Flow rate measurement using ultrasonic Doppler method with cavitation bubbles

The current principle of the flow velocity measurement method is based on the detection of the echoes of ultrasonic pulse Doppler method (UDM). However, in some applications, for example, a flow rate measurement in clean water, any particle does not exist in the flow and hence, the conventional UDM cannot be applied. The authors group proposed to employ the ultrasonic cavitation bubbles as reflectors in the flow measurement by UDM. The low frequency Langevin transducer attached to the outside wall of the pipe produces the cavitation bubbles in the flow. Therefore, UDM can be applied to the flow rate measurement without any suspending particle tracers. In this report, applicability and accuracy of the flow rate measurement are investigated in the case of the cavitations bubbles as reflectors. The measurement system with the cavitation production system is also designed and fabricated.