Experimental study of bubble size in semi-cylindrical and cylindrical bubbling fluidized beds

Bubbles size was mesured in a gas-solid semi-cylindrical fluidized bed and compared with those in the cylindrical fluidized bed. Experiments were carried out in two Plexiglas fluidized beds with different cross sections (semi-circular and circular) of 0.14 cm in diameter. The superficial gas velocity was changed in the range of 0.2-0.7 m/s and both beds were opertaing in the bubling fluidization regime. Glass beads with average size of 450 µm were used as the bed materials. Bubble size was directly measured in the semi-cylindrical fluidized bed by digital imaging from the flat wall side. A reflection-type of fiber optic probe was used to determined the bubble size in the cylindrcial fluidized bed. Results indicated that the semi-cylindrical fluidized bed was approptiate for visual observation of bubble movements due to its flat wall. Moreover, it was found that, in the bubbling fluidization regime, the bubble size in the semi-cylindrical fluidized bed was almost the same as in the cylindrical fluidized bed.

Keywords:

Semi-cylindrical fluidized bed , Cylindrical fluidized bed , Bubble size , fiber optic probe