Ultrasonic Self-oscillating Media Parameters Meters

Abstract

Today, ultrasound-based instrumentation equipment is used in various fields of science and technology. The issues of improving the accuracy of ultrasonic control devices by developing a new class of ultrasonic resonant methods for measuring or controlling quantities based on the use of a standing ultrasonic wave is relevant. The aim of the work is to improve the technical parameters of ultrasonic meters by using the phenomenon of resonance and standing wave. The basis of the resonant control method is the study of the parameters and characteristics of standing acoustic waves arising in the medium due to the interference of the incident and reflected acoustic waves. The paper proposes a mathematical model of the ultrasonic resonance method for measuring parameters of liquid and gaseous media, which can be used for measuring control of parameters such as density, temperature, thickness of the test object and the like. To test the adequacy of the proposed model of ultrasonic wave propagation, its computer simulation and experimental studies were carried out. Air was chosen as the test medium (temperature 20 °С, sound velocity 343 m/s, atmospheric pressure 1 atm). The time diagram of the signal at the receiver for a distance of 34,3 mm, when the resonance condition is satisfied, and for a distance of 34,73 mm, when the antiresonance condition is satisfied, is modeled according to the proposed mathematical model. The amplitudes of the signals differ about 5 times, which confirms the sensitivity of the model. The dependence of the amplitude of the signal at the receiver is given for signal frequencies of 170…205 kHz with a transmitter-receiver distance of 35,85 mm and a speed of sound of 340,8 m/s. The simulation results are highly consistent with the results of experimental studies, confirms the adequacy of the mathematical model. This allows, on its basis, to propose a new class of self-generating ultrasonic methods for measuring control of medium parameters. The block diagram and the principle of operation of the developed autogenerating meters for measuring the thickness, temperature of gas and density of the test object are described.