Abstract
This work deals with Ike problem of transient conjugated forced convection heat transfer with fully developed laminar flow in an infinitely long pipe, in which the external surface over a finite length of pipe is subject to a constant wall temperature. The effects are presented of Pécles number, ratios of pipe radii, wall-to-fluid diffusivity, and conductivity on the interfacial heat flux. The predicted results show that the unsteady heat transfer characteristics depend strongly on the ratios of outside and inside radix, wall-to-fluid conductivity, and thermal diffusivity. Additionally, the decrease in diffusivity ratio A from 10 to 0.1 results in a longer time for the system to reach the steady state condition from τ = 6.4 to τ = 265.