Research on temperature measurement method based on longitudinal mode ultrasonic guided waves using high-purity graphite rods
To meet the temperature measurement requirements in a confined high-temperature environment,a longitudinal mode ultrasonic guided wave temperature measurement method based on a high-purity graphite rod is proposed. By considering the temperature-dependent dispersion equation,the main factors affecting the wave velocity due to temperature are analyzed,and suitable excitation frequency and modes for temperature measurement are selected. A prediction model for the variation in the guided wave signal transit time with temperature in a waveguide rod with non-uniform temperature distribution is established,allowing for the calculation of accurate echo transit times in the graphite rod. Temperature measurement experiments using guided waves within the range of 1000℃ were conducted to verify the model's accuracy. The experimental results demonstrate that the temperature measurement accuracy of L(0,1) mode guided waves with an excitation frequency of 30 kHz is within 10℃,with good repeatability across multiple trials. The research in this paper proves the high-temperature measurement capability of ultrasonic guided wave,providing a feasible solution for temperature measurement in extrem high-temperature environments.
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维普
