Study of the effects of wall conductance on natural convection in differently oriented square cavities

Abstract

This paper reports experimental and numerical results on the effects of wall conductance on natural convection in a two-dimensional rectangular cavity. Three different configurations in which the external wall is heated from the side, top and bottom and cooled from the side, bottom and top respectively have been investigated. Experiments have been performed in a square enclosure with solid walls made from Lexan and forming a square air-filled cavity. A Mach–Zehnder interferometer was used to determine the temperature distributions in the fluid. Solutions for stationary two-dimensional equations of energy and motion governing heat conduction in the solid and natural convection flow and heat transfer of a Boussinesq fluid contained in the cavity have been obtained numerically. The coupled flow distributions, including the appearance of multicellular flow, temperature profiles and heat-transfer predictions compare favourably with experimental results. Heat conduction in the connecting (unheated) walls is shown to simultaneously stabilize and destabilize the fluid in the cavity.