Abstract
Heat transfer in peaked beds has been investigated by calculating point values of the effective thermal conductivities and values of the wall heat transfer coefficient, from experimental radial temperature measurements. Spherical peaking materials of several different diameters were used in a 2 inch nominal diameter tube. The object of the research was to investigate the effect on the effective thermal conductivity of using packing which gave a large ratio of particle diameter to tube diameter. It was found that the effect of increasing this ratio beyond a critical value was to decrease the effective thermal conductivity. This effect was explained by the increase in the Feclet number at this ratio and the subsequent decrease in eddy diffusion. The error introduced by neglecting the heat transferred arially other than by convection in the calculation of the effective thermal conductivity is shown to be negligible. The object in calculating the values of the wall heat transfer coefficient was to attempt to obtain more consistent results and a more valid correlation than the preliminary correlation suggested by Coberly and Marshall. It was found what the results of this research could be correlated with an expression which has some theocratical basis. This correlation is compared with the results given in some other recently published papers.