Blade non-integral order vibration analysis method and system of multi-physical field dynamic signal

Abstract

The present application relates to the field of gas turbine engine compressor test, and discloses a blade non-integer order vibration analysis method and system of multi-physical field dynamic signal, wherein the airflow excitation frequency and the circumferential mode order generated by unstable aerodynamic disturbance are obtained through dynamic pressure test, and the circumferential unstable flow mode characteristics causing blade non-integer order vibration are obtained; the blade vibration frequency and the pitch diameter are obtained through blade vibration dynamic test, and the test parameters of the two physical fields are comprehensively processed to realize the judgment of blade non-integer order vibration. The present application can effectively identify the occurrence of blade non-integer order vibration, can be used for the test of non-integer order vibration of aero-engine compressor blade and the mechanism analysis of related blade vibration failure fault, and has important significance for improving the overall safety and reliability of aero-engine compressor.

Description

Technical Field

[0001] This invention relates to the field of compressor testing for gas turbine engines, and discloses a method and system for analyzing non-integer-order vibrations of blades using multi-physics dynamic signals. Background Technology

[0002] High-performance aero engines are placing increasingly stringent demands on design parameters such as thrust-to-weight ratio and fuel consumption. Compressors made of more efficient and lighter materials have become the mainstream choice for advanced aero engines. In terms of aerodynamic design, the single-stage aerodynamic load of compressor components is constantly increasing. Structurally, lightweight integral bladed disks and integral bladed rings are commonly used, while the circumferential distance between compressor stages is further shortened. These design measures effectively reduce the weight of compressor components, minimize flow losses, and improve the aerodynamic efficiency of the compressor.

[0003] In compressor structural design, integral bladed disk (IB) structures are increasingly being adopted. IIB structures effectively reduce flow losses caused by airflow leakage between the blade root and the disk in traditional separate disk structures. Furthermore, because the disk and blades are an integrated structure, the stress level in the blade root region is lower.

[0004] However, due to the relatively small structural damping of the integral bladed disk, the unsteady aerodynamic forces on the blades are continuously enhanced as the aerodynamic load components of the compressor increase. The blades, with their small structural damping, bear larger alternating loads, and the blades are increasingly encountering high-cycle fatigue problems caused by non-integer order vibrations.

[0005] Non-integer order vibration of aero-engine compressor blades is a typical fluid-structure interaction problem, involving multiple physical fields such as fluid, solid, and heat transfer. Currently, the generation mechanism of non-integer order vibration of compressor blades is not fully understood, and there are no relevant experimental testing methods. Summary of the Invention

[0006] The purpose of this invention is to provide a method and system for analyzing non-integer-order vibrations of blades using multi-physics dynamic signals, which can effectively identify the occurrence of non-integer-order vibrations of blades.

[0007] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0008] Methods for analyzing non-integer-order vibrations of blades using multiphysics dynamic signals include:

[0009] Obtain the vibration frequency, pitch diameter, airflow excitation frequency of airflow disturbance at the blade tip, and circumferential mode order of the rotor blade under multiple vibration modes under compressor test conditions;

[0010] Calculate the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under each vibration mode to the compressor rotation frequency, and round it to the nearest integer.

[0011] If at least one rounded ratio under the corresponding mode shape is equal to the circumferential mode order, and the absolute value of the sum or difference between the circumferential mode order and the pitch diameter is an integer multiple of the number of rotor blades, then it is determined that the rotor blades under the corresponding mode shape are vibrating at non-integer order.

[0012] Furthermore, a BTT sensor was used to obtain the pitch diameter of the rotor blades under different vibration modes under the compressor test conditions, wherein the axial position of the BTT sensor is located near the leading edge of the rotor blade tip.

[0013] Furthermore, the sampling frequency of the BTT sensor is higher than 100kHz, and the head of the BTT sensor is 0.5 to 2 mm away from the inner wall of the compressor casing.

[0014] Furthermore, the vibration frequency of the blade under the corresponding mode shape under the compressor test conditions was obtained by attaching strain gauges, and the sampling frequency of the strain gauges was greater than 25kHz.

[0015] Furthermore, the compressor frequency =n / 60, where n is the compressor speed under test conditions.

