CN116146289A - A method and device for assessing the state of a ship's gas turbine blade - Google Patents

Abstract

The embodiment of the application provides a ship gas turbine blade state evaluation method and device. The problems of false triggering caused by factors such as complex tip end surface morphology of the rotor blade of the ship gas turbine, pollution scaling on the surfaces of the tip and the timing sensor and the like are solved through a data validity judging algorithm and a data cleaning algorithm; the calculation problem of the rotating speed under the full working condition is solved through a rotating speed matrix solving algorithm; the problem of comprehensive and accurate calculation of transient displacement and steady displacement is solved through a blade vibration calculation algorithm; and the blade state evaluation is realized through the reconstruction analysis of the transient displacement and the steady displacement of the blade to the stress of the blade and the comparison with the state stress threshold value. Compared with the prior art, the invention improves the engineering applicability of the blade tip timing technology in the vibration monitoring and state evaluation of the rotor blade of the ship gas turbine, and has the evaluation capability of all working conditions and higher accuracy.

Description

A method and device for evaluating the condition of a ship gas turbine blade

Technical Field

The present application relates to the technical field of rotor blade status assessment and health management in a ship gas turbine compressor and turbine, and in particular to a ship gas turbine blade status assessment method and assessment device.

Background Art

Blades are the core components for energy conversion in ship gas turbines, and their operation safety is extremely important. Dynamic monitoring of blade vibration and status assessment is a necessary step to understand the health status and functional characteristics of blades, and plays an important basic role in improving their operational reliability and fault tracing and root-causing. After years of development, the gas turbine dynamic monitoring system, which mainly monitors casing vibration and cooperates with oil, gas path and performance parameters, has been able to diagnose most faults and has functions such as warning, alarm and indication, but it is difficult to monitor and evaluate the status of blades.

The blade tip timing method is currently the mainstream method for online monitoring of blade vibration and has been widely studied and developed in recent years. This method installs several blade tip timing sensors on the casing to measure the time when the blade reaches the sensor, calculates the blade vibration displacement based on the difference between the theoretical arrival time and the actual arrival time and the rotation speed, and further analyzes the vibration displacement sequence to evaluate the operating status of the blade. This technology has been valued and recognized by the industry and academia due to its non-invasive measurement, simple system structure, easy sensor installation, and low measurement cost. However, this technology has the following shortcomings when applied to the status assessment of ship gas turbine rotor blades:

(1) The basic principle of blade tip timing technology assumes that the speed of the blade is constant within one rotation. However, the start-up, speed increase and decrease, and emergency stop of a ship gas turbine are often a process of rapid speed change. Its operating conditions include variable speed conditions and constant speed conditions. The current technology cannot meet the monitoring needs of all operating conditions.

(2) This technology only considers the transient displacement caused by the modal vibration of the blade during resonance. During the operation of ship gas turbine blades, they are also subject to steady-state displacement caused by aerodynamic loads, centrifugal loads, thermal loads, and corrosion deformation. The current technology cannot meet the comprehensive monitoring needs of transient displacement and steady-state displacement.

(3) The tip surface morphology of the ship gas turbine rotor blade is complex, and the tip and timing sensor surface are easily affected by factors such as contamination and scaling, which leads to the false triggering of lost data or redundant data in the tip timing signal. The false triggering affects the accuracy of the vibration displacement calculation results.

Therefore, the blade vibration displacement calculated by current technology is inaccurate and incomplete, and cannot meet the engineering needs of ship gas turbine rotor blade status assessment.

Summary of the invention

In view of this, the purpose of this application is to provide a method and device for evaluating the state of a ship gas turbine blade, so as to comprehensively monitor and evaluate the state of the gas turbine rotor blade under all working conditions. The false triggering problem of the blade tip timing signal is solved by the data validity judgment algorithm and the data cleaning algorithm; the speed matrix solution algorithm is used to solve the speed calculation problem under all working conditions; the blade vibration displacement calculation algorithm is used to solve the comprehensive calculation problem of transient displacement and steady-state displacement; the stress of the blade is obtained by reconstructing and analyzing the transient displacement and steady-state displacement of the blade into dynamic stress and steady-state stress, and compared with the state stress threshold, and finally the blade state evaluation is realized. Thereby improving the applicability and accuracy of the blade tip timing technology in the state evaluation of ship gas turbine rotor blades.

