Local instantaneous temperature and time-averaged heat transfer coefficient in the bottom zone of a circulating fluidized bed

Local instantaneous temperature signal and time-averaged heat transfer coefficient were measured using a miniature heat transfer probe. The experiments were carried out in the bottom zone of a 5.8m high, 0.3m×0.5m rectangular cross-section circulating fluidized bed. The results show that the heat transfer coefficient was higher near the walls, and became lower near the central region, and that the heat transfer coefficient decreases with increment of the air velocity due to the associated reduction of solids holdup in the bottom zone. In addition, the power spectrum density functions of the local instantaneous temperature signal can be characterized by the 1/f-like distribution. Copyright © 2004 John Wiley & Sons, Ltd.