| Abstract: | Ultrasonic clamp-on flowmeters (USCF) are popular among measurement technologies due to the versatility of applications, increasing accuracy, and easy, non-intrusive mounting, with the sensors being mounted directly on the external surface of the pipe. In industrial applications, installation space is usually restricted and therefore, flowmeters must be mounted often directly downstream of flow disturbances (FD). A major issue of USCF is the long inlet run needed downstream of FD to achieve a measurement within the specified accuracy. A configuration of two V-paths is proposed, axially rotated 90° relative to each other, that compensates for the flow error introduced due to disturbed flow conditions, independent of the rotational position of the flowmeter. Flow disturbance compensation (FlowDC) is achieved, i.e., accurate measurements within the specification of 2% flow rate accuracy, when the flowmeter is mounted as close as 2 pipe diameters (D) downstream of a FD. Computational fluid dynamics (CFD) are employed to generate rotationally independent correction factors that compensate for the error introduced from disturbed inlet conditions. An automated simulation method is developed to generate correction factors for 90° bend, out-of-plane bend, expansion, and contraction, at mounting distances from 2D to 100D, several flow rates, and rotational positions 0°, 90°, 180°, 270°. This study would be practically impossible with non-automated simulations or solely with measurements. In-house experiments were performed with an industrial clamp-on device at selected distances from the FD with the aim of verifying the simulation results. An independent field-test is presented that showcases the value of FlowDC in USCF applications. The automated simulations have the capability to simulate further FDs on-demand, with the aim of creating a database for the needs of the respective application in industry. |
