Ultrasonic Strip Waveguide-Based Distributed Sensor for Temperature Monitoring

Ultrasonic waveguide techniques are most familiar to monitor temperatures in the hostile environments. A single waveguide could be used as multiple sensors. In the present work, a thin strip waveguide comprising reflectors (holes) at appropriate gauge length was fabricated, and a shear wave transducer (0.5 MHz) was used in the pulse echo technique to propagate $S_{0}$ wave mode. The strip waveguide was mounted on the pipe to monitor temperatures at various locations. The Difference in flight time $\left(\delta T_{F}\right)$ collected between pair of reflectors was used to correlate with the temperatures measured by calibrated K-type thermocouple at various temperature instances. A set of experiments were carried out to calibrate waveguide sensor. It was observed that the calibrated wave guide sensor and thermocouple readings are good in agreement while measuring the temperatures at multiple locations on a Copper pipe. The developed single strip waveguide sensor for measuring temperatures at multiple locations is easy to use, durable, and affordable. It is suitable to track the temperatures even for difficult to access regions.