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CN-122016029-A - Calibrating device and method for blade tip timing system

CN122016029ACN 122016029 ACN122016029 ACN 122016029ACN-122016029-A

Abstract

The invention discloses a calibrating device and a calibrating method of a blade tip timing system, which relate to the technical field of precision photoelectric measurement and comprise a laser vibration meter and a wedge prism lens barrel, wherein the wedge prism lens barrel is connected to the top end of a rotating shaft of an impeller to be measured, the wedge prism lens barrel and the rotating shaft are coaxial and synchronously rotate, the laser vibration meter is placed outside a laboratory bench, and measuring laser emitted by the laser vibration meter is directed to the top end of the rotating shaft. The invention provides a device and a method for calibrating a blade tip timing sensor through a laser vibration meter, which solve three main problems that the measuring point is fixed, the reference data is unreliable and the calibration cannot be carried out in a working state in the prior art. The measuring technology is non-contact measurement, and has wide application prospect in health monitoring and safety maintenance of high-end rotary machinery such as an aero-engine, a gas turbine and the like.

Inventors

  • WEI ZHIPENG
  • XIAO ZHICHENG
  • CHEN YONG
  • OUYANG HUA

Assignees

  • 上海交通大学

Dates

Publication Date
20260512
Application Date
20260227

Claims (10)

  1. 1. The utility model provides a calibrating device of apex timing system, its characterized in that includes laser vibrometer and wedge prism lens cone, wherein, wedge prism lens cone is connected on the top of the pivot of the impeller that awaits measuring, wedge prism lens cone with the pivot is coaxial, synchronous rotation, laser vibrometer places in the laboratory bench outside, the measurement laser of laser vibrometer transmission is directional the top of pivot.
  2. 2. The tip timing system calibration device of claim 1, wherein said wedge prism barrel is rigidly secured to a top end of said shaft by a threaded top cap and a prism holder.
  3. 3. The calibrating device for a blade tip timing system according to claim 1, wherein the rotating shaft of the impeller to be measured is fixed by a bearing seat supporting casing, the bearing seat supporting casing is stably supported by a casing supporting vertical plate, and the blade tip timing sensor group is circumferentially and uniformly arranged on an installation casing of the blade tip timing system.
  4. 4. The tip timing system calibration device of claim 1, wherein said wedge prism barrel is axially movable.
  5. 5. A method for calibrating axial displacement of a tip of a calibrating device for a tip timing system according to any of claims 1 to 4, comprising the steps of: step 1, for a selected blade, at a plurality of different stable rotational speed points Measuring; step 2, establishing displacement of the blade tip timing system along the direction of the light path Reference axial displacement with laser vibrometer A calibration relationship between; Step 3, by In the abscissa of a circle Drawing all data points as ordinate, and performing linear fitting by a least square method to obtain an axial displacement calibration curve of the blade: Wherein a is a proportionality coefficient, Is zero offset; step 4, establishing axial displacement output by the blade tip timing system through comparison of multiple groups of rotating speeds and vibration working conditions Reference axial displacement with the laser vibrometer A calibration relationship between; step 5, repeatedly obtaining under the same working condition And (5) calibrating the result once, calculating the mean value and the sample standard deviation, and calculating the uncertainty of the calibrating result.
  6. 6. The tip axial displacement calibration method according to claim 5, wherein in said step 2, said laser vibrometer references an axial displacement The displacement of the blade tip timing system along the direction of the light path is measured by a wedge prism which rotates synchronously Axial displacement output by tip timing system And (3) obtaining by conversion: Wherein, the Is the included angle between the light path and the axial direction of the blade after the prism deflects.
  7. 7. The tip axial displacement calibration method according to claim 5, wherein the mean value Standard deviation from the sample Respectively denoted as Class a standard uncertainty fetch: 。
  8. 8. the tip axial displacement calibration method according to claim 7, wherein in said step 5, said uncertainty is expressed as: Wherein, the measurement error of the laser vibration meter is And can be processed according to uniform distribution Is the included angle Is a measurement uncertainty of (2).
  9. 9. A method of calibrating the amplitude of blade vibration of a calibrating apparatus for a tip timing system according to any of claims 1 to 4, comprising the steps of: step 1, enabling the impeller to be tested to stably rotate at a set rotating speed, and applying excitation to a target blade through an excitation device to enable the blade to vibrate; step 2, establishing a component of vibration amplitude of the blade tip timing system along the optical path direction of the laser vibration meter Reference amplitude with laser vibration meter A calibration relationship between; step 3, changing excitation intensity and rotating speed to obtain N groups of data pairs covering the target amplitude range To As an independent variable, to And (3) performing least square fitting on the dependent variables, and establishing an amplitude calibration model: Wherein a is a proportionality coefficient, and b is a zero offset; step 4, comparing a plurality of groups of rotating speeds with vibration working conditions to establish the vibration amplitude output by the blade tip timing system Reference amplitude with the laser vibration meter Calibration relation between the two.
  10. 10. The method for calibrating vibration amplitude of blade according to claim 9, wherein in the step 2, the laser vibration meter irradiates a measuring light spot to a blade tip target measuring point through a wedge prism to obtain a reference amplitude of the laser vibration meter The component of the vibration amplitude of the blade tip timing system along the optical path direction of the laser vibration meter Expressed as: Wherein, the Is the included angle between the direction of the light path of the laser vibration meter after being refracted by the wedge prism and the measuring direction of the blade tip timing system, The vibration amplitude of the same blade and the same measuring point output by the blade tip timing system under the same excitation condition at the same rotating speed as the reference amplitude of the laser vibration meter.

