Decomposition of flow velocity by using "X"-shaped arrangement of ultrasound paths in a turbulent pipe flow

Wet-type multi-path ultrasonic flow meters can measure flow velocity distribution in turbulent pipe flows. However, the flow velocity has been limited in evaluating the mean flow velocity to convert into flow rate. Information other than the mean flow velocity was not available up to date. Some information on transverse flow velocity can be obtained by arranging ultrasound paths in two directions. An “X”-shaped ultrasound path is one of such examples. In this study, a wet-type ten-path ultrasonic flow meter is used to measure both axial and transverse flow velocity simultaneously by applying the second law of cosines. Two velocity vectors along the X-shaped ultrasound path are combined to decompose the flow velocity into axial and transverse components. As a result, flow disturbances can be observed by monitoring the magnitude of the transverse flow velocity. A half-orifice plate with the blockage ratio of 30 % is placed in the upstream direction of the ultrasonic flow meter to investigate the effect of flow disturbance on the transverse flow velocity component. As a result, the magnitude of transverse flow velocity was decreased gradually as the installation length between the half-orifice plate and ultrasonic flow meter was increased.