HEAT TRANSFER AUGMENTATION IN DIFFERENT GEOMETRIES OF DIMPLED SURFACE UNDER NATURAL CONVECTION VAN EXPERIMENTAL APPROACH

M.A.Dafedar, Najeem M, Fakruddin Y, Chirag P

Abstract: The prime objective of present work is to study experimentally the heat transfer augmentation through various geometries of dimpled surfaces in longitudinal and lateral directions. In this paper horizontal rectangular plates of copper and aluminum with different dimpled geometries (like square, circular and triangular) for in-line arrangements were studied in natural convection with steady laminar external flow condition. The various parameters considered for study are Nusselt number, heat transfer coefficient and heat transfer rate for a constant Prandtl number (0.7) and Grashof number (104 -107 ).It has been found that the heat transfer coefficient and heat transfer rate increases for various dimpled surfaces as compared to plane surface. It has been also found that the heat transfer coefficient and heat transfer rate increases along longitudinal direction as compared to lateral direction. And it is seen that heat transfer rate is maximum for triangular shape dimple when the apex of triangle is faced towards inlet of air flow Finally it is concluded that heat transfer enhancement takes place along the dimpled surface.

Keywords: Dimpled plates, Natural Convection, Heat transfer augmentation.

DOI: https://doi.org/10.15623/ijret.2013.0206004