Diseño y construcción de un montaje experimental para el estudio del efecto de las burbujas sobre el espectro de fourier de ondas ultrasónicas en flujos bifásicos

Abstract

This work shows the development of an experimental setup to study the effect of bubbles on the Fourier spectrum of ultrasonic waves. 262/5000 Two water columns were designed and built in order to generate a two-phase water-bubble flow, and they were also instrumented with ultrasonic transducers to perform measurements in pulse-echo, transmission-reception and backscattering modes. The transducers were characterized, selecting those with the best frequency response. Experiments were performed in the range between 0;5 and 5;0 MHZ. From the ultrasonic signals a loss coefficient was calculated. This coefficient models the drop in amplitude of the waves as a result of the presence of the bubbles, with respect to the a reference case without bubbles. The loss coefficient allowed the calculation of the velocity and attenuation spectra. In order to estimate the radius and number of bubbles, as a function of the amount of air injected, image processing techniques were applied. This was made taking into account the acoustic field generated by each transducer. The results showed that the changes obtained in the acoustic parameters of the waves allow to infere of the amount of bubbles