超音波定在音場中を浮上・沈降する固体粒子の挙動(<小特集>音響利用技術-音響情報・音響エネルギー-)

概要

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The purpose of this report is to clarify the behavior of single solid particles falling or rising in liquids with a standing wave field. The behavior of particles in degassed and ion exchanged water in the formation of a standing wave field was studied experimentally using an ultrasonic field of 45 kHz. In the experiment for particles falling in liquids, the decreased velocity of the glass particles in the ultrasonic field exhibited the greater deceleration In the degassed water, since the ultrasonic power effectively acts on a particle as a radiation force. In the case of the rising experiment, however, the greater deceleration of a particle is obtained in the ion exchanged water due to the motion of cavitaion bubbles. On the basis of this study, the falling velocity of a particle was analyzed numerically. The equation for motion of a sphere in a viscous fluid is based on the Basset-Boussinseq-Ossen equation, in addition to which, the acoustic radiation force must be included. The velocity of a particle is periodically changed due to influence of the radiation force of the standing wave. The terminal velocity of a small particle in an ultrasonic field is lower than that for which there is no ultrasonic field.
一般社団法人日本機械学会の論文
2001-05-25