Description

Calibrating device and method for blade tip timing system Technical Field The invention relates to the technical field of precision photoelectric measurement, in particular to a calibrating device and method of a blade tip timing system. Background In large-scale impeller machines such as aeroengines, gas turbines, steam turbines and the like, rotor blades are required to bear higher load under a high-speed rotation working condition, and in order to ensure safe and stable operation of equipment, key operation parameters in the rotation process of the blades are required to be measured in real time, and the parameters comprise vibration frequency, vibration amplitude and the like. The tip timing vibration measurement technology is a hotspot of the current on-line monitoring research of blade vibration, and the technical principle is that a group of sensors are arranged on a casing, so that the time node of each blade tip reaching the sensor is captured, the circumferential displacement of the blade tip is further converted, and finally the vibration frequency and amplitude of the blade are calculated. The measurement principle is as follows: The blade tip timing sensor is arranged on the casing, the key phase sensor is arranged on the stator, the key direction mark is pasted on the synchronous shaft of the rotor, and the measuring circuit generates a pulse signal to record the arrival time of the blade relative to the key direction sensor when the blade sweeps across the blade tip timing sensor. And comparing the measured blade arrival time with the theoretical blade arrival time under the condition of no vibration, and combining the current rotating speed to obtain the vibration displacement of the blade. And then obtaining parameters such as the vibration frequency, the amplitude and the like of the blade through an upper computer program and a related identification algorithm. In order to verify the measurement accuracy of the measurement system and define the error range, it is important to calibrate the system. However, the number of calibration methods for the tip timing measurement system is small at present, and the measurement accuracy is to be improved. The existing calibration schemes related to the present invention mainly include the following two types. The invention relates to a relative displacement calibration method, which comprises the steps of not directly exciting a blade in a rotating state, mounting a blade tip timing sensor on a vibrating table, driving the sensor to vibrate by controlling the vibrating table, simulating the working state of the rotating vibrating blade by using the relative motion of the blade and the sensor, and comparing the vibration frequency and the amplitude set by the vibrating table as reference standard values with the measurement result of a blade tip timing system to determine a measurement error to realize calibration. The invention discloses a rotary reference calibration method, which is 1, an invention patent grant number CN115435734, and designs a set of device, wherein a laser displacement sensor is fixed on a blade disc by a customized bracket, so that coaxial rotation of the sensor and the blade is realized, and a reference standard quantity of a blade tip vibration displacement value is acquired under the condition, thereby completing high-precision calibration of a blade tip timing measurement system. 2. The invention relates to an invention No. CN113959556, which is characterized in that a blade and a laser displacement sensor are simultaneously fixed on a disc, the disc is driven to rotate by a motor, blade tip timing sensors are circumferentially distributed on a simulation casing at the periphery of the disc and do not rotate along with the disc, and blade tip vibration displacement values measured under the condition are used as reference standards. The relative displacement calibration method takes data measured when the blade tip timing sensor vibrates as a reference, the vibration is not generated by the blade, and the standard quantity has a principle difference with the real vibration displacement of the blade tip in a rotating state. The rotation reference calibration method needs to fix the laser displacement sensor on the rotor through a specific bracket, and the fixed bracket itself can vibrate when the rotating speed is too high. The reference quantity adopted in the prior art is unreliable and cannot be used for high-precision calibration. Therefore, a person skilled in the art is dedicated to develop a calibrating device and method for a tip timing system, which solves three main problems of fixed measuring points, unreliable reference data and incapability of calibrating in a working state in the prior art. Disclosure of Invention In view of the above-mentioned drawbacks of the prior art, the present invention aims to solve the problems that the measurement point of the existing tip timing vibration measurement technology is fi