Effect of Dilute and Dense Phase Conditions on Bed-to-Wall Heat Transfer Mechanism in the Riser Column of a Circulating Fluidized Bed Combustor

摘要

The bed-to-wall heat transfer in the riser column of a circulating fluidized bed (CFB) combustor depends on the contributions of particle convection, gas convection and radiation heat transfer. The percentage contribution of each of these components depends on the operating conditions i.e., dilute and dense phase bed conditions and bed temperature in the riser column. In the present paper, the contribution of particle convection, gas convection and radiation heat transfer components with operating conditions is estimated using the cluster renewal mechanistic model. The present results contribute some fundamental information on bed-to-wall heat transfer mechanism under dilute and dense phase conditions with bed temperature. The results will further aid for better understanding of heat transfer mechanism to water-wall surfaces in the upper region of the riser column.