calculation method under all working conditions proposed in this application is as follows:

[0044] The rotational speed of the gas turbine rotor blade can be expressed as:

[0045]

[0046] In formula (8), f0 is the initial rotational speed of the blade when the keyphasor arrives at the keyphasor timing sensor, is the term of the rotational speed changing with time, represents the constant speed working condition when, c = 1 represents the linear variable speed working condition, and c > 1 represents the non-linear variable speed working condition;

[0047] Since the transient displacement and steady-state displacement of the rotor blade will cause deviations in the blade arrival time, calculating the rotational speed using the blade arrival time data will introduce calculation errors. Therefore, a rotational speed measurement matrix is constructed based on the keyphasor arrival time as follows:

[0048]

[0049] Equation (9) written in matrix form is:

[0050] C = MF (10)

[0051] In Equation (10), C is a matrix related to the number of revolutions of the blade, the value of c is related to the rotational speed change rate, and in this application, it is taken as 4. M is a matrix related to the arrival time of the key phase, F is the rotational speed matrix, and it can be obtained by the least squares method:

[0052] F = (M T M) -1 M T C (11)

[0053] After obtaining the rotational speed matrix, the blade rotational speed can be calculated according to Equation (8).

[0054] In some embodiments, calculating the blade vibration displacement based on the blade arrival time, key phase arrival time, blade rotational speed, blade tip rotation radius, and the angle between the blade and the key phase includes:

[0055] In the blade tip timing technology, the method for calculating the blade vibration displacement is:

[0056]

[0057]

[0058] In Equation (13), is the angle between the b-th blade and the key phase, and R is the blade tip rotation radius; since the rotational speed in Equation (12) is the average rotational speed of one revolution of the blade, the blade vibration displacement calculated by Equation (12) is the vibration displacement under constant speed conditions and is not applicable to variable speed conditions; the present application proposes the following method for calculating the blade vibration displacement under all conditions:

[0059]

[0060] The blade vibration displacement calculated by Equation (14) includes the blade tip vibration displacement caused by the modal response of the blade and the blade tip steady-state displacement caused by axial thrust, pneumatic pressure, rotor thermal expansion, and corrosion deformation.

[0061] In some embodiments, analyzing and processing the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade includes:

[0062] Analyzing and processing the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade, the blade vibration displacement can be expressed as:

[0063] x = x s +x t (15)

[0064] Where xs is the steady-state displacement, and the extraction method is to filter the blade vibration displacement using an SG filter. The low-frequency displacement component obtained by filtering is the steady-state displacement of the blade; x t is the transient displacement, and the transient displacement can be obtained by subtracting the steady-state displacement from the blade vibration displacement.

[0065] In some embodiments, the transient displacement and steady-state displacement of the blade are reconstructed into the stress of the blade. By comparing the stress of the blade with the stress thresholds in different states, the blade state assessment is performed, including:

[0066] Through blade modal analysis, the displacement-stress transfer function of the vibration mode corresponding to the transient displacement of the blade and the displacement-stress reconstruction coefficient of the steady-state displacement are obtained. The analyzed transient displacement and steady-state displacement are reconstructed into dynamic stress and steady-state stress, and then the stress of the blade is calculated as:

[0067]

[0068] where μ s is the displacement-stress reconstruction coefficient of the steady-state displacement, is the displacement-stress transfer function of the vibration mode, and σ is the stress value of the blade;

[0069] Then, the state of the blade is divided into a healthy state, a sub-healthy state, and a faulty state. By combining dynamic simulation calculations with calibration tests, the stress thresholds for different states of the blade are determined. The stress threshold for the healthy state is σ1, and the stress threshold for the sub-healthy state is σ2. By comparing the relationship between σ and σ1, σ2, the blade state assessment is realized;

[0070] where, when σ < σ1, the blade is in a healthy state; when σ1 < σ < σ2, the blade is in a sub-healthy state; when σ > σ2, the blade is in a faulty state.

