Investigation on the Nonconstant Behavior of a Vortex Flow Meter with Narrow Gauge Pipe via Conducting Measurements and Numerical Simulations

Vortex shedding flowmeters can be used for a wide range of flow measurement applications with various kinds of fluids. The critical point in applying this method comes from the assumption that the Strouhal number is constant for the given Reynolds number range. In some cases – typically regarding flowmeters with narrow gauge pipes –, this assumption is only partially met, thus limiting the widespread use of these instruments in certain industrial appliances. The paper presents a diagnostic investigation on the effects of this nonconstant behavior. The method elaborated in this report can be applied to vortex flowmeters with narrow gauge pipes. In these instruments – usually due to the narrow cross-sections of the gauge pipe – measurement possibilities are limited, thus it is not possible for the user to determine the effects of the nonconstant behavior. To conduct these investigations, a calibration rig was designed and assembled. The presented diagnostic method combines measurements and numerical simulations. The results of the investigations can be used in the data processing phase, in order to reduce the uncertainty of the volume flow rate measured by vortex flowmeters.