[0016] To achieve the above-mentioned technical effects, the present invention also provides a blade non-integer order vibration analysis system for multi-physics dynamic signals, comprising:

[0017] The data acquisition module is used to acquire the vibration frequency, pitch diameter, airflow excitation frequency of airflow disturbance at the blade tip, and circumferential mode order of the rotor blades under multiple vibration modes under compressor test conditions.

[0018] The data analysis module is used to calculate the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under each vibration mode to the compressor rotation frequency, and then round it to the nearest integer.

[0019] The non-integer order vibration judgment module is used to determine that the rotor blades under the corresponding vibration mode are vibrating in a non-integer order when at least one rounded ratio under the corresponding vibration mode is equal to the circumferential mode order, and the absolute value of the sum or difference between the circumferential mode order and the pitch diameter is an integer multiple of the number of rotor blades.

[0020] Furthermore, the data acquisition module uses a BTT sensor to obtain the pitch diameter of the rotor blades under different vibration modes under the compressor test conditions, wherein the axial position of the BTT sensor is located near the leading edge of the rotor blade tip.

[0021] Furthermore, in the data acquisition module, the sampling frequency of the BTT sensor is higher than 100kHz, and the distance between the head of the BTT sensor and the inner wall of the compressor casing is 0.5 to 2mm.

[0022] Furthermore, in the data acquisition module, the vibration frequency of the blade under the corresponding vibration mode under the compressor test conditions is obtained by attaching strain gauges, and the sampling frequency of the strain gauges is greater than 25kHz.

[0023] Furthermore, in the data analysis module, the compressor frequency... =n / 60, where n is the compressor speed under test conditions.

[0024] Compared with the prior art, the beneficial effects of this invention are as follows: This invention obtains the airflow excitation frequency and circumferential mode order generated by unstable aerodynamic disturbances through dynamic pressure testing, and obtains the circumferential unstable flow mode characteristics that trigger non-integer order vibrations of the blade; it obtains the blade vibration frequency and nodal diameter through dynamic blade vibration testing, and integrates the test parameters of the two physical fields to determine the non-integer order vibrations of the blade. It can effectively identify the occurrence of non-integer order vibrations of the blade and can be used for testing non-integer order vibrations of aero-engine compressor blades and analyzing the mechanism of related blade vibration failure faults. This is of great significance for improving the overall safety and reliability of aero-engine compressors. Attached Figure Description

[0025] Figure 1 The flowchart shows the blade non-integer order vibration analysis method for multi-physics field dynamic signals in Example 1 or 2.

[0026] Figure 2 This is a block diagram of the blade non-integer order vibration analysis system for multi-physics dynamic signals in Example 1;

[0027] The system includes: 1. Data acquisition module; 2. Data analysis module; 3. Non-integer order vibration judgment module. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0029] Example 1

[0030] See Figure 1 and Figure 2 Methods for analyzing non-integer-order vibrations of blades based on multi-physics dynamic signals include:

[0031] Obtain the vibration frequency, pitch diameter, airflow excitation frequency of airflow disturbance at the blade tip, and circumferential mode order of the rotor blade under multiple vibration modes under compressor test conditions;

[0032] Calculate the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under each vibration mode to the compressor rotation frequency, and round it to the nearest integer.

[0033] If at least one rounded ratio under the corresponding mode shape is equal to the circumferential mode order, and the absolute value of the sum or difference between the circumferential mode order and the pitch diameter is an integer multiple of the number of rotor blades, then it is determined that the rotor blades under the corresponding mode shape are vibrating at non-integer order.

[0034] In this embodiment, the airflow excitation frequency and circumferential mode order generated by unstable aerodynamic disturbances are obtained through dynamic pressure testing, thereby acquiring the circumferential unstable flow mode characteristics that trigger non-integer-order vibrations of the blades. The blade vibration frequency and nodal diameter are obtained through dynamic blade vibration testing. The test parameters of the two physical fields are comprehensively processed to determine the non-integer-order vibrations of the blades. This method can effectively identify the occurrence of non-integer-order vibrations of blades and can be used for testing non-integer-order vibrations of aero-engine compressor blades and for analyzing the mechanism of related blade vibration failures. This is of great significance for improving the overall safety and reliability of aero-engine compressors.

