压力下流化床流动特性的实验研究

利用摄像技术在φ60mm×800mm压力为0.1MPa～1.5MPa的冷模加压流化床实验装置上, 对两种不同粒径颗粒的最小流化速度和床层膨胀高度进行了研究。研究结果表明，大粒径聚苯乙烯颗粒的Umf与p-0.3成比例，小粒径石英砂的Umf与p-0.21成比例，并根据实验值拟合出压力下最小流化速度公式为: Umf=μdp ρg｛［(34.15)2+0.05916×dp3 ρg( ρs- ρg)gμ2］12-34.15｝ 床层膨胀高度随气速的增大而不断增高，在相同U Umf下床层膨胀高度随压力的增大而增高，在大于0.7MPa时，压力对膨胀高度的影响减弱。对于聚苯乙烯颗粒，相同的H/Hmf下，U Umf随压力的增大而逐渐减小，当H/Hmf＝1.4～1.6时，U Umf与p-0.52～p-0.58成比例。

Experimental study on flow characteristics of fluidized bed at elevated pressure

An experimental study of the influence of pressure on Umf and bed expansion height by the photographing with a camera was carried out in a fluidized bed of 60mm i.d.in the range of operating absolute pressure 0.1MPa~1.5MPa with two kinds of different size particles . Experimental results indicate that for the polystyrene(Ps) particle with a larger size， Umf changes with p-0.3, and for the sand particle with a smaller size， Umf changes with p-0.21. An empirical equation about Umf is proposed based on the experimental data: Umf=μdp ρg｛［(34.15)2+0.05916×dp3 ρg( ρs- ρg)gμ2］12-34.15｝ It is found that the bed expansion height increases with the increasing of gas velocity, and increases with pressure for fixed value of U Umf, when the pressure exceeds 0.7MPa, the influence of pressure on the bed expansion height is weakened. For the polystyrene(Ps) particle, U Umf decreases with the increasing of pressure for fixed value of H/Hmf . When H/Hmf＝1.4～1.6，U Umf varies with p-0.52～p-0.58.