Radiative heat transfer in circulating fluidized beds

The radiation contributions to heat transfer in circulating fluidized beds are investigated based on a simple model involving clusters and dilute suspension. Local and length-averaged cluster transfer coefficients are derived based on a cluster renewal model with combined transient conduction and radiation. A three-component network is analyzed leading to a concise relation for the suspension-to-wall radiative transfer. Previous experimental data for heat transfer to a membrane wall with bed temperatures of 407 and 860°C (Wu et al., 1989) are in good agreement with model predictions.