Optical fiber bundle type tip timing sensor based on self-focusing lens

Abstract

The invention belongs to the field of sensors, and aims to effectively reduce the diameter of a light spot and improve the timing resolution of an optical fiber type tip timing sensor. According to the technical scheme adopted in the invention, an optical fiber bundle type tip timing sensor based on a self-focusing lens is characterized in that a plurality of multi-mode optical fibers closely surround one single-mode optical fiber to form an optical fiber bundle; the self-focusing lens is assembled at the front end of the optical fiber bundle; the single-mode optical fiber is connected with alaser and a photoelectric receiver through a circulator; the multi-mode optical fibers are only connected with the photoelectric receiver; laser light emitted by the laser is projected onto the end face of a blade through the single-mode optical fiber and the self-focusing lens; and laser light reflected by the end face of the blade passes through the self-focusing lens, and is projected onto thephotoelectric receiver through the single-mode optical fiber and the multi-mode optical fibers. The optical fiber bundle type tip timing sensor is mainly applied to the design and manufacturing occasions of optical fiber sensors.

Description

technical field [0001] The invention belongs to the field of sensors. Specifically, the present invention relates to a fiber optic blade tip timing sensor, in particular to a fiber bundle blade tip timing sensor based on a self-focusing lens that improves timing resolution by reducing the spot diameter. Background technique [0002] The blades of large rotating machines such as aeroengines, gas turbines, flue gas turbines and steam turbines are the core working components. The online monitoring of their state parameters, especially vibration parameters, is crucial to ensure the quality of engine operation and the safety of major equipment. Especially since the development of modern aero-engines, rotor blades with high performance requirements and highly optimized structures are in a more complex flow field environment, and the fluid-solid coupling between the blade and the surrounding flow will produce low-order Various forms of coupled vibration such as torsional compound ...

AI Technical Summary

Problems solved by technology

The rotational speed of the aero-engine compressor motor blade can reach 700m / s, and when the vibration displacement measurement accuracy is 10μm, the timing resolution of the blade tip timing measurement system is required to reach 3ns, and the spot diameter needs to be less than 63μm, while the traditional fiber optic blade tip timing sensor , when the numerical aperture of the launching fiber is 0.22, the spot diameter at the smallest tip clearance of 0.5mm is still 220μm, which is difficult to meet the needs of modern aero-engines

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