Paper Title
Heat Transfer Enhancement Using Concave And Ribbed Surfaces In Laminar Flows

Abstract
In the present study, the heat transfer enhancement of laminar air flows over concave and ribbed surfaces have been investigated experimentally in a wind tunnel. The experiments were performed over a flat plate, a curved surface with a radius of 2.54 m in concave curvatures and a ribbed surface has a rib aspect ratio (the ratio of the rib width to the rib height)of 1.2 for the free stream velocity of 2 m/s. A constant-temperature hot wire anemometer and copper-constant thermocouples were used to the velocity and temperature measurements, respectively. The results show that the heat transfer rates are increased up to 60% by the concave and 175% by the ribbed surface comparing to the flat plate. It is noted that ribs give the higher heat transfer augmentation than concave surface. Keywords — Heat Transfer Enhancement, Laminar Flow, Ribbed Surface, Concave Surface.