Flow measurement based on two-dimensional flexural ultrasonic phased arrays

Transit-time flow measurement is a technology which has been increasingly utilized in recent years, in industries such as petrochemical, water, and gas. In general, this method of flow measurement employs two ultrasonic transducers, one situated upstream, and the other downstream. The fluid flow is then characterized via transmission and detection of ultrasound using the transducers. However, there are notable limitations of the transit-time method, including drift of the propagation direction of the ultrasonic beam. This is termed the sound drift effect. This paper reports on the latest developments of ultrasonic phased arrays, which are a potentially robust and economic solution to compensating for this sound drift effect. The design and fabrication of phased arrays is discussed, and experimental flow measurement results are reported, utilizing flow rates from 0 to 2500 m3/h. The results show that the compensation of the sound drift effect has been achieved, demonstrating the feasibility of phased arrays for accurate ultrasonic flow measurement.