[0071] In a second aspect, an embodiment of the present application provides a device for assessing the state of a marine gas turbine blade, including: a data acquisition module, a data validity judgment module, a data cleaning module, a rotational speed calculation module, a vibration calculation module, a vibration analysis module, a state assessment module, and a state warning module;

[0072] The data acquisition module is used to acquire the arrival time of the rotor blade and the arrival time of the key phase;

[0073] The data validity judgment module is used to judge the validity of the blade arrival time data;

[0074] The data cleaning module is used to clean the mis-triggered blade arrival time data;

[0075] The rotational speed calculation module is used to solve the rotational speed measurement matrix constructed at the key phase arrival moment, and further calculate the rotational speed of the rotor blade;

[0076] The vibration calculation module is used to calculate the blade vibration displacement based on the blade arrival moment, the key phase arrival moment, the blade rotational speed, the tip rotation radius, and the angle between the blade and the key phase;

[0077] The vibration analysis module is used to analyze and process the blade vibration displacement, and extract the steady-state displacement and transient displacement of the blade;

[0078] The state evaluation module is used to reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and evaluate the blade state by comparing the stress of the blade with the stress thresholds of different states;

[0079] The state warning module is used to send feedback information according to the blade state evaluation result. When the blade is in a healthy state, the state warning module does not send a warning message. When the blade is in a sub-healthy state, the state warning module issues a warning. When the blade is in a faulty state, the state warning module issues an alarm.

[0080] The above embodiments of the present application provide a method and device for evaluating the state of a marine gas turbine blade. Through the data validity judgment algorithm and the data cleaning algorithm, the problem of false triggering caused by complex tip end face topography of the rotor blade of the marine gas turbine, surface pollution and scaling of the tip and timing sensors, etc. is solved; through the rotational speed matrix solving algorithm, the problem of calculating the rotational speed under all working conditions is solved; through the blade vibration calculation algorithm, the problem of comprehensively and accurately calculating the transient displacement and steady-state displacement is solved; through the reconstruction analysis of the blade transient displacement and steady-state displacement into the blade stress and comparison with the state stress threshold, the blade state evaluation is realized. Compared with the prior art, the present invention improves the engineering applicability of the tip timing technology in the vibration monitoring and state evaluation of the rotor blade of the marine gas turbine, and has the evaluation ability under all working conditions and higher accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The drawings generally illustrate, by way of example and not limitation, the various embodiments discussed herein.

[0082] Figure 1 It is a schematic flow chart of a method for evaluating the state of a marine gas turbine blade;

[0083] Figure 2 It is a schematic diagram for obtaining the blade arrival moment and the key phase arrival moment;

[0084] Figure 3 It is the cleaning result when there are redundant false triggering signals in the blade arrival moment signal;

[0085] Figure 4The cleaning result when there is a missing false trigger signal in the blade arrival time signal;

[0086] Figure 5 It is a schematic structural diagram of a blade state evaluation device for a marine gas turbine. Specific implementation manners

[0087] In order to understand the features and technical content of the embodiments of the present application in more detail, the implementation of the embodiments of the present application will be described in detail below with reference to the accompanying drawings. The accompanying drawings are only for reference and explanation, and are not used to limit the embodiments of the present application.

[0088] In the description of the embodiments of the present application, it should be noted that unless otherwise specified and limited, the term "connection" should be understood in a broad sense. For example, it can be an electrical connection, or the connection inside two components. It can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meaning of the above terms can be understood according to specific situations.

[0089] It should be noted that the terms "first / second / third" involved in the embodiments of the present application are only used to distinguish similar objects, and do not represent a specific order for the objects. It can be understood that "first / second / third" can be interchanged with a specific order or sequence when allowed. It should be understood that the objects distinguished by "first / second / third" can be interchanged under appropriate circumstances, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here.

[0090] Refer to Figure 1 , Figure 1 It is a flowchart of a method for evaluating the state of blades of a marine gas turbine provided by the present application, including the following steps:

[0091] S110. Arrange a tip timing sensor on the casing corresponding to the top of the rotor blade of the marine gas turbine to measure the blade arrival time, set a key phase on the rotor of the marine gas turbine, and arrange a key phase timing sensor on the top of the key phase to measure the key phase arrival time.

