【摘要】 用新型 5 -光纤速度探头对 16m高循环床提升管 8个截面上的颗粒速度进行了直接测量。结果表明 :沿提升管轴向 ,颗粒速度径向分布不均匀性逐渐增加 ,并最终趋于较为稳定的抛物线分布 ;通常认为近壁区颗粒速度Vp <0的情形 ,只能在离开提升管底部一定距离且在Gs相对较高或Ug 相对较低的操作条件下才会出现。表观气速Ug 对颗粒速度的影响明显大于颗粒循环量Gs的影响 ,Ug提高 ,提升管内颗粒速度都将显著增加 ;提高Gs将使颗粒速度降低 ,但对提升管充分发展段中心区影响较小。更多还原

【Abstract】 Particle velocities in a 16 m long CFB riser were directly measured by using a novel 5-optical-fiber probe, with superficial gas velocity U g  ranging from 3.5 to 8.2 m/s and solids circulating rate G s  from 50 to 201 kg/(m 2·s). The results show that the radial distribution of particle velocities always becomes less uniform along the riser height and finally reaches a parabolic profile in the upper section. The variations of particle velocity V p  near the wall of riser indicates that the situation of V p <0 occurs only in some distance away from the riser bottom and under the conditions of a relatively high G s  or/and a relatively low U g . Compared with G s , the superficial gas velocity U g  has greater effects on V p . With increasing U g  , the particle velocities increase visibly in whole riser, but, with increasing G s , they become decreased, except in the core region of fully developed section of riser where the variation of G s  has little effect on them.更多还原