Investigation of the influence of the flow velocity of the measured liquid on the oscillation frequency of the resonator of a vibration-frequency density meter for the chemical industry

The article is devoted to the study of the influence of the flow velocity of the measured pity on the readings of the vibration-frequency density meter. For this purpose, the process of free proper transverse vibrations of a resonator made in the form of a homogeneous tube rigidly fixed at the ends, along which the fluid flow is organized, is investigated. A differential equation of the resonator’s own transverse oscillations is compiled, taking into account the elastic forces, inertia forces and friction forces acting on the resonator. At the same time, the Coriolis force is neglected, in view of the rigid fastening of the ends of the tube. Taking into account the fact that the resonator oscillations are supported by the self-oscillation system, the friction force is compensated by an external force and in the differential equation the friction force becomes zero. As a result of solving the differential equation, the dependence of the frequency of self-oscillations of the resonator on the flow velocity of the measured liquid is determined. Possible ways to reduce the influence of the fluid flow velocity are determined. The conclusion is made about the expediency of determining the limit value of the fluid flow rate when determining the operating conditions of the density meter.