Numerical analysis of fluid flow and heat transfer in periodic wavy channels

The two-dimensional steady and time-dependent fluid flow and heat transfer through periodic, wavy channels is numerically studied, for a fluid with a Prandtl number of 0.7, by means of an unstructured covolume method. The two geometrical configurations considered, a sinusoidal channel and an are-shaped channel, are shown to provide little or no heat transfer augmentation, in comparison to a parallel-plate channel, in steady flow regimes at lower values of the Reynolds number. In addition, they both have higher pressure drop than that of the parallel-plate channel under fully developed flow conditions. For the unsteady regime, reached at about Re = 175-200 for the sinusoidal channel, and Re = 60-80 for the arc-shaped channel, both geometries exhibit a significant increase in the heat transfer rate, up to three times for the highest Reynolds number investigated. This increase is higher for the arc-shaped flow passage, but is accompanied by a higher friction factor than that of the sinusoidal channel. (C) 2001 Elsevier Science Inc. All rights reserved.