Abstract
Hydrodynamic characteristics of a new mode of liquid-solid fluidization, termed as “inverse fluidization” in which low density floating particles are fluidized with downward flow of liquid, are experimentally investigated. The experiments are carried out with low density particles (<534 kg/m3) which allow high liquid throughputs in the system. During the operation, three regimes, namely, packed, semi-fluidization and fully fluidization are encountered. Empirical correlations are proposed to predict the pressure drop in each regime. A computational procedure is developed to simulate the variation of pressure drop with liquid velocity.
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Abbreviations
- Ar :
-
modified Archimedes number, d 3 p ϱ(ϱ−ϱ s)g/μ2
- d p :
-
particle diameter, mm
- f :
-
friction factor (eq. 2)
- g :
-
acceleration due to gravity, m/s2
- H:
-
total bed height, m
- H c :
-
height of the column, m
- Hf :
-
height of fluidized bed, m
- H0 :
-
height of initial bed, m
- Hp :
-
height of the packed bed, m
- (Δp):
-
pressure drop across the bed, N/m2
- (Δp) f :
-
pressure drop across fluidized bed section, N/m2
- (Δp) p :
-
pressure drop across the packed bed section, N/m2
- (Δp) sf :
-
total pressure drop in semifluidization regime, N/m2
- Re:
-
Reynolds number, d pϱU 1/μ
- Rem :
-
modified Reynolds number, d pϱU 1/μ(1−ɛ p)
- U 1 :
-
superficial liquid velocity, m/s
- Umf :
-
minimum fluidization velocity, m/s
- Uosf :
-
onset fluidization velocity, m/s
- ɛ f :
-
voidage of fluidized bed
- ɛp :
-
voidage of packed bed
- μ:
-
liquid viscosity, kg/ms
- ϱ:
-
liquid density, kg/m3
- ϱ s :
-
particle density, kg/m3
References
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Ulaganathan, N., Krishnaiah, K. Hydrodynamic characteristics of two-phase inverse fluidized bed. Bioprocess Engineering 15, 159–164 (1996). https://doi.org/10.1007/BF00369620
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DOI: https://doi.org/10.1007/BF00369620