非均匀布风对流化床埋管换热特性的影响

THE EFFECT OF UNEVEN FLUIDIZED AIR ON THE HEAT TRANSFER ON IMMERSED TUBES IN A FLUIDIZED BED

非均匀布风对流化床埋管换热特性有一定的影响，埋管的对流换热系数不仅是埋管所处换热区流化速度的函数，而且与相邻的流动区流化速度有一定关系。本文通过试验研究了埋管换热系数同换热区以及流动区流化速度之间的关系：换热系数变化的趋势及数值的大小与鼓泡床有明显不同，较大的流动区流化速度（６．０ｕｍｆ～２４．０ｕｍｆ）直接影响换热区埋管的换热系数，换热系数同流化速度之间较为平缓的关系便于利用埋管进行非均匀布风流化床中浓相床区温度的调整与控制。

The heat transfer of immersed tubes in fluidized beds is influenced by the uneven distribution of fluidized air, and the coefficient of that is not only a function of fluidized air velocity in heat transfer zone, but also is correlative with the air velocity in fluidized zone nearby. In this paper? the relationship between the heat transfer coefficient and the air velocities of heat transfer zone and fluidized zone is investigated experimentally. The trend and data of heat transfer coefficients are different obviously with those of bubbling bed. They are influenced directly by the grater air velocity in fluidized zone (6.0umf ~ 24.0umf). The flat relation curve between the heat transfer coefficients and fluidized air velocities is favorable to adjust the dense bed temperature using the immersed tubes in fluidized bed with uneven distribution of air.