Transfer processes in the flow of gases through packed and distended beds of spheres



Simultaneous mass, heat, and momentum transfer was experimentally investigated for the flow of air through packed and distended beds of spheres saturated with water. The porous spheres were approximately ⅝ in. in diameter. The void fraction of the packed bed was ϵ = 0.416, and the distended beds, whose spheres were positioned in a body-centered cubic arrangement, had respective void fractions of ϵ = 0.576 and 0.778. The distended beds were formed by separating the spheres and connecting them with short lengths of fine rigid wire.

Similar relationships for the packed and the distended fixed beds were obtained when the transfer factors were related to the modified Reynolds number. The relationship obtained for mass transfer in packed and distended beds was found to apply to data reported for fluidized beds of spheres.

Pressure drop measurements were made which were not exacting but which indicate that the Ergun relationship for packed beds can be used to relate the friction factor to the modified Reynolds number for both the packed and distended beds investigated.