Velocity Extension Method for Use with UVP and Application for Flow Rate Measurement

Abstract

The ultrasonic velocity profile (UVP) method is a powerful tool for measuring velocity profiles in a pipe and it has been applied for measuring flow rate. In this paper, a velocity extension method for use with ultrasonic pulsed Doppler method is introduced to increase the maximum detectable velocity which is limited by the Nyquist sampling theorem. The measurement volume is shown to be among the important parameters that must be considered in assessing the traceability of the reflector during the pulse emission interval. Hence, a larger measurement volume is required to measure higher velocities. In order to improve the flow rate accuracy, multi-wave ultrasonic method is introduced. The velocity profiles in the near-wall region are measured using an 8-MHz sensor with a small diameter, while those far from the transducer are measured using a hollow 2-MHz sensor in the multi-wave transducer. The techniques are shown to be particularly effective for measuring higher flow rates in a large-diameter pipe.