ABSTRAKT

A theoretical study of laminar forced convection with a parabolic velocity profile inside parallel-plate channels and circular ducts, subjected to a sinusoidally varying inlet temperature is presented. A thermal diffusion in the duct wall and a boundary condition which accounts for external convection are considered. A finite-volume finite difference scheme is developed and compared with a new methodology based on a variational Ritz method. The results obtained are listed and compared. The wall heat flux along the channel, amplitude and the phase lags are determinated for the centreline, wall and bulk temperature.