Analysis of models for heat transfer between gas-fluidized beds and immersed surfaces at high temperatures

G.D. MAZZA ; G. F. BARRETO

POWDER TECHNOLOGY

Elsevier Science S.A.

Lugar: Amsterdam; Año: 1993 vol. 75 p. 173 - 179

0032-5910

A comparative analysis is carried out between continuous and discontinuous approaches to evaluating heat transfer rates between the dense phase of a gas-fluidized bed and immersed surfaces. Significant differences in values of the global heat transfer coefficient and radiant contribution have been found when they are evaluated either from the continuous or discontinuous models. The discontinuous "multiple-layer model" is considered as a good choice because it is based on a realistic description of the dense phase near the wall surface and involves a reasonable mathematical complexity. an approximate analytical expression to evaluate the global coefficient and radiant component is proposed. The results obtained with this approximation are in good agreement with those given by the numerical solution of the multiple-layer model equations.