Heat transfer to immersed surfaces in gas-fluidized beds of large particles and powder characterization

A particle classification scheme is proposed for fluidized beds by considering simultaneously the hydrodynamic and thermal properties. The powder characterization is obtained by considering Archimedes number together with Reynolds number at minimum fluidization. The powders are classified in three groups and the validity of the scheme is demonstrated by considering heat transfer data from fluidized beds of sands (d_p = 0.794 and 1.225 mm) and fire clay (3.0 mm) at ambient temperature and pressure in conjunction with heat transfer correlations and models developed for ‘large-particles’.