气液固三相流化床局部相含率轴径向分布

Axial and radial distribution of local phase holdups in gas-liquid-solid fluidized beds with small size particles

应用开发的微电导探针测试技术,对小尺寸颗粒玻璃珠(粒径分别为0.48、0.80、1.25 mm)和1.45 mm苯乙烯树脂为固相,空气和水分别为气相和液相的三相流化床的各相局部含率进行了同时测定.在较宽操作条件下,获得了一系列局部相含率实验数据.通过对实验数据研究发现:在充分发展段,局部固含率在r/R=0.75～0.85范围内有一个极大值,床层截面平均气含率随表观液速的变化存在一个极小值.在气体分布器区,在距气体分布器轴向一定距离范围内,三相局部含率的径向分布存在明显的不对称分布.随着轴向距离的增加,局部气含率径向不对称分布逐渐消失,最终过渡到对称分布,而局部固含率的径向不对称分布消失得不明显.

Local holdups in gas-liquid-solid fluidized beds with small size glass beads (density of 2460 kg&middot m-3) and styrene resin (density of 1264 kg&middotm-3) were measured simultaneously by improved micro-conductivity probe technique with air and water as the gas and liquid under a wide range of operation conditions. It was found that for the fluidized system, the distribution of local solid holdup showed a maximum at r/R = 0.75-0.85, the cross-sectional average gas holdup showed a minimum with the superficial liquid velocity. In a certain range of axial distance from the gas distributor, radial profiles of local holdups showed severe radial mal-distribution. Such radial mal-distribution of local gas holdup disappeared with the increase of axial height, while the local solid holdup did not disappear apparently.