摘要
在鼓泡域中,从直射式光纤探头在二维床的测试与图像分析的结果得到气泡的平均直径与平均刺穿长度的关系为:d_b=1.6E[l]气泡的球形度为0.96。通过反射式和直射式光纤探头信号的比较表明,直射式探头的信号便于处理,并可用来测定气泡内的粒子含量。直射式光纤探头在二维床和三维床的测定结果对比表明,两种塔内的气泡行为规律一致但有明显的差异。
Direct shot fiber-optic probes were developed to determine,in one measurement,five parameters of bubble characteristiscs in gas-solid fluidized beds;namely:1)bubble diameters,2)ascending veloci- ties,3)frequency,4)volume fractions in the bed,and 5)solid content. Prbes were constructed for both two and three dimensional beds.The probes had a gap of 5 mm, and the dual heads were displaced 20 mm apart in the vertical direction.The time of light passage through a bubble was correlated with babble dimensions by Fast Fourier Transforms,and the time lapse between the adjacent vertical heads gave ascending velocities. The results for the two dimensional bed,with 0.66 mm diameter industrial catalyst particles. were compared with those from an image analyzer on photographs taken simultaneously with the probe measurements.The correlation between the penetration length,E[l],and the equivalent bubble diameter,d_b,was d_b=1.6 E[l] which is close to Glieksman's investigation in l mm particle fluidized beds. The results obtained in a 200 mm diameter cylindrical bed were compared to the two dimensional bed.In particular the change in gas bubble parameters with gas velocity and bed height were measured and explained. All results show that direct shot fiber optic probes provide rich information in bubble behavior, and all phenomena observed can explained physically.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
1990年第2期70-79,共10页
Chemical Reaction Engineering and Technology
关键词
流化床
气泡
光纤探头
气相
固相
Direct shot fiber-optic probe
Bubble characteristics
Gas-solid fluidized-bed.
