Optical fiber measurement method and device of blade tip clearance

Abstract

Provided is an optical fiber measurement method and device of blade tip clearance. A multipoint orientation reflecting compensation type optical fiber is adopted to carry out distance measurement; laser emitted by a laser device in a working wavelength range is transmitted to the surface of an object to be measured through a fiber probe, is reflected back to the fiber probe after being reflected through the surface of the object to be measured, and then enters multiple channels of receiving optical fibers respectively; filtering is carried out on laser entering the receiving optical fibers through optical filters, energy of laser entering the multiple channels of receiving optical fibers in the working wavelength range after the laser is reflected by the surface of the object to be measured is obtained respectively, the energy of the laser is converted into weak current signals through photoelectric detection, the weak current signals are amplified into current or voltage signals for being collected through a signal amplification filtering circuit, comparison processing is carried out by collecting the multiplexed output current signals or voltage signals, and the distance between the optical fiber probe and the object to be measured is obtained. The invention further discloses a measurement device for achieving the method.

Description

technical field [0001] The invention relates to a method for measuring blade tip clearance optical fiber. [0002] The invention also relates to a measuring device for carrying out the method described above. Background technique [0003] Turbine moving blade tip clearance is an important parameter that affects the performance of ground gas turbines or aero-engines. If the clearance is too large, the gas leakage flow will increase, resulting in a decrease in the efficiency of the gas turbine or aero-engine and an increase in fuel consumption; a decrease in the clearance will easily lead to contact between the blade and the casing. , causing blade wear or even damage. Because the influencing factors of the blade tip clearance are quite complex, it is difficult to determine by calculation and analysis alone, so the clearance must be measured in the test to provide reliable data for the control of the blade tip clearance. Real-time monitoring of gaps, diagnosis and early warn...

AI Technical Summary

Problems solved by technology

As for the optical fiber displacement measurement technology, the earliest method is to use one optical fiber to emit the measuring laser and one optical fiber to receive the reflected light signal. This measurement method is easily affected by the fluctuation of the emitting light source, the loss of the optical fiber and the reflectivity of the measured surface, so the measurement accuracy is poor.

In order to solve the above problems, the reflection compensation optical fiber displacement testing technology was developed later. One signal fiber and one reference fiber are used to receive the reflected light energy, and the distance information is obtained through comparative analysis, but it requires the verticality of the emitted beam and the measured surface Higher and smaller inclination angles of the measured surface will also cause large measurement errors, and the wavelength of the emitted light currently used is generally in the infrared region, which is easily interfered by the radiation spectrum of the blade tip itself in a high-temperature environment, and is not suitable for distances in high-temperature environments. Measurement

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