Дослідження можливості розробки фазо-частотного ультразвукового вимірювального перетворювача швидкості потоку природного газу в закритих трубопроводах малого діаметра

Abstract

The article explores the possibility of developing a phase-frequency ultrasonic measuring transducer of the gas flow velocity in closed pipelines of small diameter. Analysis of modern ultrasonic flow meters shows the presence of a dead zone with a small diameter of the pipeline, which requires other solutions in the near zone, which necessitates the creation of flow meters with high metrological characteristics and a wide range of applications. A mathematical model of a phase-frequency ultrasonic transducer has been developed, in which the flow rate can be determined using four ultrasonic wave frequencies and the corresponding phase shifts of the signals at which the phase shifts lie within the number of whole acoustic wavelengths. This allows extending the working range, selecting the optimal frequency of the ultrasonic wave for the operation of the measuring transducer and increasing the measurement accuracy. Based on the proposed mathematical model, a structural diagram of a phase-frequency measuring transducer for flow velocity and measuring means for controlling natural gas consumption was developed, which contains a pipeline section, two transmitting and two receiving piezoelectric elements, two generators, two pulse shapers, two phase detectors and a microprocessor unit. To study the proposed mathematical model of the measuring transducer, an experimental setup was assembled, consisting of a signal generator, an oscilloscope, measuring sensors located on the pipeline section, and an air flow generator, which allows to obtain the dependence of the phase shift of signals on the flow velocity. The obtained experimental data indicate the prospects for the practical application of the phase-frequency method of measuring the flow rate and create an ultrasonic flow meter based on this method with high metrological characteristics, which is able to work in near-zone conditions.