[0092] As Figure 2 shown, Figure 2 in S O is the key phase timing sensor arranged on the top of the key phase. The key phase arrival time of the nth rotation period measured is t o,n , and the key phase arrival time of the (n + 1)th rotation period is t o,n+1 , S1 is the tip timing sensor arranged on the casing corresponding to the top of the rotor blade. The arrival time of the No. 1 blade in the nth rotation period measured is t 1,n , and the arrival time of the bth blade in the nth rotation period is t b,n .

[0093] S120. Calculate the blade arrival time window width based on the key phase arrival time and the number of blades, calculate the range of the blade arrival time based on the blade arrival time window width, the key phase arrival time, and the blade number, and determine the validity of the blade arrival time data based on the range of the blade arrival time.

[0094] Specifically, calculate the blade arrival time window width through the following formula:

[0095]

[0096] Where: T = t o,n+1 - t o,n , n b is the number of blades.

[0097] Calculate the range of the blade arrival time through the following formula:

[0098] t o,n +(b - 1)t w ≤ t b,n ≤ t o,n + bt w

[0099] Furthermore, determine the validity of the blade arrival time data based on the range of the blade arrival time. If the blade arrival time t b,n meets the range of the blade arrival time, the blade arrival time data is valid. If the blade arrival time t b,n does not meet the range of the blade arrival time, the blade arrival time data is invalid.

[0100] If there are multiple blade arrival time signals or no blade arrival time signals within the range of the blade arrival time, this situation is a mis-triggering of the blade arrival time signal, and the mis-triggered data needs to be cleaned.

[0101] S130. Calculate the key phase rotation frequency based on the key phase arrival time, and calculate the actual passing frequency between two blade arrival time signals based on the blade arrival time. If the actual passing frequency between two blade arrival time signals is greater than the product of the key phase rotation frequency and the number of blades, there are redundant mis-triggered signals in the blade arrival time, and the redundant arrival time signals corresponding to this passing frequency are removed; if the actual passing frequency between two blade arrival time signals is less than the product of the key phase rotation frequency and the number of blades, there are missing mis-triggered signals in the blade arrival time, and the missing arrival time signals are supplemented based on the key phase rotation frequency.

[0102] Calculate the key phase rotation frequency through the following formula:

[0103]

[0104] Calculate the actual passing frequency between the signals of the arrival times of two blades using the following formula:

[0105]

[0106] Compare the actual passing frequency between the signals of the arrival times of two blades with the product of the keyphasor rotation frequency and the number of blades

[0107] If there are redundant false trigger signals in the signals of the arrival times of the blades. The cleaning method for this situation is to directly remove the redundant arrival time signals corresponding to this passing frequency.

[0108] If there are missing false trigger signals in the signals of the arrival times of the blades. The cleaning method for this situation is to supplement the missing arrival time signals according to the keyphasor rotation frequency. The supplement is carried out using the following formula:

[0109]

[0110] Specifically Figure 2 in [description], S1 is the tip timing sensor arranged on the casing corresponding to the top of the rotor blade. There are redundant false trigger signals in the measured signals of the arrival times of the blades. As Figure 3 shown, the actual passing frequency between the signals of the arrival times of two blades calculated from the redundant false trigger signals is greater than the product of the keyphasor rotation frequency and the number of blades. The redundant false trigger signals are removed, and the actual passing frequency between the signals of the arrival times of two blades calculated from the cleaned arrival time data is consistent with the product of the keyphasor rotation frequency and the number of blades. Figure 2 in [description], S2 is another tip timing sensor arranged on the casing corresponding to the top of the rotor blade. There are missing false trigger signals in the measured signals of the arrival times of the blades. As Figure 4 shown, when there are missing false trigger signals, the actual passing frequency between the signals of the arrival times of two blades calculated is less than the product of the keyphasor rotation frequency and the number of blades. The missing false trigger signals are supplemented, and the actual passing frequency between the signals of the arrival times of two blades calculated from the cleaned arrival time data is consistent with the product of the keyphasor rotation frequency and the number of blades.

[0111] S140. Construct a rotational speed measurement matrix based on the keyphasor arrival time, solve the rotational speed matrix by the least squares method, and calculate the blade rotational speed.

