Complex Heat Transfer in Furnaces with a Circulating Fluidized Bed

Intensity of heat transfer to screen surfaces in the furnaces with a circulating fluidized bed (CFB) is determined by both radiation and convection of particles. Due to the formation of a thermal boundary layer near the screens the role of radiation decreases and that of convection increases with an increase in concentration of particles in the furnace. Generalization of the data obtained in pilot-full-scale and industrial furnaces with a CFB allowed one to obtain a simple empirical dependence of the furnace-mean coefficient of heat transfer α (W/(m2\ub7K) on the volumetric-mean concentration of particles c (kg/m3): α = 85\ub7c0.3