Author(s)

R E Cabanillas, C A Estrada & G Alvarez

Abstract

Combined natural convection and radiation in open cavities have various applications ranging from passive solar heating of rooms to solar concentration. Earlier investigators have solved the problem considering only natural convection heat transfer in open cavities [1,2,3], but they do not include the interaction of radiation combined with natural convection heat transfer. This study presents a two dimensional computational model of the interaction of natural convection and radiation heat transfer in an open tilted square cavity containing air as a non participant fluid. The cavity has two opaque adiabatic horizontal walls and one opaque isothermal vertical wall. The momentum and energy equations were solved by finite differences using AD1 technique. Coupled to this equations are the radiative energy flux boundary conditions. The average heat transfer coefficient was calculated for several values of the Grashof number for air (Pr=0.7) for different tilted angles, with the isothermal wall at 500 K and the open side at 300 K. The results indicate that the radiation and the tilted angle have great influence on the total amount of heat lost by the cavity as well as on the pattern of flow and temperature fields. Keywords: natural convection, radiation heat transfer, open cavity, total Nusselt number.

Keywords