Surface–particle–emulsion model of heat transfer between a fluidized bed and an immersed surface

A mathematical model, the surface–particle–emulsion heat transfer model (SPE model), is developed. Considering the variance of voidage in emulsion in the vicinity of an immersed surface, heat transfer near the surface is treated as that through dispersed particles touching the surface and through the emulsion when the distance from the surface is larger than one particle diameter. A stochastic model of particle packing density on a surface is developed to calculate the coverage ratio of particles on the surface. Based on the SPE model, a heat transfer model for a horizontally immersed tube in a fluidized bed is developed. The calculation results are in reasonable agreement with experimental data from the authors and the literature. The model shows better qualitative and quantitative prediction for local heat transfer coefficients around a horizontally immersed tube in a fluidized bed.