The present application embodiment provides a method for evaluating the status of a ship gas turbine blade, comprising:

Obtain the arrival time of the rotor blades and the arrival time of the key phase;

Determine the validity of blade arrival time data;

Clean the falsely triggered blade arrival time data;

Solve the speed measurement matrix constructed by the key phase arrival time to calculate the speed of the rotor blades;

The blade vibration displacement is calculated based on the blade arrival time, the key phase arrival time, the blade speed, the blade tip rotation radius, and the angle between the blade and the key phase;

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

The transient displacement and steady-state displacement of the blade are reconstructed into the stress of the blade, and the blade state is evaluated by comparing the stress of the blade with the stress thresholds of different states;

Feedback information is sent based on the blade status assessment results. When the blade is in a healthy state, the status warning module does not send warning information. When the blade is in a sub-healthy state, the status warning module issues a warning. When the blade is in a fault state, the status warning module issues an alarm.

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

A blade tip timing sensor is arranged on the casing corresponding to the top of the ship gas turbine rotor blade to measure the time t _b,n when the blade reaches the blade tip timing sensor, a key phase is set on the ship gas turbine rotor, and a key phase timing sensor is arranged on the top of the key phase to measure the time t _o,n 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 rotations.

In some embodiments, determining the validity of blade arrival time data includes:

The period of one rotor rotation is:

T＝t _o,n+1 -t _o,n (1)

The arrival time window width of each leaf in this cycle is:

n _b is the number of leaves;

The range of blade arrival time is:

t _o,n +(b-1)t _w ≤t _b,n ≤t _o,n +bt _w (3)

In the above formula, t _o,n is the arrival time of the bond phase of the nth rotation period, t _o,n+1 is the arrival time of the bond phase of the n+1th rotation period, n _b is the number of blades on the measured blade disk, and b is the blade number;

The validity of the blade arrival time data is determined by formula (3).

In some embodiments, the cleaning of the falsely triggered blade arrival time data includes:

If there are multiple arrival time signals or no blade arrival time signal within the value range of formula (3), this is a false triggering of the blade tip timing signal. The false triggering data cleaning method is as follows:

The switching frequency of the key phase is:

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

则叶片到达时刻信号中存在多余的误触发信号，此种情况的清洗方法为直接剔除此通过频率对应的多余到达时刻信号；like

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

则叶片到达时刻信号中存在丢失的误触发信号，此种情况的清洗方法为按照键相转频补充丢失的到达时刻信号，补充方法为：like

Then there is a lost false trigger signal in the blade arrival time signal. The cleaning method in this case is to supplement the lost arrival time signal according to the key phase frequency conversion. The supplement method is:

In the above formula, _tb,n is the arrival time of blade b in the nth rotation cycle, and _tb+1,n is the arrival time of blade b+1 in the nth rotation cycle.

In some embodiments, solving the rotation speed measurement matrix constructed by the key phase arrival time, and then calculating the rotation speed of the rotor blade, includes:

In blade tip timing technology, the method for calculating blade speed is:

The speed calculated by formula (7) is the average speed of the blade rotating one circle, which is applicable to constant speed conditions but not to variable speed conditions. The speed calculation method under all conditions proposed in this application is as follows:

The rotation speed of the gas turbine rotor blades can be expressed as:

为转速随时间的变化项，

时表示恒速工况，c＝1时表示线性变速工况，c>1时表示非线性变速工况；In formula (8), _f0 is the initial speed of the blade when the key phase reaches the key phase timing sensor,

is the time-varying term of the speed,

When c=1, it indicates a constant speed condition; when c>1, it indicates a linear speed change condition;

Since the transient displacement and steady-state displacement of the rotor blades will cause deviations in the blade arrival time, using the blade arrival time data to calculate the speed will introduce calculation errors. Therefore, the speed measurement matrix is constructed based on the key phase arrival time as follows:

Formula (9) is written in matrix form as:

C＝MF (10)

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

^F ＝( ^MTM ) ^-1MTC (11)

After obtaining the speed matrix, the blade speed can be calculated according to formula (8).

