scholarly journals A Study of the Hydrodynamics Behavior of Cylindrical Gas-Solid Fluidized Beds for pharmaceutical material “Paracetamol “

2020 ◽  
Vol 26 (5) ◽  
pp. 191-210
Author(s):  
Maha Muhyi Alwan
Keyword(s):  
Fluidized Beds ◽  
Experimental Results ◽  
Inverse Relation ◽  
Direct Relation ◽  
Column Diameter ◽  
Type B ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Bed Height ◽  
Minimum Fluidization

The hydrodynamics behavior of gas - solid fluidized beds is complex and it should be analyzed  and understood due to its importance in the design and operating of the units. The effect of column inside diameter and static bed height on the minimum fluidization velocity, minimum bubbling velocity, fluidization index, minimum slugging velocity and slug index have been studied experimentally and theoretically for three cylindrical columns of 0.0762, 0.15 and 0.18 m inside diameters  and 0.05, 0.07 and 0.09 m static bed heights .The experimental results showed that the minimum fluidization and bubbling velocities had a direct relation with column diameter and static bed height .The minimum slugging velocity had an inverse relation with static bed height and a direct one with column diameter .There was no agreement between the experimental and calculated values of Umb for Di=0.0762m ,this was a result to the assumption used in the correlation development. The fluidization index values were around 1 in all cases and that proved that the material is of Geldart type B. There was not a significant dependence of fluidization index and slug index on static bed height and column diameter.       

scholarly journals CFD-DEM modeling the effect of column size and bed height on minimum fluidization velocity in micro fluidized beds with Geldart B particles

2017 ◽  
Vol 318 ◽  
pp. 321-328 ◽  
Author(s):  
Yupeng Xu ◽  
Tingwen Li ◽  
Jordan Musser ◽  
Xiaoxing Liu ◽  
Guangwen Xu ◽  
...  
Keyword(s):  
Fluidized Beds ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Bed Height ◽  
Minimum Fluidization

The effect of column diameter and bed height on minimum fluidization velocity

AIChE Journal ◽  
2010 ◽  
pp. NA-NA ◽  
Author(s):  
Akhil Rao ◽  
Jennifer S. Curtis ◽  
Bruno C. Hancock ◽  
Carl Wassgren
Keyword(s):  
Column Diameter ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Bed Height ◽  
Minimum Fluidization

scholarly journals A Study of Fluctuation and Expansion Ratios for Gas-Solid Fluidized Columns

2020 ◽  
Vol 26 (10) ◽  
pp. 15-34
Author(s):  
Maha MuhyiAlwanA Alhussaini ◽  
Hassanain Abbas Hassan ◽  
Nada Sadoon Ahmedzeki
Keyword(s):  
Experimental Results ◽  
Correlation Equations ◽  
Direct Relation ◽  
Column Diameter ◽  
Air Velocity ◽  
Minimum Fluidization Velocity ◽  
Bed Height ◽  
Bed Material ◽  
Fluidizing Medium ◽  
Good Agreement

The fluctuation and expansion ratios have been studied for cylindrical gas-solid fluidized columns by using air as fluidizing medium and Paracetamol as the bed material. The variables were the column diameter (0.0762, 0.15, and 0.18 m), static bed height (0.05, 0.07, and 0.09 m), and air velocity to several times of minimum fluidization velocity. The results showed that both the fluctuation and expansion ratios had a direct relation with air velocity and an inverse one with column diameter and static bed height. A good agreement was between the experimental results and the calculated values by using the correlation equations from the literature.

scholarly journals Reduction in minimum fluidization velocity and minimum bubbling velocity in gas-solid fluidized beds due to vibration

2021 ◽  
Vol 382 ◽  
pp. 566-572
Author(s):  
C.P. McLaren ◽  
J.P. Metzger ◽  
C.M. Boyce ◽  
C.R. Müller
Keyword(s):  
Fluidized Beds ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Minimum Fluidization

Convective Heat Transfer at Minimum Fluidization Velocity for Gas-Solid Fluidized Beds

1999 ◽  
Author(s):  
Kal R. Sharma
Keyword(s):  
Heat Transfer ◽  
Fluidized Beds ◽  
Empirical Correlations ◽  
Transfer Coefficients ◽  
Minimum Fluidization Velocity ◽  
Heat Transfer Coefficients ◽  
Fluidization Velocity ◽  
Minimum Fluidization ◽  
Semi Empirical ◽  
The Heat Transfer Coefficient

Abstract Experimentally measured values for the minimum fluidization velocities and time averaged local surface heat transfer coefficients are provided for 16 different cases of fluidizing conditions for gas-solid dense fluidized beds. Semi-empirical Correlations for the minimum fluidization velocity and the heat transfer coefficient at minimum fluidization velocities are provided. The implications of the Peclet number dependence in terms of diffusion and convection is discussed.

Bed Height Effects on Fluidized Bed Hydrodynamics

2010 ◽  
Author(s):  
David R. Escudero ◽  
Theodore J. Heindel
Keyword(s):  
Fluidized Bed ◽  
Experimental Studies ◽  
Gas Holdup ◽  
Minimum Fluidization Velocity ◽  
Non Invasive ◽  
Fluidization Velocity ◽  
Bed Height ◽  
Minimum Fluidization ◽  
Imaging Results ◽  
X Ray Computed

Characterizing the hydrodynamics of a fluidized bed is of vital importance to understand the behavior of these multiphase flow systems. Minimum fluidization velocity and gas holdup are two important factors used to understand the hydrodynamics of a fluidized bed. Experimental studies on the effects of bed height on the minimum fluidization velocity and gas holdup were carried out using a 10.2 cm diameter cylindrical fluidized bed filled with 500–600 μm glass beads. In this study, four different bed height-to-diameter ratios were used: H/D = 0.5, 1, 1.5, and 2. Minimum fluidization velocity was determined for each H/D ratio using pressure drop measurements. Local time-average gas holdup was determined using non-invasive X-ray computed tomography imaging. Results show that minimum fluidization velocity is not affected by the change in bed height, while local gas holdup does appear to be affected by the change in bed height.

Influence of surface forces and wall effects on the minimum fluidization velocity of liquid-solid micro-fluidized beds

2016 ◽  
Vol 304 ◽  
pp. 55-62 ◽  
Author(s):  
Orlando L. do Nascimento ◽  
David A. Reay ◽  
Vladimir Zivkovic
Keyword(s):  
Fluidized Beds ◽  
Surface Forces ◽  
Wall Effects ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Minimum Fluidization
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