LOCAL PARTICLE CONVECTIVE HEAT-TRANSFER ALONG SURFACES IN CIRCULATING FLUIDIZED-BEDS

The relationship between heat dissipation of individual clusters and local heat transfer to a surface in a circulating fluidized bed has been established based on a probabilistic cluster renewal model. Variations of local particle convective heat transfer coefficient with length are predicted based on the model. A simplified model assuming an identical contact distance of clusters leads to explicit expressions for the local and average particle convective heat transfer coefficients, which approximate the more rigorous model for most cases of practical interest. Previous experimental data for heat transfer to a membrane wall are in good agreement with model predictions. Information on the wall contact resistance and mean cluster contact distance is also obtained from the model in combination with the experimental data.