In some embodiments, the blade vibration displacement is calculated based on the blade arrival time, the key phase arrival time, the blade rotation speed, the blade tip rotation radius, and the angle between the blade and the key phase, including:

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

为b号叶片与键相之间的夹角，R为叶尖旋转半径；由于式(12)中的转速为叶片旋转一圈的平均转速，因此式(12)计算得到的叶片振动位移为恒速工况时的振动位移，不适用于变速工况；本申请提出全工况下的叶片振动位移计算方法如下：In formula (13),

is the angle between blade b and the key phase, and R is the blade tip rotation radius; since the speed in formula (12) is the average speed of the blade rotating for one circle, the blade vibration displacement calculated by formula (12) is the vibration displacement under constant speed conditions, which is not applicable to variable speed conditions; the present application proposes a method for calculating blade vibration displacement under all conditions as follows:

The blade vibration displacement calculated by formula (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 movement, aerodynamic pressure, rotor thermal expansion and corrosion deformation.

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

The blade vibration displacement is analyzed and processed to extract the steady-state displacement and transient displacement of the blade. The blade vibration displacement can be expressed as:

x＝ _xs + _xt (15)

Among them, _xs is the steady-state displacement. The extraction method is to use the SG filter to filter the blade vibration displacement. The low-frequency displacement component obtained by filtering is the steady-state displacement of the blade; _xt is the transient displacement. The transient displacement can be obtained by subtracting the steady-state displacement from the blade vibration displacement.

In some embodiments, the step of reconstructing the transient displacement and steady-state displacement of the blade into the stress of the blade, and evaluating the state of the blade by comparing the stress of the blade with stress thresholds of different states, includes:

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

为振动模态的位移-应力传递函数，σ为叶片的应力值；Where, _μs is the displacement-stress reconstruction coefficient of the steady-state displacement,

is the displacement-stress transfer function of the vibration mode, σ is the stress value of the blade;

Then, the blade status is divided into healthy status, subhealthy status and fault status. The stress thresholds of blades in different status are determined by dynamic simulation calculation combined with calibration test. The stress threshold of healthy status is σ ₁ , and the stress threshold of subhealthy status is σ ₂ . By comparing the relationship between σ and σ ₁ and σ ₂ , the blade status evaluation is realized.

Among them, when σ<σ ₁ , the blade is in a healthy state, when σ ₁ <σ<σ ₂ , the blade is in a sub-healthy state, and when σ>σ ₂ , the blade is in a faulty state.

In a second aspect, an embodiment of the present application provides a device for evaluating the state of a ship gas turbine blade, including: a data acquisition module, a data validity judgment module, a data cleaning module, a 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 acquire the arrival time of the rotor blades and the arrival time of the key phase;

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

The data cleaning module is used to clean the falsely triggered blade arrival time data;

The speed calculation module is used to solve the speed measurement matrix constructed by the key phase arrival time, and then calculate the speed of the rotor blade;

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

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;

The state assessment module is used to reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and to assess the state of the blade by comparing the stress of the blade with stress thresholds of different states;

The status warning module is used to send feedback information based on the blade status evaluation result. When the blade is in a healthy state, the status warning module does not send warning information. When the blade is in a sub-healthy state, the status warning module issues a warning. When the blade is in a fault state, the status warning module issues an alarm.

The above-mentioned embodiments of the present application provide a method and device for evaluating the state of a ship 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 surface morphology of the ship gas turbine rotor blade, the contamination and scaling of the blade tip and the timing sensor surface, etc. is solved; through the speed matrix solution algorithm, the problem of calculating the speed under all working conditions is solved; through the blade vibration calculation algorithm, the problem of comprehensive and accurate calculation of transient displacement and steady-state displacement is solved; through the reconstruction analysis of the blade transient displacement and steady-state displacement to the blade stress, and comparing 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 blade tip timing technology in the vibration monitoring and state evaluation of ship gas turbine rotor blades, and has the evaluation capability of all working conditions and higher accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG1 is a schematic diagram of a flow chart of a method for evaluating the condition of a ship gas turbine blade;

FIG2 is a schematic diagram showing the principle of obtaining the blade arrival time and the key phase arrival time;

FIG3 shows the cleaning result when there are redundant false trigger signals in the blade arrival timing signal;

FIG4 shows the cleaning result when there is a missing false trigger signal in the blade arrival timing signal;

FIG5 is a schematic diagram of the structure of a device for evaluating the condition of a ship gas turbine blade.

