Abstract
The air-coupled ultrasonic velocity profiler for steam flow measurement is developed. A new ultrasonic sensor for air-coupled ultrasonic measurement was manufactured and measurement system was developed for steam flow measurement. The air-coupled ultrasonic sensor has a matching layer to reduce the acoustic reflection between sensor and the air. In order to amplify detected signal, an external amplifier is developed, which can amplify the detected signal without noise from pulser/receiver and environment. Steam jet flow is measured to demonstrate the developed system, and the possibility of the steam flow measurement by air-coupled ultrasound is revealed.