The bubble velocity in a rotating fluidized bed (RFB) was experimentally
analyzed. The two components of bubble velocity in the
radial and angular directions were measured. The radial bubble
velocity was expressed using the similar type of equation for the
bubble rise velocity in conventional fluidized beds, and the angular
bubble velocity was described using the linear relationship
with the angular velocity of vessel. The coefficients of radial and
angular bubble velocities (Kr and K) were then evaluated under
various conditions of gas velocity and centrifugal acceleration. The
distributions of Kr and K could be expressed by the log-normal
distribution function. It should be noted that the distributions of Kr
and K were constant regardless of operating conditions, because
the buoyancy force acting on the bubble wasmuch higher than the
bubble–bubble interaction force. The bubble velocity coefficients
could be empirically obtained as Kr = 0.52 and K = 0.96. The correlation
to estimate the bubble velocity in RFBs was then proposed
empirically. The proposed empirical correlation could estimate the
radial and angular bubble velocities within approximately 30% and
5% of estimation error, respectively. Consequently, the radial and
angular bubble velocities could be predicted only by the operating
parameters. Itwas also confirmed that the bubble velocity in an RFB
is generally higher than that in a conventional fluidized bed if the
bubble sizes are the same, because in high centrifugal force field
the buoyancy force acting on a bubble which is the driving force
of bubble movement is much larger than that under gravitational
field.