DETAILED DESCRIPTION

In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present application, the implementation of the embodiments of the present application is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present application.

In 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 a connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

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 is understandable that the specific order or sequence of "first\second\third" can be interchanged where permitted. It should be understood that the objects distinguished by "first\second\third" can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

Refer to FIG1 , which is a flow chart of a method for evaluating the condition of a ship gas turbine blade provided by the present application, comprising the following steps:

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

As shown in Figure 2, in Figure 2, _S0 is the key phase timing sensor arranged at the top of the key phase, and the measured arrival time of the key phase in the nth rotation cycle is _t0,n , and the arrival time of the key phase in the n+1th rotation cycle is _t0,n+1 . _S1 is the blade tip timing sensor arranged on the casing corresponding to the top of the rotor blade, and the measured arrival time of blade No. 1 in the nth rotation cycle is _t1,n , and the arrival time of blade No. b in the nth rotation cycle is _tb,n .

S120, calculating the blade arrival time window width based on the key phase arrival time and the number of blades, calculating 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 judging the validity of the blade arrival time data based on the range of the blade arrival time.

Specifically, the blade arrival time window width is calculated by the following formula:

Where: T = t _o,n+1 -t _o,n , n _b is the number of blades.

The range of blade arrival times is calculated using the following formula:

t _o,n +(b-1)t _w ≤t _b,n ≤t _o,n +bt _w

Then, the validity of the blade arrival time data is judged according to the range of the blade arrival time. If the blade arrival time _tb,n satisfies the range of the blade arrival time, the blade arrival time data is valid. If the blade arrival time _tb,n does not satisfy the range of the blade arrival time, the blade arrival time data is invalid.

If there are multiple blade arrival time signals or no blade arrival time signal within the range of the blade arrival time, this is a false triggering of the blade arrival time signal, and the false triggering data needs to be cleaned.

S130, calculate the key phase rotation frequency based on the key phase arrival time, and calculate the actual passing frequency between the two blade arrival time signals based on the blade arrival time. If the actual passing frequency between the two blade arrival time signals is greater than the product of the key phase rotation frequency and the number of blades, there are redundant false trigger signals in the blade arrival time, and the redundant arrival time signals corresponding to this passing frequency are eliminated; if the actual passing frequency between the two blade arrival time signals is less than the product of the key phase rotation frequency and the number of blades, there are lost false trigger signals in the blade arrival time, and the lost arrival time signals are supplemented based on the key phase rotation frequency.

The bond phase transition frequency is calculated by the following formula:

The actual passing frequency between the arrival time signals of the two blades is calculated by the following formula:

Compare the actual passing frequency between the arrival time signals of the two blades with the product of the key phase rotation frequency and the number of blades,

则叶片到达时刻信号中存在多余的误触发信号，此种情况的清洗方法为直接剔除此通过频率对应的多余到达时刻信号。if

There are redundant false trigger signals in the blade arrival time signal. The cleaning method for this situation is to directly remove the redundant arrival time signal corresponding to the passing frequency.

则叶片到达时刻信号中存在丢失的误触发信号，此种情况的清洗方法为按照键相转频补充丢失的到达时刻信号，通过以下公式进行补充：if

There is a lost false trigger signal in the blade arrival time signal. The cleaning method for this situation is to supplement the lost arrival time signal according to the key phase frequency conversion, and supplement it through the following formula:

Specifically, _S1 in FIG2 is a blade tip timing sensor arranged on the casing corresponding to the top of the rotor blade, and there are redundant false trigger signals in the measured blade arrival time signal. As shown in FIG3, the actual passing frequency between the two blade arrival time signals calculated by the redundant false trigger signals is greater than the product of the key phase rotation frequency and the number of blades, and the redundant false trigger signals are eliminated. The actual passing frequency between the two blade arrival time signals calculated by the arrival time data after cleaning is consistent with the product of the key phase rotation frequency and the number of blades. _S2 in FIG2 is another blade tip timing sensor arranged on the casing corresponding to the top of the rotor blade, and there are lost false trigger signals in the measured blade arrival time signal. As shown in FIG4, when there is a lost false trigger signal, the actual passing frequency between the two blade arrival time signals calculated is less than the product of the key phase rotation frequency and the number of blades, and the lost false trigger signal is supplemented. The actual passing frequency between the two blade arrival time signals calculated by the arrival time data after cleaning is consistent with the product of the key phase rotation frequency and the number of blades.

