Effect of Acoustic Field and Frequency on Dynamics of Micronic Powder

摘要

According to research performed in past years, the fluidization of fine powders is complex. The difficulty of putting these powders in suspension in the fluidizing gas is related to the cohesive structure and, in particular, to the physical forces between the primary particles. This strong interaction between the powders affects the flow properties of the powders and weakened the process of fluidization. The basic aim of this research work was to improve the quality of fluidization of Marble powder (d_p =90μm) by applying external source in terms of acoustic field. In addition, effect of acoustic field on minimum fluidization velocity (U_(mf)) has been found out with variation of frequency and sound pressure level. The best effect has been found at 120Hz.The value of U_(mf) at 145dB and 120Hz is found to be 0.8cm/s, which was very less compared to U_(mf) at without sound intensity i.e.l.6cm/s for L/D=0.59. In addition, it was noted that U_(mf) decreases with increase in frequency and then increases. Also, effect of aspect ratio was studied with presence of acoustic field and frequency.