Frequency characteristics of a vortex flowmeter in various inlet velocity profiles

Abstract

Although vortex flowmeters are widely used in various industries, the accuracy of vortex flowmeter measurements depends on inlet flow conditions. In this study, flow fields of a vortex flowmeter with various inflow conditions are simulated numerically. In order to model transient turbulent flows, Large Eddy Simulation and vortex shedding frequencies are determined using fast Fourier transform techniques. To determine the frequency characteristics in the area of downstream of the vortex generator, both steady and unsteady velocity profiles are used as inlet conditions, including two different shear flows and various sinusoidal plug flows. For steady inlet conditions, the flow qualities along the pipe are quantified using a proposed definition to express a velocity profile which departs from a fully developed velocity profile. For unsteady inlet conditions, the predominant frequency pattern is successfully predicted and it is linked to the measurement accuracy of the vortex flowmeter.