Electrosensitive Fluids as a Basis of Acoustic Devices of a New Type

摘要

The present work is aimed at elucidation of the specific features in propagation of ultrasound waves in an electrostructurized medium, of their dependence on an applied electric field and implementation of the effects obtained in practice. In experiments, the use was made of electrosensitive liquid interlayers, which manifest the essential dependence of viscoelastic-plastic properties on a magnitude of an electric field applied to shear macroflows. The basis of a homogeneous suspension was the transformer oil, to which the finely divided silica powder, the corresponding surfactant and activator were added. To determine the velocity of ultrasound propagation in liquid media, the time of ultrasound signal propagation was compared with the delay time of the reference signal in the standard delay line. Ultrasound damping α was evaluated by measuring a signal in the circuit of the amplitude detector, the follower, and of the digital voltmeter. In so doing, we recorded the frequency and the amplitude of probing pulses. Preliminarily, we carried out experiments with the transformer oil, in which no changes were found in the velocity and damping of an ultrasound wave in an electric field. With increasing the electric potential for all concentrations of a solid phase the ultrasound velocity increased and the maximum change in ultrasound damping made up 30%. The results obtained provide of the possibility of creating a model of the acoustic transducer, in which an ER suspension is used as a contact medium to increase the quality of acoustic control by improving the acoustic impedance matching of the transducer, the contact medium and a controllable item.