Investigation of flow boiling in circulating three-phase fluidised bed: Part II: Theoretical correlation

The following part of this paper reviews existing theoretical correlations to predict the behaviour of two-phase (liquid-solid) and three-phase (liquid-solid-vapour) fluidised beds as well as models describing heat transfer coefficients. Moreover, a theoretical correlation is developed to describe heat transfer during boiling in a three-phase circulating fluidised bed. The approach uses earlier work on two-phase (liquid-vapour) flow boiling, two-phase (liquid-solid) fluidised beds and three-phase (liquid-vapour-solid) circulating fluidised beds. The correlation developed is validated against experimental data obtained in Part I of the presented paper. The model's ability to predict the experimental data has been successfully demonstrated. The developed expression for heat transfer coefficients is written as follows:

α_T.F.B.-[(α_nb)^t_R+(α_cb)^t_R]^1/t_R