[0112] Construct the rotational speed measurement matrix using the following formula:

[0113]

[0114] Expressed in matrix form as:

[0115] C = MF

[0116] Among them, C is a matrix related to the number of rotation cycles of the blade. The value of c is related to the rotational speed change rate, and in this application, it is taken as 4. M is a matrix related to the arrival time of the key phase, and F is the rotational speed matrix. The rotational speed matrix is obtained by the least squares method:

[0117] F = (M T M) -1 M T C

[0118] Then, the blade rotational speed is calculated through the following formula:

[0119]

[0120] Among them, f0 is the initial rotational speed of the blade when the key phase reaches the key phase timing sensor, is the change term of the rotational speed with time, indicates the constant speed working condition when, c = 1 indicates the linear variable speed working condition, and c > 1 indicates the non-linear variable speed working condition.

[0121] S150. Calculate the blade vibration displacement based on the key phase arrival time, blade arrival time, blade rotational speed, blade tip rotation radius, and the angle between the blade and the key phase.

[0122] The blade vibration displacement is calculated through the following formula:

[0123]

[0124] Among them, is the angle between the b-th blade and the key phase, and R is the blade tip rotation radius.

[0125] S160. Analyze and process the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade.

[0126] The steady-state displacement and transient displacement of the blade are extracted through the following method:

[0127] Use the SG filter (Savitzky-Golay filter) to filter the blade vibration displacement. The low-frequency displacement component obtained by filtering is the steady-state displacement of the blade. Then, the transient displacement of the blade is calculated through the following formula:

[0128] x t = x - x s

[0129] Among them, x s is the steady-state displacement, and x t is the transient displacement.

[0130] S170. Reconstruct the transient displacement and steady-state displacement of the blade into dynamic stress and steady-state stress, calculate the stress of the blade, compare the stress of the blade with the stress thresholds in different states, and evaluate the blade state.

[0131] The stress of the blade is calculated by the following method:

[0132]

[0133] where μ s is the displacement-stress reconstruction coefficient of the steady-state displacement, is the displacement-stress transfer function of the vibration mode, both obtained through blade modal analysis, and σ is the stress value of the blade.

[0134] Furthermore, by comparing the relationship between σ and σ1, σ2, the blade state evaluation is achieved by the following method:

[0135] When σ < σ1, the blade is in a healthy state;

[0136] When σ1 < σ < σ2, the blade is in a sub-healthy state;

[0137] When σ > σ2, the blade is in a faulty state.

[0138] where σ1 is the stress threshold for the healthy state of the blade, and σ2 is the stress threshold for the sub-healthy state of the blade. The values of σ1 and σ2 are determined through dynamic simulation calculation combined with calibration tests.

[0139] S180. Send feedback information based on the blade state evaluation result.

[0140] Specifically, when the blade is in a healthy state, no warning information is sent. When the blade is in a sub-healthy state, a warning is issued. When the blade is in a faulty state, an alarm is issued.

[0141] Refer to Figure 5 , a blade state evaluation device 500 provided by the present application includes:

[0142] A data acquisition module 510, configured to acquire the arrival time of the rotor blade and the arrival time of the key phase.

[0143] A data validity judgment module 520, configured to judge the validity of the blade arrival time data.

[0144] A data cleaning module 530, configured to clean the mis-triggered blade arrival time data.

[0145] A rotational speed calculation module 540, configured to solve the rotational speed measurement matrix constructed by the key phase arrival time, and then calculate the rotational speed of the rotor blade.

[0146] A vibration calculation module 550 is configured to calculate the vibration displacement of the blade based on the blade arrival time, the key phase arrival time, the blade rotation speed, the tip rotation radius, and the angle between the blade and the key phase.

[0147] A vibration analysis module 560 is configured to analyze and process the vibration displacement of the blade, and extract the steady-state displacement and transient displacement of the blade.

[0148] A state evaluation module 570 is configured to reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and evaluate the blade state by comparing the stress of the blade with the stress thresholds of different states.

[0149] A state warning module 580 is configured to send feedback information according to the blade state evaluation result. When the blade is in a healthy state, the state warning module does not send a warning message. When the blade is in a sub-healthy state, the state warning module issues a warning. When the blade is in a faulty state, the state warning module issues an alarm.

[0150] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is run by a processor, it can execute all the processes of the method for evaluating the state of a marine gas turbine blade in the above-mentioned embodiments. The specific implementation manner can be referred to the method embodiments and will not be elaborated here.

