In order to determine the mechanism of heat transfer of the fluidized bed, the movement of fluidizing gas bubbles were inspected by means of tracer technique, and the fluidization quality including bubble frequency and number of density fluctuation per unit time were measured by the leak current method in the gas-solid fluidized bed.
Of the movement of gas bubbles, very little amount of gas is exchanged through the opening hole of vertical intermediate wall, especially when linear velocity is several times larger than that of incipient fluidization, the flow pattern of gas is plug flow. And when linear velocity is larger than 20 ㎝/sec, the flow pattern does not change considerably.
The movement of fluidized particles, the packet diameter is calculated by bubble frequency per unit time, and the conception of packet defined by Mickley and Fairbanks will enable a qualitative treatment.
So far as examined with the experimental data on the heat transfer coefficient, the rate of solid mixing, and with the number of density fluctuation per unit time, the mechanism of heat transfer proposed by Mickley and Fairbank is found to be reasonable.