Feedback active cooling high temperature fiber tip timing sensor

Abstract

The invention discloses a feedback active cooling high temperature fiber tip timing sensor which comprises a sensor probe, a temperature data acquisition module, a feedback control module and a cooling air source. The sensor probe is composed of a probe shell, a sealed air intake cover, a fiber fixing piece, a head thermocouple, a middle thermocouple, a tail thermocouple and a fiber bundle. The fiber bundle is composed of a transmitting fiber and a receiving fiber. One end of the fiber bundle is installed on the top of the sensor probe, and the other end is divided into two channels through abifurcation adapter. The transmitting fiber and the receiving fiber are connected to a tip timing vibration measurement system through a transmitting coupler and a receiving coupler. A stainless steelflexible pipe is fixed in the fiber bundle hole, and the stainless steel flexible pipe is communicated with a cooling air source through the bifurcation adapter. The head thermocouple, the middle thermocouple and the tail thermocouple are respectively arranged at the head, the middle and the tail of the sensor probe. The tail ends of all the thermocouples are connected with the temperature data acquisition module, the feedback control module and the cooling air source in turn through connecting wires.

Description

Technical field [0001] The invention belongs to the field of non-contact vibration measurement of rotating blades. Specifically, it is a feedback type active cooling high temperature optical fiber tip timing sensor. Background technique [0002] The application of non-contact blade vibration measurement for large rotating machinery such as aero-engines, steam turbines, compressors, gas turbines, etc. is increasingly widespread. The basic measurement principle is the technology of timing blade tip vibration measurement. In order to meet the needs of the working environment of the rotating blades of the engine, domestic and foreign scholars have researched and developed different types of sensors such as optical fiber, capacitive, eddy current, and microwave. Among them, the optical fiber tip timing sensor has the advantages of small structure, fast response, high resolution, anti-electromagnetic compatibility, etc., and is currently the most widely used tip timing sensor. Especi...

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Problems solved by technology

The probe of the fiber optic blade tip timing sensor is directly installed on the static casing of the equipment under test. Under the action of high temperature and high speed airflow, it is required that the probe tip should have the same temperature resistance as the blade under test within 10 mm. The sensor cannot withstand such a high temperature. At present, the heat-resistant temperature of the optical fiber using ordinary plastic as the coating material on the market is only about 650°C. Even the heat-resistant temperature of the optical fiber using polyimide as the coating material does not exceed 650°C

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