A gas convection model of heat transfer in large particle fluidized beds

Abstract

A steady gas convection model of heat transfer to a horizontal cylinder immersed in a large particle gas fluidized bed has been developed. The model is based upon the hypothesis that the large particles will be isothermal and includes the effect of radiation as well as interstitial turbulence. Results of calculations based on the model, for a two‐dimensional bubbling bed, indicate that a single bubble, having a diameter equal to the cylinder diameter, has a relatively small influence on the total heat transfer.

Hydrodynamics of fluidization: Prediction of wall to bed heat transfer coefficients

“…Although such detailed models describe the means by which surface-to-bed heat transfer takes place, they are of limited application because they require a knowledge of parameters which are not easily available (Botterill, 1975;Ozkaynak and Chen, 1980). For large-particle fluidized beds, a gas convection model of heat transfer was proposed by Adams and Welty (1979). In their work, the heat transfer from a horizontal tube is modeled using boundary layer equations for the gas phase.…”

“…In the area of gasification a workshop chaired by Ghate and Martin (1982) summarized the models developed by the Systems, Science and Software group (Schneyer et al, 1981) and by the JAYCOR group . For fluidized bed combustion, the model by Adams and Welty (1979) proved to be very useful for explaining heat transfer coefficients from a horizontal tube to a fluidized bed. A cold fluidized bed model developed at Illinois Institute of Technology (IIT) Ettehadieh, 1982) for a twodimensional bed was able to predict void distributions, solids circulation, and bubbling behaviors.…”

Heat transfer to fine powders in a bubbling fluidized bed with sound assistance

“…Studies of heat transfer in a fluidized bed with a horizontal tube have been carried out by many investigators, with the most complete understanding of the heat-transfer process obtained for Geldart B and D powders (Vreedenberg, 1958;Adams and Welty, 1979;Decker and Glicksman, 1983). There is very little information available on heat transfer in Type A and C powders.…”

Enhancement in mass transfer due to motion of a particle: An experimental study

“…A brief summary of these attempts can be found in a paper by Adams (1982). In modeling the fluid convective transfer, the particles are assumed to be stationary and their influence on the thermal layer has been considered (Adams and Welty, 1979;Adams, 1982;Ganzha et al, 1982). A more realistic model should take account of the motion of particies.…”