二维喷动床颗粒流动的脉动特性实验研究

EXPERIMENTAL STUDY ON PULSANT BEHAVIORS OF PARTICLE FLOW IN A TWO-DIMENSIONAL SPOUTED BED

二维喷动床横截面为152mm×15mm,锥角为60°,喷口宽度为9mm,实验物料为平均粒径2．0mm的玻璃珠。床体的颗粒流动表现出整体的喷动周期性,属于不连贯喷动流型。本文基于PIV处理颗粒流动图像获得了颗粒流动的瞬时速度;基于功率谱密度分布对瞬时速度的分析结果表明,喷射区轴线的中下部颗粒存在较强的速度脉动,环隙区颗粒速度脉动较弱;研究发现喷动周期与床体压力脉动周期基本一致。

Experimental investigations on pulsant behaviors of particle flow were carried out on a two-dimensional spouted bed using PIV. The bed consists of a cube with a cross-section of 152 mm× 15 mm connected to a conical base with an included angle of 60° and an inlet nozzle with width of 9 mm. The bed was under a state of incoherent spouting, marked with obvious periodicity. Analysis on power specral densenties of instantaneous particle velocities shows that fluctuations of particle velocity in the lower and middle parts of the spout axis are relatively strong while neglectable in the annulus. The bed spouting periodicity is found to be basically identical to that of bed pressure drop fluctuation.