著者

TAKEDA Hiroshi YAMAMOTO Yutaka

出版者

Atomic Energy Society of Japan

雑誌

Journal of Nuclear Science and Technology (ISSN:00223131)

巻号頁・発行日

vol.13, no.7, pp.372-381, 1976

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For analyzing the mixing of particles in a spouted bed, a model is proposed, which assumes that : (a) the spouted bed consists of a spout part characterized by perfect mixing and an annulus part occupied by piston flow, (b) the ingress of particles from annulus into spout takes place within a zone below a depth h below the top of the annulus, and (c) the rate of ingress of particles into the spout is constant throughout the bed. <BR>The time-dependence of the concentration <I>C</I>*(<I>t</I>) of marked particles within the spout can be calculated with this model assuming suitable values for unmeasurable parameters. <BR>The value of <I>C</I>*(<I>t</I>) was measured from mixing experiments undertaken using alumina particles, to which a small batch of marked alumina particles was dropped transiently onto the bed in stable operation. <BR>Comparing the experimental data with the calculated results, it was found that : (a) the mixing of particles in the bed can be satisfactorily described with this model, pro-vided that a suitable correction is added to the quantity of particles present in the spout to account for the existence of mixing in the annulus, whereas the model assumed piston flow ; (b) the upper edge of the ingress zone of particles from the spout into the annulus is located in the conical part of the bed. Increasing the flow rate of spouting air short-ened the cycle time of particles, while the mixing rate within one cycle was not affected to any significant extent by changes in flow rate.