Investigations of axial and radial variations of heat transfer coefficient in bubbling fluidized bed with fast response probe

A fast response probe used in this study allowed measurements of local heat transfer variations with time in a gas fluidized bed. These variations have been related to local hydrodynamic conditions in the fluidized bed. Measurements have been carried out in a Plexiglas column of inside diameter 0.15 m in the fluidized bed section and height of about 2 m. The bed consisted of 150 μm sand particles of static bed height 0.45 m. The gas velocity was varied up to 0.4 m/s. The bed hydrodynamics could be mapped by the radial and axial variations in heat transfer coefficients captured by the probe. The limitations and applicability of literature correlations and models for predictions of heat transfer coefficient in gas fluidized bed are pointed out. A correlation to predict heat transfer coefficients at a given radial location is proposed.