The present work is addressed to the numerical study of laminar natural convection induced by a line heat source in an open space. Also the net radiation exchange between the heat source and surrounding was studied. The governing equations - Navier-Stokes and energy equation are discretized in a staggered grid by a control volume approach, and they are solved using a segregated technique. The equations for the fluid and solid (line heat source) phases are solved simultaneously. Some of the physical and thermophysical properties of the fluid (air) such as density, thermal conductivity and viscosity were considered to vary with temperature. The present predictions are compared with those using the Boussinesq approximation, with the results for the boundary layer equations, and with the experimental results. The present predictions reveal considerable departure from the Boussinesq-based solution and from the boundary layer results. This study also shows the radiation exchange between the heat source and surrounding has major effect in the results. Thus, the departure between the experimental and analytical results can be explained by the effect of radiation exchange.

Keywords