[0035] Based on the same inventive concept, this embodiment also provides a blade non-integer order vibration analysis system for multi-physics dynamic signals, including:

[0036] Data acquisition module 1 is used to acquire the vibration frequency, pitch diameter, airflow excitation frequency and circumferential mode order of rotor blades under multiple vibration modes under compressor test conditions.

[0037] Data analysis module 2 is used to calculate the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under each vibration mode to the compressor rotation frequency, and round it to the nearest integer.

[0038] The non-integer order vibration judgment module 3 is used to determine that the rotor blades under the corresponding vibration mode are vibrating in a non-integer order when at least one rounded ratio under the corresponding vibration mode is equal to the circumferential mode order and the absolute value of the sum or difference between the circumferential mode order and the pitch diameter is an integer multiple of the number of rotor blades.

[0039] Example 2

[0040] See Figure 1 Methods for analyzing non-integer-order vibrations of blades based on multi-physics dynamic signals include:

[0041] Step 1: Obtain the vibration frequency, pitch diameter, airflow excitation frequency of airflow disturbance at the blade tip, and circumferential mode order of the rotor blades under multiple vibration modes under the compressor test conditions.

[0042] In this embodiment, a BTT sensor is used to obtain the pitch diameter of the rotor blades under different vibration modes under compressor test conditions. The axial position of the BTT sensor is located near the leading edge of the rotor blade tip, and the sampling frequency of the BTT sensor is higher than 100kHz. When installing the BTT sensor, it is necessary to ensure that the fiber optic sensor head is retracted 0.5-2mm from the inner wall of the casing to avoid the fiber optic sensor head rubbing against the rotor blade tip during the test.

[0043] In this embodiment, strain gauges are used to monitor modal vibrations that may have dangerous resonance. The sampling frequency of the strain gauges is generally higher than 25kHz to obtain the vibration frequency of the blade under the corresponding vibration mode under the compressor test conditions.

[0044] In this embodiment, the circumferential layout and number of dynamic pressure test arrays are determined based on the number of rotor blades. If the number of dynamic pressure test arrays is sufficient, they are evenly distributed circumferentially, with the number ensuring it is more than twice the number of rotor blades. If the number of dynamic pressure test arrays is insufficient, compressed sensing sampling methods can be used to arrange the circumferential positions of the dynamic pressure test arrays. After determining the layout of the dynamic pressure test arrays, they are installed to acquire information such as the airflow excitation frequency fstat and the circumferential modal order AWN of the airflow disturbance at the rotor blade tips. The sampling frequency of the dynamic pressure test arrays is generally higher than 50kHz. The airflow excitation frequency is obtained through Fourier transform of the dynamic pressure test array data, and the circumferential modal order is obtained through spatial Fourier transform.

[0045] Step 2: Calculate the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under each vibration mode to the compressor rotation frequency, and round it to the nearest integer.

[0046] In this embodiment, the eigenvalue is the rounded characteristic value of the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under the corresponding vibration mode to the compressor rotation frequency. ,in The airflow excitation frequency is... The vibration frequency is... For compressor frequency, =n / 60, where n is the compressor speed under test conditions. This is the symbol for the floor function.

[0047] Step 3: If at least one rounded ratio under the corresponding mode shape is equal to the circumferential mode order, and the absolute value of the sum or difference between the circumferential mode order and the pitch diameter is an integer multiple of the number of rotor blades, then it is determined that the rotor blades under the corresponding mode shape are vibrating at non-integer order.