[0151] In several embodiments provided by the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. The above-described embodiments are merely illustrative. For example, the data validity judgment module can be incorporated into the data acquisition module, and the data acquisition module directly judges the data validity. The vibration calculation module can also be incorporated into the rotation speed calculation module, or both the vibration calculation module and the rotation speed calculation module can be incorporated into the vibration analysis module.

[0152] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principle. Those skilled in the art should understand that the scope of disclosure involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but also covers other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosure concept. For example, the above features are mutually replaced with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A method for evaluating the state of a marine gas turbine blade, characterized in that The method includes: Obtaining the arrival time of the rotor blade and the arrival time of the key phase; Judging the validity of the blade arrival time data; Cleaning the mis-triggered blade arrival time data; Solving the rotational speed measurement matrix constructed by the arrival time of the key phase, and then calculating the rotational speed of the rotor blade; Calculating the blade vibration displacement based on the blade arrival time, the key phase arrival time, the blade rotational speed, the tip rotation radius, and the angle between the blade and the key phase; Analyzing and processing the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade; Reconstructing the transient displacement and steady-state displacement of the blade into the stress of the blade, and evaluating the blade state by comparing the stress of the blade with the stress thresholds in different states; According to the blade state evaluation result, sending feedback information. When the blade is in a healthy state, the state warning module does not send a warning message. When the blade is in a sub-healthy state, the state warning module issues a warning. When the blade is in a faulty state, the state warning module issues an alarm; The obtaining of the arrival time of the rotor blade and the arrival time of the key phase includes: Arrange tip timing sensors on the casing corresponding to the top of the rotor blades of a marine gas turbine to measure the moment when the blade reaches the tip timing sensor , set a key phase on the rotor of the marine gas turbine, and arrange a key phase timing sensor on the top of the key phase to measure the moment when the key phase reaches the key phase timing sensor , the subscript b represents the blade number, the subscript o represents the key phase, and the subscript n represents the number of rotation cycles; The judging of the validity of the blade arrival time data includes: The period of one rotation of the rotor is: (1) The arrival time window width of each blade within this period is: (2) is the number of blades on the bladed disk under test; The range of the blade arrival time is: (3) In the above formula, is the arrival time of the key phase in the (n + 1)-th rotation period, and b is the blade number; Judging the validity of the blade arrival time data by formula (3).

2. The method according to claim 1, characterized in that, The cleaning of the mis-triggered blade arrival time data includes: If there are multiple arrival time signals within the value range of formula (3) or there is no blade arrival time signal, this situation is a mis-trigger of the tip timing signal. The mis-triggered data cleaning method is as follows: The rotational frequency of the key phase is: (4) The actual passing frequency between adjacent blade arrival time signals is: (5) If , there are redundant false trigger signals in the blade arrival time signal. The cleaning method in this case is to directly remove the redundant arrival time signals corresponding to this passing frequency; If , there is a missing false trigger signal in the blade arrival time signal. The cleaning method for this situation is to supplement the missing arrival time signal according to the key phase rotation frequency. The supplement method is as follows: (6) In the above formula, is the arrival time of the (b + 1)-th blade in the n-th rotation period.

3. The method according to claim 2, wherein The solving of the rotational speed measurement matrix constructed by the arrival time of the key phase, and then calculating the rotational speed of the rotor blade includes: In the tip timing technology, the method for calculating the blade rotational speed is: (7) The rotational speed calculated by formula (7) is the average rotational speed of one rotation of the blade, which is applicable to the constant speed working condition and not applicable to the variable speed working condition. The rotational speed calculation method under all working conditions proposed in this application is as follows: The rotational speed of the gas turbine rotor blade can be expressed as: (8) In Equation (8), is the term of rotational speed varying with time, represents the constant-speed working condition when, and represents the linear variable-speed working condition when c = 1. When c 1 represents the non-linear variable-speed working condition; Since the transient displacement and steady-state displacement of the rotor blade will cause a deviation in the blade arrival time, if the blade arrival time data is used to calculate the rotational speed, a calculation error will be introduced. Therefore, a rotational speed measurement matrix is constructed based on the key phase arrival time as follows: (9) Formula (9) written in matrix form is: (10) In formula (10), C is a matrix related to the number of blade rotation circles, the value of c is related to the rotational speed change rate, and 4 is taken in this application. M is a matrix related to the key phase arrival time, F is the rotational speed matrix, and can be obtained by the least squares method: (11) After obtaining the rotational speed matrix, the blade rotational speed can be calculated according to formula (8).

