Development of Distributed and Coupled Ultrasonic Waveguide Sensors for Hot Chamber’s Temperature Measurements

The ultrasonic waveguide concept is used for developing distributed and reconfigured ultrasonic temperature sensors using thermocouple wires for measuring the temperature profile of the hot chamber. The characteristic of ultrasonic waveguide-based sensing techniques is particularly very useful in high-temperature industrial applications. This paper briefly explains the ultrasonic technique for multi-locations/level temperature measurements of a hot chamber using integrated ultrasonic-thermocouple sensors and bent waveguides. These ultrasonic sensors can measure a wide range of temperatures. Here, the ultrasonic excitation uses a single longitudinal or shear transducer that is connected to one end of the waveguide, which acts as a transmitter as well as the receiver. These ultrasonic waveguides have multiple reflector embodiments (bends) that allow the reference reflections of input ultrasonic waves in pulse-echo mode. Using the time of flight (TOF) concept at multiple predefined reflector locations to measure the hot laboratory chamber temperature profile and compare it with co-located thermocouples. The signal’s peak and change in TOF are due to the effect of the waveguide materials’ moduli as a function of temperature that can use to measure the temperature. The sensor can measure physical properties such as temperature, rheology, fluid level, etc. The ultrasonic sensors have several advantages in remote temperature measurements, small footprint, low cost, and distributed measurements using a single thermocouple as an integrated thermocouple-waveguide system instead of multiple thermocouples.