Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/66410
Type: Artigo de periódico
Title: Experiments on the local heat transfer characteristics of a circulating fluidized bed
Author: Pagliuso, JD
Lombardi, G
Goldstein, L
Abstract: The role of particle diameter in the heat transfer of a gas-solid suspension to the walls of a circulating fluidized bed was studied for particles of uniform size. This work reports and analyzes new experimental results for the local bed to wall heat transfer coefficient. not including the radiation component, in a long active heat transfer surface length laboratory bed, which extend previous findings and clear up some divergences. The research included determining the effects of extension and location of the heat transfer surface. circulating solids mass flux and average suspension density. An experimental set-up was built, with a 72.5 mm internal diameter riser. 6.0 m high, composed of six double pipe heat exchangers, 0.93 m high, located one above the other. Five narrow sized diameter quartz sand particles - 179. 230, 385. 460 and 545 mu m - were tested. Temperature was kept approximately constant at 423 K and the superficial gas velocity at 10.5 m/s. The major influence of suspension density on the wall heat transfer was confirmed, and contrary to other authors. a significant effect of particle size was found. which becomes more relevant for smaller particles and increasing suspension density. It was observed that the extension of the heat transfer surface area did not influence the heat transfer coefficient for lengths greater than 0.93 m. The heat transfer surface location did not show any effect, except fur the exchanger at the botton of the riser. A simple correlation was proposed to calculate the heat transfer coefficient as a function of particle diameter and suspension density. (C) 2000 Elsevier Science Inc. All rights reserved.
Subject: circulating fluidized bed
long active heat transfer surface length
local heat transfer
particle size effect
Country: EUA
Editor: Elsevier Science Inc
Rights: fechado
Identifier DOI: 10.1016/S0894-1777(99)00042-4
Date Issue: 2000
Appears in Collections:Unicamp - Artigos e Outros Documentos

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