Heat transfer from immersed vertical tube in a fluidized bed of group A particles near the transition to the turbulent fluidization flow regime

摘要

Experiments were performed in a 0.29 m ID fluidization column to investigate heat transfer from a vertical tube immersed in a bed of 70 urn FCC particles in the range of superficial velocities close to the transition to the turbulent fluidization regime. The results show that the transition is a gradual process and that the changing hydrodynamics affect the heat transfer. The highest heat transfer coefficients were found in the range of superficial gas velocities where the transition to turbulent regime occurred. Radial profiles of heat transfer coefficient were almost flat in the turbulent fluidization regime and changed very little with increasing superficial gas velocity.