Radial heat transfer to fixed beds of particles

Abstract

Radial temperature distributions have been measured when air flows through a fixed bed of large particles heated at the wall. The measurements have been interpreted by two models. In the first, the axial and radial thermal conductivities are assumed constant throughout the bed, and there is a thermal resistance at the wall. In the second, thermal properties have been assumed constant in the bulk, but allowed to vary in a narrow boundary region adjacent to the wall without an additional resistance so that both temperature and temperature gradient are continuous throughout both regions. For small particles and particles of high thermal conductivity, both models interpreted the measurements equally well. For large particles of low thermal conductivity the two-region model was much better.