Design of an Ultrasonic Transducer Encapsulation for High-Temperature Applications

A novel approach to designing the encapsulation for a high-temperature ultrasonic transducer to be capable of continuous operation over a temperature range of 25 to 650 °C is proposed. The transducer’s active element is a heavily damped lithium niobate disc of 3 MHz resonance frequency, operating in pulse-echo mode. The initial encapsulation design is developed based on the geometrical, thermal, mechanical, electrical, and ultrasonic requirements. Two finite element modeling systems are developed to analyze the thermal-induced stresses in the transducer at low and high temperatures as well as its ultrasonic performance. The simulation results are used to optimize the design before manufacturing a transducer prototype. The prototype is tested at room and elevated temperatures to verify performance.