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ISSN Online: 2377-424X

ISBN Print: 0-89116-299-2

International Heat Transfer Conference 7
September, 6-10, 1982, Munich, Germany

HEAT TRANSFER FROM AN IMMERSED SURFACE TO ADJACENT PARTICLES IN A FLUIDIZED BED THE ROLE OF RADIATION AND PARTICLE PACKING

Get access (open in a dialog) DOI: 10.1615/IHTC7.80
pages 45-50

Abstract

The heat transfer from a fluidized bed to an immersed surface is examined using simplified physical models. For residence times representative of particles in vigorously bubbling beds it is shown that packet models using continuum properties are reasonable only when particle diameters are less than 0.3 to 0.6 mm. As the conduction between a surface and adjacent particles is proportional to the local density of particle packing, numerical estimates of random packing densities suggest dense phase heat transfer coefficients up to 50% greater for spherical particles than for irregular particles. The contribution of radiation to the total heat flux of high temperature beds is demonstrated to be a function of fluid mechanical variables as well as particle size and bed and surface temperature.