Ultrasonic dual-path differential method for temperature measurement via metal waveguides

This paper proposes an innovative dual-path differential method for waveguide temperature measurement through the time-of-flight difference of waves, adopting a transmitted wave propagation approach. Two geometric structures, namely Dual-Path and Spiral Dual-Path are designed. Tube diameter ratio and acoustic energy distribution are discussed to obtain optimal received waveforms. In finite element simulations and practical experiments, 6061 aluminum alloy is selected as the experimental material, and experiments are conducted within the temperature range of 0-400℃. The two new structures are compared with three traditional waveguide structures, including L-Form, Notched, and Perforated, improving the average resolution from 4℃/10 ns to 2℃/10 ns and 1℃/10 ns, reducing the absolute value of average error from 3.6℃ to 1.9℃ and 1.6℃, and decreasing the standard deviation by 43% and 57% respectively. The results indicate that optimizing the waveguide geometry is an effective approach to enhancing performance.