Abstract
A series of experiments was performed on a circulating fluidized bed (CFB) in order to investigate effects of the ship motion on gas-solid heat transfer in the riser. Superficial velocity, rolling period and inclination angle were varied in the experiments, while amplitude of the rolling motion was fixed at 15deg. The following results were obtained: (1) At upright attitude, local heat transfer coefficient in the lower part of the riser had a large scatter in the bubbling fluidization mode, because suspension density had a steep gradient along the vertical direction. In the upper/mid part of the riser, on the other hand, scatter in the local heat transfer rate is negligible. (2) At inclined attitudes, except for the riser bottom in the bubbling fluidization where particle motion was locally suppressed by inclination locally, heat transfer rate at lower side of the riser wall was larger than that at upright attitude, and heat transfer was promoted with the increase of inclination angle. (3) When the CFB underwent rolling motion, heat transfer coefficient at the riser wall was augmented. Considering scatter in the local heat transfer coefficient, the rolling period had almost no effect on heat transfer at the riser wall. Therefore, it is concluded that gravity plays a dominant role in heat transfer at the riser wall.
