S. Takashima et al., LOCAL HEAT-TRANSFER AND MODES OF PARTICLE MOTION AT A HORIZONTAL CYLINDRICAL SURFACE IN A CIRCULATING FLUIDIZED-BED, Kagaku kogaku ronbunshu, 24(3), 1998, pp. 431-436
Experimental study on the local heat transfer characteristics around a
heater rod installed horizontally in a circulating fluidized bed 4 m-
high and 0.1 m-i. d. was carried out under fast fluidization condition
s. Air and FCC catalyst particle were used as a gas-solids suspension.
The heater rod was electrically heated with 10 mu m-thick nickrome fo
il heater on a wooden base rod of 10 mm-o, d. In order to understand p
article motion, a glass pipe was mounted to simulate the heater rod an
d the particle motion on the surface of this glass pipe was observed f
rom inside of the pipe using a borescope and CCD camera. The result sh
owed that heat convection around a pipe is influenced by solid fractio
n in the bed and particle motion on the heater surface, such as collis
ion against the lower surface, formation of a stack on the upper surfa
ce, and downflow along the wall caused by core-annulus flow. The corre
lation between the mode of particle motion and the local heat transfer
around a pipe is interpreted based on the results obtained.