HEAT-BALANCE OVER THE FLUID-DYNAMIC BOUNDARY-LAYER OF A CIRCULATING FLUIDIZED-BED FURNACE

A heat balance over the fluid-dynamic boundary layer of a circulating fluidized bed furnace has been formulated in order to calculate the he at transfer to the walls. The convective heat transfer is related to a horizontal particle how from the core to the wall region, and an addi tive radiative heat transfer constituent is calculated for the particu late medium. An empirical description of the vertical distribution of solids and the transversal temperature profile are needed for the eval uation. The calculated heat transfer coefficients were compared with m easurements in three commercial boilers and the deviation was less tha n 40%, which is in the same order as the uncertainty of the experiment al data. (C) 1997 Elsevier Science Ltd.