CALCULATION OF FREQUENCY OF OSCILLATIONS OF A PIEZOCERAMIC PRIMARY
CONVERTER FOR MASS FLOWMETER OF LIQUIDS

Shikina Viktoriya Evgen'evna, Senior lecturer, sub-department of measuring-computing complexes,
Ulyanovsk State Technical University (32 Severniy Venets street, Ulyanovsk, Russia), shik7789@gmail.com

681.586, 532 (075.8)

Background. Measurement of mass flow rate is necessary in industries such as chemical, petrochemical, food, pharmaceutical, pulp and paper. Traditional designs of mass flowmeters contain one or two metal measuring tubes, performing Coriolis fluctuations due to the presence of an external vibrogenerator located in the centre, and two sensors registering these fluctuations at the ends of the measuring tube. Pie-zoelements in the form of plates may be applied as vibrogenerators or as sensors. The development of measuring tubes completely made of piezoceramic material with printed electrodes os of interest. It simplifies the design as it does not require exter-nal exciters and sensors. The aim of this work is to study the characteristics of a primary converter of a mass flowmeter, which is a piezoelectric resonator, through which there flows the measured liquid.
Materials and methods. To determine the dependence of the frequency of flexural vibrations of the transducer on the mass flow of the flow medium the author carried out a synthesis study of dynamic characteristics and stability of body rotation and hydrodynamic processes in oscillating flows of liquids. Taking into account the peculiarities of the interaction of the flow with the inner surface of a piezoresonator as the main parameters of liquids, influencing its walls, the researcher defined tangential stress and maximum dimensionless height of a viscous sublayer.
Results. The author researched the dependence of the oscillation frequency of apiezoresonator on the flow velocity, density and viscosity of different liquids that ultimately determine the mass flow. The researcher conducted the experiments of pouring the water, beer, milk and antifreeze-40 through a resonator. All the dependencies of the initial segment are non-linear. There is a trend of repeatability of the results subject to the same conditions.
Conclusions. Experimental research of the converter confirmed the theoretical calculations and showed the possibility of its use in low flow measurement in food, chemical and pharmaceutical industries.

piezoceramic primary converter, piezoelectric resonator, rate oscillations, flowing liquid, mass flow

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