Turbulent natural convection and surface radiation in a closed air cavity with a local energy source

We have investigated the flow structure and the heat exchange inside a closed square cavity with isothermal vertical and adiabatic horizontal walls in the presence of a local constant-temperature energy source. Analysis has been performed on the basis of solving the equations of mathematical physics describing the considered process in dimensionless variables "stream function–velocity vorticity–temperature." We have obtained the isoline distributions of the stream function and temperature reflecting the influence of the lifting force and the reduced emissivity factor of enclosing surfaces on the flow pattern and the heat transfer. It has been established that an increase in the emissivity of the walls intensifies the convective flow inside the cavity and enhances the heat exchange. © 2017 The Author(s).