Ultrasonic Fluid Velocity Estimation System with Self-Optimised Switched Mode Transmit Schemes

For fluid travelling through a pipe, time-of-flight velocity estimation uses the difference in flight time of ultrasound pulses travelling upstream and downstream to determine flow rate. Cross-correlation is a suitable method to attain transit times. It has already been shown that generating an appropriate cross-correlation reference signal can be done via measurement or modelling. In this paper, tones and LFM signals were generated and transmitted using the arbitrary switched-mode excitation capability of the UARPII-16 system (part of the University of Leeds's Ultrasound Array Research Platform project), and the same signals used as cross-correlation reference signals for time lag detection. The approach was tested on 4” and 6” diameter closed flow loops systems, and flow velocity measurements compared against a calibrated turbine meter. This method can be used to test and evaluate many transmit schemes automatically, allowing the optimal transmit scheme to be selected without intervention.