Flow Velocity Measurement Using an Orthogonally Radiated Ultrasonic Beam

Abstract

A method of measuring flow velocity using an orthogonally radiated ultrasonic beam based on Doppler spectra is discussed. We run numerical simulations of an ultrasonic wave scattered by particles and received at a circular planar transducer when particles flow perpendicular to the axis of the transducer. It is observed that spectrum bandwidth varies depending on flow velocity as the simulation is validated using an experimental result. In particular, when the beam diverges, the spectrum bandwidth is consistent with the amount of Doppler shift that is supposed to occur owing to the velocity of the particles. The simulation also shows that the spectrum bandwidth when multiple particles continuously flow along a line at a constant velocity is consistent with that when a single particle flows. Furthermore, in the case of multiple flow paths having positional variations in terms of both the distance from the transducer to the path and the offset of the path from the axis of the transducer, the bandwidth is still consistent with the case of a single flow path. This result implies the expansion of the applications of the proposed velocimetry such as to flow running in a pipe with a finite radius.