KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Heat Transfer Coefficient between Bed and Inserted Vertical Tube Wall in Three-Phase Fluidized Beds
Yasuo KatoYoshifumi TauraTokihiro KagoShigeharu Morooka
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1984 Volume 10 Issue 4 Pages 427-431

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Abstract

The heat transfer coefficient between bed and vertical tube wall was measured in three-phase fluidized beds of 12 and 19 cm i. d. Glass spheres of various diameters (particle diameter = 0.52-2.2 mm, particle density =2500 kg · m-3) and alumina spheres (particle diameter = 3.2 mm, apparent particle density 1620 kg · m-3) were fluidized by fluid media of air-water or air-aqueous solution of carboxymethyl cellulose. The superficial velocities of gas and liquid were varied in the range of 2.0-16 cm · s-1 and 0.05-8.0 cm · s-1, respectively.
The critical liquid velocity, ul3, of the stable fluidization state was correlated as follows.
ul3/ut=0.336 (ηl0l) 0.5/ (1.9+Fr0.9)
where ut =terminal velocity of particle, ηl3=water viscosity, ηl=liquid viscosity, Fr=ug2/gdp, ug = superficial gas velocity, g = acceleration of gravity, and dp=particle diameter.
The heat transfer coefficient, h, in the stable fluidization state was correlated as follows.
Nu'= {0.058 (RePr) 0.78+2.3} (dh/dh0) -0.5
where, Nu'=hdpεl/ {kl (1-εl)}, Re'=dpulρl/ {ηl (1-εl)}, Pr=cplηl/kl, dh=heater diameter (2.2-6.3 cm), dh0 =2.2 cm, εl =liquid holdup, kl =thermal conductivity of liquid, ul=superficial liquid velocity, ρl =liquid density, and cplspecific heat of liquid.

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© by THE SOCIETY OF CHEMICAL ENGINEERS, JAPAN
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