Fluid Flow and Heat Transfer in Wavy Channel Consisting of Walls with Unequal Amplitudes

Abstract

  Convective heat transfer in wavy channels is investigated for laminar flow between the wavy walls with unequal amplitudes. The fluid flow and heat transfer characteristics are evaluated and a thermal enhanced factor defined as a ratio of the heat transfer augmentation to the increase of pressure drop is examined. The results show that the heat transfer enhancement becomes more when the amplitude of either of the wavy walls increases. This increase of convection heat transfer is due to the formation of vortices near the wavy walls and these local circulations facilitate the mixing of the colder coolant at the center with the hotter coolant near the walls. Moreover, it was found that the location of the vortices shifts to the mainstream centerline with an increase in Reynolds number. The results also reveal that nevertheless the heat transfer augments due to better mixing of the flow as either of the wall amplitude is increased, the corresponding pressure drop is even larger for the examined cases.