Heat Transfer in Laminar How with Wall Axial Conduction and External Convection

Analytical solution is obtained for laminar forced convection inside tubes including wall conduction effects in the axial direction, based on a radially lumped wall temperature model, and accounting for external convection. The ideas in the generalized integral transform technique are extended to accommodate for the resulting more involved boundary condition and accurate numerical results obtained for quantities of practical interest such as bulk fluid temperature, lumped wall temperature, and Nusselt number. The effects of external convection and axial conduction along the wall on these heat transfer quantities are then investigated through consideration of typical values for, respectively, Biot number and a wall-to-fluid conjugation parameter. Convergence characteristics of the present approach are also briefly examined.