Heat transfer and hydrodynamic studies in gas-fluidized beds

Abstract

Heat-transfer coefficients are reported as a function of air velocity between the surfaces of immersed horizontal tubes of 28.6 and 50.8 mm o.d. and fluidized beds of silica sand particles with average diameters of 730, 1237 and 2356 μm. For the same particles, bubble velocities were measured cine-photographically in two-dimensional beds with thicknesses of 20.0 and 63.5 mm. The data are analyzed as a function of bubble frontal area. Elutriation of solid particles from the surface of the 63.5-mm thick bed was measured for the three sand beds at a particular fluidizing velocity as a function of bubble radius. These data on heat transfer, bubble velocity and solids elutriation are discussed in the light of governing theories involving the principles of fluid mechanics and heat transfer. © 1989.