4. The method according to claim 3, characterized in that The calculating of the blade vibration displacement based on the blade arrival time, the key phase arrival time, the blade rotational speed, the tip rotation radius, and the angle between the blade and the key phase includes: In the tip timing technology, the method for calculating the blade vibration displacement is: (12) (13) In formula (13), is the angle between the blade No. b and the key phase, and R is the tip rotation radius; since the rotational speed in formula (12) is the average rotational speed for one revolution of the blade, the blade vibration displacement calculated by formula (12) is the vibration displacement under the constant speed condition and is not applicable to the variable speed condition; the method for calculating the blade vibration displacement under all working conditions proposed in this application is as follows: (14) The blade vibration displacement calculated by formula (14) includes the tip vibration displacement caused by the modal response of the blade and the tip steady-state displacement caused by axial thrust, pneumatic pressure, rotor thermal expansion, and corrosion deformation.

5. The method according to claim 4, wherein Analyze and process the vibration displacement of the blade to extract the steady-state displacement and transient displacement of the blade, including: Analyze and process the vibration displacement of the blade to extract the steady-state displacement and transient displacement of the blade. The vibration displacement of the blade can be expressed as: (15) Among them, is the steady-state displacement. The extraction method is to filter the blade vibration displacement using an SG filter, and the low-frequency displacement component obtained by filtering is the steady-state displacement of the blade; is the transient displacement. The transient displacement can be obtained by subtracting the steady-state displacement from the blade vibration displacement.

6. The method according to claim 5, characterized in that, Reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and evaluate the blade state by comparing the stress of the blade with the stress thresholds in different states, including: Through blade modal analysis, obtain the displacement-stress transfer function of the vibration mode corresponding to the transient displacement of the blade and the displacement-stress reconstruction coefficient of the steady-state displacement. Reconstruct the analyzed transient displacement and steady-state displacement into dynamic stress and steady-state stress, and then calculate the stress of the blade as: (16) Among them, is the displacement-stress reconstruction coefficient of the steady-state displacement, is the displacement-stress transfer function of the vibration mode, is the stress value of the blade; Then, the states of the blades are divided into healthy state, sub-healthy state and fault state, and the stress thresholds for different blade states are determined through dynamic simulation calculations combined with calibration tests. The stress threshold for the healthy state is , and the stress threshold for the sub-healthy state is . By comparing with and , the blade state assessment is realized; Among them, when , the blade is in a healthy state. When , the blade is in a sub-healthy state. When , the blade is in a faulty state.

7. A device for evaluating the state of a marine gas turbine blade, characterized in that, For implementing the method described in claim 1, the device includes: a data acquisition module, a data validity judgment module, a data cleaning module, a rotational speed calculation module, a vibration calculation module, a vibration analysis module, a state evaluation module, and a state warning module; The data acquisition module is used to obtain the arrival time of the rotor blade and the arrival time of the key phase; The data validity judgment module is used to judge the data validity of the arrival time of the blade; The data cleaning module is used to clean the data of the arrival time of the blade with mis-triggering; The rotational speed calculation module is used to solve the rotational speed measurement matrix constructed by the arrival time of the key phase, and then calculate the rotational speed of the rotor blade; The vibration calculation module is used to calculate the vibration displacement of the blade based on the arrival time of the blade, the arrival time of the key phase, the rotational speed of the blade, the tip rotation radius, and the angle between the blade and the key phase; The vibration analysis module is used to analyze and process the vibration displacement of the blade to extract the steady-state displacement and transient displacement of the blade; The state evaluation module is used to reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and evaluate the blade state by comparing the stress of the blade with the stress thresholds in different states; The state warning module is used to send feedback information according to the blade state evaluation result. When the blade is in a healthy state, the state warning module does not send a warning message. When the blade is in a sub-healthy state, the state warning module issues a warning. When the blade is in a faulty state, the state warning module issues an alarm.

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