粗颗粒在锥型床中的流化特性

通过Ｇｅｌｄａｒｔ－Ｄ类粗颗粒在三种锥形床中的实验表明：随着入口的表观气速的增加，在床中依次出现固定床流区，部分流化区和喷动流区。在固定床区内，压降和表观气速关系可以通过Ｅｒｇｕｎ公式求得：在部分流化床区内；实验和理论计算均表明了由于颗粒所受到的曳力档的轴向高度增加而减小，造成床层轴向上部未流化的颗粒对下部硫化颗粒膨和压制作用，在喷动流化区内，给出了预测锥形床的初始喷动气速和喷动压降的经验公式。

Fluidization of Coarse Powder in Tapered Beds

In this paper, the conclusion has been drawn regarding Geldart-D powder, that there are three successive regimes, namely: fixed bed regime, local fluidized regime and spouting regime, in three tapered beds with different cone angles when the superficial gas velocity is increased. The pressure drop in fixed bed regime can be predicted by Ergun equation. In local fluidized regime, experimental results and theoretical analysis have shown that because the drag force decreases progressively along the height of tapered bed, the powder in upper section, which is not fluidized, compresses the expansion of powder in lower section. In the spouting regime, the correlations for the minimum spouting velocity and pressure drop are also given.