[0048] If the circumferential modal order With one of the corresponding mode shapes The values ​​are equal, and If so, it is determined that the rotor blades are undergoing non-integer order vibration under the corresponding mode shape; where It is an integer. This refers to the number of rotor blades. It is the diameter of the node.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for analyzing non-integer order vibrations of blades using multi-physics dynamic signals, characterized in that, include: Obtain the vibration frequency, pitch diameter, airflow excitation frequency of airflow disturbance at the blade tip, and circumferential mode order of the rotor blade under multiple vibration modes under compressor test conditions; Calculate the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under each vibration mode to the compressor rotation frequency, and round it to the nearest integer; the eigenvalue of the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under the corresponding vibration mode to the compressor rotation frequency is rounded to the nearest integer. ,in The airflow excitation frequency is... The vibration frequency is... For compressor frequency, =n / 60, where n is the compressor speed under test conditions. This is the symbol for the floor function; If at least one rounded ratio under the corresponding mode shape is equal to the circumferential modal order, and the absolute value of the sum or difference between the circumferential modal order and the pitch diameter is an integer multiple of the number of rotor blades, that is: if the circumferential modal order With one of the eigenvalues ​​under the corresponding mode shape Equal, and If so, it is determined that the rotor blades are undergoing non-integer order vibration under the corresponding mode shape; where It is an integer. This refers to the number of rotor blades. It is the diameter of the node.

2. The method for analyzing non-integer-order vibrations of blades using multi-physics dynamic signals according to claim 1, characterized in that, The BTT sensor was used to obtain the pitch diameter of the rotor blades under different vibration modes under the test conditions of the compressor. The axial position of the BTT sensor was located near the leading edge of the rotor blade tip.

3. The method for analyzing non-integer-order vibrations of blades using multi-physics dynamic signals according to claim 2, characterized in that, The sampling frequency of the BTT sensor is higher than 100kHz, and the head of the BTT sensor is 0.5 to 2mm away from the inner wall of the compressor casing.

4. The method for analyzing non-integer-order vibrations of blades using multi-physics dynamic signals according to claim 1, characterized in that, The vibration frequency of the blade under the corresponding mode shape under the compressor test conditions was obtained by attaching strain gauges. The sampling frequency of the strain gauges was greater than 25 kHz.

5. The method for analyzing non-integer-order vibrations of blades using multi-physics dynamic signals according to claim 1, characterized in that, compressor frequency =n / 60, where n is the compressor speed under test conditions.

6. A blade non-integer order vibration analysis system based on multi-physics dynamic signals, characterized in that, include: The data acquisition module is used to acquire the vibration frequency, pitch diameter, airflow excitation frequency of airflow disturbance at the blade tip, and circumferential mode order of the rotor blades under multiple vibration modes under compressor test conditions. The data analysis module is used to calculate the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under each vibration mode to the compressor rotation frequency, and then round it to the nearest integer; the characteristic value of the ratio of the absolute value of the sum or difference of the airflow excitation frequency and the vibration frequency under the corresponding vibration mode to the compressor rotation frequency after rounding is also included. ,in The airflow excitation frequency is... The vibration frequency is... For compressor frequency, =n / 60, where n is the compressor speed under test conditions. This is the symbol for the floor function; The non-integer order vibration judgment module is used when, under the corresponding mode shape, at least one rounded ratio equals the circumferential modal order, and the absolute value of the sum or difference between the circumferential modal order and the pitch diameter is an integer multiple of the number of rotor blades; that is, if the circumferential modal order... With one of the eigenvalues ​​under the corresponding mode shape Equal, and If so, it is determined that the rotor blades are undergoing non-integer order vibration under the corresponding mode shape; where It is an integer. This refers to the number of rotor blades. It is the diameter of the node.

7. The blade non-integer order vibration analysis system based on multi-physics dynamic signals according to claim 6, characterized in that, The data acquisition module uses a BTT sensor to obtain the pitch diameter of the rotor blades under different vibration modes under the compressor test conditions. The axial position of the BTT sensor is located near the leading edge of the rotor blade tip.

8. The blade non-integer order vibration analysis system based on multi-physics dynamic signals according to claim 7, characterized in that, In the data acquisition module, the sampling frequency of the BTT sensor is higher than 100kHz, and the head of the BTT sensor is 0.5 to 2mm away from the inner wall of the compressor casing.

9. The blade non-integer order vibration analysis system based on multi-physics dynamic signals according to claim 6, characterized in that, In the data acquisition module, strain gauges are used to obtain the vibration frequency of the blades under the corresponding mode shape under the compressor test conditions. The sampling frequency of the strain gauges is greater than 25kHz.

10. The blade non-integer order vibration analysis system based on multi-physics dynamic signals according to claim 6, characterized in that, In the data analysis module, the compressor frequency... =n / 60, where n is the compressor speed under test conditions.

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