Publication: Ultrasonic Waveguide Technique for Temperature Measurement Using T(0,1) Wave Mode
Date
01-01-2021
Authors
Balasubramaniam, Krishnan
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Abstract
This paper describes a technique for measurement of temperatures at multiple locations using the multiple waveguide configurations. A single transducer has been used for transmitting and receiving the torsional wave T(0,1) mode in the waveguides. Here, a single transducer is attached to multiple waveguides of different lengths (each waveguide is designed with a single bend). This method improves upon the earlier reported studies using straight waveguides, where the non-consideration of the temperature gradient issues. The temperature measurement range is from room temperature to the maximum utility temperature of the waveguide material. The time of flight difference (δTOF) of reflected ultrasonic torsional guided wave modes (T(0,1)) from the bend, which is the reference signal, and another signal from the end of the waveguide is utilized to measure the corresponding temperature of the surrounding media. The T(0,1) wave mode is less dispersive as compared to L(0,1) mode in the same material from the early reported work. The wavelength of the T(0,1) mode is significantly smaller than that of L(0,1) mode due to torsional velocity is less than the longitudinal velocity of ultrasonic sensor. Hence, it can be improved the sensitivity of the temperature measurements. This temperature measurement technique is more interest in several industrial applications, where using the furnaces and melters.
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Keywords
Bent waveguide, Elevated temperatures, Sensors, Temperature measurements, Ultrasonic transducers