On-line rotor and stator axial gap measuring device based on dual-wavelength sweep frequency polarization modulation

Abstract

The invention discloses a rotor and stator axial clearance online measuring device based on dual-wavelength sweep frequency polarization modulation. The rotor and stator axial clearance online measuring device comprises a secondary modulation light path unit, a measuring light path unit, a reference light path unit, a sweep frequency signal generating unit and a data collecting and processing unit. The secondary modulation light path unit is composed of a first laser, a second laser, a coupler, an isolator, a first collimator, a polarization splitting prism, an electro-optical modulator, a 1 / 4 wave plate, a second collimator and a first wavelength division multiplexer. The secondary modulation light path unit is connected with the measurement light path unit and the reference light path unit; and the data acquisition and processing unit consists of a third collimator, a second wavelength division multiplexer, a first detector, a second detector, a first acquisition card, a second acquisition card and a PC (Personal Computer) upper computer.

Description

technical field [0001] The invention relates to the field of non-contact distance measurement, in particular to the field of axial gap measurement of aero-engine rotor and stator. Specifically, the present invention relates to an on-line measuring device and method for rotor-stator axial gap based on dual-wavelength swept frequency polarization modulation. Background technique [0002] Studies have shown that when the axial gap between the aero-engine blades is reduced from 0.66 times the axial chord length of the blades to 0.23 times, the compressor stage efficiency can be increased from 1% to 1.4%; The reason is that the axial clearance of the rotor and stator is too small, which may also lead to faults such as friction and breakage, resulting in equipment damage, huge economic losses, and a threat to personal safety. In order to improve the performance and efficiency of equipment, the implementation of active clearance control and the realization of variable operating co...

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Problems solved by technology

[0004] The capacitance method has the characteristics of high temperature resistance, fast response speed, and good reliability, but the size of the probe will increase sharply with the increase of the measurement range, and due to the temperature characteristics of the medium, the temperature drift of the measurement results is large; the eddy current method It has the advantages of being resistant to harsh environments such as water vapor and oil pollution, and can measure the gap in a heavily polluted environment. The leakage capacitance, leakage conductance and other parameters of the eddy current sensor are significantly affected by temperature changes, and even cause circuit saturation in severe cases, resulting in measurement failure; the microwave method is not easily affected by the internal working environment of the engine, and is suitable for the measurement of tiny gaps in the engine, but the current temperature The problem of drift compensation has not been effectively solved. In addition, due to the use of high-frequency microwaves and high-temperature mineral cables, the transmission loss is relatively large, so it is not suitable for use in the measurement environment of narrow spaces inside major equipment, long distances, and complex lead-out paths.

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