Johann Turnow

Fluid Mechanics and Heat Transfer in a Channel with Spherical and Oval Dimples

Vortex mechanism of heat transfer enhancement in a narrow channel with dimples has been investigated numerically using unsteady Reynolds averaged Navier Stokes equations (URANS SST and SAS) and Large Eddy Simulations (LES). The flow separation results in a formation of vortex structures which significantly enhance the heat transfer on dimpled surfaces conducted by a small increase of the pressure loss. The vortex structures and the flow are sufficiently unsteady. The vortex structure inside of the dimple changes steadily its orientation causing the long period oscillations with opposite-of-phase motion. The heat transfer enhancement is caused mostly by the amplification of convection. The effect of the wetted area increase is sufficiently smaller.