Methods and features of vortex flowmeters investigation

The use of vortex flowmeters in industry is very popular due to their reliability and low cost, but there is a need to expand the measuring range towards low flows. Due to the specific design and operation principle, the vortex flowmeters have significant physical limitations when measuring flow at low flow rates. Commercial research of vortex flowmeters lasted for several decades and much attention was paid to improving the accuracy of flow measurement. Authors critically comprehended the traditional methods of improving the metrological characteristics of such flowmeters: methods of flow body and flow part investigation, methods of sensor and device for processing the signals of the measuring information investigation and algorithmic methods for increasing the accuracy of flow measurement. Attention was paid to algorithmic methods for increasing the accuracy of flow measurement, since the use of such methods requires only a change in the program of operation of the flowmeter’s microcontroller. Experimental investigation of the flowmeter measurement equation shows that the value of the Strouhal number at low flow rates is not constant, and consequently affects on the accuracy of flow measurement in this range. Subsequent investigations and the choice of the convertion function, considering the actual value of the Strouhal number, reduced the measurement error at low flows from 3 % to 0.5 %.