S140, constructing a rotation speed measurement matrix based on the key phase arrival time, solving the rotation speed matrix by the least square method, and calculating the blade rotation speed.

The speed measurement matrix is constructed using the following formula:

It is expressed in matrix form as:

C＝MF

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

F＝( ^{MTM ) -1MTC}

Then, the blade speed is calculated by the following formula:

为转速随时间的变化项，

时表示恒速工况，c＝1时表示线性变速工况，c>1时表示非线性变速工况。Where _f0 is the initial speed of the blade when the key phase reaches the key phase timing sensor,

is the time-varying term of the speed,

When c=1, it indicates a constant speed condition; when c>1, it indicates a linear speed change condition;

S150, calculating the blade vibration displacement based on the key phase arrival time, the blade arrival time, the blade rotation speed, the blade tip rotation radius, and the angle between the blade and the key phase.

The blade vibration displacement is calculated by the following formula:

为b号叶片与键相之间的夹角，R为叶尖旋转半径。in,

is the angle between blade b and the key phase, and R is the blade tip rotation radius.

S160, analyzing and processing the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade.

The steady-state displacement and transient displacement of the blade are extracted by:

The blade vibration displacement is filtered using the SG filter (Savitzky-Golay filter), and 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 using the following formula:

x _t = x _s

Among them, _xs is the steady-state displacement and _xt is the transient displacement.

S170, reconstructing the transient displacement and steady-state displacement of the blade into dynamic stress and steady-state stress, calculating the stress of the blade, comparing the stress of the blade with stress thresholds of different states, and evaluating the state of the blade.

The stresses in the blade are calculated by:

为振动模态的位移-应力传递函数，均通过叶片模态分析得到，σ为叶片的应力值。Where, _μs is the displacement-stress reconstruction coefficient of the steady-state displacement,

is the displacement-stress transfer function of the vibration mode, which is obtained through blade modal analysis, and σ is the stress value of the blade.

Then, by comparing the relationship between σ and σ ₁ and σ ₂ , the blade status evaluation can be achieved in the following way:

When σ<σ ₁ , the leaves are in a healthy state;

When σ ₁ <σ<σ ₂ , the leaves are in a sub-healthy state;

When σ>σ ₂ , the blade is in a fault state.

Among them, σ ₁ is the stress threshold of the healthy state of the blade, and σ ₂ is the stress threshold of the sub-healthy state of the blade. The values of σ ₁ and σ ₂ are determined by dynamic simulation calculation combined with calibration test.

S180: Send feedback information based on the blade status evaluation result.

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; and when the blade is in a fault state, an alarm is issued.

Referring to FIG. 5 , a ship gas turbine blade state assessment device 500 provided in the present application includes:

The data acquisition module 510 is used to acquire the arrival time of the rotor blades and the arrival time of the key phase.

The data validity judgment module 520 is used to judge the validity of the blade arrival time data.

The data cleaning module 530 is used to clean the falsely triggered blade arrival time data.

The speed calculation module 540 is used to solve the speed measurement matrix constructed by the key phase arrival time, and then calculate the speed of the rotor blade.

The vibration calculation module 550 is used to calculate the blade vibration displacement based on the blade arrival time, the key phase arrival time, the blade rotation speed, the blade tip rotation radius, and the angle between the blade and the key phase.

The vibration analysis module 560 is used to analyze and process the blade vibration displacement and extract the steady-state displacement and transient displacement of the blade.

The state assessment module 570 is used to reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and to assess the state of the blade by comparing the stress of the blade with stress thresholds of different states.

The status warning module 580 is used to send feedback information based on the blade status evaluation results. When the blade is in a healthy state, the status warning module does not send warning information. When the blade is in a sub-healthy state, the status warning module issues a warning. When the blade is in a fault state, the status warning module issues an alarm.

