Method and device for on-line measurement of rotor-stator axial gap based on microwave

Abstract

The invention belongs to the field of non-contact distance measurement, and aims to realize the non-contact real-time online accurate measurement of the axial gap of the rotor and stator of an aero-engine under the condition of limited space. To this end, the technical solution adopted in the present invention is that a microwave-based rotor-stator axial gap online measuring device is composed of a microwave signal generating module, a signal power amplifying module, a signal receiving and frequency mixing module, a signal conditioning and acquisition module, a circulator, a microwave It consists of a sensor. The carrier signal generated by the microwave signal generating module is amplified by the signal power amplifying module, and then enters the first port of the circulator and is output from the second port of the circulator; the second port of the circulator is connected to the microwave sensor. , the microwave sensor transmits the carrier signal to the axial end face of the rotor under test, and simultaneously receives the reflected signal of the carrier wave from the axial end face of the rotor, returns it to the second port of the circulator, and outputs it from the third port of the circulator. The invention is mainly applied to the occasion of non-contact distance measurement.

Description

technical field [0001] The invention belongs to the field of non-contact distance measurement. Specifically, the present invention relates to a method and device for on-line measurement of the rotor-stator axial clearance based on microwaves, in particular to an on-line measurement of the rotor-stator axial clearance using a cross-mixing structure of the carrier path and the reference path to suppress co-frequency interference signals. Measurement methods and devices. Background technique [0002] Modern aero-engines are developing in the direction of high thrust-to-weight ratio, high boost ratio and high vortex front temperature. On the one hand, aero-engines are affected by speed changes, temperature loads and aerodynamic loads. The thermal expansion of the casing is inconsistent, and too small axial clearance will increase the shaft work, reduce the efficiency, reduce the flow capacity, deteriorate the aerodynamic performance, and even cause the rotor and the stator to r...

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Problems solved by technology

[0004] In the traditional method of measuring the micro-gap of aero-engine, the optical method is easily affected by environmental oil pollution and the measurement life is shortened, and the processing cost is very high when it is applied in a high-temperature (450°C) test environment; when the capacitance method has a measurement range of 10mm, the diameter of the probe end face reaches 60mm The size of the sensor is too large, so it is not suitable for the measurement environment where the internal space of the aeroengine is very limited; the eddy current method is only suitable for the working environment of the engine at room temperature and low speed, and is not suitable for the gap measurement at high temperature; the microwave method is less susceptible to the internal work of the engine than other methods Environmental impact, it is more suitable for the measurement of small gaps in the engine, but under the condition of limited space, the sensor is easy to receive the stray reflection signal of the stator parts around the rotor part to be tested

[0005] The microwave method can be divided into reflection intensity method, linear frequency modulation method and phase difference method. The reflection intensity method is easily affected by temperature, and the measurement accuracy cannot meet the measurement requirements; the linear frequency modulation method needs a high signal bandwidth to achieve high measurement accuracy, but The structure is too complicated; the phase difference method adopts quadrature demodulation and high-low-pass filtering method to realize the measurement of the rotor-stator axial gap, but there are radio frequency leakage signals, sensor end face reflection signals and stray reflection signals of the stator parts around the object to be tested and other interference of the same frequency The signal affects the measurement accuracy of the axial clearance

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