A numerical investigation of laminar mixed convection heat transfer of air in concave and convex channels is presented. Six different channel aspects ratios (R/L chemical bounds 1.04, 1.25, 2.5, 5, 10, and infinity ) and five different values of Gr/Re~2(GSr/Re cheical bounds 0, 0.1, 1, 3, 5) are considered. Results are displayed in terms of streamline and isothermal plots, velocity and temperature profiles, and local and average Nusselt number estimates. Numerical proedictions reveal that compared to straight channels of equal height, concave channels of low aspect ratio have lower heat transfer at realtively low values of Gr/Re~2 and higher heat transfer at hgh values of Gr/Re~2. When compared to straight channels of equal heated length, concave channels are always found to have lower heat transfer and for all values of Gr/Re~2. On the other hand, predictions for convex channels revealed enhancement in heat transfer compared to straight channels of equal height and/or equal heated length for all values of Gr/R~2.
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