The bubble velocity in a two-dimensional rotating fluidized bed (RFB) was experimentally analyzed. The
motion of bubbles was observed by means of a high-speed video camera, and the radial and angular
components of bubble velocitywere experimentally measured. The radial bubble velocity (UBr) and angular
bubble velocity (ùB) were expressed as a function of actual centrifugal acceleration acting on the
bubble (g
B), bubble diameter (Db), and angular velocity of the rotating vessel (v): UBr = Kr(g
BDb)0.5 and
ùB = Kùv, respectively. The effects of the operating parameters (gas velocity and centrifugal acceleration)
on the bubble velocity coefficients (Kr and K ) were analyzed experimentally. The distribution of both
bubble velocity coefficients could be well correlated by the log-normal distribution function. The distributions
of Kr and K showed almost unchanged with the gas velocity and centrifugal acceleration, because
the buoyancy force acting on a bubble under high centrifugal force field is so high, and the interaction from
other bubbles can be neglected. The bubble velocity coefficients in an RFB could be empirically obtained
as Kr = 0.52 and K = 0.96. The experimental mean bubble velocities at the various operating conditions
were compared with the predicted ones by using the obtained bubble velocity coefficients and our proposed
model for the bubble diameter [H. Nakamura, T. Iwasaki, S. Watano, Modeling and measurement
of bubble size in a rotating fluidized bed, AIChE J. 53 (2007) 2795–2803]. The radial and angular bubble
velocities could be predicted only by the operating parameters.
The bubble velocity in a two-dimensional rotating fluidized bed (RFB) was experimentally analyzed. The
motion of bubbles was observed by means of a high-speed video camera, and the radial and angular
components of bubble velocitywere experimentally measured. The radial bubble velocity (UBr) and angular
bubble velocity (ùB) were expressed as a function of actual centrifugal acceleration acting on the
bubble (g
B), bubble diameter (Db), and angular velocity of the rotating vessel (v): UBr = Kr(g
BDb)0.5 and
ùB = Kùv, respectively. The effects of the operating parameters (gas velocity and centrifugal acceleration)
on the bubble velocity coefficients (Kr and K ) were analyzed experimentally. The distribution of both
bubble velocity coefficients could be well correlated by the log-normal distribution function. The distributions
of Kr and K showed almost unchanged with the gas velocity and centrifugal acceleration, because
the buoyancy force acting on a bubble under high centrifugal force field is so high, and the interaction from
other bubbles can be neglected. The bubble velocity coefficients in an RFB could be empirically obtained
as Kr = 0.52 and K = 0.96. The experimental mean bubble velocities at the various operating conditions
were compared with the predicted ones by using the obtained bubble velocity coefficients and our proposed
model for the bubble diameter [H. Nakamura, T. Iwasaki, S. Watano, Modeling and measurement
of bubble size in a rotating fluidized bed, AIChE J. 53 (2007) 2795–2803]. The radial and angular bubble
velocities could be predicted only by the operating parameters.
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