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, the entire process of the ship gas turbine blade condition assessment method in the above-mentioned embodiment can be executed. The specific implementation method can be found in the method embodiment, which will not be repeated here.

In the several embodiments provided in the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. The embodiments described above 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 speed calculation module, or both the vibration calculation module and the speed calculation module can be incorporated into the vibration analysis module.

The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. 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 a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above features are formed by replacing each other with the technical features with similar functions disclosed in this application (but not limited to).

Claims (9)

1. A method for evaluating the condition of a ship gas turbine blade, characterized in that the method comprises: Obtain the arrival time of the rotor blades and the arrival time of the key phase; Determine the validity of blade arrival time data; Clean the falsely triggered blade arrival time data; Solve the speed measurement matrix constructed by the key phase arrival time to calculate the speed of the rotor blades; The blade vibration displacement is calculated based on the blade arrival time, the key phase arrival time, the blade speed, the blade tip rotation radius, and the angle between the blade and the key phase; Analyze and process the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade; The transient displacement and steady-state displacement of the blade are reconstructed into the stress of the blade, and the blade state is evaluated by comparing the stress of the blade with the stress thresholds of different states; Feedback information is sent based on the blade status assessment results. When the blade is in a healthy state, the status warning module does not send warning information. When the blade is in a sub-healthy state, the status warning module issues a warning. When the blade is in a fault state, the status warning module issues an alarm. 2. The method according to claim 1, characterized in that the obtaining of the rotor blade arrival time and the key phase arrival time comprises: A blade tip timing sensor is arranged on the casing corresponding to the top of the ship gas turbine rotor blade to measure the time t _b,n when the blade reaches the blade tip timing sensor, a key phase is set on the ship gas turbine rotor, and a key phase timing sensor is arranged on the top of the key phase to measure the time t _o,n 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 rotations. 3. The method according to claim 2, characterized in that the step of judging the validity of the blade arrival time data comprises: The period of one rotor rotation is: T＝t _o,n+1 -t _o,n (1) The arrival time window width of each leaf in this cycle is:

n _b is the number of leaves; The range of blade arrival time is: t _o,n +(b-1)t _w ≤t _b,n ≤t _o,n +bt _w (3) In the above formula, t _o,n is the arrival time of the bond phase of the nth rotation period, t _o,n+1 is the arrival time of the bond phase of the n+1th rotation period, n _b is the number of blades on the measured blade disk, and b is the blade number; The validity of the blade arrival time data is determined by formula (3). 4. The method according to claim 3, characterized in that the cleaning of the falsely triggered blade arrival time data comprises: If there are multiple arrival time signals or no blade arrival time signal within the value range of formula (3), this is a false triggering of the blade tip timing signal. The false triggering data cleaning method is as follows: The switching frequency of the key phase is:

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

like

Then there are redundant false trigger signals in the blade arrival time signal. The cleaning method for this case is to directly remove the redundant arrival time signal corresponding to this passing frequency; like

Then there is a lost false trigger signal in the blade arrival time signal. The cleaning method in this case is to supplement the lost arrival time signal according to the key phase frequency conversion. The supplement method is:

In the above formula, _tb,n is the arrival time of blade b in the nth rotation cycle, and _tb+1,n is the arrival time of blade b+1 in the nth rotation cycle. 5. The method according to claim 4, characterized in that the solving of the rotation speed measurement matrix constructed by the key phase arrival time and then calculating the rotation speed of the rotor blades comprises: In blade tip timing technology, the method for calculating blade speed is:

The speed calculated by formula (7) is the average speed of the blade rotating one circle, which is applicable to constant speed conditions but not to variable speed conditions. The speed calculation method under all conditions proposed in this application is as follows: The rotation speed of the gas turbine rotor blades can be expressed as:

In formula (8), _f0 is the initial speed of the blade when the key phase reaches the key phase timing sensor,

is the time-varying term of the speed,

When c=1, it indicates a constant speed condition; when c>1, it indicates a linear speed change condition; Since the transient displacement and steady-state displacement of the rotor blades will cause deviations in the blade arrival time, using the blade arrival time data to calculate the speed will introduce calculation errors. Therefore, the speed measurement matrix is constructed based on the key phase arrival time as follows:

