Computer experiments have been performed in which the effects of the radial nonuniformities of the granular bed packed in tubular flow apparatus as well as those of the heat sources and sinks on the axial effective thermal conductivity of the system have been analysed. The computations have been compared to the experiments performed by Yagi el al. (1960, A.I.Ch.E. J. 6, 543-546) on the axial thermal effective conductivity.