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Longitudinal mixing in fluidization
Author(s) -
Cairns E. J.,
Prausnitz J. M.
Publication year - 1960
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690060311
Subject(s) - eddy diffusion , thermal diffusivity , mixing (physics) , fluidization , tracer , spheres , particle (ecology) , chemistry , materials science , mechanics , thermodynamics , analytical chemistry (journal) , fluidized bed , chromatography , turbulence , physics , geology , oceanography , organic chemistry , quantum mechanics , astronomy , nuclear physics
Abstract Longitudinal mixing properties in liquid‐solid fluidized beds were investigated by means of a salt‐solution tracer technique. The electrical conductance breakthrough curves were measured with very small electrical conductivity probes for a step‐function input of salt‐solution tracer. Longitudinal eddy diffusivities were determined for 1.3‐ and 3.0‐mm. lead spheres and 3.2‐mm. glass spheres in 2‐ and 4‐in.–diameter beds at a distance of 5 bed diam. from the injector and for various radial positions. The longitudinal mixing properties are strongly affected by particle concentration; maximum mixing occurs at a fraction voids of 0.7. Longitudinal eddy diffusivity increases with particle density and with decreasing d p /D ratio. Velocity profiles markedly influence the eddy‐diffusivity profiles.