Heat transfer to a moving packed bed of nickel pellets

Heat transfer between a bed of nickel pellets and a vertical section of electrically heated steel pipe has been measured, with the pellet bed inside the vertical pipe. Most of the data are for a 20.27 cm diameter pipe but some data were also obtained for a 10.23 cm diameter pipe. The effective thermal conductivity of the stationary pellet bed has been estimated approximately from the results of unsteady heating tests. Tests have been carried out with a downwardly moving bed, including the effect of air flowing upwards through the bed. Average values of the pellet‐side heat transfer coefficient are between 72 and 135 W/(m 2 °C) depending on the mass fluxes of air and pellets, and have been expressed as an empirical correlation.