Waveguide Structure Design and Simulation for High-Temperature Corrosion Thickness Detection

Equipment corrosion often happens in the petrochemical industry, especially when high temperature materials are transported. The corrosion phenomenon should be monitored as a leak may occur due to corrosion and even cause fires and explosions. However, ordinary ultrasonic testing is not suitable for high temperature conditions because the probe may break. A waveguide structure was designed to economically detect corrosion thickness even at a high temperature 500 deg C and avoid the failure of the ultrasonic probe. Based on the heat transfer simulation, a waveguide rod was determined with optimized material, length, width and thickness, and the experiment validated the calculated result. Then, ultrasonic propagation through the designed waveguide rod and specimen was simulated. Propagation, reflection, attenuation and dissipation of the ultrasonic wave within the combined structure were displayed. A clear ultrasound signal was found near the center, while signal attenuation and dispersion occurred as it is gradually far away from the center. With the waveguide structure, an ultrasonic-guided wave testing device was developed to measure the thickness at high temperatures. Measurement error increases with temperature if the wave velocity is regarded as a constant. A temperature-dependent method was applied to achieve high precision detection at high temperatures. The research has good application potential for the corrosion detection of high-temperature equipment.