Promotion effect of particle fluidization with ultrasonic vibration

Abstract

This work examined the effects of applying ultrasonic vibrations to a fluidized particle bed while varying the particle diameter, vibrational amplitude, pipe diameter and air flow rate. The bed was contained in a vibration pipe having eight antinodes, and the vibrational amplitudes were monitored using a laser Doppler vibrometer. Experiments using 100 and 250 μm diameter particles showed that the minimum air velocity required for fluidization and the pressure loss were both reduced with increasing vibrational amplitude. The extent to which these parameters were reduced was greater in experiments with the 250 μm particles and when using a pipe having a smaller diameter. In addition, the fluidization of 40 μm particles was found to be challenging because they did not reduce the cohesion among the particles themselves. In general, ultrasonic vibration to promote particle bed fluidization is most beneficial in conjunction with a small sized pipe and larger particles.