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Local and average interphase heat transfer coefficients in a randomly packed bed of spheres
Author(s) -
Gillespie Bernard M.,
Crandall Edward D.,
Carberry James J.
Publication year - 1968
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.690140326
Subject(s) - spheres , reynolds number , heat transfer , mechanics , laminar flow , heat transfer coefficient , packed bed , thermodynamics , boundary layer , range (aeronautics) , materials science , chemistry , physics , composite material , chromatography , turbulence , astronomy
Local and average heat transfer coefficients have been measured for a sphere in a randomly packed bed. A steady state technique was employed in which internally heated spheres were placed in a bed 35 in. deep and 12 in. sq. Air passed through the bed in downflow, the range of Reynolds numbers being from 120 to 1,700 based on the sphere diameter and the superficial velocity. Average heat transfer coefficients have been measured at twenty‐five positions permitting the assessment of the effect of position. An entrance region limited to the first two particle layers in the bed has been verified. Distributions of the local heat transfer coefficient on the surface of a single sphere in the top layer and in the nineteenth layer of the bed have also been measured. These distributions indicate that a laminar boundary layer exists over portions of the sphere surface.