Formula (9) is written in matrix form as: C＝MF (10) In formula (10), C is a matrix related to the number of blade rotations, the value of c is related to the speed change rate, and in this application, it is taken as 4, M is a matrix related to the key phase arrival time, and F is a speed matrix, which can be obtained by the least squares method: ^F ＝( ^MTM ) ^-1MTC (11) After obtaining the speed matrix, the blade speed can be calculated according to formula (8). 6. The method according to claim 5, characterized in that the blade vibration displacement is calculated based on the blade arrival time, the key phase arrival time, the blade rotation speed, the blade tip rotation radius, and the angle between the blade and the key phase, comprising: In blade tip timing technology, the method for calculating blade vibration displacement is:

In formula (13),

is the angle between blade b and the key phase, and R is the blade tip rotation radius; since the speed in formula (12) is the average speed of the blade rotating for one circle, the blade vibration displacement calculated by formula (12) is the vibration displacement under constant speed conditions, which is not applicable to variable speed conditions; the present application proposes a method for calculating blade vibration displacement under all conditions as follows:

The blade vibration displacement calculated by formula (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 movement, aerodynamic pressure, rotor thermal expansion and corrosion deformation. 7. The method according to claim 6, characterized in that the analyzing and processing of the blade vibration displacement to extract the steady-state displacement and transient displacement of the blade comprises: The blade vibration displacement is analyzed and processed to extract the steady-state displacement and transient displacement of the blade. The blade vibration displacement can be expressed as: x＝ _xs + _xt (15) Among them, _xs is the steady-state displacement. The extraction method is to use the SG filter to filter the blade vibration displacement. The low-frequency displacement component obtained by filtering is the steady-state displacement of the blade; _xt is the transient displacement. The transient displacement can be obtained by subtracting the steady-state displacement from the blade vibration displacement. 8. The method according to claim 7, characterized in that the step of reconstructing the transient displacement and steady-state displacement of the blade into the stress of the blade and evaluating the state of the blade by comparing the stress of the blade with stress thresholds of different states comprises: Through the blade modal analysis, the displacement-stress transfer function of the vibration mode corresponding to the blade transient displacement and the displacement-stress reconstruction coefficient of the steady-state displacement are obtained. The transient displacement and steady-state displacement obtained by the analysis are reconstructed into dynamic stress and steady-state stress, and then the stress of the blade is calculated as:

Where, _μs is the displacement-stress reconstruction coefficient of the steady-state displacement,

is the displacement-stress transfer function of the vibration mode, σ is the stress value of the blade; Then, the blade status is divided into healthy status, subhealthy status and fault status. The stress thresholds of blades in different status are determined by dynamic simulation calculation combined with calibration test. The stress threshold of healthy status is σ ₁ , and the stress threshold of subhealthy status is σ ₂ . By comparing the relationship between σ and σ ₁ and σ ₂ , the blade status evaluation is realized. Among them, when σ<σ ₁ , the blade is in a healthy state, when σ ₁ <σ<σ ₂ , the blade is in a sub-healthy state, and when σ>σ ₂ , the blade is in a faulty state. 9. A device for evaluating the status of a ship gas turbine blade, characterized in that the device comprises: a data acquisition module, a data validity judgment module, a data cleaning module, a speed calculation module, a vibration calculation module, a vibration analysis module, a status evaluation module and a status warning module; The data acquisition module is used to acquire the arrival time of the rotor blades and the arrival time of the key phase; The data validity judgment module is used to judge the validity of the blade arrival time data; The data cleaning module is used to clean the falsely triggered blade arrival time data; The speed calculation module is used to solve the speed measurement matrix constructed by the key phase arrival time, and then calculate the speed of the rotor blade; The vibration calculation module is used to calculate the blade vibration displacement based on the blade arrival time, the key phase arrival time, the blade speed, the blade tip rotation radius, and the angle between the blade and the key phase; 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; The state assessment module is used to reconstruct the transient displacement and steady-state displacement of the blade into the stress of the blade, and to assess the state of the blade by comparing the stress of the blade with stress thresholds of different states; The status warning module is used to send feedback information based on the blade status evaluation result. When the blade is in a healthy state, the status warning module does not send warning information. When the blade is in a sub-healthy state, the status warning module issues a warning. When the blade is in a fault state, the status warning module issues an alarm.

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