As a part of study of heat transfer mechanism of fluidized beds, heat transfer coefficients were measured in the bubble bed, the gas-liquid-solid and the gas-solid fluidized beds. The fluidizing gas was air at room temperature, and the liquid was water. The solid was a silica, 0.006 mm in diameter. Superficial velocities of air based on the cross sectional areas of column were 1∼30 cm/sec.
Heat transfer element was copper tube, 10 mm in diameter and 10 mm in length, with nichrome heater inside.
The results were in fair agreement with the previous data. But, in the gas-liquid-solid fluidized bed, when silica was 1∼10 % in weight, heat transfer coefficients scatteredconsiderablly.
Particularly, in the gas-solid fluidized bed, the relation between the heat transfer coefficients and the rate of mixing gave a straight line on the log-log plot.